diff options
Diffstat (limited to 'arch/mips/kernel')
| -rw-r--r-- | arch/mips/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/mips/kernel/ptrace.c | 88 | ||||
| -rw-r--r-- | arch/mips/kernel/signal.c | 4 | ||||
| -rw-r--r-- | arch/mips/kernel/traps.c | 12 | ||||
| -rw-r--r-- | arch/mips/kernel/uprobes.c | 341 |
5 files changed, 446 insertions, 0 deletions
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile index 3f5cf8aff6f3..a61435b1ceb1 100644 --- a/arch/mips/kernel/Makefile +++ b/arch/mips/kernel/Makefile @@ -100,6 +100,7 @@ obj-$(CONFIG_PERF_EVENTS) += perf_event.o obj-$(CONFIG_HW_PERF_EVENTS) += perf_event_mipsxx.o obj-$(CONFIG_JUMP_LABEL) += jump_label.o +obj-$(CONFIG_UPROBES) += uprobes.o obj-$(CONFIG_MIPS_CM) += mips-cm.o obj-$(CONFIG_MIPS_CPC) += mips-cpc.o diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index e933a309f2ea..4f0ac78d17f1 100644 --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -25,6 +25,7 @@ #include <linux/regset.h> #include <linux/smp.h> #include <linux/security.h> +#include <linux/stddef.h> #include <linux/tracehook.h> #include <linux/audit.h> #include <linux/seccomp.h> @@ -490,6 +491,93 @@ enum mips_regset { REGSET_FPR, }; +struct pt_regs_offset { + const char *name; + int offset; +}; + +#define REG_OFFSET_NAME(reg, r) { \ + .name = #reg, \ + .offset = offsetof(struct pt_regs, r) \ +} + +#define REG_OFFSET_END { \ + .name = NULL, \ + .offset = 0 \ +} + +static const struct pt_regs_offset regoffset_table[] = { + REG_OFFSET_NAME(r0, regs[0]), + REG_OFFSET_NAME(r1, regs[1]), + REG_OFFSET_NAME(r2, regs[2]), + REG_OFFSET_NAME(r3, regs[3]), + REG_OFFSET_NAME(r4, regs[4]), + REG_OFFSET_NAME(r5, regs[5]), + REG_OFFSET_NAME(r6, regs[6]), + REG_OFFSET_NAME(r7, regs[7]), + REG_OFFSET_NAME(r8, regs[8]), + REG_OFFSET_NAME(r9, regs[9]), + REG_OFFSET_NAME(r10, regs[10]), + REG_OFFSET_NAME(r11, regs[11]), + REG_OFFSET_NAME(r12, regs[12]), + REG_OFFSET_NAME(r13, regs[13]), + REG_OFFSET_NAME(r14, regs[14]), + REG_OFFSET_NAME(r15, regs[15]), + REG_OFFSET_NAME(r16, regs[16]), + REG_OFFSET_NAME(r17, regs[17]), + REG_OFFSET_NAME(r18, regs[18]), + REG_OFFSET_NAME(r19, regs[19]), + REG_OFFSET_NAME(r20, regs[20]), + REG_OFFSET_NAME(r21, regs[21]), + REG_OFFSET_NAME(r22, regs[22]), + REG_OFFSET_NAME(r23, regs[23]), + REG_OFFSET_NAME(r24, regs[24]), + REG_OFFSET_NAME(r25, regs[25]), + REG_OFFSET_NAME(r26, regs[26]), + REG_OFFSET_NAME(r27, regs[27]), + REG_OFFSET_NAME(r28, regs[28]), + REG_OFFSET_NAME(r29, regs[29]), + REG_OFFSET_NAME(r30, regs[30]), + REG_OFFSET_NAME(r31, regs[31]), + REG_OFFSET_NAME(c0_status, cp0_status), + REG_OFFSET_NAME(hi, hi), + REG_OFFSET_NAME(lo, lo), +#ifdef CONFIG_CPU_HAS_SMARTMIPS + REG_OFFSET_NAME(acx, acx), +#endif + REG_OFFSET_NAME(c0_badvaddr, cp0_badvaddr), + REG_OFFSET_NAME(c0_cause, cp0_cause), + REG_OFFSET_NAME(c0_epc, cp0_epc), +#ifdef CONFIG_MIPS_MT_SMTC + REG_OFFSET_NAME(c0_tcstatus, cp0_tcstatus), +#endif +#ifdef CONFIG_CPU_CAVIUM_OCTEON + REG_OFFSET_NAME(mpl0, mpl[0]), + REG_OFFSET_NAME(mpl1, mpl[1]), + REG_OFFSET_NAME(mpl2, mpl[2]), + REG_OFFSET_NAME(mtp0, mtp[0]), + REG_OFFSET_NAME(mtp1, mtp[1]), + REG_OFFSET_NAME(mtp2, mtp[2]), +#endif + REG_OFFSET_END, +}; + +/** + * regs_query_register_offset() - query register offset from its name + * @name: the name of a register + * + * regs_query_register_offset() returns the offset of a register in struct + * pt_regs from its name. If the name is invalid, this returns -EINVAL; + */ +int regs_query_register_offset(const char *name) +{ + const struct pt_regs_offset *roff; + for (roff = regoffset_table; roff->name != NULL; roff++) + if (!strcmp(roff->name, name)) + return roff->offset; + return -EINVAL; +} + #if defined(CONFIG_32BIT) || defined(CONFIG_MIPS32_O32) static const struct user_regset mips_regsets[] = { diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c index fa13a52713df..2fec67bfc457 100644 --- a/arch/mips/kernel/signal.c +++ b/arch/mips/kernel/signal.c @@ -21,6 +21,7 @@ #include <linux/wait.h> #include <linux/ptrace.h> #include <linux/unistd.h> +#include <linux/uprobes.h> #include <linux/compiler.h> #include <linux/syscalls.h> #include <linux/uaccess.h> @@ -856,6 +857,9 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused, user_exit(); + if (thread_info_flags & _TIF_UPROBE) + uprobe_notify_resume(regs); + /* deal with pending signal delivery */ if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index cea964daf400..fdb392b27e81 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -984,6 +984,18 @@ asmlinkage void do_bp(struct pt_regs *regs) * pertain to them. */ switch (bcode) { + case BRK_UPROBE: + if (notify_die(DIE_UPROBE, "uprobe", regs, bcode, + current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP) + goto out; + else + break; + case BRK_UPROBE_XOL: + if (notify_die(DIE_UPROBE_XOL, "uprobe_xol", regs, bcode, + current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP) + goto out; + else + break; case BRK_KPROBE_BP: if (notify_die(DIE_BREAK, "debug", regs, bcode, current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP) diff --git a/arch/mips/kernel/uprobes.c b/arch/mips/kernel/uprobes.c new file mode 100644 index 000000000000..8452d933a645 --- /dev/null +++ b/arch/mips/kernel/uprobes.c @@ -0,0 +1,341 @@ +#include <linux/highmem.h> +#include <linux/kdebug.h> +#include <linux/types.h> +#include <linux/notifier.h> +#include <linux/sched.h> +#include <linux/uprobes.h> + +#include <asm/branch.h> +#include <asm/cpu-features.h> +#include <asm/ptrace.h> +#include <asm/inst.h> + +static inline int insn_has_delay_slot(const union mips_instruction insn) +{ + switch (insn.i_format.opcode) { + /* + * jr and jalr are in r_format format. + */ + case spec_op: + switch (insn.r_format.func) { + case jalr_op: + case jr_op: + return 1; + } + break; + + /* + * This group contains: + * bltz_op, bgez_op, bltzl_op, bgezl_op, + * bltzal_op, bgezal_op, bltzall_op, bgezall_op. + */ + case bcond_op: + switch (insn.i_format.rt) { + case bltz_op: + case bltzl_op: + case bgez_op: + case bgezl_op: + case bltzal_op: + case bltzall_op: + case bgezal_op: + case bgezall_op: + case bposge32_op: + return 1; + } + break; + + /* + * These are unconditional and in j_format. + */ + case jal_op: + case j_op: + case beq_op: + case beql_op: + case bne_op: + case bnel_op: + case blez_op: /* not really i_format */ + case blezl_op: + case bgtz_op: + case bgtzl_op: + return 1; + + /* + * And now the FPA/cp1 branch instructions. + */ + case cop1_op: +#ifdef CONFIG_CPU_CAVIUM_OCTEON + case lwc2_op: /* This is bbit0 on Octeon */ + case ldc2_op: /* This is bbit032 on Octeon */ + case swc2_op: /* This is bbit1 on Octeon */ + case sdc2_op: /* This is bbit132 on Octeon */ +#endif + return 1; + } + + return 0; +} + +/** + * arch_uprobe_analyze_insn - instruction analysis including validity and fixups. + * @mm: the probed address space. + * @arch_uprobe: the probepoint information. + * @addr: virtual address at which to install the probepoint + * Return 0 on success or a -ve number on error. + */ +int arch_uprobe_analyze_insn(struct arch_uprobe *aup, + struct mm_struct *mm, unsigned long addr) +{ + union mips_instruction inst; + + /* + * For the time being this also blocks attempts to use uprobes with + * MIPS16 and microMIPS. + */ + if (addr & 0x03) + return -EINVAL; + + inst.word = aup->insn[0]; + aup->ixol[0] = aup->insn[insn_has_delay_slot(inst)]; + aup->ixol[1] = UPROBE_BRK_UPROBE_XOL; /* NOP */ + + return 0; +} + +/** + * is_trap_insn - check if the instruction is a trap variant + * @insn: instruction to be checked. + * Returns true if @insn is a trap variant. + * + * This definition overrides the weak definition in kernel/events/uprobes.c. + * and is needed for the case where an architecture has multiple trap + * instructions (like PowerPC or MIPS). We treat BREAK just like the more + * modern conditional trap instructions. + */ +bool is_trap_insn(uprobe_opcode_t *insn) +{ + union mips_instruction inst; + + inst.word = *insn; + + switch (inst.i_format.opcode) { + case spec_op: + switch (inst.r_format.func) { + case break_op: + case teq_op: + case tge_op: + case tgeu_op: + case tlt_op: + case tltu_op: + case tne_op: + return 1; + } + break; + + case bcond_op: /* Yes, really ... */ + switch (inst.u_format.rt) { + case teqi_op: + case tgei_op: + case tgeiu_op: + case tlti_op: + case tltiu_op: + case tnei_op: + return 1; + } + break; + } + + return 0; +} + +#define UPROBE_TRAP_NR ULONG_MAX + +/* + * 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 *aup, struct pt_regs *regs) +{ + struct uprobe_task *utask = current->utask; + union mips_instruction insn; + + /* + * Now find the EPC where to resume after the breakpoint has been + * dealt with. This may require emulation of a branch. + */ + aup->resume_epc = regs->cp0_epc + 4; + if (insn_has_delay_slot((union mips_instruction) aup->insn[0])) { + unsigned long epc; + + epc = regs->cp0_epc; + __compute_return_epc_for_insn(regs, insn); + aup->resume_epc = regs->cp0_epc; + } + + utask->autask.saved_trap_nr = current->thread.trap_nr; + current->thread.trap_nr = UPROBE_TRAP_NR; + regs->cp0_epc = current->utask->xol_vaddr; + + return 0; +} + +int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs) +{ + struct uprobe_task *utask = current->utask; + + current->thread.trap_nr = utask->autask.saved_trap_nr; + regs->cp0_epc = aup->resume_epc; + + return 0; +} + +/* + * 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 *tsk) +{ + if (tsk->thread.trap_nr != UPROBE_TRAP_NR) + return true; + + return false; +} + +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; + + /* regs == NULL is a kernel bug */ + if (WARN_ON(!regs)) + return NOTIFY_DONE; + + /* We are only interested in userspace traps */ + if (!user_mode(regs)) + return NOTIFY_DONE; + + switch (val) { + case DIE_BREAK: + if (uprobe_pre_sstep_notifier(regs)) + return NOTIFY_STOP; + break; + case DIE_UPROBE_XOL: + if (uprobe_post_sstep_notifier(regs)) + return NOTIFY_STOP; + default: + break; + } + + return 0; +} + +/* + * This function gets called when XOL instruction either gets trapped or + * the thread has a fatal signal. Reset the instruction pointer to its + * probed address for the potential restart or for post mortem analysis. + */ +void arch_uprobe_abort_xol(struct arch_uprobe *aup, + struct pt_regs *regs) +{ + struct uprobe_task *utask = current->utask; + + instruction_pointer_set(regs, utask->vaddr); +} + +unsigned long arch_uretprobe_hijack_return_addr( + unsigned long trampoline_vaddr, struct pt_regs *regs) +{ + unsigned long ra; + + ra = regs->regs[31]; + + /* Replace the return address with the trampoline address */ + regs->regs[31] = ra; + + return ra; +} + +/** + * 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. + * + * For mm @mm, store the breakpoint instruction at @vaddr. + * Return 0 (success) or a negative errno. + * + * This version overrides the weak version in kernel/events/uprobes.c. + * It is required to handle MIPS16 and microMIPS. + */ +int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, + unsigned long vaddr) +{ + return uprobe_write_opcode(mm, vaddr, UPROBE_SWBP_INSN); +} + +/** + * set_orig_insn - Restore the original instruction. + * @mm: the probed process address space. + * @auprobe: arch specific probepoint information. + * @vaddr: the virtual address to insert the opcode. + * + * For mm @mm, restore the original opcode (opcode) at @vaddr. + * Return 0 (success) or a negative errno. + * + * This overrides the weak version in kernel/events/uprobes.c. + */ +int set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, + unsigned long vaddr) +{ + return uprobe_write_opcode(mm, vaddr, + *(uprobe_opcode_t *)&auprobe->orig_inst[0].word); +} + +void __weak arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr, + void *src, unsigned long len) +{ + void *kaddr; + + /* Initialize the slot */ + kaddr = kmap_atomic(page); + memcpy(kaddr + (vaddr & ~PAGE_MASK), src, len); + kunmap_atomic(kaddr); + + /* + * The MIPS version of flush_icache_range will operate safely on + * user space addresses and more importantly, it doesn't require a + * VMA argument. + */ + flush_icache_range(vaddr, vaddr + len); +} + +/** + * 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. + * + * This overrides the weak version in kernel/events/uprobes.c. + */ +unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) +{ + return instruction_pointer(regs); +} + +/* + * See if the instruction can be emulated. + * Returns true if instruction was emulated, false otherwise. + * + * For now we always emulate so this function just returns 0. + */ +bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + return 0; +} |