diff options
Diffstat (limited to 'arch/x86/kernel/alternative.c')
| -rw-r--r-- | arch/x86/kernel/alternative.c | 30 |
1 files changed, 23 insertions, 7 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 89de61243272..d17518ca19b8 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -432,6 +432,11 @@ static int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a) return 5; } +static inline u8 * instr_va(struct alt_instr *i) +{ + return (u8 *)&i->instr_offset + i->instr_offset; +} + /* * Replace instructions with better alternatives for this CPU type. This runs * before SMP is initialized to avoid SMP problems with self modifying code. @@ -447,7 +452,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start, { u8 insn_buff[MAX_PATCH_LEN]; u8 *instr, *replacement; - struct alt_instr *a; + struct alt_instr *a, *b; DPRINTK(ALT, "alt table %px, -> %px", start, end); @@ -473,7 +478,18 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start, for (a = start; a < end; a++) { int insn_buff_sz = 0; - instr = (u8 *)&a->instr_offset + a->instr_offset; + /* + * In case of nested ALTERNATIVE()s the outer alternative might + * add more padding. To ensure consistent patching find the max + * padding for all alt_instr entries for this site (nested + * alternatives result in consecutive entries). + */ + for (b = a+1; b < end && instr_va(b) == instr_va(a); b++) { + u8 len = max(a->instrlen, b->instrlen); + a->instrlen = b->instrlen = len; + } + + instr = instr_va(a); replacement = (u8 *)&a->repl_offset + a->repl_offset; BUG_ON(a->instrlen > sizeof(insn_buff)); BUG_ON(a->cpuid >= (NCAPINTS + NBUGINTS) * 32); @@ -885,8 +901,8 @@ void __init_or_module apply_seal_endbr(s32 *start, s32 *end) { } #endif /* CONFIG_X86_KERNEL_IBT */ -#ifdef CONFIG_FINEIBT -#define __CFI_DEFAULT CFI_DEFAULT +#ifdef CONFIG_CFI_AUTO_DEFAULT +#define __CFI_DEFAULT CFI_AUTO #elif defined(CONFIG_CFI_CLANG) #define __CFI_DEFAULT CFI_KCFI #else @@ -994,7 +1010,7 @@ static __init int cfi_parse_cmdline(char *str) } if (!strcmp(str, "auto")) { - cfi_mode = CFI_DEFAULT; + cfi_mode = CFI_AUTO; } else if (!strcmp(str, "off")) { cfi_mode = CFI_OFF; cfi_rand = false; @@ -1254,7 +1270,7 @@ static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline, "FineIBT preamble wrong size: %ld", fineibt_preamble_size)) return; - if (cfi_mode == CFI_DEFAULT) { + if (cfi_mode == CFI_AUTO) { cfi_mode = CFI_KCFI; if (HAS_KERNEL_IBT && cpu_feature_enabled(X86_FEATURE_IBT)) cfi_mode = CFI_FINEIBT; @@ -1641,7 +1657,7 @@ static noinline void __init alt_reloc_selftest(void) */ asm_inline volatile ( ALTERNATIVE("", "lea %[mem], %%" _ASM_ARG1 "; call __alt_reloc_selftest;", X86_FEATURE_ALWAYS) - : /* output */ + : ASM_CALL_CONSTRAINT : [mem] "m" (__alt_reloc_selftest_addr) : _ASM_ARG1 ); |