diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2022-09-15 14:11:20 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-10-17 17:41:11 +0300 |
| commit | fe54d0793796ccdb213d8ea7bff0b49903b6afaa (patch) | |
| tree | a93858add4a90d2595767de3e46df9a41ecf0daf | |
| parent | 80e4c1cd42fff110bfdae8fce7ac4f22465f9664 (diff) | |
| download | linux-fe54d0793796ccdb213d8ea7bff0b49903b6afaa.tar.xz | |
x86/alternatives: Provide text_poke_copy_locked()
The upcoming call thunk patching must hold text_mutex and needs access to
text_poke_copy(), which takes text_mutex.
Provide a _locked postfixed variant to expose the inner workings.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111147.159977224@infradead.org
| -rw-r--r-- | arch/x86/include/asm/text-patching.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/alternative.c | 37 |
2 files changed, 23 insertions, 15 deletions
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h index 1cc15528ce29..f4b87f08f5c5 100644 --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -45,6 +45,7 @@ extern void *text_poke(void *addr, const void *opcode, size_t len); 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, bool core_ok); 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); diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 5cadcea035e0..fad3c0e4838e 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -1236,27 +1236,15 @@ void *text_poke_kgdb(void *addr, const void *opcode, size_t len) return __text_poke(text_poke_memcpy, addr, opcode, len); } -/** - * text_poke_copy - Copy instructions into (an unused part of) RX memory - * @addr: address to modify - * @opcode: source of the copy - * @len: length to copy, could be more than 2x PAGE_SIZE - * - * Not safe against concurrent execution; useful for JITs to dump - * new code blocks into unused regions of RX memory. Can be used in - * conjunction with synchronize_rcu_tasks() to wait for existing - * execution to quiesce after having made sure no existing functions - * pointers are live. - */ -void *text_poke_copy(void *addr, const void *opcode, size_t len) +void *text_poke_copy_locked(void *addr, const void *opcode, size_t len, + bool core_ok) { unsigned long start = (unsigned long)addr; size_t patched = 0; - if (WARN_ON_ONCE(core_kernel_text(start))) + if (WARN_ON_ONCE(!core_ok && core_kernel_text(start))) return NULL; - mutex_lock(&text_mutex); while (patched < len) { unsigned long ptr = start + patched; size_t s; @@ -1266,6 +1254,25 @@ void *text_poke_copy(void *addr, const void *opcode, size_t len) __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 + * @opcode: source of the copy + * @len: length to copy, could be more than 2x PAGE_SIZE + * + * Not safe against concurrent execution; useful for JITs to dump + * new code blocks into unused regions of RX memory. Can be used in + * conjunction with synchronize_rcu_tasks() to wait for existing + * execution to quiesce after having made sure no existing functions + * pointers are live. + */ +void *text_poke_copy(void *addr, const void *opcode, size_t len) +{ + mutex_lock(&text_mutex); + addr = text_poke_copy_locked(addr, opcode, len, false); mutex_unlock(&text_mutex); return addr; } |