diff options
Diffstat (limited to 'arch/x86/include/asm/alternative.h')
| -rw-r--r-- | arch/x86/include/asm/alternative.h | 430 |
1 files changed, 217 insertions, 213 deletions
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h index 9542c582d546..15bc07a5ebb3 100644 --- a/arch/x86/include/asm/alternative.h +++ b/arch/x86/include/asm/alternative.h @@ -4,12 +4,19 @@ #include <linux/types.h> #include <linux/stringify.h> +#include <linux/objtool.h> #include <asm/asm.h> +#include <asm/bug.h> -#define ALTINSTR_FLAG_INV (1 << 15) -#define ALT_NOT(feat) ((feat) | ALTINSTR_FLAG_INV) +#define ALT_FLAGS_SHIFT 16 -#ifndef __ASSEMBLY__ +#define ALT_FLAG_NOT (1 << 0) +#define ALT_NOT(feature) ((ALT_FLAG_NOT << ALT_FLAGS_SHIFT) | (feature)) +#define ALT_FLAG_DIRECT_CALL (1 << 1) +#define ALT_DIRECT_CALL(feature) ((ALT_FLAG_DIRECT_CALL << ALT_FLAGS_SHIFT) | (feature)) +#define ALT_CALL_ALWAYS ALT_DIRECT_CALL(X86_FEATURE_ALWAYS) + +#ifndef __ASSEMBLER__ #include <linux/stddef.h> @@ -42,7 +49,7 @@ ".popsection\n" \ "671:" -#define LOCK_PREFIX LOCK_PREFIX_HERE "\n\tlock; " +#define LOCK_PREFIX LOCK_PREFIX_HERE "\n\tlock " #else /* ! CONFIG_SMP */ #define LOCK_PREFIX_HERE "" @@ -50,23 +57,38 @@ #endif /* - * objtool annotation to ignore the alternatives and only consider the original - * instruction(s). + * The patching flags are part of the upper bits of the @ft_flags parameter when + * specifying them. The split is currently like this: + * + * [31... flags ...16][15... CPUID feature bit ...0] + * + * but since this is all hidden in the macros argument being split, those fields can be + * extended in the future to fit in a u64 or however the need arises. */ -#define ANNOTATE_IGNORE_ALTERNATIVE \ - "999:\n\t" \ - ".pushsection .discard.ignore_alts\n\t" \ - ".long 999b - .\n\t" \ - ".popsection\n\t" - struct alt_instr { s32 instr_offset; /* original instruction */ s32 repl_offset; /* offset to replacement instruction */ - u16 cpuid; /* cpuid bit set for replacement */ + + union { + struct { + u32 cpuid: 16; /* CPUID bit set for replacement */ + u32 flags: 16; /* patching control flags */ + }; + u32 ft_flags; + }; + u8 instrlen; /* length of original instruction */ u8 replacementlen; /* length of new instruction */ } __packed; +extern struct alt_instr __alt_instructions[], __alt_instructions_end[]; + +extern s32 __retpoline_sites[], __retpoline_sites_end[]; +extern s32 __return_sites[], __return_sites_end[]; +extern s32 __cfi_sites[], __cfi_sites_end[]; +extern s32 __ibt_endbr_seal[], __ibt_endbr_seal_end[]; +extern s32 __smp_locks[], __smp_locks_end[]; + /* * Debug flag that can be tested to see whether alternative * instructions were patched in already: @@ -77,10 +99,69 @@ extern void alternative_instructions(void); extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end); extern void apply_retpolines(s32 *start, s32 *end); extern void apply_returns(s32 *start, s32 *end); -extern void apply_ibt_endbr(s32 *start, s32 *end); +extern void apply_seal_endbr(s32 *start, s32 *end); +extern void apply_fineibt(s32 *start_retpoline, s32 *end_retpoine, + s32 *start_cfi, s32 *end_cfi); struct module; +struct callthunk_sites { + s32 *call_start, *call_end; +}; + +#ifdef CONFIG_CALL_THUNKS +extern void callthunks_patch_builtin_calls(void); +extern void callthunks_patch_module_calls(struct callthunk_sites *sites, + struct module *mod); +extern void *callthunks_translate_call_dest(void *dest); +extern int x86_call_depth_emit_accounting(u8 **pprog, void *func, void *ip); +#else +static __always_inline void callthunks_patch_builtin_calls(void) {} +static __always_inline void +callthunks_patch_module_calls(struct callthunk_sites *sites, + struct module *mod) {} +static __always_inline void *callthunks_translate_call_dest(void *dest) +{ + return dest; +} +static __always_inline int x86_call_depth_emit_accounting(u8 **pprog, + void *func, void *ip) +{ + return 0; +} +#endif + +#ifdef CONFIG_MITIGATION_ITS +extern void its_init_mod(struct module *mod); +extern void its_fini_mod(struct module *mod); +extern void its_free_mod(struct module *mod); +extern u8 *its_static_thunk(int reg); +#else /* CONFIG_MITIGATION_ITS */ +static inline void its_init_mod(struct module *mod) { } +static inline void its_fini_mod(struct module *mod) { } +static inline void its_free_mod(struct module *mod) { } +static inline u8 *its_static_thunk(int reg) +{ + WARN_ONCE(1, "ITS not compiled in"); + + return NULL; +} +#endif + +#if defined(CONFIG_MITIGATION_RETHUNK) && defined(CONFIG_OBJTOOL) +extern bool cpu_wants_rethunk(void); +extern bool cpu_wants_rethunk_at(void *addr); +#else +static __always_inline bool cpu_wants_rethunk(void) +{ + return false; +} +static __always_inline bool cpu_wants_rethunk_at(void *addr) +{ + return false; +} +#endif + #ifdef CONFIG_SMP extern void alternatives_smp_module_add(struct module *mod, char *name, void *locks, void *locks_end, @@ -101,101 +182,52 @@ static inline int alternatives_text_reserved(void *start, void *end) } #endif /* CONFIG_SMP */ -#define b_replacement(num) "664"#num -#define e_replacement(num) "665"#num +#define ALT_CALL_INSTR "call BUG_func" -#define alt_end_marker "663" -#define alt_slen "662b-661b" -#define alt_total_slen alt_end_marker"b-661b" -#define alt_rlen(num) e_replacement(num)"f-"b_replacement(num)"f" +#define alt_slen "772b-771b" +#define alt_total_slen "773b-771b" +#define alt_rlen "775f-774f" -#define OLDINSTR(oldinstr, num) \ - "# ALT: oldnstr\n" \ - "661:\n\t" oldinstr "\n662:\n" \ +#define OLDINSTR(oldinstr) \ + "# ALT: oldinstr\n" \ + "771:\n\t" oldinstr "\n772:\n" \ "# ALT: padding\n" \ - ".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * " \ - "((" alt_rlen(num) ")-(" alt_slen ")),0x90\n" \ - alt_end_marker ":\n" - -/* - * gas compatible max based on the idea from: - * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax - * - * The additional "-" is needed because gas uses a "true" value of -1. - */ -#define alt_max_short(a, b) "((" a ") ^ (((" a ") ^ (" b ")) & -(-((" a ") < (" b ")))))" - -/* - * Pad the second replacement alternative with additional NOPs if it is - * additionally longer than the first replacement alternative. - */ -#define OLDINSTR_2(oldinstr, num1, num2) \ - "# ALT: oldinstr2\n" \ - "661:\n\t" oldinstr "\n662:\n" \ - "# ALT: padding2\n" \ - ".skip -((" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")) > 0) * " \ - "(" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")), 0x90\n" \ - alt_end_marker ":\n" - -#define OLDINSTR_3(oldinsn, n1, n2, n3) \ - "# ALT: oldinstr3\n" \ - "661:\n\t" oldinsn "\n662:\n" \ - "# ALT: padding3\n" \ - ".skip -((" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \ - " - (" alt_slen ")) > 0) * " \ - "(" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \ - " - (" alt_slen ")), 0x90\n" \ - alt_end_marker ":\n" - -#define ALTINSTR_ENTRY(feature, num) \ - " .long 661b - .\n" /* label */ \ - " .long " b_replacement(num)"f - .\n" /* new instruction */ \ - " .word " __stringify(feature) "\n" /* feature bit */ \ + ".skip -(((" alt_rlen ")-(" alt_slen ")) > 0) * " \ + "((" alt_rlen ")-(" alt_slen ")),0x90\n" \ + "773:\n" + +#define ALTINSTR_ENTRY(ft_flags) \ + ".pushsection .altinstructions,\"a\"\n" \ + " .long 771b - .\n" /* label */ \ + " .long 774f - .\n" /* new instruction */ \ + " .4byte " __stringify(ft_flags) "\n" /* feature + flags */ \ " .byte " alt_total_slen "\n" /* source len */ \ - " .byte " alt_rlen(num) "\n" /* replacement len */ - -#define ALTINSTR_REPLACEMENT(newinstr, num) /* replacement */ \ - "# ALT: replacement " #num "\n" \ - b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n" - -/* alternative assembly primitive: */ -#define ALTERNATIVE(oldinstr, newinstr, feature) \ - OLDINSTR(oldinstr, 1) \ - ".pushsection .altinstructions,\"a\"\n" \ - ALTINSTR_ENTRY(feature, 1) \ - ".popsection\n" \ - ".pushsection .altinstr_replacement, \"ax\"\n" \ - ALTINSTR_REPLACEMENT(newinstr, 1) \ + " .byte " alt_rlen "\n" /* replacement len */ \ ".popsection\n" -#define ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2)\ - OLDINSTR_2(oldinstr, 1, 2) \ - ".pushsection .altinstructions,\"a\"\n" \ - ALTINSTR_ENTRY(feature1, 1) \ - ALTINSTR_ENTRY(feature2, 2) \ - ".popsection\n" \ +#define ALTINSTR_REPLACEMENT(newinstr) /* replacement */ \ ".pushsection .altinstr_replacement, \"ax\"\n" \ - ALTINSTR_REPLACEMENT(newinstr1, 1) \ - ALTINSTR_REPLACEMENT(newinstr2, 2) \ + "# ALT: replacement\n" \ + "774:\n\t" newinstr "\n775:\n" \ ".popsection\n" +/* alternative assembly primitive: */ +#define ALTERNATIVE(oldinstr, newinstr, ft_flags) \ + OLDINSTR(oldinstr) \ + ALTINSTR_ENTRY(ft_flags) \ + ALTINSTR_REPLACEMENT(newinstr) + +#define ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \ + ALTERNATIVE(ALTERNATIVE(oldinstr, newinstr1, ft_flags1), newinstr2, ft_flags2) + /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */ -#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \ - ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \ - newinstr_yes, feature) - -#define ALTERNATIVE_3(oldinsn, newinsn1, feat1, newinsn2, feat2, newinsn3, feat3) \ - OLDINSTR_3(oldinsn, 1, 2, 3) \ - ".pushsection .altinstructions,\"a\"\n" \ - ALTINSTR_ENTRY(feat1, 1) \ - ALTINSTR_ENTRY(feat2, 2) \ - ALTINSTR_ENTRY(feat3, 3) \ - ".popsection\n" \ - ".pushsection .altinstr_replacement, \"ax\"\n" \ - ALTINSTR_REPLACEMENT(newinsn1, 1) \ - ALTINSTR_REPLACEMENT(newinsn2, 2) \ - ALTINSTR_REPLACEMENT(newinsn3, 3) \ - ".popsection\n" +#define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \ + ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, newinstr_yes, ft_flags) + +#define ALTERNATIVE_3(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, \ + newinstr3, ft_flags3) \ + ALTERNATIVE(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \ + newinstr3, ft_flags3) /* * Alternative instructions for different CPU types or capabilities. @@ -209,14 +241,11 @@ static inline int alternatives_text_reserved(void *start, void *end) * For non barrier like inlines please define new variants * without volatile and memory clobber. */ -#define alternative(oldinstr, newinstr, feature) \ - asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) : : : "memory") +#define alternative(oldinstr, newinstr, ft_flags) \ + asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory") -#define alternative_2(oldinstr, newinstr1, feature1, newinstr2, feature2) \ - asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2) ::: "memory") - -#define alternative_ternary(oldinstr, feature, newinstr_yes, newinstr_no) \ - asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) ::: "memory") +#define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \ + asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory") /* * Alternative inline assembly with input. @@ -226,33 +255,31 @@ static inline int alternatives_text_reserved(void *start, void *end) * Argument numbers start with 1. * Leaving an unused argument 0 to keep API compatibility. */ -#define alternative_input(oldinstr, newinstr, feature, input...) \ - asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) \ - : : "i" (0), ## input) - -/* - * This is similar to alternative_input. But it has two features and - * respective instructions. - * - * If CPU has feature2, newinstr2 is used. - * Otherwise, if CPU has feature1, newinstr1 is used. - * Otherwise, oldinstr is used. - */ -#define alternative_input_2(oldinstr, newinstr1, feature1, newinstr2, \ - feature2, input...) \ - asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, \ - newinstr2, feature2) \ +#define alternative_input(oldinstr, newinstr, ft_flags, input...) \ + asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags) \ : : "i" (0), ## input) /* Like alternative_input, but with a single output argument */ -#define alternative_io(oldinstr, newinstr, feature, output, input...) \ - asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) \ +#define alternative_io(oldinstr, newinstr, ft_flags, output, input...) \ + asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags) \ : output : "i" (0), ## input) -/* Like alternative_io, but for replacing a direct call with another one. */ -#define alternative_call(oldfunc, newfunc, feature, output, input...) \ - asm_inline volatile (ALTERNATIVE("call %P[old]", "call %P[new]", feature) \ - : output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input) +/* + * Like alternative_io, but for replacing a direct call with another one. + * + * Use the %c operand modifier which is the generic way to print a bare + * constant expression with all syntax-specific punctuation omitted. %P + * is the x86-specific variant which can handle constants too, for + * historical reasons, but it should be used primarily for PIC + * references: i.e., if used for a function, it would add the PLT + * suffix. + */ +#define alternative_call(oldfunc, newfunc, ft_flags, output, input, clobbers...) \ + asm_inline volatile(ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \ + : ALT_OUTPUT_SP(output) \ + : [old] "i" (oldfunc), [new] "i" (newfunc) \ + COMMA(input) \ + : clobbers) /* * Like alternative_call, but there are two features and respective functions. @@ -260,27 +287,35 @@ static inline int alternatives_text_reserved(void *start, void *end) * Otherwise, if CPU has feature1, function1 is used. * Otherwise, old function is used. */ -#define alternative_call_2(oldfunc, newfunc1, feature1, newfunc2, feature2, \ - output, input...) \ - asm_inline volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", feature1,\ - "call %P[new2]", feature2) \ - : output, ASM_CALL_CONSTRAINT \ - : [old] "i" (oldfunc), [new1] "i" (newfunc1), \ - [new2] "i" (newfunc2), ## input) - -/* - * use this macro(s) if you need more than one output parameter - * in alternative_io - */ -#define ASM_OUTPUT2(a...) a - -/* - * use this macro if you need clobbers but no inputs in - * alternative_{input,io,call}() - */ -#define ASM_NO_INPUT_CLOBBER(clbr...) "i" (0) : clbr - -#else /* __ASSEMBLY__ */ +#define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2, \ + output, input, clobbers...) \ + asm_inline volatile(ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1, \ + "call %c[new2]", ft_flags2) \ + : ALT_OUTPUT_SP(output) \ + : [old] "i" (oldfunc), [new1] "i" (newfunc1), \ + [new2] "i" (newfunc2) \ + COMMA(input) \ + : clobbers) + +#define ALT_OUTPUT_SP(...) ASM_CALL_CONSTRAINT, ## __VA_ARGS__ + +/* Macro for creating assembler functions avoiding any C magic. */ +#define DEFINE_ASM_FUNC(func, instr, sec) \ + asm (".pushsection " #sec ", \"ax\"\n" \ + ".global " #func "\n\t" \ + ".type " #func ", @function\n\t" \ + ASM_FUNC_ALIGN "\n" \ + #func ":\n\t" \ + ASM_ENDBR \ + instr "\n\t" \ + ASM_RET \ + ".size " #func ", . - " #func "\n\t" \ + ".popsection") + +void BUG_func(void); +void nop_func(void); + +#else /* __ASSEMBLER__ */ #ifdef CONFIG_SMP .macro LOCK_PREFIX @@ -296,99 +331,68 @@ static inline int alternatives_text_reserved(void *start, void *end) #endif /* - * objtool annotation to ignore the alternatives and only consider the original - * instruction(s). - */ -.macro ANNOTATE_IGNORE_ALTERNATIVE - .Lannotate_\@: - .pushsection .discard.ignore_alts - .long .Lannotate_\@ - . - .popsection -.endm - -/* * Issue one struct alt_instr descriptor entry (need to put it into * the section .altinstructions, see below). This entry contains * enough information for the alternatives patching code to patch an * instruction. See apply_alternatives(). */ -.macro altinstruction_entry orig alt feature orig_len alt_len +.macro altinstr_entry orig alt ft_flags orig_len alt_len .long \orig - . .long \alt - . - .word \feature + .4byte \ft_flags .byte \orig_len .byte \alt_len .endm +.macro ALT_CALL_INSTR + call BUG_func +.endm + /* * Define an alternative between two instructions. If @feature is * present, early code in apply_alternatives() replaces @oldinstr with * @newinstr. ".skip" directive takes care of proper instruction padding * in case @newinstr is longer than @oldinstr. */ -.macro ALTERNATIVE oldinstr, newinstr, feature -140: - \oldinstr -141: - .skip -(((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)),0x90 -142: - - .pushsection .altinstructions,"a" - altinstruction_entry 140b,143f,\feature,142b-140b,144f-143f - .popsection - - .pushsection .altinstr_replacement,"ax" -143: - \newinstr -144: - .popsection +#define __ALTERNATIVE(oldinst, newinst, flag) \ +740: \ + oldinst ; \ +741: \ + .skip -(((744f-743f)-(741b-740b)) > 0) * ((744f-743f)-(741b-740b)),0x90 ;\ +742: \ + .pushsection .altinstructions,"a" ; \ + altinstr_entry 740b,743f,flag,742b-740b,744f-743f ; \ + .popsection ; \ + .pushsection .altinstr_replacement,"ax" ; \ +743: \ + newinst ; \ +744: \ + .popsection ; + +.macro ALTERNATIVE oldinstr, newinstr, ft_flags + __ALTERNATIVE(\oldinstr, \newinstr, \ft_flags) .endm -#define old_len 141b-140b -#define new_len1 144f-143f -#define new_len2 145f-144f - -/* - * gas compatible max based on the idea from: - * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax - * - * The additional "-" is needed because gas uses a "true" value of -1. - */ -#define alt_max_short(a, b) ((a) ^ (((a) ^ (b)) & -(-((a) < (b))))) - - /* * Same as ALTERNATIVE macro above but for two alternatives. If CPU * has @feature1, it replaces @oldinstr with @newinstr1. If CPU has * @feature2, it replaces @oldinstr with @feature2. */ -.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2 -140: - \oldinstr -141: - .skip -((alt_max_short(new_len1, new_len2) - (old_len)) > 0) * \ - (alt_max_short(new_len1, new_len2) - (old_len)),0x90 -142: - - .pushsection .altinstructions,"a" - altinstruction_entry 140b,143f,\feature1,142b-140b,144f-143f - altinstruction_entry 140b,144f,\feature2,142b-140b,145f-144f - .popsection +.macro ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2 + __ALTERNATIVE(__ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1), + \newinstr2, \ft_flags2) +.endm - .pushsection .altinstr_replacement,"ax" -143: - \newinstr1 -144: - \newinstr2 -145: - .popsection +.macro ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3 + __ALTERNATIVE(ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2), + \newinstr3, \ft_flags3) .endm /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */ -#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \ +#define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \ ALTERNATIVE_2 oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \ - newinstr_yes, feature + newinstr_yes, ft_flags -#endif /* __ASSEMBLY__ */ +#endif /* __ASSEMBLER__ */ #endif /* _ASM_X86_ALTERNATIVE_H */ |