diff options
Diffstat (limited to 'arch/arm64/include/asm/alternative-macros.h')
| -rw-r--r-- | arch/arm64/include/asm/alternative-macros.h | 66 |
1 files changed, 60 insertions, 6 deletions
diff --git a/arch/arm64/include/asm/alternative-macros.h b/arch/arm64/include/asm/alternative-macros.h index 7e157ab6cd50..3622e9f4fb44 100644 --- a/arch/arm64/include/asm/alternative-macros.h +++ b/arch/arm64/include/asm/alternative-macros.h @@ -2,10 +2,22 @@ #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__ @@ -73,8 +85,8 @@ #define _ALTERNATIVE_CFG(oldinstr, newinstr, feature, cfg, ...) \ __ALTERNATIVE_CFG(oldinstr, newinstr, feature, IS_ENABLED(cfg)) -#define ALTERNATIVE_CB(oldinstr, cb) \ - __ALTERNATIVE_CFG_CB(oldinstr, ARM64_CB_PATCH, 1, cb) +#define ALTERNATIVE_CB(oldinstr, feature, cb) \ + __ALTERNATIVE_CFG_CB(oldinstr, (1 << ARM64_CB_SHIFT) | (feature), 1, cb) #else #include <asm/assembler.h> @@ -82,7 +94,7 @@ .macro altinstruction_entry orig_offset alt_offset feature orig_len alt_len .word \orig_offset - . .word \alt_offset - . - .hword \feature + .hword (\feature) .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 @@ -207,4 +219,46 @@ alternative_endif #define ALTERNATIVE(oldinstr, newinstr, ...) \ _ALTERNATIVE_CFG(oldinstr, newinstr, __VA_ARGS__, 1) +#ifndef __ASSEMBLY__ + +#include <linux/types.h> + +static __always_inline bool +alternative_has_feature_likely(unsigned long feature) +{ + compiletime_assert(feature < ARM64_NCAPS, + "feature must be < ARM64_NCAPS"); + + asm_volatile_goto( + ALTERNATIVE_CB("b %l[l_no]", %[feature], alt_cb_patch_nops) + : + : [feature] "i" (feature) + : + : l_no); + + return true; +l_no: + return false; +} + +static __always_inline bool +alternative_has_feature_unlikely(unsigned long feature) +{ + compiletime_assert(feature < ARM64_NCAPS, + "feature must be < ARM64_NCAPS"); + + asm_volatile_goto( + ALTERNATIVE("nop", "b %l[l_yes]", %[feature]) + : + : [feature] "i" (feature) + : + : l_yes); + + return false; +l_yes: + return true; +} + +#endif /* __ASSEMBLY__ */ + #endif /* __ASM_ALTERNATIVE_MACROS_H */ |