diff options
Diffstat (limited to 'arch/x86/include/asm/special_insns.h')
| -rw-r--r-- | arch/x86/include/asm/special_insns.h | 50 |
1 files changed, 33 insertions, 17 deletions
diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h index 6266d6b9e0b8..fde2bd7af19e 100644 --- a/arch/x86/include/asm/special_insns.h +++ b/arch/x86/include/asm/special_insns.h @@ -10,30 +10,19 @@ #include <linux/irqflags.h> #include <linux/jump_label.h> -/* - * The compiler should not reorder volatile asm statements with respect to each - * other: they should execute in program order. However GCC 4.9.x and 5.x have - * a bug (which was fixed in 8.1, 7.3 and 6.5) where they might reorder - * volatile asm. The write functions are not affected since they have memory - * clobbers preventing reordering. To prevent reads from being reordered with - * respect to writes, use a dummy memory operand. - */ - -#define __FORCE_ORDER "m"(*(unsigned int *)0x1000UL) - void native_write_cr0(unsigned long val); static inline unsigned long native_read_cr0(void) { unsigned long val; - asm volatile("mov %%cr0,%0\n\t" : "=r" (val) : __FORCE_ORDER); + asm volatile("mov %%cr0,%0" : "=r" (val)); return val; } static __always_inline unsigned long native_read_cr2(void) { unsigned long val; - asm volatile("mov %%cr2,%0\n\t" : "=r" (val) : __FORCE_ORDER); + asm volatile("mov %%cr2,%0" : "=r" (val)); return val; } @@ -45,7 +34,7 @@ static __always_inline void native_write_cr2(unsigned long val) static __always_inline unsigned long __native_read_cr3(void) { unsigned long val; - asm volatile("mov %%cr3,%0\n\t" : "=r" (val) : __FORCE_ORDER); + asm volatile("mov %%cr3,%0" : "=r" (val)); return val; } @@ -66,10 +55,10 @@ static inline unsigned long native_read_cr4(void) asm volatile("1: mov %%cr4, %0\n" "2:\n" _ASM_EXTABLE(1b, 2b) - : "=r" (val) : "0" (0), __FORCE_ORDER); + : "=r" (val) : "0" (0)); #else /* CR4 always exists on x86_64. */ - asm volatile("mov %%cr4,%0\n\t" : "=r" (val) : __FORCE_ORDER); + asm volatile("mov %%cr4,%0" : "=r" (val)); #endif return val; } @@ -115,9 +104,36 @@ static inline void wrpkru(u32 pkru) } #endif +/* + * Write back all modified lines in all levels of cache associated with this + * logical processor to main memory, and then invalidate all caches. Depending + * on the micro-architecture, WBINVD (and WBNOINVD below) may or may not affect + * lower level caches associated with another logical processor that shares any + * level of this processor's cache hierarchy. + */ static __always_inline void wbinvd(void) { - asm volatile("wbinvd": : :"memory"); + asm volatile("wbinvd" : : : "memory"); +} + +/* Instruction encoding provided for binutils backwards compatibility. */ +#define ASM_WBNOINVD _ASM_BYTES(0xf3,0x0f,0x09) + +/* + * Write back all modified lines in all levels of cache associated with this + * logical processor to main memory, but do NOT explicitly invalidate caches, + * i.e. leave all/most cache lines in the hierarchy in non-modified state. + */ +static __always_inline void wbnoinvd(void) +{ + /* + * Explicitly encode WBINVD if X86_FEATURE_WBNOINVD is unavailable even + * though WBNOINVD is backwards compatible (it's simply WBINVD with an + * ignored REP prefix), to guarantee that WBNOINVD isn't used if it + * needs to be avoided for any reason. For all supported usage in the + * kernel, WBINVD is functionally a superset of WBNOINVD. + */ + alternative("wbinvd", ASM_WBNOINVD, X86_FEATURE_WBNOINVD); } static inline unsigned long __read_cr4(void) |