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Diffstat (limited to '')
| -rw-r--r-- | arch/x86/include/asm/cpuid/api.h | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/arch/x86/include/asm/cpuid/api.h b/arch/x86/include/asm/cpuid/api.h new file mode 100644 index 000000000000..4d1da9cc8b6f --- /dev/null +++ b/arch/x86/include/asm/cpuid/api.h @@ -0,0 +1,208 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _ASM_X86_CPUID_API_H +#define _ASM_X86_CPUID_API_H + +#include <linux/build_bug.h> +#include <linux/types.h> + +#include <asm/cpuid/types.h> +#include <asm/string.h> + +/* + * Raw CPUID accessors + */ + +#ifdef CONFIG_X86_32 +bool have_cpuid_p(void); +#else +static inline bool have_cpuid_p(void) +{ + return true; +} +#endif +static inline void native_cpuid(unsigned int *eax, unsigned int *ebx, + unsigned int *ecx, unsigned int *edx) +{ + /* ecx is often an input as well as an output. */ + asm volatile("cpuid" + : "=a" (*eax), + "=b" (*ebx), + "=c" (*ecx), + "=d" (*edx) + : "0" (*eax), "2" (*ecx) + : "memory"); +} + +#define native_cpuid_reg(reg) \ +static inline unsigned int native_cpuid_##reg(unsigned int op) \ +{ \ + unsigned int eax = op, ebx, ecx = 0, edx; \ + \ + native_cpuid(&eax, &ebx, &ecx, &edx); \ + \ + return reg; \ +} + +/* + * Native CPUID functions returning a single datum. + */ +native_cpuid_reg(eax) +native_cpuid_reg(ebx) +native_cpuid_reg(ecx) +native_cpuid_reg(edx) + +#ifdef CONFIG_PARAVIRT_XXL +#include <asm/paravirt.h> +#else +#define __cpuid native_cpuid +#endif + +/* + * Generic CPUID function + * clear %ecx since some cpus (Cyrix MII) do not set or clear %ecx + * resulting in stale register contents being returned. + */ +static inline void cpuid(unsigned int op, + unsigned int *eax, unsigned int *ebx, + unsigned int *ecx, unsigned int *edx) +{ + *eax = op; + *ecx = 0; + __cpuid(eax, ebx, ecx, edx); +} + +/* Some CPUID calls want 'count' to be placed in ecx */ +static inline void cpuid_count(unsigned int op, int count, + unsigned int *eax, unsigned int *ebx, + unsigned int *ecx, unsigned int *edx) +{ + *eax = op; + *ecx = count; + __cpuid(eax, ebx, ecx, edx); +} + +/* + * CPUID functions returning a single datum + */ + +static inline unsigned int cpuid_eax(unsigned int op) +{ + unsigned int eax, ebx, ecx, edx; + + cpuid(op, &eax, &ebx, &ecx, &edx); + + return eax; +} + +static inline unsigned int cpuid_ebx(unsigned int op) +{ + unsigned int eax, ebx, ecx, edx; + + cpuid(op, &eax, &ebx, &ecx, &edx); + + return ebx; +} + +static inline unsigned int cpuid_ecx(unsigned int op) +{ + unsigned int eax, ebx, ecx, edx; + + cpuid(op, &eax, &ebx, &ecx, &edx); + + return ecx; +} + +static inline unsigned int cpuid_edx(unsigned int op) +{ + unsigned int eax, ebx, ecx, edx; + + cpuid(op, &eax, &ebx, &ecx, &edx); + + return edx; +} + +static inline void __cpuid_read(unsigned int leaf, unsigned int subleaf, u32 *regs) +{ + regs[CPUID_EAX] = leaf; + regs[CPUID_ECX] = subleaf; + __cpuid(regs + CPUID_EAX, regs + CPUID_EBX, regs + CPUID_ECX, regs + CPUID_EDX); +} + +#define cpuid_subleaf(leaf, subleaf, regs) { \ + static_assert(sizeof(*(regs)) == 16); \ + __cpuid_read(leaf, subleaf, (u32 *)(regs)); \ +} + +#define cpuid_leaf(leaf, regs) { \ + static_assert(sizeof(*(regs)) == 16); \ + __cpuid_read(leaf, 0, (u32 *)(regs)); \ +} + +static inline void __cpuid_read_reg(unsigned int leaf, unsigned int subleaf, + enum cpuid_regs_idx regidx, u32 *reg) +{ + u32 regs[4]; + + __cpuid_read(leaf, subleaf, regs); + *reg = regs[regidx]; +} + +#define cpuid_subleaf_reg(leaf, subleaf, regidx, reg) { \ + static_assert(sizeof(*(reg)) == 4); \ + __cpuid_read_reg(leaf, subleaf, regidx, (u32 *)(reg)); \ +} + +#define cpuid_leaf_reg(leaf, regidx, reg) { \ + static_assert(sizeof(*(reg)) == 4); \ + __cpuid_read_reg(leaf, 0, regidx, (u32 *)(reg)); \ +} + +static __always_inline bool cpuid_function_is_indexed(u32 function) +{ + switch (function) { + case 4: + case 7: + case 0xb: + case 0xd: + case 0xf: + case 0x10: + case 0x12: + case 0x14: + case 0x17: + case 0x18: + case 0x1d: + case 0x1e: + case 0x1f: + case 0x24: + case 0x8000001d: + return true; + } + + return false; +} + +#define for_each_possible_hypervisor_cpuid_base(function) \ + for (function = 0x40000000; function < 0x40010000; function += 0x100) + +static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves) +{ + uint32_t base, eax, signature[3]; + + for_each_possible_hypervisor_cpuid_base(base) { + cpuid(base, &eax, &signature[0], &signature[1], &signature[2]); + + /* + * This must not compile to "call memcmp" because it's called + * from PVH early boot code before instrumentation is set up + * and memcmp() itself may be instrumented. + */ + if (!__builtin_memcmp(sig, signature, 12) && + (leaves == 0 || ((eax - base) >= leaves))) + return base; + } + + return 0; +} + +#endif /* _ASM_X86_CPUID_API_H */ |