diff options
Diffstat (limited to 'arch/x86/kernel/alternative.c')
| -rw-r--r-- | arch/x86/kernel/alternative.c | 32 |
1 files changed, 29 insertions, 3 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index f65ab8b014c..5079f24c955 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -195,7 +195,7 @@ static void __init_or_module add_nops(void *insns, unsigned int len) extern struct alt_instr __alt_instructions[], __alt_instructions_end[]; extern s32 __smp_locks[], __smp_locks_end[]; -static void *text_poke_early(void *addr, const void *opcode, size_t len); +void *text_poke_early(void *addr, const void *opcode, size_t len); /* Replace instructions with better alternatives for this CPU type. This runs before SMP is initialized to avoid SMP problems with @@ -522,7 +522,7 @@ void __init alternative_instructions(void) * instructions. And on the local CPU you need to be protected again NMI or MCE * handlers seeing an inconsistent instruction while you patch. */ -static void *__init_or_module text_poke_early(void *addr, const void *opcode, +void *__init_or_module text_poke_early(void *addr, const void *opcode, size_t len) { unsigned long flags; @@ -637,7 +637,33 @@ void *__kprobes text_poke_smp(void *addr, const void *opcode, size_t len) tpp.len = len; atomic_set(&stop_machine_first, 1); wrote_text = 0; - stop_machine(stop_machine_text_poke, (void *)&tpp, NULL); + /* Use __stop_machine() because the caller already got online_cpus. */ + __stop_machine(stop_machine_text_poke, (void *)&tpp, cpu_online_mask); return addr; } +#if defined(CONFIG_DYNAMIC_FTRACE) || defined(HAVE_JUMP_LABEL) + +#ifdef CONFIG_X86_64 +unsigned char ideal_nop5[5] = { 0x66, 0x66, 0x66, 0x66, 0x90 }; +#else +unsigned char ideal_nop5[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 }; +#endif + +void __init arch_init_ideal_nop5(void) +{ + /* + * There is no good nop for all x86 archs. This selection + * algorithm should be unified with the one in find_nop_table(), + * but this should be good enough for now. + * + * For cases other than the ones below, use the safe (as in + * always functional) defaults above. + */ +#ifdef CONFIG_X86_64 + /* Don't use these on 32 bits due to broken virtualizers */ + if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) + memcpy(ideal_nop5, p6_nops[5], 5); +#endif +} +#endif |