Messages in this thread Patch in this message | | | From | Thomas Gleixner <> | Subject | [patch 20/38] x86/alternatives: Provide text_poke_[copy|set]_locked() | Date | Sun, 17 Jul 2022 01:17:42 +0200 (CEST) |
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The upcoming call thunk patching must hold text_mutex and needs access to text_poke_copy() and text_poke_set(), which take text_mutex.
Provide _locked postfixed variants to expose the inner workings.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- arch/x86/include/asm/text-patching.h | 2 + arch/x86/kernel/alternative.c | 48 +++++++++++++++++++++-------------- 2 files changed, 32 insertions(+), 18 deletions(-)
--- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -45,6 +45,8 @@ extern void *text_poke(void *addr, const extern void text_poke_sync(void); extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len); extern void *text_poke_copy(void *addr, const void *opcode, size_t len); +extern void *text_poke_copy_locked(void *addr, const void *opcode, size_t len); +extern void *text_poke_set_locked(void *addr, int c, size_t len); extern void *text_poke_set(void *addr, int c, size_t len); extern int poke_int3_handler(struct pt_regs *regs); extern void text_poke_bp(void *addr, const void *opcode, size_t len, const void *emulate); --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -1225,6 +1225,26 @@ void *text_poke_kgdb(void *addr, const v return __text_poke(text_poke_memcpy, addr, opcode, len); } +void *text_poke_copy_locked(void *addr, const void *opcode, size_t len) +{ + unsigned long start = (unsigned long)addr; + size_t patched = 0; + + if (WARN_ON_ONCE(core_kernel_text(start))) + return NULL; + + while (patched < len) { + unsigned long ptr = start + patched; + size_t s; + + s = min_t(size_t, PAGE_SIZE * 2 - offset_in_page(ptr), len - patched); + + __text_poke(text_poke_memcpy, (void *)ptr, opcode + patched, s); + patched += s; + } + return addr; +} + /** * text_poke_copy - Copy instructions into (an unused part of) RX memory * @addr: address to modify @@ -1239,23 +1259,29 @@ void *text_poke_kgdb(void *addr, const v */ void *text_poke_copy(void *addr, const void *opcode, size_t len) { + mutex_lock(&text_mutex); + addr = text_poke_copy_locked(addr, opcode, len); + mutex_unlock(&text_mutex); + return addr; +} + +void *text_poke_set_locked(void *addr, int c, size_t len) +{ unsigned long start = (unsigned long)addr; size_t patched = 0; if (WARN_ON_ONCE(core_kernel_text(start))) return NULL; - mutex_lock(&text_mutex); while (patched < len) { unsigned long ptr = start + patched; size_t s; s = min_t(size_t, PAGE_SIZE * 2 - offset_in_page(ptr), len - patched); - __text_poke(text_poke_memcpy, (void *)ptr, opcode + patched, s); + __text_poke(text_poke_memset, (void *)ptr, (void *)&c, s); patched += s; } - mutex_unlock(&text_mutex); return addr; } @@ -1270,22 +1296,8 @@ void *text_poke_copy(void *addr, const v */ void *text_poke_set(void *addr, int c, size_t len) { - unsigned long start = (unsigned long)addr; - size_t patched = 0; - - if (WARN_ON_ONCE(core_kernel_text(start))) - return NULL; - mutex_lock(&text_mutex); - while (patched < len) { - unsigned long ptr = start + patched; - size_t s; - - s = min_t(size_t, PAGE_SIZE * 2 - offset_in_page(ptr), len - patched); - - __text_poke(text_poke_memset, (void *)ptr, (void *)&c, s); - patched += s; - } + addr = text_poke_set_locked(addr, c, len); mutex_unlock(&text_mutex); return addr; }
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