diff options
| -rw-r--r-- | arch/arm64/include/asm/runtime-const.h | 88 | ||||
| -rw-r--r-- | arch/arm64/kernel/vmlinux.lds.S | 3 | ||||
| -rw-r--r-- | arch/x86/include/asm/runtime-const.h | 61 | ||||
| -rw-r--r-- | arch/x86/kernel/vmlinux.lds.S | 3 | ||||
| -rw-r--r-- | fs/dcache.c | 17 | ||||
| -rw-r--r-- | include/asm-generic/Kbuild | 1 | ||||
| -rw-r--r-- | include/asm-generic/runtime-const.h | 15 | ||||
| -rw-r--r-- | include/asm-generic/vmlinux.lds.h | 8 |
8 files changed, 192 insertions, 4 deletions
diff --git a/arch/arm64/include/asm/runtime-const.h b/arch/arm64/include/asm/runtime-const.h new file mode 100644 index 000000000000..be5915669d23 --- /dev/null +++ b/arch/arm64/include/asm/runtime-const.h @@ -0,0 +1,88 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_RUNTIME_CONST_H +#define _ASM_RUNTIME_CONST_H + +#include <asm/cacheflush.h> + +/* Sigh. You can still run arm64 in BE mode */ +#include <asm/byteorder.h> + +#define runtime_const_ptr(sym) ({ \ + typeof(sym) __ret; \ + asm_inline("1:\t" \ + "movz %0, #0xcdef\n\t" \ + "movk %0, #0x89ab, lsl #16\n\t" \ + "movk %0, #0x4567, lsl #32\n\t" \ + "movk %0, #0x0123, lsl #48\n\t" \ + ".pushsection runtime_ptr_" #sym ",\"a\"\n\t" \ + ".long 1b - .\n\t" \ + ".popsection" \ + :"=r" (__ret)); \ + __ret; }) + +#define runtime_const_shift_right_32(val, sym) ({ \ + unsigned long __ret; \ + asm_inline("1:\t" \ + "lsr %w0,%w1,#12\n\t" \ + ".pushsection runtime_shift_" #sym ",\"a\"\n\t" \ + ".long 1b - .\n\t" \ + ".popsection" \ + :"=r" (__ret) \ + :"r" (0u+(val))); \ + __ret; }) + +#define runtime_const_init(type, sym) do { \ + extern s32 __start_runtime_##type##_##sym[]; \ + extern s32 __stop_runtime_##type##_##sym[]; \ + runtime_const_fixup(__runtime_fixup_##type, \ + (unsigned long)(sym), \ + __start_runtime_##type##_##sym, \ + __stop_runtime_##type##_##sym); \ +} while (0) + +/* 16-bit immediate for wide move (movz and movk) in bits 5..20 */ +static inline void __runtime_fixup_16(__le32 *p, unsigned int val) +{ + u32 insn = le32_to_cpu(*p); + insn &= 0xffe0001f; + insn |= (val & 0xffff) << 5; + *p = cpu_to_le32(insn); +} + +static inline void __runtime_fixup_caches(void *where, unsigned int insns) +{ + unsigned long va = (unsigned long)where; + caches_clean_inval_pou(va, va + 4*insns); +} + +static inline void __runtime_fixup_ptr(void *where, unsigned long val) +{ + __le32 *p = lm_alias(where); + __runtime_fixup_16(p, val); + __runtime_fixup_16(p+1, val >> 16); + __runtime_fixup_16(p+2, val >> 32); + __runtime_fixup_16(p+3, val >> 48); + __runtime_fixup_caches(where, 4); +} + +/* Immediate value is 6 bits starting at bit #16 */ +static inline void __runtime_fixup_shift(void *where, unsigned long val) +{ + __le32 *p = lm_alias(where); + u32 insn = le32_to_cpu(*p); + insn &= 0xffc0ffff; + insn |= (val & 63) << 16; + *p = cpu_to_le32(insn); + __runtime_fixup_caches(where, 1); +} + +static inline void runtime_const_fixup(void (*fn)(void *, unsigned long), + unsigned long val, s32 *start, s32 *end) +{ + while (start < end) { + fn(*start + (void *)start, val); + start++; + } +} + +#endif diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 755a22d4f840..55a8e310ea12 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -264,6 +264,9 @@ SECTIONS EXIT_DATA } + RUNTIME_CONST(shift, d_hash_shift) + RUNTIME_CONST(ptr, dentry_hashtable) + PERCPU_SECTION(L1_CACHE_BYTES) HYPERVISOR_PERCPU_SECTION diff --git a/arch/x86/include/asm/runtime-const.h b/arch/x86/include/asm/runtime-const.h new file mode 100644 index 000000000000..24e3a53ca255 --- /dev/null +++ b/arch/x86/include/asm/runtime-const.h @@ -0,0 +1,61 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_RUNTIME_CONST_H +#define _ASM_RUNTIME_CONST_H + +#define runtime_const_ptr(sym) ({ \ + typeof(sym) __ret; \ + asm_inline("mov %1,%0\n1:\n" \ + ".pushsection runtime_ptr_" #sym ",\"a\"\n\t" \ + ".long 1b - %c2 - .\n\t" \ + ".popsection" \ + :"=r" (__ret) \ + :"i" ((unsigned long)0x0123456789abcdefull), \ + "i" (sizeof(long))); \ + __ret; }) + +// The 'typeof' will create at _least_ a 32-bit type, but +// will happily also take a bigger type and the 'shrl' will +// clear the upper bits +#define runtime_const_shift_right_32(val, sym) ({ \ + typeof(0u+(val)) __ret = (val); \ + asm_inline("shrl $12,%k0\n1:\n" \ + ".pushsection runtime_shift_" #sym ",\"a\"\n\t" \ + ".long 1b - 1 - .\n\t" \ + ".popsection" \ + :"+r" (__ret)); \ + __ret; }) + +#define runtime_const_init(type, sym) do { \ + extern s32 __start_runtime_##type##_##sym[]; \ + extern s32 __stop_runtime_##type##_##sym[]; \ + runtime_const_fixup(__runtime_fixup_##type, \ + (unsigned long)(sym), \ + __start_runtime_##type##_##sym, \ + __stop_runtime_##type##_##sym); \ +} while (0) + +/* + * The text patching is trivial - you can only do this at init time, + * when the text section hasn't been marked RO, and before the text + * has ever been executed. + */ +static inline void __runtime_fixup_ptr(void *where, unsigned long val) +{ + *(unsigned long *)where = val; +} + +static inline void __runtime_fixup_shift(void *where, unsigned long val) +{ + *(unsigned char *)where = val; +} + +static inline void runtime_const_fixup(void (*fn)(void *, unsigned long), + unsigned long val, s32 *start, s32 *end) +{ + while (start < end) { + fn(*start + (void *)start, val); + start++; + } +} + +#endif diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 3509afc6a672..6e73403e874f 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -357,6 +357,9 @@ SECTIONS PERCPU_SECTION(INTERNODE_CACHE_BYTES) #endif + RUNTIME_CONST(shift, d_hash_shift) + RUNTIME_CONST(ptr, dentry_hashtable) + . = ALIGN(PAGE_SIZE); /* freed after init ends here */ diff --git a/fs/dcache.c b/fs/dcache.c index 4c144519aa70..5f9ffe5c9917 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -35,6 +35,8 @@ #include "internal.h" #include "mount.h" +#include <asm/runtime-const.h> + /* * Usage: * dcache->d_inode->i_lock protects: @@ -100,9 +102,10 @@ static unsigned int d_hash_shift __ro_after_init; static struct hlist_bl_head *dentry_hashtable __ro_after_init; -static inline struct hlist_bl_head *d_hash(unsigned int hash) +static inline struct hlist_bl_head *d_hash(unsigned long hashlen) { - return dentry_hashtable + (hash >> d_hash_shift); + return runtime_const_ptr(dentry_hashtable) + + runtime_const_shift_right_32(hashlen, d_hash_shift); } #define IN_LOOKUP_SHIFT 10 @@ -2110,7 +2113,7 @@ static noinline struct dentry *__d_lookup_rcu_op_compare( unsigned *seqp) { u64 hashlen = name->hash_len; - struct hlist_bl_head *b = d_hash(hashlen_hash(hashlen)); + struct hlist_bl_head *b = d_hash(hashlen); struct hlist_bl_node *node; struct dentry *dentry; @@ -2177,7 +2180,7 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent, { u64 hashlen = name->hash_len; const unsigned char *str = name->name; - struct hlist_bl_head *b = d_hash(hashlen_hash(hashlen)); + struct hlist_bl_head *b = d_hash(hashlen); struct hlist_bl_node *node; struct dentry *dentry; @@ -3132,6 +3135,9 @@ static void __init dcache_init_early(void) 0, 0); d_hash_shift = 32 - d_hash_shift; + + runtime_const_init(shift, d_hash_shift); + runtime_const_init(ptr, dentry_hashtable); } static void __init dcache_init(void) @@ -3160,6 +3166,9 @@ static void __init dcache_init(void) 0, 0); d_hash_shift = 32 - d_hash_shift; + + runtime_const_init(shift, d_hash_shift); + runtime_const_init(ptr, dentry_hashtable); } /* SLAB cache for __getname() consumers */ diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild index b20fa25a7e8d..052e5c98c105 100644 --- a/include/asm-generic/Kbuild +++ b/include/asm-generic/Kbuild @@ -46,6 +46,7 @@ mandatory-y += pci.h mandatory-y += percpu.h mandatory-y += pgalloc.h mandatory-y += preempt.h +mandatory-y += runtime-const.h mandatory-y += rwonce.h mandatory-y += sections.h mandatory-y += serial.h diff --git a/include/asm-generic/runtime-const.h b/include/asm-generic/runtime-const.h new file mode 100644 index 000000000000..670499459514 --- /dev/null +++ b/include/asm-generic/runtime-const.h @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_RUNTIME_CONST_H +#define _ASM_RUNTIME_CONST_H + +/* + * This is the fallback for when the architecture doesn't + * support the runtime const operations. + * + * We just use the actual symbols as-is. + */ +#define runtime_const_ptr(sym) (sym) +#define runtime_const_shift_right_32(val, sym) ((u32)(val)>>(sym)) +#define runtime_const_init(type,sym) do { } while (0) + +#endif diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 5703526d6ebf..389a78415b9b 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -944,6 +944,14 @@ #define CON_INITCALL \ BOUNDED_SECTION_POST_LABEL(.con_initcall.init, __con_initcall, _start, _end) +#define RUNTIME_NAME(t,x) runtime_##t##_##x + +#define RUNTIME_CONST(t,x) \ + . = ALIGN(8); \ + RUNTIME_NAME(t,x) : AT(ADDR(RUNTIME_NAME(t,x)) - LOAD_OFFSET) { \ + *(RUNTIME_NAME(t,x)); \ + } + /* Alignment must be consistent with (kunit_suite *) in include/kunit/test.h */ #define KUNIT_TABLE() \ . = ALIGN(8); \ |