diff options
Diffstat (limited to 'arch/arm64/include/asm/alternative-macros.h')
| -rw-r--r-- | arch/arm64/include/asm/alternative-macros.h | 94 |
1 files changed, 74 insertions, 20 deletions
diff --git a/arch/arm64/include/asm/alternative-macros.h b/arch/arm64/include/asm/alternative-macros.h index 7e157ab6cd50..d328f549b1a6 100644 --- a/arch/arm64/include/asm/alternative-macros.h +++ b/arch/arm64/include/asm/alternative-macros.h @@ -2,26 +2,38 @@ #ifndef __ASM_ALTERNATIVE_MACROS_H #define __ASM_ALTERNATIVE_MACROS_H +#include <linux/const.h> +#include <vdso/bits.h> + #include <asm/cpucaps.h> #include <asm/insn-def.h> -#define ARM64_CB_PATCH ARM64_NCAPS +/* + * Binutils 2.27.0 can't handle a 'UL' suffix on constants, so for the assembly + * macros below we must use we must use `(1 << ARM64_CB_SHIFT)`. + */ +#define ARM64_CB_SHIFT 15 +#define ARM64_CB_BIT BIT(ARM64_CB_SHIFT) + +#if ARM64_NCAPS >= ARM64_CB_BIT +#error "cpucaps have overflown ARM64_CB_BIT" +#endif #ifndef __ASSEMBLY__ #include <linux/stringify.h> -#define ALTINSTR_ENTRY(feature) \ +#define ALTINSTR_ENTRY(cpucap) \ " .word 661b - .\n" /* label */ \ " .word 663f - .\n" /* new instruction */ \ - " .hword " __stringify(feature) "\n" /* feature bit */ \ + " .hword " __stringify(cpucap) "\n" /* cpucap */ \ " .byte 662b-661b\n" /* source len */ \ " .byte 664f-663f\n" /* replacement len */ -#define ALTINSTR_ENTRY_CB(feature, cb) \ +#define ALTINSTR_ENTRY_CB(cpucap, cb) \ " .word 661b - .\n" /* label */ \ - " .word " __stringify(cb) "- .\n" /* callback */ \ - " .hword " __stringify(feature) "\n" /* feature bit */ \ + " .word " __stringify(cb) "- .\n" /* callback */ \ + " .hword " __stringify(cpucap) "\n" /* cpucap */ \ " .byte 662b-661b\n" /* source len */ \ " .byte 664f-663f\n" /* replacement len */ @@ -41,13 +53,13 @@ * * Alternatives with callbacks do not generate replacement instructions. */ -#define __ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg_enabled) \ +#define __ALTERNATIVE_CFG(oldinstr, newinstr, cpucap, cfg_enabled) \ ".if "__stringify(cfg_enabled)" == 1\n" \ "661:\n\t" \ oldinstr "\n" \ "662:\n" \ ".pushsection .altinstructions,\"a\"\n" \ - ALTINSTR_ENTRY(feature) \ + ALTINSTR_ENTRY(cpucap) \ ".popsection\n" \ ".subsection 1\n" \ "663:\n\t" \ @@ -58,31 +70,31 @@ ".previous\n" \ ".endif\n" -#define __ALTERNATIVE_CFG_CB(oldinstr, feature, cfg_enabled, cb) \ +#define __ALTERNATIVE_CFG_CB(oldinstr, cpucap, cfg_enabled, cb) \ ".if "__stringify(cfg_enabled)" == 1\n" \ "661:\n\t" \ oldinstr "\n" \ "662:\n" \ ".pushsection .altinstructions,\"a\"\n" \ - ALTINSTR_ENTRY_CB(feature, cb) \ + ALTINSTR_ENTRY_CB(cpucap, cb) \ ".popsection\n" \ "663:\n\t" \ "664:\n\t" \ ".endif\n" -#define _ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg, ...) \ - __ALTERNATIVE_CFG(oldinstr, newinstr, feature, IS_ENABLED(cfg)) +#define _ALTERNATIVE_CFG(oldinstr, newinstr, cpucap, cfg, ...) \ + __ALTERNATIVE_CFG(oldinstr, newinstr, cpucap, IS_ENABLED(cfg)) -#define ALTERNATIVE_CB(oldinstr, cb) \ - __ALTERNATIVE_CFG_CB(oldinstr, ARM64_CB_PATCH, 1, cb) +#define ALTERNATIVE_CB(oldinstr, cpucap, cb) \ + __ALTERNATIVE_CFG_CB(oldinstr, (1 << ARM64_CB_SHIFT) | (cpucap), 1, cb) #else #include <asm/assembler.h> -.macro altinstruction_entry orig_offset alt_offset feature orig_len alt_len +.macro altinstruction_entry orig_offset alt_offset cpucap orig_len alt_len .word \orig_offset - . .word \alt_offset - . - .hword \feature + .hword (\cpucap) .byte \orig_len .byte \alt_len .endm @@ -141,10 +153,10 @@ 661: .endm -.macro alternative_cb cb +.macro alternative_cb cap, cb .set .Lasm_alt_mode, 0 .pushsection .altinstructions, "a" - altinstruction_entry 661f, \cb, ARM64_CB_PATCH, 662f-661f, 0 + altinstruction_entry 661f, \cb, (1 << ARM64_CB_SHIFT) | \cap, 662f-661f, 0 .popsection 661: .endm @@ -198,13 +210,55 @@ alternative_endif #endif /* __ASSEMBLY__ */ /* - * Usage: asm(ALTERNATIVE(oldinstr, newinstr, feature)); + * Usage: asm(ALTERNATIVE(oldinstr, newinstr, cpucap)); * - * Usage: asm(ALTERNATIVE(oldinstr, newinstr, feature, CONFIG_FOO)); + * Usage: asm(ALTERNATIVE(oldinstr, newinstr, cpucap, CONFIG_FOO)); * N.B. If CONFIG_FOO is specified, but not selected, the whole block * will be omitted, including oldinstr. */ #define ALTERNATIVE(oldinstr, newinstr, ...) \ _ALTERNATIVE_CFG(oldinstr, newinstr, __VA_ARGS__, 1) +#ifndef __ASSEMBLY__ + +#include <linux/types.h> + +static __always_inline bool +alternative_has_cap_likely(const unsigned long cpucap) +{ + if (!cpucap_is_possible(cpucap)) + return false; + + asm goto( + ALTERNATIVE_CB("b %l[l_no]", %[cpucap], alt_cb_patch_nops) + : + : [cpucap] "i" (cpucap) + : + : l_no); + + return true; +l_no: + return false; +} + +static __always_inline bool +alternative_has_cap_unlikely(const unsigned long cpucap) +{ + if (!cpucap_is_possible(cpucap)) + return false; + + asm goto( + ALTERNATIVE("nop", "b %l[l_yes]", %[cpucap]) + : + : [cpucap] "i" (cpucap) + : + : l_yes); + + return false; +l_yes: + return true; +} + +#endif /* __ASSEMBLY__ */ + #endif /* __ASM_ALTERNATIVE_MACROS_H */ |