From 2b144498350860b6ee9dc57ff27a93ad488de5dc Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Thu, 9 Feb 2012 14:56:42 +0530 Subject: uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints Add uprobes support to the core kernel, with x86 support. This commit adds the kernel facilities, the actual uprobes user-space ABI and perf probe support comes in later commits. General design: Uprobes are maintained in an rb-tree indexed by inode and offset (the offset here is from the start of the mapping). For a unique (inode, offset) tuple, there can be at most one uprobe in the rb-tree. Since the (inode, offset) tuple identifies a unique uprobe, more than one user may be interested in the same uprobe. This provides the ability to connect multiple 'consumers' to the same uprobe. Each consumer defines a handler and a filter (optional). The 'handler' is run every time the uprobe is hit, if it matches the 'filter' criteria. The first consumer of a uprobe causes the breakpoint to be inserted at the specified address and subsequent consumers are appended to this list. On subsequent probes, the consumer gets appended to the existing list of consumers. The breakpoint is removed when the last consumer unregisters. For all other unregisterations, the consumer is removed from the list of consumers. Given a inode, we get a list of the mms that have mapped the inode. Do the actual registration if mm maps the page where a probe needs to be inserted/removed. We use a temporary list to walk through the vmas that map the inode. - The number of maps that map the inode, is not known before we walk the rmap and keeps changing. - extending vm_area_struct wasn't recommended, it's a size-critical data structure. - There can be more than one maps of the inode in the same mm. We add callbacks to the mmap methods to keep an eye on text vmas that are of interest to uprobes. When a vma of interest is mapped, we insert the breakpoint at the right address. Uprobe works by replacing the instruction at the address defined by (inode, offset) with the arch specific breakpoint instruction. We save a copy of the original instruction at the uprobed address. This is needed for: a. executing the instruction out-of-line (xol). b. instruction analysis for any subsequent fixups. c. restoring the instruction back when the uprobe is unregistered. We insert or delete a breakpoint instruction, and this breakpoint instruction is assumed to be the smallest instruction available on the platform. For fixed size instruction platforms this is trivially true, for variable size instruction platforms the breakpoint instruction is typically the smallest (often a single byte). Writing the instruction is done by COWing the page and changing the instruction during the copy, this even though most platforms allow atomic writes of the breakpoint instruction. This also mirrors the behaviour of a ptrace() memory write to a PRIVATE file map. The core worker is derived from KSM's replace_page() logic. In essence, similar to KSM: a. allocate a new page and copy over contents of the page that has the uprobed vaddr b. modify the copy and insert the breakpoint at the required address c. switch the original page with the copy containing the breakpoint d. flush page tables. replace_page() is being replicated here because of some minor changes in the type of pages and also because Hugh Dickins had plans to improve replace_page() for KSM specific work. Instruction analysis on x86 is based on instruction decoder and determines if an instruction can be probed and determines the necessary fixups after singlestep. Instruction analysis is done at probe insertion time so that we avoid having to repeat the same analysis every time a probe is hit. A lot of code here is due to the improvement/suggestions/inputs from Peter Zijlstra. Changelog: (v10): - Add code to clear REX.B prefix as suggested by Denys Vlasenko and Masami Hiramatsu. (v9): - Use insn_offset_modrm as suggested by Masami Hiramatsu. (v7): Handle comments from Peter Zijlstra: - Dont take reference to inode. (expect inode to uprobe_register to be sane). - Use PTR_ERR to set the return value. - No need to take reference to inode. - use PTR_ERR to return error value. - register and uprobe_unregister share code. (v5): - Modified del_consumer as per comments from Peter. - Drop reference to inode before dropping reference to uprobe. - Use i_size_read(inode) instead of inode->i_size. - Ensure uprobe->consumers is NULL, before __uprobe_unregister() is called. - Includes errno.h as recommended by Stephen Rothwell to fix a build issue on sparc defconfig - Remove restrictions while unregistering. - Earlier code leaked inode references under some conditions while registering/unregistering. - Continue the vma-rmap walk even if the intermediate vma doesnt meet the requirements. - Validate the vma found by find_vma before inserting/removing the breakpoint - Call del_consumer under mutex_lock. - Use hash locks. - Handle mremap. - Introduce find_least_offset_node() instead of close match logic in find_uprobe - Uprobes no more depends on MM_OWNER; No reference to task_structs while inserting/removing a probe. - Uses read_mapping_page instead of grab_cache_page so that the pages have valid content. - pass NULL to get_user_pages for the task parameter. - call SetPageUptodate on the new page allocated in write_opcode. - fix leaking a reference to the new page under certain conditions. - Include Instruction Decoder if Uprobes gets defined. - Remove const attributes for instruction prefix arrays. - Uses mm_context to know if the application is 32 bit. Signed-off-by: Srikar Dronamraju Also-written-by: Jim Keniston Reviewed-by: Peter Zijlstra Cc: Oleg Nesterov Cc: Andi Kleen Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Roland McGrath Cc: Masami Hiramatsu Cc: Arnaldo Carvalho de Melo Cc: Anton Arapov Cc: Ananth N Mavinakayanahalli Cc: Stephen Rothwell Cc: Denys Vlasenko Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Andrew Morton Cc: Linux-mm Link: http://lkml.kernel.org/r/20120209092642.GE16600@linux.vnet.ibm.com [ Made various small edits to the commit log ] Signed-off-by: Ingo Molnar --- arch/x86/include/asm/uprobes.h | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 arch/x86/include/asm/uprobes.h (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h new file mode 100644 index 000000000000..8208234391ff --- /dev/null +++ b/arch/x86/include/asm/uprobes.h @@ -0,0 +1,42 @@ +#ifndef _ASM_UPROBES_H +#define _ASM_UPROBES_H +/* + * Userspace Probes (UProbes) for x86 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) IBM Corporation, 2008-2011 + * Authors: + * Srikar Dronamraju + * Jim Keniston + */ + +typedef u8 uprobe_opcode_t; +#define MAX_UINSN_BYTES 16 +#define UPROBES_XOL_SLOT_BYTES 128 /* to keep it cache aligned */ + +#define UPROBES_BKPT_INSN 0xcc +#define UPROBES_BKPT_INSN_SIZE 1 + +struct uprobe_arch_info { + u16 fixups; +#ifdef CONFIG_X86_64 + unsigned long rip_rela_target_address; +#endif +}; + +struct uprobe; +extern int analyze_insn(struct mm_struct *mm, struct uprobe *uprobe); +#endif /* _ASM_UPROBES_H */ -- cgit v1.2.3 From 7b2d81d48a2d8e37efb6ce7b4d5ef58822b30d89 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 17 Feb 2012 09:27:41 +0100 Subject: uprobes/core: Clean up, refactor and improve the code Make the uprobes code readable to me: - improve the Kconfig text so that a mere mortal gets some idea what CONFIG_UPROBES=y is really about - do trivial renames to standardize around the uprobes_*() namespace - clean up and simplify various code flow details - separate basic blocks of functionality - line break artifact and white space related removal - use standard local varible definition blocks - use vertical spacing to make things more readable - remove unnecessary volatile - restructure comment blocks to make them more uniform and more readable in general Cc: Srikar Dronamraju Cc: Jim Keniston Cc: Peter Zijlstra Cc: Oleg Nesterov Cc: Masami Hiramatsu Cc: Arnaldo Carvalho de Melo Cc: Anton Arapov Cc: Ananth N Mavinakayanahalli Link: http://lkml.kernel.org/n/tip-ewbwhb8o6navvllsauu7k07p@git.kernel.org Signed-off-by: Ingo Molnar --- arch/Kconfig | 14 ++- arch/x86/include/asm/uprobes.h | 17 ++-- arch/x86/kernel/uprobes.c | 129 ++++++++++++------------ include/linux/uprobes.h | 28 +++--- kernel/uprobes.c | 219 ++++++++++++++++++++++++----------------- mm/mmap.c | 12 +-- 6 files changed, 233 insertions(+), 186 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/Kconfig b/arch/Kconfig index 284f5898f526..cca5b545d806 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -66,13 +66,19 @@ config OPTPROBES depends on !PREEMPT config UPROBES - bool "User-space probes (EXPERIMENTAL)" + bool "Transparent user-space probes (EXPERIMENTAL)" depends on ARCH_SUPPORTS_UPROBES default n help - Uprobes enables kernel subsystems to establish probepoints - in user applications and execute handler functions when - the probepoints are hit. + Uprobes is the user-space counterpart to kprobes: they + enable instrumentation applications (such as 'perf probe') + to establish unintrusive probes in user-space binaries and + libraries, by executing handler functions when the probes + are hit by user-space applications. + + ( These probes come in the form of single-byte breakpoints, + managed by the kernel and kept transparent to the probed + application. ) If in doubt, say "N". diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 8208234391ff..072df3902636 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -1,7 +1,7 @@ #ifndef _ASM_UPROBES_H #define _ASM_UPROBES_H /* - * Userspace Probes (UProbes) for x86 + * User-space Probes (UProbes) for x86 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -24,19 +24,20 @@ */ typedef u8 uprobe_opcode_t; -#define MAX_UINSN_BYTES 16 -#define UPROBES_XOL_SLOT_BYTES 128 /* to keep it cache aligned */ -#define UPROBES_BKPT_INSN 0xcc -#define UPROBES_BKPT_INSN_SIZE 1 +#define MAX_UINSN_BYTES 16 +#define UPROBES_XOL_SLOT_BYTES 128 /* to keep it cache aligned */ + +#define UPROBES_BKPT_INSN 0xcc +#define UPROBES_BKPT_INSN_SIZE 1 struct uprobe_arch_info { - u16 fixups; + u16 fixups; #ifdef CONFIG_X86_64 - unsigned long rip_rela_target_address; + unsigned long rip_rela_target_address; #endif }; struct uprobe; -extern int analyze_insn(struct mm_struct *mm, struct uprobe *uprobe); +extern int arch_uprobes_analyze_insn(struct mm_struct *mm, struct uprobe *uprobe); #endif /* _ASM_UPROBES_H */ diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 2a301bb91bdb..cf2a18498425 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -1,5 +1,5 @@ /* - * Userspace Probes (UProbes) for x86 + * User-space Probes (UProbes) for x86 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -20,7 +20,6 @@ * Srikar Dronamraju * Jim Keniston */ - #include #include #include @@ -42,10 +41,10 @@ #define UPROBES_FIX_RIP_CX 0x4000 /* Adaptations for mhiramat x86 decoder v14. */ -#define OPCODE1(insn) ((insn)->opcode.bytes[0]) -#define OPCODE2(insn) ((insn)->opcode.bytes[1]) -#define OPCODE3(insn) ((insn)->opcode.bytes[2]) -#define MODRM_REG(insn) X86_MODRM_REG(insn->modrm.value) +#define OPCODE1(insn) ((insn)->opcode.bytes[0]) +#define OPCODE2(insn) ((insn)->opcode.bytes[1]) +#define OPCODE3(insn) ((insn)->opcode.bytes[2]) +#define MODRM_REG(insn) X86_MODRM_REG(insn->modrm.value) #define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\ (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \ @@ -55,7 +54,7 @@ << (row % 32)) #ifdef CONFIG_X86_64 -static volatile u32 good_insns_64[256 / 32] = { +static u32 good_insns_64[256 / 32] = { /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ /* ---------------------------------------------- */ W(0x00, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) | /* 00 */ @@ -81,7 +80,7 @@ static volatile u32 good_insns_64[256 / 32] = { /* Good-instruction tables for 32-bit apps */ -static volatile u32 good_insns_32[256 / 32] = { +static u32 good_insns_32[256 / 32] = { /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ /* ---------------------------------------------- */ W(0x00, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0) | /* 00 */ @@ -105,7 +104,7 @@ static volatile u32 good_insns_32[256 / 32] = { }; /* Using this for both 64-bit and 32-bit apps */ -static volatile u32 good_2byte_insns[256 / 32] = { +static u32 good_2byte_insns[256 / 32] = { /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ /* ---------------------------------------------- */ W(0x00, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1) | /* 00 */ @@ -132,42 +131,47 @@ static volatile u32 good_2byte_insns[256 / 32] = { /* * opcodes we'll probably never support: - * 6c-6d, e4-e5, ec-ed - in - * 6e-6f, e6-e7, ee-ef - out - * cc, cd - int3, int - * cf - iret - * d6 - illegal instruction - * f1 - int1/icebp - * f4 - hlt - * fa, fb - cli, sti - * 0f - lar, lsl, syscall, clts, sysret, sysenter, sysexit, invd, wbinvd, ud2 + * + * 6c-6d, e4-e5, ec-ed - in + * 6e-6f, e6-e7, ee-ef - out + * cc, cd - int3, int + * cf - iret + * d6 - illegal instruction + * f1 - int1/icebp + * f4 - hlt + * fa, fb - cli, sti + * 0f - lar, lsl, syscall, clts, sysret, sysenter, sysexit, invd, wbinvd, ud2 * * invalid opcodes in 64-bit mode: - * 06, 0e, 16, 1e, 27, 2f, 37, 3f, 60-62, 82, c4-c5, d4-d5 * - * 63 - we support this opcode in x86_64 but not in i386. + * 06, 0e, 16, 1e, 27, 2f, 37, 3f, 60-62, 82, c4-c5, d4-d5 + * 63 - we support this opcode in x86_64 but not in i386. * * opcodes we may need to refine support for: - * 0f - 2-byte instructions: For many of these instructions, the validity - * depends on the prefix and/or the reg field. On such instructions, we - * just consider the opcode combination valid if it corresponds to any - * valid instruction. - * 8f - Group 1 - only reg = 0 is OK - * c6-c7 - Group 11 - only reg = 0 is OK - * d9-df - fpu insns with some illegal encodings - * f2, f3 - repnz, repz prefixes. These are also the first byte for - * certain floating-point instructions, such as addsd. - * fe - Group 4 - only reg = 0 or 1 is OK - * ff - Group 5 - only reg = 0-6 is OK + * + * 0f - 2-byte instructions: For many of these instructions, the validity + * depends on the prefix and/or the reg field. On such instructions, we + * just consider the opcode combination valid if it corresponds to any + * valid instruction. + * + * 8f - Group 1 - only reg = 0 is OK + * c6-c7 - Group 11 - only reg = 0 is OK + * d9-df - fpu insns with some illegal encodings + * f2, f3 - repnz, repz prefixes. These are also the first byte for + * certain floating-point instructions, such as addsd. + * + * fe - Group 4 - only reg = 0 or 1 is OK + * ff - Group 5 - only reg = 0-6 is OK * * others -- Do we need to support these? - * 0f - (floating-point?) prefetch instructions - * 07, 17, 1f - pop es, pop ss, pop ds - * 26, 2e, 36, 3e - es:, cs:, ss:, ds: segment prefixes -- + * + * 0f - (floating-point?) prefetch instructions + * 07, 17, 1f - pop es, pop ss, pop ds + * 26, 2e, 36, 3e - es:, cs:, ss:, ds: segment prefixes -- * but 64 and 65 (fs: and gs:) seem to be used, so we support them - * 67 - addr16 prefix - * ce - into - * f0 - lock prefix + * 67 - addr16 prefix + * ce - into + * f0 - lock prefix */ /* @@ -182,11 +186,11 @@ static bool is_prefix_bad(struct insn *insn) for (i = 0; i < insn->prefixes.nbytes; i++) { switch (insn->prefixes.bytes[i]) { - case 0x26: /*INAT_PFX_ES */ - case 0x2E: /*INAT_PFX_CS */ - case 0x36: /*INAT_PFX_DS */ - case 0x3E: /*INAT_PFX_SS */ - case 0xF0: /*INAT_PFX_LOCK */ + case 0x26: /* INAT_PFX_ES */ + case 0x2E: /* INAT_PFX_CS */ + case 0x36: /* INAT_PFX_DS */ + case 0x3E: /* INAT_PFX_SS */ + case 0xF0: /* INAT_PFX_LOCK */ return true; } } @@ -201,12 +205,15 @@ static int validate_insn_32bits(struct uprobe *uprobe, struct insn *insn) insn_get_opcode(insn); if (is_prefix_bad(insn)) return -ENOTSUPP; + if (test_bit(OPCODE1(insn), (unsigned long *)good_insns_32)) return 0; + if (insn->opcode.nbytes == 2) { if (test_bit(OPCODE2(insn), (unsigned long *)good_2byte_insns)) return 0; } + return -ENOTSUPP; } @@ -282,12 +289,12 @@ static void prepare_fixups(struct uprobe *uprobe, struct insn *insn) * disastrous. * * Some useful facts about rip-relative instructions: - * - There's always a modrm byte. - * - There's never a SIB byte. - * - The displacement is always 4 bytes. + * + * - There's always a modrm byte. + * - There's never a SIB byte. + * - The displacement is always 4 bytes. */ -static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, - struct insn *insn) +static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn) { u8 *cursor; u8 reg; @@ -342,13 +349,12 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, } /* Target address = address of next instruction + (signed) offset */ - uprobe->arch_info.rip_rela_target_address = (long)insn->length - + insn->displacement.value; + uprobe->arch_info.rip_rela_target_address = (long)insn->length + insn->displacement.value; + /* Displacement field is gone; slide immediate field (if any) over. */ if (insn->immediate.nbytes) { cursor++; - memmove(cursor, cursor + insn->displacement.nbytes, - insn->immediate.nbytes); + memmove(cursor, cursor + insn->displacement.nbytes, insn->immediate.nbytes); } return; } @@ -361,8 +367,10 @@ static int validate_insn_64bits(struct uprobe *uprobe, struct insn *insn) insn_get_opcode(insn); if (is_prefix_bad(insn)) return -ENOTSUPP; + if (test_bit(OPCODE1(insn), (unsigned long *)good_insns_64)) return 0; + if (insn->opcode.nbytes == 2) { if (test_bit(OPCODE2(insn), (unsigned long *)good_2byte_insns)) return 0; @@ -370,34 +378,31 @@ static int validate_insn_64bits(struct uprobe *uprobe, struct insn *insn) return -ENOTSUPP; } -static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, - struct insn *insn) +static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn) { if (mm->context.ia32_compat) return validate_insn_32bits(uprobe, insn); return validate_insn_64bits(uprobe, insn); } -#else -static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, - struct insn *insn) +#else /* 32-bit: */ +static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn) { - return; + /* No RIP-relative addressing on 32-bit */ } -static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, - struct insn *insn) +static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn) { return validate_insn_32bits(uprobe, insn); } #endif /* CONFIG_X86_64 */ /** - * analyze_insn - instruction analysis including validity and fixups. + * arch_uprobes_analyze_insn - instruction analysis including validity and fixups. * @mm: the probed address space. * @uprobe: the probepoint information. * Return 0 on success or a -ve number on error. */ -int analyze_insn(struct mm_struct *mm, struct uprobe *uprobe) +int arch_uprobes_analyze_insn(struct mm_struct *mm, struct uprobe *uprobe) { int ret; struct insn insn; @@ -406,7 +411,9 @@ int analyze_insn(struct mm_struct *mm, struct uprobe *uprobe) ret = validate_insn_bits(mm, uprobe, &insn); if (ret != 0) return ret; + handle_riprel_insn(mm, uprobe, &insn); prepare_fixups(uprobe, &insn); + return 0; } diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index f1d13fd140f2..64e45f116b2a 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -1,7 +1,7 @@ #ifndef _LINUX_UPROBES_H #define _LINUX_UPROBES_H /* - * Userspace Probes (UProbes) + * User-space Probes (UProbes) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -40,8 +40,10 @@ struct uprobe_arch_info {}; #define uprobe_opcode_sz sizeof(uprobe_opcode_t) /* flags that denote/change uprobes behaviour */ + /* Have a copy of original instruction */ #define UPROBES_COPY_INSN 0x1 + /* Dont run handlers when first register/ last unregister in progress*/ #define UPROBES_RUN_HANDLER 0x2 @@ -70,27 +72,23 @@ struct uprobe { }; #ifdef CONFIG_UPROBES -extern int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, - unsigned long vaddr); -extern int __weak set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, - unsigned long vaddr, bool verify); +extern int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr); +extern int __weak set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, bool verify); extern bool __weak is_bkpt_insn(uprobe_opcode_t *insn); -extern int register_uprobe(struct inode *inode, loff_t offset, - struct uprobe_consumer *consumer); -extern void unregister_uprobe(struct inode *inode, loff_t offset, - struct uprobe_consumer *consumer); -extern int mmap_uprobe(struct vm_area_struct *vma); +extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer); +extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer); +extern int uprobe_mmap(struct vm_area_struct *vma); #else /* CONFIG_UPROBES is not defined */ -static inline int register_uprobe(struct inode *inode, loff_t offset, - struct uprobe_consumer *consumer) +static inline int +uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer) { return -ENOSYS; } -static inline void unregister_uprobe(struct inode *inode, loff_t offset, - struct uprobe_consumer *consumer) +static inline void +uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer) { } -static inline int mmap_uprobe(struct vm_area_struct *vma) +static inline int uprobe_mmap(struct vm_area_struct *vma) { return 0; } diff --git a/kernel/uprobes.c b/kernel/uprobes.c index 72e8bb3b52cd..884817f1b0d3 100644 --- a/kernel/uprobes.c +++ b/kernel/uprobes.c @@ -1,5 +1,5 @@ /* - * Userspace Probes (UProbes) + * User-space Probes (UProbes) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -29,24 +29,26 @@ #include /* anon_vma_prepare */ #include /* set_pte_at_notify */ #include /* try_to_free_swap */ + #include static struct rb_root uprobes_tree = RB_ROOT; + static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */ #define UPROBES_HASH_SZ 13 + /* serialize (un)register */ static struct mutex uprobes_mutex[UPROBES_HASH_SZ]; -#define uprobes_hash(v) (&uprobes_mutex[((unsigned long)(v)) %\ - UPROBES_HASH_SZ]) + +#define uprobes_hash(v) (&uprobes_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ]) /* serialize uprobe->pending_list */ static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ]; -#define uprobes_mmap_hash(v) (&uprobes_mmap_mutex[((unsigned long)(v)) %\ - UPROBES_HASH_SZ]) +#define uprobes_mmap_hash(v) (&uprobes_mmap_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ]) /* - * uprobe_events allows us to skip the mmap_uprobe if there are no uprobe + * uprobe_events allows us to skip the uprobe_mmap if there are no uprobe * events active at this time. Probably a fine grained per inode count is * better? */ @@ -58,9 +60,9 @@ static atomic_t uprobe_events = ATOMIC_INIT(0); * vm_area_struct wasnt recommended. */ struct vma_info { - struct list_head probe_list; - struct mm_struct *mm; - loff_t vaddr; + struct list_head probe_list; + struct mm_struct *mm; + loff_t vaddr; }; /* @@ -79,8 +81,7 @@ static bool valid_vma(struct vm_area_struct *vma, bool is_register) if (!is_register) return true; - if ((vma->vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)) == - (VM_READ|VM_EXEC)) + if ((vma->vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)) == (VM_READ|VM_EXEC)) return true; return false; @@ -92,6 +93,7 @@ static loff_t vma_address(struct vm_area_struct *vma, loff_t offset) vaddr = vma->vm_start + offset; vaddr -= vma->vm_pgoff << PAGE_SHIFT; + return vaddr; } @@ -105,8 +107,7 @@ static loff_t vma_address(struct vm_area_struct *vma, loff_t offset) * * Returns 0 on success, -EFAULT on failure. */ -static int __replace_page(struct vm_area_struct *vma, struct page *page, - struct page *kpage) +static int __replace_page(struct vm_area_struct *vma, struct page *page, struct page *kpage) { struct mm_struct *mm = vma->vm_mm; pgd_t *pgd; @@ -163,7 +164,7 @@ out: */ bool __weak is_bkpt_insn(uprobe_opcode_t *insn) { - return (*insn == UPROBES_BKPT_INSN); + return *insn == UPROBES_BKPT_INSN; } /* @@ -203,6 +204,7 @@ static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe, ret = get_user_pages(NULL, mm, vaddr, 1, 0, 0, &old_page, &vma); if (ret <= 0) return ret; + ret = -EINVAL; /* @@ -239,6 +241,7 @@ static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe, vaddr_new = kmap_atomic(new_page); memcpy(vaddr_new, vaddr_old, PAGE_SIZE); + /* poke the new insn in, ASSUMES we don't cross page boundary */ vaddr &= ~PAGE_MASK; BUG_ON(vaddr + uprobe_opcode_sz > PAGE_SIZE); @@ -260,7 +263,8 @@ unlock_out: page_cache_release(new_page); put_out: - put_page(old_page); /* we did a get_page in the beginning */ + put_page(old_page); + return ret; } @@ -276,8 +280,7 @@ put_out: * For mm @mm, read the opcode at @vaddr and store it in @opcode. * Return 0 (success) or a negative errno. */ -static int read_opcode(struct mm_struct *mm, unsigned long vaddr, - uprobe_opcode_t *opcode) +static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t *opcode) { struct page *page; void *vaddr_new; @@ -293,15 +296,18 @@ static int read_opcode(struct mm_struct *mm, unsigned long vaddr, memcpy(opcode, vaddr_new + vaddr, uprobe_opcode_sz); kunmap_atomic(vaddr_new); unlock_page(page); - put_page(page); /* we did a get_user_pages in the beginning */ + + put_page(page); + return 0; } static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr) { uprobe_opcode_t opcode; - int result = read_opcode(mm, vaddr, &opcode); + int result; + result = read_opcode(mm, vaddr, &opcode); if (result) return result; @@ -320,11 +326,11 @@ static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr) * For mm @mm, store the breakpoint instruction at @vaddr. * Return 0 (success) or a negative errno. */ -int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, - unsigned long vaddr) +int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr) { - int result = is_bkpt_at_addr(mm, vaddr); + int result; + result = is_bkpt_at_addr(mm, vaddr); if (result == 1) return -EEXIST; @@ -344,35 +350,35 @@ int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, * For mm @mm, restore the original opcode (opcode) at @vaddr. * Return 0 (success) or a negative errno. */ -int __weak set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, - unsigned long vaddr, bool verify) +int __weak +set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, bool verify) { if (verify) { - int result = is_bkpt_at_addr(mm, vaddr); + int result; + result = is_bkpt_at_addr(mm, vaddr); if (!result) return -EINVAL; if (result != 1) return result; } - return write_opcode(mm, uprobe, vaddr, - *(uprobe_opcode_t *)uprobe->insn); + return write_opcode(mm, uprobe, vaddr, *(uprobe_opcode_t *)uprobe->insn); } static int match_uprobe(struct uprobe *l, struct uprobe *r) { if (l->inode < r->inode) return -1; + if (l->inode > r->inode) return 1; - else { - if (l->offset < r->offset) - return -1; - if (l->offset > r->offset) - return 1; - } + if (l->offset < r->offset) + return -1; + + if (l->offset > r->offset) + return 1; return 0; } @@ -391,6 +397,7 @@ static struct uprobe *__find_uprobe(struct inode *inode, loff_t offset) atomic_inc(&uprobe->ref); return uprobe; } + if (match < 0) n = n->rb_left; else @@ -411,6 +418,7 @@ static struct uprobe *find_uprobe(struct inode *inode, loff_t offset) spin_lock_irqsave(&uprobes_treelock, flags); uprobe = __find_uprobe(inode, offset); spin_unlock_irqrestore(&uprobes_treelock, flags); + return uprobe; } @@ -436,16 +444,18 @@ static struct uprobe *__insert_uprobe(struct uprobe *uprobe) p = &parent->rb_right; } + u = NULL; rb_link_node(&uprobe->rb_node, parent, p); rb_insert_color(&uprobe->rb_node, &uprobes_tree); /* get access + creation ref */ atomic_set(&uprobe->ref, 2); + return u; } /* - * Acquires uprobes_treelock. + * Acquire uprobes_treelock. * Matching uprobe already exists in rbtree; * increment (access refcount) and return the matching uprobe. * @@ -460,6 +470,7 @@ static struct uprobe *insert_uprobe(struct uprobe *uprobe) spin_lock_irqsave(&uprobes_treelock, flags); u = __insert_uprobe(uprobe); spin_unlock_irqrestore(&uprobes_treelock, flags); + return u; } @@ -490,19 +501,22 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset) kfree(uprobe); uprobe = cur_uprobe; iput(inode); - } else + } else { atomic_inc(&uprobe_events); + } + return uprobe; } /* Returns the previous consumer */ -static struct uprobe_consumer *add_consumer(struct uprobe *uprobe, - struct uprobe_consumer *consumer) +static struct uprobe_consumer * +consumer_add(struct uprobe *uprobe, struct uprobe_consumer *consumer) { down_write(&uprobe->consumer_rwsem); consumer->next = uprobe->consumers; uprobe->consumers = consumer; up_write(&uprobe->consumer_rwsem); + return consumer->next; } @@ -511,8 +525,7 @@ static struct uprobe_consumer *add_consumer(struct uprobe *uprobe, * Return true if the @consumer is deleted successfully * or return false. */ -static bool del_consumer(struct uprobe *uprobe, - struct uprobe_consumer *consumer) +static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *consumer) { struct uprobe_consumer **con; bool ret = false; @@ -526,6 +539,7 @@ static bool del_consumer(struct uprobe *uprobe, } } up_write(&uprobe->consumer_rwsem); + return ret; } @@ -557,15 +571,15 @@ static int __copy_insn(struct address_space *mapping, memcpy(insn, vaddr + off1, nbytes); kunmap_atomic(vaddr); page_cache_release(page); + return 0; } -static int copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, - unsigned long addr) +static int copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr) { struct address_space *mapping; - int bytes; unsigned long nbytes; + int bytes; addr &= ~PAGE_MASK; nbytes = PAGE_SIZE - addr; @@ -605,6 +619,7 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, return -EEXIST; addr = (unsigned long)vaddr; + if (!(uprobe->flags & UPROBES_COPY_INSN)) { ret = copy_insn(uprobe, vma, addr); if (ret) @@ -613,7 +628,7 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, if (is_bkpt_insn((uprobe_opcode_t *)uprobe->insn)) return -EEXIST; - ret = analyze_insn(mm, uprobe); + ret = arch_uprobes_analyze_insn(mm, uprobe); if (ret) return ret; @@ -624,8 +639,7 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, return ret; } -static void remove_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, - loff_t vaddr) +static void remove_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, loff_t vaddr) { set_orig_insn(mm, uprobe, (unsigned long)vaddr, true); } @@ -649,9 +663,11 @@ static struct vma_info *__find_next_vma_info(struct list_head *head, struct prio_tree_iter iter; struct vm_area_struct *vma; struct vma_info *tmpvi; - loff_t vaddr; - unsigned long pgoff = offset >> PAGE_SHIFT; + unsigned long pgoff; int existing_vma; + loff_t vaddr; + + pgoff = offset >> PAGE_SHIFT; vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { if (!valid_vma(vma, is_register)) @@ -659,6 +675,7 @@ static struct vma_info *__find_next_vma_info(struct list_head *head, existing_vma = 0; vaddr = vma_address(vma, offset); + list_for_each_entry(tmpvi, head, probe_list) { if (tmpvi->mm == vma->vm_mm && tmpvi->vaddr == vaddr) { existing_vma = 1; @@ -670,14 +687,15 @@ static struct vma_info *__find_next_vma_info(struct list_head *head, * Another vma needs a probe to be installed. However skip * installing the probe if the vma is about to be unlinked. */ - if (!existing_vma && - atomic_inc_not_zero(&vma->vm_mm->mm_users)) { + if (!existing_vma && atomic_inc_not_zero(&vma->vm_mm->mm_users)) { vi->mm = vma->vm_mm; vi->vaddr = vaddr; list_add(&vi->probe_list, head); + return vi; } } + return NULL; } @@ -685,11 +703,12 @@ static struct vma_info *__find_next_vma_info(struct list_head *head, * Iterate in the rmap prio tree and find a vma where a probe has not * yet been inserted. */ -static struct vma_info *find_next_vma_info(struct list_head *head, - loff_t offset, struct address_space *mapping, - bool is_register) +static struct vma_info * +find_next_vma_info(struct list_head *head, loff_t offset, struct address_space *mapping, + bool is_register) { struct vma_info *vi, *retvi; + vi = kzalloc(sizeof(struct vma_info), GFP_KERNEL); if (!vi) return ERR_PTR(-ENOMEM); @@ -700,6 +719,7 @@ static struct vma_info *find_next_vma_info(struct list_head *head, if (!retvi) kfree(vi); + return retvi; } @@ -711,16 +731,23 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register) struct vma_info *vi, *tmpvi; struct mm_struct *mm; loff_t vaddr; - int ret = 0; + int ret; mapping = uprobe->inode->i_mapping; INIT_LIST_HEAD(&try_list); - while ((vi = find_next_vma_info(&try_list, uprobe->offset, - mapping, is_register)) != NULL) { + + ret = 0; + + for (;;) { + vi = find_next_vma_info(&try_list, uprobe->offset, mapping, is_register); + if (!vi) + break; + if (IS_ERR(vi)) { ret = PTR_ERR(vi); break; } + mm = vi->mm; down_read(&mm->mmap_sem); vma = find_vma(mm, (unsigned long)vi->vaddr); @@ -755,19 +782,21 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register) break; } } + list_for_each_entry_safe(vi, tmpvi, &try_list, probe_list) { list_del(&vi->probe_list); kfree(vi); } + return ret; } -static int __register_uprobe(struct uprobe *uprobe) +static int __uprobe_register(struct uprobe *uprobe) { return register_for_each_vma(uprobe, true); } -static void __unregister_uprobe(struct uprobe *uprobe) +static void __uprobe_unregister(struct uprobe *uprobe) { if (!register_for_each_vma(uprobe, false)) delete_uprobe(uprobe); @@ -776,15 +805,15 @@ static void __unregister_uprobe(struct uprobe *uprobe) } /* - * register_uprobe - register a probe + * uprobe_register - register a probe * @inode: the file in which the probe has to be placed. * @offset: offset from the start of the file. * @consumer: information on howto handle the probe.. * - * Apart from the access refcount, register_uprobe() takes a creation + * Apart from the access refcount, uprobe_register() takes a creation * refcount (thro alloc_uprobe) if and only if this @uprobe is getting * inserted into the rbtree (i.e first consumer for a @inode:@offset - * tuple). Creation refcount stops unregister_uprobe from freeing the + * tuple). Creation refcount stops uprobe_unregister from freeing the * @uprobe even before the register operation is complete. Creation * refcount is released when the last @consumer for the @uprobe * unregisters. @@ -792,28 +821,29 @@ static void __unregister_uprobe(struct uprobe *uprobe) * Return errno if it cannot successully install probes * else return 0 (success) */ -int register_uprobe(struct inode *inode, loff_t offset, - struct uprobe_consumer *consumer) +int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer) { struct uprobe *uprobe; - int ret = -EINVAL; + int ret; if (!inode || !consumer || consumer->next) - return ret; + return -EINVAL; if (offset > i_size_read(inode)) - return ret; + return -EINVAL; ret = 0; mutex_lock(uprobes_hash(inode)); uprobe = alloc_uprobe(inode, offset); - if (uprobe && !add_consumer(uprobe, consumer)) { - ret = __register_uprobe(uprobe); + + if (uprobe && !consumer_add(uprobe, consumer)) { + ret = __uprobe_register(uprobe); if (ret) { uprobe->consumers = NULL; - __unregister_uprobe(uprobe); - } else + __uprobe_unregister(uprobe); + } else { uprobe->flags |= UPROBES_RUN_HANDLER; + } } mutex_unlock(uprobes_hash(inode)); @@ -823,15 +853,14 @@ int register_uprobe(struct inode *inode, loff_t offset, } /* - * unregister_uprobe - unregister a already registered probe. + * uprobe_unregister - unregister a already registered probe. * @inode: the file in which the probe has to be removed. * @offset: offset from the start of the file. * @consumer: identify which probe if multiple probes are colocated. */ -void unregister_uprobe(struct inode *inode, loff_t offset, - struct uprobe_consumer *consumer) +void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer) { - struct uprobe *uprobe = NULL; + struct uprobe *uprobe; if (!inode || !consumer) return; @@ -841,15 +870,14 @@ void unregister_uprobe(struct inode *inode, loff_t offset, return; mutex_lock(uprobes_hash(inode)); - if (!del_consumer(uprobe, consumer)) - goto unreg_out; - if (!uprobe->consumers) { - __unregister_uprobe(uprobe); - uprobe->flags &= ~UPROBES_RUN_HANDLER; + if (consumer_del(uprobe, consumer)) { + if (!uprobe->consumers) { + __uprobe_unregister(uprobe); + uprobe->flags &= ~UPROBES_RUN_HANDLER; + } } -unreg_out: mutex_unlock(uprobes_hash(inode)); if (uprobe) put_uprobe(uprobe); @@ -870,6 +898,7 @@ static struct rb_node *find_least_offset_node(struct inode *inode) while (n) { uprobe = rb_entry(n, struct uprobe, rb_node); match = match_uprobe(&u, uprobe); + if (uprobe->inode == inode) close_node = n; @@ -881,6 +910,7 @@ static struct rb_node *find_least_offset_node(struct inode *inode) else n = n->rb_right; } + return close_node; } @@ -890,11 +920,13 @@ static struct rb_node *find_least_offset_node(struct inode *inode) static void build_probe_list(struct inode *inode, struct list_head *head) { struct uprobe *uprobe; - struct rb_node *n; unsigned long flags; + struct rb_node *n; spin_lock_irqsave(&uprobes_treelock, flags); + n = find_least_offset_node(inode); + for (; n; n = rb_next(n)) { uprobe = rb_entry(n, struct uprobe, rb_node); if (uprobe->inode != inode) @@ -903,6 +935,7 @@ static void build_probe_list(struct inode *inode, struct list_head *head) list_add(&uprobe->pending_list, head); atomic_inc(&uprobe->ref); } + spin_unlock_irqrestore(&uprobes_treelock, flags); } @@ -912,42 +945,44 @@ static void build_probe_list(struct inode *inode, struct list_head *head) * * Return -ve no if we fail to insert probes and we cannot * bail-out. - * Return 0 otherwise. i.e : + * Return 0 otherwise. i.e: + * * - successful insertion of probes * - (or) no possible probes to be inserted. * - (or) insertion of probes failed but we can bail-out. */ -int mmap_uprobe(struct vm_area_struct *vma) +int uprobe_mmap(struct vm_area_struct *vma) { struct list_head tmp_list; struct uprobe *uprobe, *u; struct inode *inode; - int ret = 0; + int ret; if (!atomic_read(&uprobe_events) || !valid_vma(vma, true)) - return ret; /* Bail-out */ + return 0; inode = vma->vm_file->f_mapping->host; if (!inode) - return ret; + return 0; INIT_LIST_HEAD(&tmp_list); mutex_lock(uprobes_mmap_hash(inode)); build_probe_list(inode, &tmp_list); + + ret = 0; + list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) { loff_t vaddr; list_del(&uprobe->pending_list); if (!ret) { vaddr = vma_address(vma, uprobe->offset); - if (vaddr < vma->vm_start || vaddr >= vma->vm_end) { - put_uprobe(uprobe); - continue; + if (vaddr >= vma->vm_start && vaddr < vma->vm_end) { + ret = install_breakpoint(vma->vm_mm, uprobe, vma, vaddr); + /* Ignore double add: */ + if (ret == -EEXIST) + ret = 0; } - ret = install_breakpoint(vma->vm_mm, uprobe, vma, - vaddr); - if (ret == -EEXIST) - ret = 0; } put_uprobe(uprobe); } diff --git a/mm/mmap.c b/mm/mmap.c index 1aed183636d7..5a863d328a44 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -618,10 +618,10 @@ again: remove_next = 1 + (end > next->vm_end); mutex_unlock(&mapping->i_mmap_mutex); if (root) { - mmap_uprobe(vma); + uprobe_mmap(vma); if (adjust_next) - mmap_uprobe(next); + uprobe_mmap(next); } if (remove_next) { @@ -646,7 +646,7 @@ again: remove_next = 1 + (end > next->vm_end); } } if (insert && file) - mmap_uprobe(insert); + uprobe_mmap(insert); validate_mm(mm); @@ -1340,7 +1340,7 @@ out: } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) make_pages_present(addr, addr + len); - if (file && mmap_uprobe(vma)) + if (file && uprobe_mmap(vma)) /* matching probes but cannot insert */ goto unmap_and_free_vma; @@ -2301,7 +2301,7 @@ int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) security_vm_enough_memory_mm(mm, vma_pages(vma))) return -ENOMEM; - if (vma->vm_file && mmap_uprobe(vma)) + if (vma->vm_file && uprobe_mmap(vma)) return -EINVAL; vma_link(mm, vma, prev, rb_link, rb_parent); @@ -2374,7 +2374,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, if (new_vma->vm_file) { get_file(new_vma->vm_file); - if (mmap_uprobe(new_vma)) + if (uprobe_mmap(new_vma)) goto out_free_mempol; if (vma->vm_flags & VM_EXECUTABLE) -- cgit v1.2.3 From 3ff54efdfaace9e9b2b7c1959a865be6b91de96c Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Wed, 22 Feb 2012 14:46:02 +0530 Subject: uprobes/core: Move insn to arch specific structure Few cleanups suggested by Ingo Molnar. - Rename struct uprobe_arch_info to struct arch_uprobe. - Move insn from struct uprobe to struct arch_uprobe. - Make arch specific uprobe functions to accept struct arch_uprobe instead of struct uprobe. - Move struct uprobe to kernel/uprobes.c from include/linux/uprobes.h Signed-off-by: Srikar Dronamraju Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Masami Hiramatsu Cc: Anton Arapov Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Jiri Olsa Cc: Josh Stone Link: http://lkml.kernel.org/r/20120222091602.15880.40249.sendpatchset@srdronam.in.ibm.com [ Made various small improvements ] Signed-off-by: Ingo Molnar --- arch/x86/include/asm/uprobes.h | 6 ++--- arch/x86/kernel/uprobes.c | 60 +++++++++++++++++++++--------------------- include/linux/uprobes.h | 23 ++-------------- kernel/events/uprobes.c | 38 +++++++++++++++++--------- 4 files changed, 61 insertions(+), 66 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 072df3902636..f7ce310a429d 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -31,13 +31,13 @@ typedef u8 uprobe_opcode_t; #define UPROBES_BKPT_INSN 0xcc #define UPROBES_BKPT_INSN_SIZE 1 -struct uprobe_arch_info { +struct arch_uprobe { u16 fixups; + u8 insn[MAX_UINSN_BYTES]; #ifdef CONFIG_X86_64 unsigned long rip_rela_target_address; #endif }; -struct uprobe; -extern int arch_uprobes_analyze_insn(struct mm_struct *mm, struct uprobe *uprobe); +extern int arch_uprobes_analyze_insn(struct mm_struct *mm, struct arch_uprobe *arch_uprobe); #endif /* _ASM_UPROBES_H */ diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 13d616d6519b..04dfcef2d028 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -200,9 +200,9 @@ static bool is_prefix_bad(struct insn *insn) return false; } -static int validate_insn_32bits(struct uprobe *uprobe, struct insn *insn) +static int validate_insn_32bits(struct arch_uprobe *auprobe, struct insn *insn) { - insn_init(insn, uprobe->insn, false); + insn_init(insn, auprobe->insn, false); /* Skip good instruction prefixes; reject "bad" ones. */ insn_get_opcode(insn); @@ -222,11 +222,11 @@ static int validate_insn_32bits(struct uprobe *uprobe, struct insn *insn) /* * Figure out which fixups post_xol() will need to perform, and annotate - * uprobe->arch_info.fixups accordingly. To start with, - * uprobe->arch_info.fixups is either zero or it reflects rip-related + * arch_uprobe->fixups accordingly. To start with, + * arch_uprobe->fixups is either zero or it reflects rip-related * fixups. */ -static void prepare_fixups(struct uprobe *uprobe, struct insn *insn) +static void prepare_fixups(struct arch_uprobe *auprobe, struct insn *insn) { bool fix_ip = true, fix_call = false; /* defaults */ int reg; @@ -269,17 +269,17 @@ static void prepare_fixups(struct uprobe *uprobe, struct insn *insn) break; } if (fix_ip) - uprobe->arch_info.fixups |= UPROBES_FIX_IP; + auprobe->fixups |= UPROBES_FIX_IP; if (fix_call) - uprobe->arch_info.fixups |= UPROBES_FIX_CALL; + auprobe->fixups |= UPROBES_FIX_CALL; } #ifdef CONFIG_X86_64 /* - * If uprobe->insn doesn't use rip-relative addressing, return + * If arch_uprobe->insn doesn't use rip-relative addressing, return * immediately. Otherwise, rewrite the instruction so that it accesses * its memory operand indirectly through a scratch register. Set - * uprobe->arch_info.fixups and uprobe->arch_info.rip_rela_target_address + * arch_uprobe->fixups and arch_uprobe->rip_rela_target_address * accordingly. (The contents of the scratch register will be saved * before we single-step the modified instruction, and restored * afterward.) @@ -297,7 +297,7 @@ static void prepare_fixups(struct uprobe *uprobe, struct insn *insn) * - There's never a SIB byte. * - The displacement is always 4 bytes. */ -static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn) +static void handle_riprel_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn) { u8 *cursor; u8 reg; @@ -305,7 +305,7 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru if (mm->context.ia32_compat) return; - uprobe->arch_info.rip_rela_target_address = 0x0; + auprobe->rip_rela_target_address = 0x0; if (!insn_rip_relative(insn)) return; @@ -315,7 +315,7 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru * we want to encode rax/rcx, not r8/r9. */ if (insn->rex_prefix.nbytes) { - cursor = uprobe->insn + insn_offset_rex_prefix(insn); + cursor = auprobe->insn + insn_offset_rex_prefix(insn); *cursor &= 0xfe; /* Clearing REX.B bit */ } @@ -324,7 +324,7 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru * displacement. Beyond the displacement, for some instructions, * is the immediate operand. */ - cursor = uprobe->insn + insn_offset_modrm(insn); + cursor = auprobe->insn + insn_offset_modrm(insn); insn_get_length(insn); /* @@ -341,18 +341,18 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru * is NOT the register operand, so we use %rcx (register * #1) for the scratch register. */ - uprobe->arch_info.fixups = UPROBES_FIX_RIP_CX; + auprobe->fixups = UPROBES_FIX_RIP_CX; /* Change modrm from 00 000 101 to 00 000 001. */ *cursor = 0x1; } else { /* Use %rax (register #0) for the scratch register. */ - uprobe->arch_info.fixups = UPROBES_FIX_RIP_AX; + auprobe->fixups = UPROBES_FIX_RIP_AX; /* Change modrm from 00 xxx 101 to 00 xxx 000 */ *cursor = (reg << 3); } /* Target address = address of next instruction + (signed) offset */ - uprobe->arch_info.rip_rela_target_address = (long)insn->length + insn->displacement.value; + auprobe->rip_rela_target_address = (long)insn->length + insn->displacement.value; /* Displacement field is gone; slide immediate field (if any) over. */ if (insn->immediate.nbytes) { @@ -362,9 +362,9 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru return; } -static int validate_insn_64bits(struct uprobe *uprobe, struct insn *insn) +static int validate_insn_64bits(struct arch_uprobe *auprobe, struct insn *insn) { - insn_init(insn, uprobe->insn, true); + insn_init(insn, auprobe->insn, true); /* Skip good instruction prefixes; reject "bad" ones. */ insn_get_opcode(insn); @@ -381,42 +381,42 @@ static int validate_insn_64bits(struct uprobe *uprobe, struct insn *insn) return -ENOTSUPP; } -static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn) +static int validate_insn_bits(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn) { if (mm->context.ia32_compat) - return validate_insn_32bits(uprobe, insn); - return validate_insn_64bits(uprobe, insn); + return validate_insn_32bits(auprobe, insn); + return validate_insn_64bits(auprobe, insn); } #else /* 32-bit: */ -static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn) +static void handle_riprel_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn) { /* No RIP-relative addressing on 32-bit */ } -static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn) +static int validate_insn_bits(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn) { - return validate_insn_32bits(uprobe, insn); + return validate_insn_32bits(auprobe, insn); } #endif /* CONFIG_X86_64 */ /** * arch_uprobes_analyze_insn - instruction analysis including validity and fixups. * @mm: the probed address space. - * @uprobe: the probepoint information. + * @arch_uprobe: the probepoint information. * Return 0 on success or a -ve number on error. */ -int arch_uprobes_analyze_insn(struct mm_struct *mm, struct uprobe *uprobe) +int arch_uprobes_analyze_insn(struct mm_struct *mm, struct arch_uprobe *auprobe) { int ret; struct insn insn; - uprobe->arch_info.fixups = 0; - ret = validate_insn_bits(mm, uprobe, &insn); + auprobe->fixups = 0; + ret = validate_insn_bits(mm, auprobe, &insn); if (ret != 0) return ret; - handle_riprel_insn(mm, uprobe, &insn); - prepare_fixups(uprobe, &insn); + handle_riprel_insn(mm, auprobe, &insn); + prepare_fixups(auprobe, &insn); return 0; } diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index fd45b70750d4..9c6be62787ed 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -29,12 +29,6 @@ struct vm_area_struct; #ifdef CONFIG_ARCH_SUPPORTS_UPROBES #include -#else - -typedef u8 uprobe_opcode_t; -struct uprobe_arch_info {}; - -#define MAX_UINSN_BYTES 4 #endif /* flags that denote/change uprobes behaviour */ @@ -56,22 +50,9 @@ struct uprobe_consumer { struct uprobe_consumer *next; }; -struct uprobe { - struct rb_node rb_node; /* node in the rb tree */ - atomic_t ref; - struct rw_semaphore consumer_rwsem; - struct list_head pending_list; - struct uprobe_arch_info arch_info; - struct uprobe_consumer *consumers; - struct inode *inode; /* Also hold a ref to inode */ - loff_t offset; - int flags; - u8 insn[MAX_UINSN_BYTES]; -}; - #ifdef CONFIG_UPROBES -extern int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr); -extern int __weak set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, bool verify); +extern int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr); +extern int __weak set_orig_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr, bool verify); extern bool __weak is_bkpt_insn(uprobe_opcode_t *insn); extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer); extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer); diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index ee496ad95db3..13f1b5909af4 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -65,6 +65,18 @@ struct vma_info { loff_t vaddr; }; +struct uprobe { + struct rb_node rb_node; /* node in the rb tree */ + atomic_t ref; + struct rw_semaphore consumer_rwsem; + struct list_head pending_list; + struct uprobe_consumer *consumers; + struct inode *inode; /* Also hold a ref to inode */ + loff_t offset; + int flags; + struct arch_uprobe arch; +}; + /* * valid_vma: Verify if the specified vma is an executable vma * Relax restrictions while unregistering: vm_flags might have @@ -180,7 +192,7 @@ bool __weak is_bkpt_insn(uprobe_opcode_t *insn) /* * write_opcode - write the opcode at a given virtual address. * @mm: the probed process address space. - * @uprobe: the breakpointing information. + * @arch_uprobe: the breakpointing information. * @vaddr: the virtual address to store the opcode. * @opcode: opcode to be written at @vaddr. * @@ -190,13 +202,14 @@ bool __weak is_bkpt_insn(uprobe_opcode_t *insn) * For mm @mm, write the opcode at @vaddr. * Return 0 (success) or a negative errno. */ -static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe, +static int write_opcode(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr, uprobe_opcode_t opcode) { struct page *old_page, *new_page; struct address_space *mapping; void *vaddr_old, *vaddr_new; struct vm_area_struct *vma; + struct uprobe *uprobe; loff_t addr; int ret; @@ -216,6 +229,7 @@ static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe, if (!valid_vma(vma, is_bkpt_insn(&opcode))) goto put_out; + uprobe = container_of(auprobe, struct uprobe, arch); mapping = uprobe->inode->i_mapping; if (mapping != vma->vm_file->f_mapping) goto put_out; @@ -326,7 +340,7 @@ static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr) * For mm @mm, store the breakpoint instruction at @vaddr. * Return 0 (success) or a negative errno. */ -int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr) +int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr) { int result; @@ -337,7 +351,7 @@ int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long v if (result) return result; - return write_opcode(mm, uprobe, vaddr, UPROBES_BKPT_INSN); + return write_opcode(mm, auprobe, vaddr, UPROBES_BKPT_INSN); } /** @@ -351,7 +365,7 @@ int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long v * Return 0 (success) or a negative errno. */ int __weak -set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, bool verify) +set_orig_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr, bool verify) { if (verify) { int result; @@ -363,7 +377,7 @@ set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, if (result != 1) return result; } - return write_opcode(mm, uprobe, vaddr, *(uprobe_opcode_t *)uprobe->insn); + return write_opcode(mm, auprobe, vaddr, *(uprobe_opcode_t *)auprobe->insn); } static int match_uprobe(struct uprobe *l, struct uprobe *r) @@ -593,13 +607,13 @@ static int copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned /* Instruction at the page-boundary; copy bytes in second page */ if (nbytes < bytes) { - if (__copy_insn(mapping, vma, uprobe->insn + nbytes, + if (__copy_insn(mapping, vma, uprobe->arch.insn + nbytes, bytes - nbytes, uprobe->offset + nbytes)) return -ENOMEM; bytes = nbytes; } - return __copy_insn(mapping, vma, uprobe->insn, bytes, uprobe->offset); + return __copy_insn(mapping, vma, uprobe->arch.insn, bytes, uprobe->offset); } static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, @@ -625,23 +639,23 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, if (ret) return ret; - if (is_bkpt_insn((uprobe_opcode_t *)uprobe->insn)) + if (is_bkpt_insn((uprobe_opcode_t *)uprobe->arch.insn)) return -EEXIST; - ret = arch_uprobes_analyze_insn(mm, uprobe); + ret = arch_uprobes_analyze_insn(mm, &uprobe->arch); if (ret) return ret; uprobe->flags |= UPROBES_COPY_INSN; } - ret = set_bkpt(mm, uprobe, addr); + ret = set_bkpt(mm, &uprobe->arch, addr); return ret; } static void remove_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, loff_t vaddr) { - set_orig_insn(mm, uprobe, (unsigned long)vaddr, true); + set_orig_insn(mm, &uprobe->arch, (unsigned long)vaddr, true); } static void delete_uprobe(struct uprobe *uprobe) -- cgit v1.2.3 From 900771a483ef28915a48066d7895d8252315607a Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Mon, 12 Mar 2012 14:55:14 +0530 Subject: uprobes/core: Make macro names consistent Rename macros that refer to individual uprobe to start with UPROBE_ instead of UPROBES_. This is pure cleanup, no functional change intended. Signed-off-by: Srikar Dronamraju Cc: Linus Torvalds Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Linux-mm Cc: Oleg Nesterov Cc: Andi Kleen Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120312092514.5379.36595.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/uprobes.h | 6 +++--- arch/x86/kernel/uprobes.c | 18 +++++++++--------- include/linux/uprobes.h | 4 ++-- kernel/events/uprobes.c | 18 +++++++++--------- 4 files changed, 23 insertions(+), 23 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index f7ce310a429d..5c399e446512 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -26,10 +26,10 @@ typedef u8 uprobe_opcode_t; #define MAX_UINSN_BYTES 16 -#define UPROBES_XOL_SLOT_BYTES 128 /* to keep it cache aligned */ +#define UPROBE_XOL_SLOT_BYTES 128 /* to keep it cache aligned */ -#define UPROBES_BKPT_INSN 0xcc -#define UPROBES_BKPT_INSN_SIZE 1 +#define UPROBE_BKPT_INSN 0xcc +#define UPROBE_BKPT_INSN_SIZE 1 struct arch_uprobe { u16 fixups; diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 04dfcef2d028..6dfa89e6f24a 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -31,14 +31,14 @@ /* Post-execution fixups. */ /* No fixup needed */ -#define UPROBES_FIX_NONE 0x0 +#define UPROBE_FIX_NONE 0x0 /* Adjust IP back to vicinity of actual insn */ -#define UPROBES_FIX_IP 0x1 +#define UPROBE_FIX_IP 0x1 /* Adjust the return address of a call insn */ -#define UPROBES_FIX_CALL 0x2 +#define UPROBE_FIX_CALL 0x2 -#define UPROBES_FIX_RIP_AX 0x8000 -#define UPROBES_FIX_RIP_CX 0x4000 +#define UPROBE_FIX_RIP_AX 0x8000 +#define UPROBE_FIX_RIP_CX 0x4000 /* Adaptations for mhiramat x86 decoder v14. */ #define OPCODE1(insn) ((insn)->opcode.bytes[0]) @@ -269,9 +269,9 @@ static void prepare_fixups(struct arch_uprobe *auprobe, struct insn *insn) break; } if (fix_ip) - auprobe->fixups |= UPROBES_FIX_IP; + auprobe->fixups |= UPROBE_FIX_IP; if (fix_call) - auprobe->fixups |= UPROBES_FIX_CALL; + auprobe->fixups |= UPROBE_FIX_CALL; } #ifdef CONFIG_X86_64 @@ -341,12 +341,12 @@ static void handle_riprel_insn(struct mm_struct *mm, struct arch_uprobe *auprobe * is NOT the register operand, so we use %rcx (register * #1) for the scratch register. */ - auprobe->fixups = UPROBES_FIX_RIP_CX; + auprobe->fixups = UPROBE_FIX_RIP_CX; /* Change modrm from 00 000 101 to 00 000 001. */ *cursor = 0x1; } else { /* Use %rax (register #0) for the scratch register. */ - auprobe->fixups = UPROBES_FIX_RIP_AX; + auprobe->fixups = UPROBE_FIX_RIP_AX; /* Change modrm from 00 xxx 101 to 00 xxx 000 */ *cursor = (reg << 3); } diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index f85797e1ccd4..838fb312926a 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -35,10 +35,10 @@ struct vm_area_struct; /* flags that denote/change uprobes behaviour */ /* Have a copy of original instruction */ -#define UPROBES_COPY_INSN 0x1 +#define UPROBE_COPY_INSN 0x1 /* Dont run handlers when first register/ last unregister in progress*/ -#define UPROBES_RUN_HANDLER 0x2 +#define UPROBE_RUN_HANDLER 0x2 struct uprobe_consumer { int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs); diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 5ce32e3ae9e9..0d36bf3920ba 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -177,7 +177,7 @@ out: */ bool __weak is_bkpt_insn(uprobe_opcode_t *insn) { - return *insn == UPROBES_BKPT_INSN; + return *insn == UPROBE_BKPT_INSN; } /* @@ -259,8 +259,8 @@ static int write_opcode(struct mm_struct *mm, struct arch_uprobe *auprobe, /* poke the new insn in, ASSUMES we don't cross page boundary */ vaddr &= ~PAGE_MASK; - BUG_ON(vaddr + UPROBES_BKPT_INSN_SIZE > PAGE_SIZE); - memcpy(vaddr_new + vaddr, &opcode, UPROBES_BKPT_INSN_SIZE); + BUG_ON(vaddr + UPROBE_BKPT_INSN_SIZE > PAGE_SIZE); + memcpy(vaddr_new + vaddr, &opcode, UPROBE_BKPT_INSN_SIZE); kunmap_atomic(vaddr_new); kunmap_atomic(vaddr_old); @@ -308,7 +308,7 @@ static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_ lock_page(page); vaddr_new = kmap_atomic(page); vaddr &= ~PAGE_MASK; - memcpy(opcode, vaddr_new + vaddr, UPROBES_BKPT_INSN_SIZE); + memcpy(opcode, vaddr_new + vaddr, UPROBE_BKPT_INSN_SIZE); kunmap_atomic(vaddr_new); unlock_page(page); @@ -352,7 +352,7 @@ int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned if (result) return result; - return write_opcode(mm, auprobe, vaddr, UPROBES_BKPT_INSN); + return write_opcode(mm, auprobe, vaddr, UPROBE_BKPT_INSN); } /** @@ -635,7 +635,7 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, addr = (unsigned long)vaddr; - if (!(uprobe->flags & UPROBES_COPY_INSN)) { + if (!(uprobe->flags & UPROBE_COPY_INSN)) { ret = copy_insn(uprobe, vma, addr); if (ret) return ret; @@ -647,7 +647,7 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, if (ret) return ret; - uprobe->flags |= UPROBES_COPY_INSN; + uprobe->flags |= UPROBE_COPY_INSN; } ret = set_bkpt(mm, &uprobe->arch, addr); @@ -857,7 +857,7 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer * uprobe->consumers = NULL; __uprobe_unregister(uprobe); } else { - uprobe->flags |= UPROBES_RUN_HANDLER; + uprobe->flags |= UPROBE_RUN_HANDLER; } } @@ -889,7 +889,7 @@ void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consume if (consumer_del(uprobe, consumer)) { if (!uprobe->consumers) { __uprobe_unregister(uprobe); - uprobe->flags &= ~UPROBES_RUN_HANDLER; + uprobe->flags &= ~UPROBE_RUN_HANDLER; } } -- cgit v1.2.3 From e3343e6a2819ff5d0dfc4bb5c9fb7f9a4d04da73 Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Mon, 12 Mar 2012 14:55:30 +0530 Subject: uprobes/core: Make order of function parameters consistent across functions If a function takes struct uprobe or struct arch_uprobe, then it is passed as the first parameter. This is pure cleanup, no functional change intended. Signed-off-by: Srikar Dronamraju Cc: Linus Torvalds Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Linux-mm Cc: Oleg Nesterov Cc: Andi Kleen Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120312092530.5379.18394.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/uprobes.h | 2 +- arch/x86/kernel/uprobes.c | 15 +++---- include/linux/uprobes.h | 12 +++--- kernel/events/uprobes.c | 93 ++++++++++++++++++++++-------------------- 4 files changed, 63 insertions(+), 59 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 5c399e446512..384f1bebf884 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -39,5 +39,5 @@ struct arch_uprobe { #endif }; -extern int arch_uprobes_analyze_insn(struct mm_struct *mm, struct arch_uprobe *arch_uprobe); +extern int arch_uprobes_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm); #endif /* _ASM_UPROBES_H */ diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 6dfa89e6f24a..851a11b0d38c 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -297,7 +297,8 @@ static void prepare_fixups(struct arch_uprobe *auprobe, struct insn *insn) * - There's never a SIB byte. * - The displacement is always 4 bytes. */ -static void handle_riprel_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn) +static void +handle_riprel_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, struct insn *insn) { u8 *cursor; u8 reg; @@ -381,19 +382,19 @@ static int validate_insn_64bits(struct arch_uprobe *auprobe, struct insn *insn) return -ENOTSUPP; } -static int validate_insn_bits(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn) +static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm, struct insn *insn) { if (mm->context.ia32_compat) return validate_insn_32bits(auprobe, insn); return validate_insn_64bits(auprobe, insn); } #else /* 32-bit: */ -static void handle_riprel_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn) +static void handle_riprel_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, struct insn *insn) { /* No RIP-relative addressing on 32-bit */ } -static int validate_insn_bits(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn) +static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm, struct insn *insn) { return validate_insn_32bits(auprobe, insn); } @@ -405,17 +406,17 @@ static int validate_insn_bits(struct mm_struct *mm, struct arch_uprobe *auprobe, * @arch_uprobe: the probepoint information. * Return 0 on success or a -ve number on error. */ -int arch_uprobes_analyze_insn(struct mm_struct *mm, struct arch_uprobe *auprobe) +int arch_uprobes_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm) { int ret; struct insn insn; auprobe->fixups = 0; - ret = validate_insn_bits(mm, auprobe, &insn); + ret = validate_insn_bits(auprobe, mm, &insn); if (ret != 0) return ret; - handle_riprel_insn(mm, auprobe, &insn); + handle_riprel_insn(auprobe, mm, &insn); prepare_fixups(auprobe, &insn); return 0; diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 838fb312926a..58699182e9a7 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -52,20 +52,20 @@ struct uprobe_consumer { }; #ifdef CONFIG_UPROBES -extern int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr); -extern int __weak set_orig_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr, bool verify); +extern int __weak set_bkpt(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr); +extern int __weak set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr, bool verify); extern bool __weak is_bkpt_insn(uprobe_opcode_t *insn); -extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer); -extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer); +extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); +extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); extern int uprobe_mmap(struct vm_area_struct *vma); #else /* CONFIG_UPROBES is not defined */ static inline int -uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer) +uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) { return -ENOSYS; } static inline void -uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer) +uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) { } static inline int uprobe_mmap(struct vm_area_struct *vma) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 0d36bf3920ba..9c5ddff1c8da 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -192,8 +192,8 @@ bool __weak is_bkpt_insn(uprobe_opcode_t *insn) /* * write_opcode - write the opcode at a given virtual address. + * @auprobe: arch breakpointing information. * @mm: the probed process address space. - * @arch_uprobe: the breakpointing information. * @vaddr: the virtual address to store the opcode. * @opcode: opcode to be written at @vaddr. * @@ -203,7 +203,7 @@ bool __weak is_bkpt_insn(uprobe_opcode_t *insn) * For mm @mm, write the opcode at @vaddr. * Return 0 (success) or a negative errno. */ -static int write_opcode(struct mm_struct *mm, struct arch_uprobe *auprobe, +static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t opcode) { struct page *old_page, *new_page; @@ -334,14 +334,14 @@ static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr) /** * set_bkpt - store breakpoint at a given address. + * @auprobe: arch specific probepoint information. * @mm: the probed process address space. - * @uprobe: the probepoint information. * @vaddr: the virtual address to insert the opcode. * * For mm @mm, store the breakpoint instruction at @vaddr. * Return 0 (success) or a negative errno. */ -int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr) +int __weak set_bkpt(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) { int result; @@ -352,13 +352,13 @@ int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned if (result) return result; - return write_opcode(mm, auprobe, vaddr, UPROBE_BKPT_INSN); + return write_opcode(auprobe, mm, vaddr, UPROBE_BKPT_INSN); } /** * set_orig_insn - Restore the original instruction. * @mm: the probed process address space. - * @uprobe: the probepoint information. + * @auprobe: arch specific probepoint information. * @vaddr: the virtual address to insert the opcode. * @verify: if true, verify existance of breakpoint instruction. * @@ -366,7 +366,7 @@ int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned * Return 0 (success) or a negative errno. */ int __weak -set_orig_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr, bool verify) +set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, bool verify) { if (verify) { int result; @@ -378,7 +378,7 @@ set_orig_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long v if (result != 1) return result; } - return write_opcode(mm, auprobe, vaddr, *(uprobe_opcode_t *)auprobe->insn); + return write_opcode(auprobe, mm, vaddr, *(uprobe_opcode_t *)auprobe->insn); } static int match_uprobe(struct uprobe *l, struct uprobe *r) @@ -525,30 +525,30 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset) /* Returns the previous consumer */ static struct uprobe_consumer * -consumer_add(struct uprobe *uprobe, struct uprobe_consumer *consumer) +consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc) { down_write(&uprobe->consumer_rwsem); - consumer->next = uprobe->consumers; - uprobe->consumers = consumer; + uc->next = uprobe->consumers; + uprobe->consumers = uc; up_write(&uprobe->consumer_rwsem); - return consumer->next; + return uc->next; } /* - * For uprobe @uprobe, delete the consumer @consumer. - * Return true if the @consumer is deleted successfully + * For uprobe @uprobe, delete the consumer @uc. + * Return true if the @uc is deleted successfully * or return false. */ -static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *consumer) +static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *uc) { struct uprobe_consumer **con; bool ret = false; down_write(&uprobe->consumer_rwsem); for (con = &uprobe->consumers; *con; con = &(*con)->next) { - if (*con == consumer) { - *con = consumer->next; + if (*con == uc) { + *con = uc->next; ret = true; break; } @@ -558,8 +558,8 @@ static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *consumer return ret; } -static int __copy_insn(struct address_space *mapping, - struct vm_area_struct *vma, char *insn, +static int +__copy_insn(struct address_space *mapping, struct vm_area_struct *vma, char *insn, unsigned long nbytes, unsigned long offset) { struct file *filp = vma->vm_file; @@ -590,7 +590,8 @@ static int __copy_insn(struct address_space *mapping, return 0; } -static int copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr) +static int +copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr) { struct address_space *mapping; unsigned long nbytes; @@ -617,8 +618,9 @@ static int copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned return __copy_insn(mapping, vma, uprobe->arch.insn, bytes, uprobe->offset); } -static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, - struct vm_area_struct *vma, loff_t vaddr) +static int +install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, + struct vm_area_struct *vma, loff_t vaddr) { unsigned long addr; int ret; @@ -643,20 +645,21 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, if (is_bkpt_insn((uprobe_opcode_t *)uprobe->arch.insn)) return -EEXIST; - ret = arch_uprobes_analyze_insn(mm, &uprobe->arch); + ret = arch_uprobes_analyze_insn(&uprobe->arch, mm); if (ret) return ret; uprobe->flags |= UPROBE_COPY_INSN; } - ret = set_bkpt(mm, &uprobe->arch, addr); + ret = set_bkpt(&uprobe->arch, mm, addr); return ret; } -static void remove_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, loff_t vaddr) +static void +remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, loff_t vaddr) { - set_orig_insn(mm, &uprobe->arch, (unsigned long)vaddr, true); + set_orig_insn(&uprobe->arch, mm, (unsigned long)vaddr, true); } static void delete_uprobe(struct uprobe *uprobe) @@ -671,9 +674,9 @@ static void delete_uprobe(struct uprobe *uprobe) atomic_dec(&uprobe_events); } -static struct vma_info *__find_next_vma_info(struct list_head *head, - loff_t offset, struct address_space *mapping, - struct vma_info *vi, bool is_register) +static struct vma_info * +__find_next_vma_info(struct address_space *mapping, struct list_head *head, + struct vma_info *vi, loff_t offset, bool is_register) { struct prio_tree_iter iter; struct vm_area_struct *vma; @@ -719,8 +722,8 @@ static struct vma_info *__find_next_vma_info(struct list_head *head, * yet been inserted. */ static struct vma_info * -find_next_vma_info(struct list_head *head, loff_t offset, struct address_space *mapping, - bool is_register) +find_next_vma_info(struct address_space *mapping, struct list_head *head, + loff_t offset, bool is_register) { struct vma_info *vi, *retvi; @@ -729,7 +732,7 @@ find_next_vma_info(struct list_head *head, loff_t offset, struct address_space * return ERR_PTR(-ENOMEM); mutex_lock(&mapping->i_mmap_mutex); - retvi = __find_next_vma_info(head, offset, mapping, vi, is_register); + retvi = __find_next_vma_info(mapping, head, vi, offset, is_register); mutex_unlock(&mapping->i_mmap_mutex); if (!retvi) @@ -754,7 +757,7 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register) ret = 0; for (;;) { - vi = find_next_vma_info(&try_list, uprobe->offset, mapping, is_register); + vi = find_next_vma_info(mapping, &try_list, uprobe->offset, is_register); if (!vi) break; @@ -784,9 +787,9 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register) } if (is_register) - ret = install_breakpoint(mm, uprobe, vma, vi->vaddr); + ret = install_breakpoint(uprobe, mm, vma, vi->vaddr); else - remove_breakpoint(mm, uprobe, vi->vaddr); + remove_breakpoint(uprobe, mm, vi->vaddr); up_read(&mm->mmap_sem); mmput(mm); @@ -823,25 +826,25 @@ static void __uprobe_unregister(struct uprobe *uprobe) * uprobe_register - register a probe * @inode: the file in which the probe has to be placed. * @offset: offset from the start of the file. - * @consumer: information on howto handle the probe.. + * @uc: information on howto handle the probe.. * * Apart from the access refcount, uprobe_register() takes a creation * refcount (thro alloc_uprobe) if and only if this @uprobe is getting * inserted into the rbtree (i.e first consumer for a @inode:@offset * tuple). Creation refcount stops uprobe_unregister from freeing the * @uprobe even before the register operation is complete. Creation - * refcount is released when the last @consumer for the @uprobe + * refcount is released when the last @uc for the @uprobe * unregisters. * * Return errno if it cannot successully install probes * else return 0 (success) */ -int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer) +int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) { struct uprobe *uprobe; int ret; - if (!inode || !consumer || consumer->next) + if (!inode || !uc || uc->next) return -EINVAL; if (offset > i_size_read(inode)) @@ -851,7 +854,7 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer * mutex_lock(uprobes_hash(inode)); uprobe = alloc_uprobe(inode, offset); - if (uprobe && !consumer_add(uprobe, consumer)) { + if (uprobe && !consumer_add(uprobe, uc)) { ret = __uprobe_register(uprobe); if (ret) { uprobe->consumers = NULL; @@ -871,13 +874,13 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer * * uprobe_unregister - unregister a already registered probe. * @inode: the file in which the probe has to be removed. * @offset: offset from the start of the file. - * @consumer: identify which probe if multiple probes are colocated. + * @uc: identify which probe if multiple probes are colocated. */ -void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer) +void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) { struct uprobe *uprobe; - if (!inode || !consumer) + if (!inode || !uc) return; uprobe = find_uprobe(inode, offset); @@ -886,7 +889,7 @@ void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consume mutex_lock(uprobes_hash(inode)); - if (consumer_del(uprobe, consumer)) { + if (consumer_del(uprobe, uc)) { if (!uprobe->consumers) { __uprobe_unregister(uprobe); uprobe->flags &= ~UPROBE_RUN_HANDLER; @@ -993,7 +996,7 @@ int uprobe_mmap(struct vm_area_struct *vma) if (!ret) { vaddr = vma_address(vma, uprobe->offset); if (vaddr >= vma->vm_start && vaddr < vma->vm_end) { - ret = install_breakpoint(vma->vm_mm, uprobe, vma, vaddr); + ret = install_breakpoint(uprobe, vma->vm_mm, vma, vaddr); /* Ignore double add: */ if (ret == -EEXIST) ret = 0; -- cgit v1.2.3 From 5cb4ac3a583d4ee18c8682ab857e093c4a0d0895 Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Mon, 12 Mar 2012 14:55:45 +0530 Subject: uprobes/core: Rename bkpt to swbp bkpt doesnt seem to be a correct abbrevation for breakpoint. Choice was between bp and breakpoint. Since bp can refer to things other than breakpoint, use swbp to refer to breakpoints. This is pure cleanup, no functional change intended. Signed-off-by: Srikar Dronamraju Cc: Linus Torvalds Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Linux-mm Cc: Oleg Nesterov Cc: Andi Kleen Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120312092545.5379.91251.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/uprobes.h | 4 ++-- include/linux/uprobes.h | 4 ++-- kernel/events/uprobes.c | 34 +++++++++++++++++----------------- 3 files changed, 21 insertions(+), 21 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 384f1bebf884..0500391f57d0 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -28,8 +28,8 @@ typedef u8 uprobe_opcode_t; #define MAX_UINSN_BYTES 16 #define UPROBE_XOL_SLOT_BYTES 128 /* to keep it cache aligned */ -#define UPROBE_BKPT_INSN 0xcc -#define UPROBE_BKPT_INSN_SIZE 1 +#define UPROBE_SWBP_INSN 0xcc +#define UPROBE_SWBP_INSN_SIZE 1 struct arch_uprobe { u16 fixups; diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 58699182e9a7..eac525f41b94 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -52,9 +52,9 @@ struct uprobe_consumer { }; #ifdef CONFIG_UPROBES -extern int __weak set_bkpt(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr); +extern int __weak set_swbp(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr); extern int __weak set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr, bool verify); -extern bool __weak is_bkpt_insn(uprobe_opcode_t *insn); +extern bool __weak is_swbp_insn(uprobe_opcode_t *insn); extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); extern int uprobe_mmap(struct vm_area_struct *vma); diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 9c5ddff1c8da..e56e56aa7535 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -170,14 +170,14 @@ out: } /** - * is_bkpt_insn - check if instruction is breakpoint instruction. + * is_swbp_insn - check if instruction is breakpoint instruction. * @insn: instruction to be checked. - * Default implementation of is_bkpt_insn + * Default implementation of is_swbp_insn * Returns true if @insn is a breakpoint instruction. */ -bool __weak is_bkpt_insn(uprobe_opcode_t *insn) +bool __weak is_swbp_insn(uprobe_opcode_t *insn) { - return *insn == UPROBE_BKPT_INSN; + return *insn == UPROBE_SWBP_INSN; } /* @@ -227,7 +227,7 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, * adding probes in write mapped pages since the breakpoints * might end up in the file copy. */ - if (!valid_vma(vma, is_bkpt_insn(&opcode))) + if (!valid_vma(vma, is_swbp_insn(&opcode))) goto put_out; uprobe = container_of(auprobe, struct uprobe, arch); @@ -259,8 +259,8 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, /* poke the new insn in, ASSUMES we don't cross page boundary */ vaddr &= ~PAGE_MASK; - BUG_ON(vaddr + UPROBE_BKPT_INSN_SIZE > PAGE_SIZE); - memcpy(vaddr_new + vaddr, &opcode, UPROBE_BKPT_INSN_SIZE); + BUG_ON(vaddr + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); + memcpy(vaddr_new + vaddr, &opcode, UPROBE_SWBP_INSN_SIZE); kunmap_atomic(vaddr_new); kunmap_atomic(vaddr_old); @@ -308,7 +308,7 @@ static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_ lock_page(page); vaddr_new = kmap_atomic(page); vaddr &= ~PAGE_MASK; - memcpy(opcode, vaddr_new + vaddr, UPROBE_BKPT_INSN_SIZE); + memcpy(opcode, vaddr_new + vaddr, UPROBE_SWBP_INSN_SIZE); kunmap_atomic(vaddr_new); unlock_page(page); @@ -317,7 +317,7 @@ static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_ return 0; } -static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr) +static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr) { uprobe_opcode_t opcode; int result; @@ -326,14 +326,14 @@ static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr) if (result) return result; - if (is_bkpt_insn(&opcode)) + if (is_swbp_insn(&opcode)) return 1; return 0; } /** - * set_bkpt - store breakpoint at a given address. + * set_swbp - store breakpoint at a given address. * @auprobe: arch specific probepoint information. * @mm: the probed process address space. * @vaddr: the virtual address to insert the opcode. @@ -341,18 +341,18 @@ static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr) * For mm @mm, store the breakpoint instruction at @vaddr. * Return 0 (success) or a negative errno. */ -int __weak set_bkpt(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) +int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) { int result; - result = is_bkpt_at_addr(mm, vaddr); + result = is_swbp_at_addr(mm, vaddr); if (result == 1) return -EEXIST; if (result) return result; - return write_opcode(auprobe, mm, vaddr, UPROBE_BKPT_INSN); + return write_opcode(auprobe, mm, vaddr, UPROBE_SWBP_INSN); } /** @@ -371,7 +371,7 @@ set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long v if (verify) { int result; - result = is_bkpt_at_addr(mm, vaddr); + result = is_swbp_at_addr(mm, vaddr); if (!result) return -EINVAL; @@ -642,7 +642,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, if (ret) return ret; - if (is_bkpt_insn((uprobe_opcode_t *)uprobe->arch.insn)) + if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn)) return -EEXIST; ret = arch_uprobes_analyze_insn(&uprobe->arch, mm); @@ -651,7 +651,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, uprobe->flags |= UPROBE_COPY_INSN; } - ret = set_bkpt(&uprobe->arch, mm, addr); + ret = set_swbp(&uprobe->arch, mm, addr); return ret; } -- cgit v1.2.3 From 0326f5a94ddea33fa331b2519f4172f4fb387baa Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Tue, 13 Mar 2012 23:30:11 +0530 Subject: uprobes/core: Handle breakpoint and singlestep exceptions Uprobes uses exception notifiers to get to know if a thread hit a breakpoint or a singlestep exception. When a thread hits a uprobe or is singlestepping post a uprobe hit, the uprobe exception notifier sets its TIF_UPROBE bit, which will then be checked on its return to userspace path (do_notify_resume() ->uprobe_notify_resume()), where the consumers handlers are run (in task context) based on the defined filters. Uprobe hits are thread specific and hence we need to maintain information about if a task hit a uprobe, what uprobe was hit, the slot where the original instruction was copied for xol so that it can be singlestepped with appropriate fixups. In some cases, special care is needed for instructions that are executed out of line (xol). These are architecture specific artefacts, such as handling RIP relative instructions on x86_64. Since the instruction at which the uprobe was inserted is executed out of line, architecture specific fixups are added so that the thread continues normal execution in the presence of a uprobe. Postpone the signals until we execute the probed insn. post_xol() path does a recalc_sigpending() before return to user-mode, this ensures the signal can't be lost. Uprobes relies on DIE_DEBUG notification to notify if a singlestep is complete. Adds x86 specific uprobe exception notifiers and appropriate hooks needed to determine a uprobe hit and subsequent post processing. Add requisite x86 fixups for xol for uprobes. Specific cases needing fixups include relative jumps (x86_64), calls, etc. Where possible, we check and skip singlestepping the breakpointed instructions. For now we skip single byte as well as few multibyte nop instructions. However this can be extended to other instructions too. Credits to Oleg Nesterov for suggestions/patches related to signal, breakpoint, singlestep handling code. Signed-off-by: Srikar Dronamraju Cc: Linus Torvalds Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Linux-mm Cc: Oleg Nesterov Cc: Andi Kleen Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120313180011.29771.89027.sendpatchset@srdronam.in.ibm.com [ Performed various cleanliness edits ] Signed-off-by: Ingo Molnar --- arch/x86/include/asm/thread_info.h | 2 + arch/x86/include/asm/uprobes.h | 16 +- arch/x86/kernel/signal.c | 6 + arch/x86/kernel/uprobes.c | 265 +++++++++++++++++++++++++++++- include/linux/sched.h | 4 + include/linux/uprobes.h | 55 ++++++- kernel/events/uprobes.c | 323 ++++++++++++++++++++++++++++++++++++- kernel/fork.c | 4 + kernel/signal.c | 4 + 9 files changed, 664 insertions(+), 15 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index ad6df8ccd715..0710c11305d4 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -85,6 +85,7 @@ struct thread_info { #define TIF_SECCOMP 8 /* secure computing */ #define TIF_MCE_NOTIFY 10 /* notify userspace of an MCE */ #define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */ +#define TIF_UPROBE 12 /* breakpointed or singlestepping */ #define TIF_NOTSC 16 /* TSC is not accessible in userland */ #define TIF_IA32 17 /* IA32 compatibility process */ #define TIF_FORK 18 /* ret_from_fork */ @@ -109,6 +110,7 @@ struct thread_info { #define _TIF_SECCOMP (1 << TIF_SECCOMP) #define _TIF_MCE_NOTIFY (1 << TIF_MCE_NOTIFY) #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY) +#define _TIF_UPROBE (1 << TIF_UPROBE) #define _TIF_NOTSC (1 << TIF_NOTSC) #define _TIF_IA32 (1 << TIF_IA32) #define _TIF_FORK (1 << TIF_FORK) diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 0500391f57d0..1e9bed14f7ae 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -23,6 +23,8 @@ * Jim Keniston */ +#include + typedef u8 uprobe_opcode_t; #define MAX_UINSN_BYTES 16 @@ -39,5 +41,17 @@ struct arch_uprobe { #endif }; -extern int arch_uprobes_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm); +struct arch_uprobe_task { + unsigned long saved_trap_nr; +#ifdef CONFIG_X86_64 + unsigned long saved_scratch_register; +#endif +}; + +extern int arch_uprobe_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm); +extern int arch_uprobe_pre_xol(struct arch_uprobe *aup, struct pt_regs *regs); +extern int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs); +extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk); +extern int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data); +extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs); #endif /* _ASM_UPROBES_H */ diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 9c73acc1c860..b3cd6913ceea 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include @@ -823,6 +824,11 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) mce_notify_process(); #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */ + if (thread_info_flags & _TIF_UPROBE) { + clear_thread_flag(TIF_UPROBE); + uprobe_notify_resume(regs); + } + /* deal with pending signal delivery */ if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 851a11b0d38c..dc4e910a7d96 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -24,22 +24,28 @@ #include #include #include +#include #include +#include #include /* Post-execution fixups. */ /* No fixup needed */ -#define UPROBE_FIX_NONE 0x0 +#define UPROBE_FIX_NONE 0x0 + /* Adjust IP back to vicinity of actual insn */ #define UPROBE_FIX_IP 0x1 + /* Adjust the return address of a call insn */ #define UPROBE_FIX_CALL 0x2 #define UPROBE_FIX_RIP_AX 0x8000 #define UPROBE_FIX_RIP_CX 0x4000 +#define UPROBE_TRAP_NR UINT_MAX + /* Adaptations for mhiramat x86 decoder v14. */ #define OPCODE1(insn) ((insn)->opcode.bytes[0]) #define OPCODE2(insn) ((insn)->opcode.bytes[1]) @@ -221,10 +227,9 @@ static int validate_insn_32bits(struct arch_uprobe *auprobe, struct insn *insn) } /* - * Figure out which fixups post_xol() will need to perform, and annotate - * arch_uprobe->fixups accordingly. To start with, - * arch_uprobe->fixups is either zero or it reflects rip-related - * fixups. + * Figure out which fixups arch_uprobe_post_xol() will need to perform, and + * annotate arch_uprobe->fixups accordingly. To start with, + * arch_uprobe->fixups is either zero or it reflects rip-related fixups. */ static void prepare_fixups(struct arch_uprobe *auprobe, struct insn *insn) { @@ -401,12 +406,12 @@ static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm, #endif /* CONFIG_X86_64 */ /** - * arch_uprobes_analyze_insn - instruction analysis including validity and fixups. + * arch_uprobe_analyze_insn - instruction analysis including validity and fixups. * @mm: the probed address space. * @arch_uprobe: the probepoint information. * Return 0 on success or a -ve number on error. */ -int arch_uprobes_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm) +int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm) { int ret; struct insn insn; @@ -421,3 +426,249 @@ int arch_uprobes_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm) return 0; } + +#ifdef CONFIG_X86_64 +/* + * If we're emulating a rip-relative instruction, save the contents + * of the scratch register and store the target address in that register. + */ +static void +pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs, + struct arch_uprobe_task *autask) +{ + if (auprobe->fixups & UPROBE_FIX_RIP_AX) { + autask->saved_scratch_register = regs->ax; + regs->ax = current->utask->vaddr; + regs->ax += auprobe->rip_rela_target_address; + } else if (auprobe->fixups & UPROBE_FIX_RIP_CX) { + autask->saved_scratch_register = regs->cx; + regs->cx = current->utask->vaddr; + regs->cx += auprobe->rip_rela_target_address; + } +} +#else +static void +pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs, + struct arch_uprobe_task *autask) +{ + /* No RIP-relative addressing on 32-bit */ +} +#endif + +/* + * arch_uprobe_pre_xol - prepare to execute out of line. + * @auprobe: the probepoint information. + * @regs: reflects the saved user state of current task. + */ +int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + struct arch_uprobe_task *autask; + + autask = ¤t->utask->autask; + autask->saved_trap_nr = current->thread.trap_nr; + current->thread.trap_nr = UPROBE_TRAP_NR; + regs->ip = current->utask->xol_vaddr; + pre_xol_rip_insn(auprobe, regs, autask); + + return 0; +} + +/* + * This function is called by arch_uprobe_post_xol() to adjust the return + * address pushed by a call instruction executed out of line. + */ +static int adjust_ret_addr(unsigned long sp, long correction) +{ + int rasize, ncopied; + long ra = 0; + + if (is_ia32_task()) + rasize = 4; + else + rasize = 8; + + ncopied = copy_from_user(&ra, (void __user *)sp, rasize); + if (unlikely(ncopied)) + return -EFAULT; + + ra += correction; + ncopied = copy_to_user((void __user *)sp, &ra, rasize); + if (unlikely(ncopied)) + return -EFAULT; + + return 0; +} + +#ifdef CONFIG_X86_64 +static bool is_riprel_insn(struct arch_uprobe *auprobe) +{ + return ((auprobe->fixups & (UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX)) != 0); +} + +static void +handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction) +{ + if (is_riprel_insn(auprobe)) { + struct arch_uprobe_task *autask; + + autask = ¤t->utask->autask; + if (auprobe->fixups & UPROBE_FIX_RIP_AX) + regs->ax = autask->saved_scratch_register; + else + regs->cx = autask->saved_scratch_register; + + /* + * The original instruction includes a displacement, and so + * is 4 bytes longer than what we've just single-stepped. + * Fall through to handle stuff like "jmpq *...(%rip)" and + * "callq *...(%rip)". + */ + if (correction) + *correction += 4; + } +} +#else +static void +handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction) +{ + /* No RIP-relative addressing on 32-bit */ +} +#endif + +/* + * If xol insn itself traps and generates a signal(Say, + * SIGILL/SIGSEGV/etc), then detect the case where a singlestepped + * instruction jumps back to its own address. It is assumed that anything + * like do_page_fault/do_trap/etc sets thread.trap_nr != -1. + * + * arch_uprobe_pre_xol/arch_uprobe_post_xol save/restore thread.trap_nr, + * arch_uprobe_xol_was_trapped() simply checks that ->trap_nr is not equal to + * UPROBE_TRAP_NR == -1 set by arch_uprobe_pre_xol(). + */ +bool arch_uprobe_xol_was_trapped(struct task_struct *t) +{ + if (t->thread.trap_nr != UPROBE_TRAP_NR) + return true; + + return false; +} + +/* + * Called after single-stepping. To avoid the SMP problems that can + * occur when we temporarily put back the original opcode to + * single-step, we single-stepped a copy of the instruction. + * + * This function prepares to resume execution after the single-step. + * We have to fix things up as follows: + * + * Typically, the new ip is relative to the copied instruction. We need + * to make it relative to the original instruction (FIX_IP). Exceptions + * are return instructions and absolute or indirect jump or call instructions. + * + * If the single-stepped instruction was a call, the return address that + * is atop the stack is the address following the copied instruction. We + * need to make it the address following the original instruction (FIX_CALL). + * + * If the original instruction was a rip-relative instruction such as + * "movl %edx,0xnnnn(%rip)", we have instead executed an equivalent + * instruction using a scratch register -- e.g., "movl %edx,(%rax)". + * We need to restore the contents of the scratch register and adjust + * the ip, keeping in mind that the instruction we executed is 4 bytes + * shorter than the original instruction (since we squeezed out the offset + * field). (FIX_RIP_AX or FIX_RIP_CX) + */ +int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + struct uprobe_task *utask; + long correction; + int result = 0; + + WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR); + + utask = current->utask; + current->thread.trap_nr = utask->autask.saved_trap_nr; + correction = (long)(utask->vaddr - utask->xol_vaddr); + handle_riprel_post_xol(auprobe, regs, &correction); + if (auprobe->fixups & UPROBE_FIX_IP) + regs->ip += correction; + + if (auprobe->fixups & UPROBE_FIX_CALL) + result = adjust_ret_addr(regs->sp, correction); + + return result; +} + +/* callback routine for handling exceptions. */ +int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data) +{ + struct die_args *args = data; + struct pt_regs *regs = args->regs; + int ret = NOTIFY_DONE; + + /* We are only interested in userspace traps */ + if (regs && !user_mode_vm(regs)) + return NOTIFY_DONE; + + switch (val) { + case DIE_INT3: + if (uprobe_pre_sstep_notifier(regs)) + ret = NOTIFY_STOP; + + break; + + case DIE_DEBUG: + if (uprobe_post_sstep_notifier(regs)) + ret = NOTIFY_STOP; + + default: + break; + } + + return ret; +} + +/* + * This function gets called when XOL instruction either gets trapped or + * the thread has a fatal signal, so reset the instruction pointer to its + * probed address. + */ +void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + struct uprobe_task *utask = current->utask; + + current->thread.trap_nr = utask->autask.saved_trap_nr; + handle_riprel_post_xol(auprobe, regs, NULL); + instruction_pointer_set(regs, utask->vaddr); +} + +/* + * Skip these instructions as per the currently known x86 ISA. + * 0x66* { 0x90 | 0x0f 0x1f | 0x0f 0x19 | 0x87 0xc0 } + */ +bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + int i; + + for (i = 0; i < MAX_UINSN_BYTES; i++) { + if ((auprobe->insn[i] == 0x66)) + continue; + + if (auprobe->insn[i] == 0x90) + return true; + + if (i == (MAX_UINSN_BYTES - 1)) + break; + + if ((auprobe->insn[i] == 0x0f) && (auprobe->insn[i+1] == 0x1f)) + return true; + + if ((auprobe->insn[i] == 0x0f) && (auprobe->insn[i+1] == 0x19)) + return true; + + if ((auprobe->insn[i] == 0x87) && (auprobe->insn[i+1] == 0xc0)) + return true; + + break; + } + return false; +} diff --git a/include/linux/sched.h b/include/linux/sched.h index 7d379a6bfd88..8379e3771690 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1590,6 +1590,10 @@ struct task_struct { #ifdef CONFIG_HAVE_HW_BREAKPOINT atomic_t ptrace_bp_refcnt; #endif +#ifdef CONFIG_UPROBES + struct uprobe_task *utask; + int uprobe_srcu_id; +#endif }; /* Future-safe accessor for struct task_struct's cpus_allowed. */ diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index eac525f41b94..5ec778fdce6f 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -28,8 +28,9 @@ #include struct vm_area_struct; + #ifdef CONFIG_ARCH_SUPPORTS_UPROBES -#include +# include #endif /* flags that denote/change uprobes behaviour */ @@ -39,6 +40,8 @@ struct vm_area_struct; /* Dont run handlers when first register/ last unregister in progress*/ #define UPROBE_RUN_HANDLER 0x2 +/* Can skip singlestep */ +#define UPROBE_SKIP_SSTEP 0x4 struct uprobe_consumer { int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs); @@ -52,13 +55,42 @@ struct uprobe_consumer { }; #ifdef CONFIG_UPROBES +enum uprobe_task_state { + UTASK_RUNNING, + UTASK_BP_HIT, + UTASK_SSTEP, + UTASK_SSTEP_ACK, + UTASK_SSTEP_TRAPPED, +}; + +/* + * uprobe_task: Metadata of a task while it singlesteps. + */ +struct uprobe_task { + enum uprobe_task_state state; + struct arch_uprobe_task autask; + + struct uprobe *active_uprobe; + + unsigned long xol_vaddr; + unsigned long vaddr; +}; + extern int __weak set_swbp(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr); extern int __weak set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr, bool verify); extern bool __weak is_swbp_insn(uprobe_opcode_t *insn); extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); extern int uprobe_mmap(struct vm_area_struct *vma); -#else /* CONFIG_UPROBES is not defined */ +extern void uprobe_free_utask(struct task_struct *t); +extern void uprobe_copy_process(struct task_struct *t); +extern unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs); +extern int uprobe_post_sstep_notifier(struct pt_regs *regs); +extern int uprobe_pre_sstep_notifier(struct pt_regs *regs); +extern void uprobe_notify_resume(struct pt_regs *regs); +extern bool uprobe_deny_signal(void); +extern bool __weak arch_uprobe_skip_sstep(struct arch_uprobe *aup, struct pt_regs *regs); +#else /* !CONFIG_UPROBES */ static inline int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) { @@ -72,5 +104,22 @@ static inline int uprobe_mmap(struct vm_area_struct *vma) { return 0; } -#endif /* CONFIG_UPROBES */ +static inline void uprobe_notify_resume(struct pt_regs *regs) +{ +} +static inline bool uprobe_deny_signal(void) +{ + return false; +} +static inline unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) +{ + return 0; +} +static inline void uprobe_free_utask(struct task_struct *t) +{ +} +static inline void uprobe_copy_process(struct task_struct *t) +{ +} +#endif /* !CONFIG_UPROBES */ #endif /* _LINUX_UPROBES_H */ diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index e56e56aa7535..b807d1566b64 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -30,9 +30,12 @@ #include /* anon_vma_prepare */ #include /* set_pte_at_notify */ #include /* try_to_free_swap */ +#include /* user_enable_single_step */ +#include /* notifier mechanism */ #include +static struct srcu_struct uprobes_srcu; static struct rb_root uprobes_tree = RB_ROOT; static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */ @@ -486,6 +489,9 @@ static struct uprobe *insert_uprobe(struct uprobe *uprobe) u = __insert_uprobe(uprobe); spin_unlock_irqrestore(&uprobes_treelock, flags); + /* For now assume that the instruction need not be single-stepped */ + uprobe->flags |= UPROBE_SKIP_SSTEP; + return u; } @@ -523,6 +529,21 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset) return uprobe; } +static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs) +{ + struct uprobe_consumer *uc; + + if (!(uprobe->flags & UPROBE_RUN_HANDLER)) + return; + + down_read(&uprobe->consumer_rwsem); + for (uc = uprobe->consumers; uc; uc = uc->next) { + if (!uc->filter || uc->filter(uc, current)) + uc->handler(uc, regs); + } + up_read(&uprobe->consumer_rwsem); +} + /* Returns the previous consumer */ static struct uprobe_consumer * consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc) @@ -645,7 +666,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn)) return -EEXIST; - ret = arch_uprobes_analyze_insn(&uprobe->arch, mm); + ret = arch_uprobe_analyze_insn(&uprobe->arch, mm); if (ret) return ret; @@ -662,10 +683,21 @@ remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, loff_t vaddr) set_orig_insn(&uprobe->arch, mm, (unsigned long)vaddr, true); } +/* + * There could be threads that have hit the breakpoint and are entering the + * notifier code and trying to acquire the uprobes_treelock. The thread + * calling delete_uprobe() that is removing the uprobe from the rb_tree can + * race with these threads and might acquire the uprobes_treelock compared + * to some of the breakpoint hit threads. In such a case, the breakpoint + * hit threads will not find the uprobe. The current unregistering thread + * waits till all other threads have hit a breakpoint, to acquire the + * uprobes_treelock before the uprobe is removed from the rbtree. + */ static void delete_uprobe(struct uprobe *uprobe) { unsigned long flags; + synchronize_srcu(&uprobes_srcu); spin_lock_irqsave(&uprobes_treelock, flags); rb_erase(&uprobe->rb_node, &uprobes_tree); spin_unlock_irqrestore(&uprobes_treelock, flags); @@ -1010,6 +1042,288 @@ int uprobe_mmap(struct vm_area_struct *vma) return ret; } +/** + * uprobe_get_swbp_addr - compute address of swbp given post-swbp regs + * @regs: Reflects the saved state of the task after it has hit a breakpoint + * instruction. + * Return the address of the breakpoint instruction. + */ +unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs) +{ + return instruction_pointer(regs) - UPROBE_SWBP_INSN_SIZE; +} + +/* + * Called with no locks held. + * Called in context of a exiting or a exec-ing thread. + */ +void uprobe_free_utask(struct task_struct *t) +{ + struct uprobe_task *utask = t->utask; + + if (t->uprobe_srcu_id != -1) + srcu_read_unlock_raw(&uprobes_srcu, t->uprobe_srcu_id); + + if (!utask) + return; + + if (utask->active_uprobe) + put_uprobe(utask->active_uprobe); + + kfree(utask); + t->utask = NULL; +} + +/* + * Called in context of a new clone/fork from copy_process. + */ +void uprobe_copy_process(struct task_struct *t) +{ + t->utask = NULL; + t->uprobe_srcu_id = -1; +} + +/* + * Allocate a uprobe_task object for the task. + * Called when the thread hits a breakpoint for the first time. + * + * Returns: + * - pointer to new uprobe_task on success + * - NULL otherwise + */ +static struct uprobe_task *add_utask(void) +{ + struct uprobe_task *utask; + + utask = kzalloc(sizeof *utask, GFP_KERNEL); + if (unlikely(!utask)) + return NULL; + + utask->active_uprobe = NULL; + current->utask = utask; + return utask; +} + +/* Prepare to single-step probed instruction out of line. */ +static int +pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long vaddr) +{ + return -EFAULT; +} + +/* + * If we are singlestepping, then ensure this thread is not connected to + * non-fatal signals until completion of singlestep. When xol insn itself + * triggers the signal, restart the original insn even if the task is + * already SIGKILL'ed (since coredump should report the correct ip). This + * is even more important if the task has a handler for SIGSEGV/etc, The + * _same_ instruction should be repeated again after return from the signal + * handler, and SSTEP can never finish in this case. + */ +bool uprobe_deny_signal(void) +{ + struct task_struct *t = current; + struct uprobe_task *utask = t->utask; + + if (likely(!utask || !utask->active_uprobe)) + return false; + + WARN_ON_ONCE(utask->state != UTASK_SSTEP); + + if (signal_pending(t)) { + spin_lock_irq(&t->sighand->siglock); + clear_tsk_thread_flag(t, TIF_SIGPENDING); + spin_unlock_irq(&t->sighand->siglock); + + if (__fatal_signal_pending(t) || arch_uprobe_xol_was_trapped(t)) { + utask->state = UTASK_SSTEP_TRAPPED; + set_tsk_thread_flag(t, TIF_UPROBE); + set_tsk_thread_flag(t, TIF_NOTIFY_RESUME); + } + } + + return true; +} + +/* + * Avoid singlestepping the original instruction if the original instruction + * is a NOP or can be emulated. + */ +static bool can_skip_sstep(struct uprobe *uprobe, struct pt_regs *regs) +{ + if (arch_uprobe_skip_sstep(&uprobe->arch, regs)) + return true; + + uprobe->flags &= ~UPROBE_SKIP_SSTEP; + return false; +} + +/* + * Run handler and ask thread to singlestep. + * Ensure all non-fatal signals cannot interrupt thread while it singlesteps. + */ +static void handle_swbp(struct pt_regs *regs) +{ + struct vm_area_struct *vma; + struct uprobe_task *utask; + struct uprobe *uprobe; + struct mm_struct *mm; + unsigned long bp_vaddr; + + uprobe = NULL; + bp_vaddr = uprobe_get_swbp_addr(regs); + mm = current->mm; + down_read(&mm->mmap_sem); + vma = find_vma(mm, bp_vaddr); + + if (vma && vma->vm_start <= bp_vaddr && valid_vma(vma, false)) { + struct inode *inode; + loff_t offset; + + inode = vma->vm_file->f_mapping->host; + offset = bp_vaddr - vma->vm_start; + offset += (vma->vm_pgoff << PAGE_SHIFT); + uprobe = find_uprobe(inode, offset); + } + + srcu_read_unlock_raw(&uprobes_srcu, current->uprobe_srcu_id); + current->uprobe_srcu_id = -1; + up_read(&mm->mmap_sem); + + if (!uprobe) { + /* No matching uprobe; signal SIGTRAP. */ + send_sig(SIGTRAP, current, 0); + return; + } + + utask = current->utask; + if (!utask) { + utask = add_utask(); + /* Cannot allocate; re-execute the instruction. */ + if (!utask) + goto cleanup_ret; + } + utask->active_uprobe = uprobe; + handler_chain(uprobe, regs); + if (uprobe->flags & UPROBE_SKIP_SSTEP && can_skip_sstep(uprobe, regs)) + goto cleanup_ret; + + utask->state = UTASK_SSTEP; + if (!pre_ssout(uprobe, regs, bp_vaddr)) { + user_enable_single_step(current); + return; + } + +cleanup_ret: + if (utask) { + utask->active_uprobe = NULL; + utask->state = UTASK_RUNNING; + } + if (uprobe) { + if (!(uprobe->flags & UPROBE_SKIP_SSTEP)) + + /* + * cannot singlestep; cannot skip instruction; + * re-execute the instruction. + */ + instruction_pointer_set(regs, bp_vaddr); + + put_uprobe(uprobe); + } +} + +/* + * Perform required fix-ups and disable singlestep. + * Allow pending signals to take effect. + */ +static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs) +{ + struct uprobe *uprobe; + + uprobe = utask->active_uprobe; + if (utask->state == UTASK_SSTEP_ACK) + arch_uprobe_post_xol(&uprobe->arch, regs); + else if (utask->state == UTASK_SSTEP_TRAPPED) + arch_uprobe_abort_xol(&uprobe->arch, regs); + else + WARN_ON_ONCE(1); + + put_uprobe(uprobe); + utask->active_uprobe = NULL; + utask->state = UTASK_RUNNING; + user_disable_single_step(current); + + spin_lock_irq(¤t->sighand->siglock); + recalc_sigpending(); /* see uprobe_deny_signal() */ + spin_unlock_irq(¤t->sighand->siglock); +} + +/* + * On breakpoint hit, breakpoint notifier sets the TIF_UPROBE flag. (and on + * subsequent probe hits on the thread sets the state to UTASK_BP_HIT) and + * allows the thread to return from interrupt. + * + * On singlestep exception, singlestep notifier sets the TIF_UPROBE flag and + * also sets the state to UTASK_SSTEP_ACK and allows the thread to return from + * interrupt. + * + * While returning to userspace, thread notices the TIF_UPROBE flag and calls + * uprobe_notify_resume(). + */ +void uprobe_notify_resume(struct pt_regs *regs) +{ + struct uprobe_task *utask; + + utask = current->utask; + if (!utask || utask->state == UTASK_BP_HIT) + handle_swbp(regs); + else + handle_singlestep(utask, regs); +} + +/* + * uprobe_pre_sstep_notifier gets called from interrupt context as part of + * notifier mechanism. Set TIF_UPROBE flag and indicate breakpoint hit. + */ +int uprobe_pre_sstep_notifier(struct pt_regs *regs) +{ + struct uprobe_task *utask; + + if (!current->mm) + return 0; + + utask = current->utask; + if (utask) + utask->state = UTASK_BP_HIT; + + set_thread_flag(TIF_UPROBE); + current->uprobe_srcu_id = srcu_read_lock_raw(&uprobes_srcu); + + return 1; +} + +/* + * uprobe_post_sstep_notifier gets called in interrupt context as part of notifier + * mechanism. Set TIF_UPROBE flag and indicate completion of singlestep. + */ +int uprobe_post_sstep_notifier(struct pt_regs *regs) +{ + struct uprobe_task *utask = current->utask; + + if (!current->mm || !utask || !utask->active_uprobe) + /* task is currently not uprobed */ + return 0; + + utask->state = UTASK_SSTEP_ACK; + set_thread_flag(TIF_UPROBE); + return 1; +} + +static struct notifier_block uprobe_exception_nb = { + .notifier_call = arch_uprobe_exception_notify, + .priority = INT_MAX-1, /* notified after kprobes, kgdb */ +}; + static int __init init_uprobes(void) { int i; @@ -1018,12 +1332,13 @@ static int __init init_uprobes(void) mutex_init(&uprobes_mutex[i]); mutex_init(&uprobes_mmap_mutex[i]); } - return 0; + init_srcu_struct(&uprobes_srcu); + + return register_die_notifier(&uprobe_exception_nb); } +module_init(init_uprobes); static void __exit exit_uprobes(void) { } - -module_init(init_uprobes); module_exit(exit_uprobes); diff --git a/kernel/fork.c b/kernel/fork.c index e2cd3e2a5ae8..eb7b63334009 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -67,6 +67,7 @@ #include #include #include +#include #include #include @@ -701,6 +702,8 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm) exit_pi_state_list(tsk); #endif + uprobe_free_utask(tsk); + /* Get rid of any cached register state */ deactivate_mm(tsk, mm); @@ -1295,6 +1298,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, INIT_LIST_HEAD(&p->pi_state_list); p->pi_state_cache = NULL; #endif + uprobe_copy_process(p); /* * sigaltstack should be cleared when sharing the same VM */ diff --git a/kernel/signal.c b/kernel/signal.c index 8511e39813c7..e93ff0a719a0 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -29,6 +29,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include @@ -2192,6 +2193,9 @@ int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, struct signal_struct *signal = current->signal; int signr; + if (unlikely(uprobe_deny_signal())) + return 0; + relock: /* * We'll jump back here after any time we were stopped in TASK_STOPPED. -- cgit v1.2.3