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Diffstat (limited to '')
| -rw-r--r-- | arch/x86/include/asm/special_insns.h | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h new file mode 100644 index 000000000..317fc59b5 --- /dev/null +++ b/arch/x86/include/asm/special_insns.h @@ -0,0 +1,245 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_SPECIAL_INSNS_H +#define _ASM_X86_SPECIAL_INSNS_H + + +#ifdef __KERNEL__ + +#include <asm/nops.h> + +/* + * Volatile isn't enough to prevent the compiler from reordering the + * read/write functions for the control registers and messing everything up. + * A memory clobber would solve the problem, but would prevent reordering of + * all loads stores around it, which can hurt performance. Solution is to + * use a variable and mimic reads and writes to it to enforce serialization + */ +extern unsigned long __force_order; + +static inline unsigned long native_read_cr0(void) +{ + unsigned long val; + asm volatile("mov %%cr0,%0\n\t" : "=r" (val), "=m" (__force_order)); + return val; +} + +static inline void native_write_cr0(unsigned long val) +{ + asm volatile("mov %0,%%cr0": : "r" (val), "m" (__force_order)); +} + +static inline unsigned long native_read_cr2(void) +{ + unsigned long val; + asm volatile("mov %%cr2,%0\n\t" : "=r" (val), "=m" (__force_order)); + return val; +} + +static inline void native_write_cr2(unsigned long val) +{ + asm volatile("mov %0,%%cr2": : "r" (val), "m" (__force_order)); +} + +static inline unsigned long __native_read_cr3(void) +{ + unsigned long val; + asm volatile("mov %%cr3,%0\n\t" : "=r" (val), "=m" (__force_order)); + return val; +} + +static inline void native_write_cr3(unsigned long val) +{ + asm volatile("mov %0,%%cr3": : "r" (val), "m" (__force_order)); +} + +static inline unsigned long native_read_cr4(void) +{ + unsigned long val; +#ifdef CONFIG_X86_32 + /* + * This could fault if CR4 does not exist. Non-existent CR4 + * is functionally equivalent to CR4 == 0. Keep it simple and pretend + * that CR4 == 0 on CPUs that don't have CR4. + */ + asm volatile("1: mov %%cr4, %0\n" + "2:\n" + _ASM_EXTABLE(1b, 2b) + : "=r" (val), "=m" (__force_order) : "0" (0)); +#else + /* CR4 always exists on x86_64. */ + asm volatile("mov %%cr4,%0\n\t" : "=r" (val), "=m" (__force_order)); +#endif + return val; +} + +static inline void native_write_cr4(unsigned long val) +{ + asm volatile("mov %0,%%cr4": : "r" (val), "m" (__force_order)); +} + +#ifdef CONFIG_X86_64 +static inline unsigned long native_read_cr8(void) +{ + unsigned long cr8; + asm volatile("movq %%cr8,%0" : "=r" (cr8)); + return cr8; +} + +static inline void native_write_cr8(unsigned long val) +{ + asm volatile("movq %0,%%cr8" :: "r" (val) : "memory"); +} +#endif + +#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS +static inline u32 __read_pkru(void) +{ + u32 ecx = 0; + u32 edx, pkru; + + /* + * "rdpkru" instruction. Places PKRU contents in to EAX, + * clears EDX and requires that ecx=0. + */ + asm volatile(".byte 0x0f,0x01,0xee\n\t" + : "=a" (pkru), "=d" (edx) + : "c" (ecx)); + return pkru; +} + +static inline void __write_pkru(u32 pkru) +{ + u32 ecx = 0, edx = 0; + + /* + * "wrpkru" instruction. Loads contents in EAX to PKRU, + * requires that ecx = edx = 0. + */ + asm volatile(".byte 0x0f,0x01,0xef\n\t" + : : "a" (pkru), "c"(ecx), "d"(edx)); +} +#else +static inline u32 __read_pkru(void) +{ + return 0; +} + +static inline void __write_pkru(u32 pkru) +{ +} +#endif + +static inline void native_wbinvd(void) +{ + asm volatile("wbinvd": : :"memory"); +} + +extern asmlinkage void native_load_gs_index(unsigned); + +static inline unsigned long __read_cr4(void) +{ + return native_read_cr4(); +} + +#ifdef CONFIG_PARAVIRT +#include <asm/paravirt.h> +#else + +static inline unsigned long read_cr0(void) +{ + return native_read_cr0(); +} + +static inline void write_cr0(unsigned long x) +{ + native_write_cr0(x); +} + +static inline unsigned long read_cr2(void) +{ + return native_read_cr2(); +} + +static inline void write_cr2(unsigned long x) +{ + native_write_cr2(x); +} + +/* + * Careful! CR3 contains more than just an address. You probably want + * read_cr3_pa() instead. + */ +static inline unsigned long __read_cr3(void) +{ + return __native_read_cr3(); +} + +static inline void write_cr3(unsigned long x) +{ + native_write_cr3(x); +} + +static inline void __write_cr4(unsigned long x) +{ + native_write_cr4(x); +} + +static inline void wbinvd(void) +{ + native_wbinvd(); +} + +#ifdef CONFIG_X86_64 + +static inline unsigned long read_cr8(void) +{ + return native_read_cr8(); +} + +static inline void write_cr8(unsigned long x) +{ + native_write_cr8(x); +} + +static inline void load_gs_index(unsigned selector) +{ + native_load_gs_index(selector); +} + +#endif + +#endif/* CONFIG_PARAVIRT */ + +static inline void clflush(volatile void *__p) +{ + asm volatile("clflush %0" : "+m" (*(volatile char __force *)__p)); +} + +static inline void clflushopt(volatile void *__p) +{ + alternative_io(".byte " __stringify(NOP_DS_PREFIX) "; clflush %P0", + ".byte 0x66; clflush %P0", + X86_FEATURE_CLFLUSHOPT, + "+m" (*(volatile char __force *)__p)); +} + +static inline void clwb(volatile void *__p) +{ + volatile struct { char x[64]; } *p = __p; + + asm volatile(ALTERNATIVE_2( + ".byte " __stringify(NOP_DS_PREFIX) "; clflush (%[pax])", + ".byte 0x66; clflush (%[pax])", /* clflushopt (%%rax) */ + X86_FEATURE_CLFLUSHOPT, + ".byte 0x66, 0x0f, 0xae, 0x30", /* clwb (%%rax) */ + X86_FEATURE_CLWB) + : [p] "+m" (*p) + : [pax] "a" (p)); +} + +#define nop() asm volatile ("nop") + + +#endif /* __KERNEL__ */ + +#endif /* _ASM_X86_SPECIAL_INSNS_H */ |