arch/x86/include/asm/cpuid.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * CPUID-related helpers/definitions
   4  */
   5
   6 #ifndef _ASM_X86_CPUID_H
   7 #define _ASM_X86_CPUID_H
   8
   9 #include <asm/string.h>
  10
  11 struct cpuid_regs {
  12         u32 eax, ebx, ecx, edx;
  13 };
  14
  15 enum cpuid_regs_idx {
  16         CPUID_EAX = 0,
  17         CPUID_EBX,
  18         CPUID_ECX,
  19         CPUID_EDX,
  20 };
  21
  22 #ifdef CONFIG_X86_32
  23 extern int have_cpuid_p(void);
  24 #else
  25 static inline int have_cpuid_p(void)
  26 {
  27         return 1;
  28 }
  29 #endif
  30 static inline void native_cpuid(unsigned int *eax, unsigned int *ebx,
  31                                 unsigned int *ecx, unsigned int *edx)
  32 {
  33         /* ecx is often an input as well as an output. */
  34         asm volatile("cpuid"
  35             : "=a" (*eax),
  36               "=b" (*ebx),
  37               "=c" (*ecx),
  38               "=d" (*edx)
  39             : "0" (*eax), "2" (*ecx)
  40             : "memory");
  41 }
  42
  43 #define native_cpuid_reg(reg)                                   \
  44 static inline unsigned int native_cpuid_##reg(unsigned int op)  \
  45 {                                                               \
  46         unsigned int eax = op, ebx, ecx = 0, edx;               \
  47                                                                 \
  48         native_cpuid(&eax, &ebx, &ecx, &edx);                   \
  49                                                                 \
  50         return reg;                                             \
  51 }
  52
  53 /*
  54  * Native CPUID functions returning a single datum.
  55  */
  56 native_cpuid_reg(eax)
  57 native_cpuid_reg(ebx)
  58 native_cpuid_reg(ecx)
  59 native_cpuid_reg(edx)
  60
  61 #ifdef CONFIG_PARAVIRT_XXL
  62 #include <asm/paravirt.h>
  63 #else
  64 #define __cpuid                 native_cpuid
  65 #endif
  66
  67 /*
  68  * Generic CPUID function
  69  * clear %ecx since some cpus (Cyrix MII) do not set or clear %ecx
  70  * resulting in stale register contents being returned.
  71  */
  72 static inline void cpuid(unsigned int op,
  73                          unsigned int *eax, unsigned int *ebx,
  74                          unsigned int *ecx, unsigned int *edx)
  75 {
  76         *eax = op;
  77         *ecx = 0;
  78         __cpuid(eax, ebx, ecx, edx);
  79 }
  80
  81 /* Some CPUID calls want 'count' to be placed in ecx */
  82 static inline void cpuid_count(unsigned int op, int count,
  83                                unsigned int *eax, unsigned int *ebx,
  84                                unsigned int *ecx, unsigned int *edx)
  85 {
  86         *eax = op;
  87         *ecx = count;
  88         __cpuid(eax, ebx, ecx, edx);
  89 }
  90
  91 /*
  92  * CPUID functions returning a single datum
  93  */
  94 static inline unsigned int cpuid_eax(unsigned int op)
  95 {
  96         unsigned int eax, ebx, ecx, edx;
  97
  98         cpuid(op, &eax, &ebx, &ecx, &edx);
  99
 100         return eax;
 101 }
 102
 103 static inline unsigned int cpuid_ebx(unsigned int op)
 104 {
 105         unsigned int eax, ebx, ecx, edx;
 106
 107         cpuid(op, &eax, &ebx, &ecx, &edx);
 108
 109         return ebx;
 110 }
 111
 112 static inline unsigned int cpuid_ecx(unsigned int op)
 113 {
 114         unsigned int eax, ebx, ecx, edx;
 115
 116         cpuid(op, &eax, &ebx, &ecx, &edx);
 117
 118         return ecx;
 119 }
 120
 121 static inline unsigned int cpuid_edx(unsigned int op)
 122 {
 123         unsigned int eax, ebx, ecx, edx;
 124
 125         cpuid(op, &eax, &ebx, &ecx, &edx);
 126
 127         return edx;
 128 }
 129
 130 static inline void __cpuid_read(unsigned int leaf, unsigned int subleaf, u32 *regs)
 131 {
 132         regs[CPUID_EAX] = leaf;
 133         regs[CPUID_ECX] = subleaf;
 134         __cpuid(regs + CPUID_EAX, regs + CPUID_EBX, regs + CPUID_ECX, regs + CPUID_EDX);
 135 }
 136
 137 #define cpuid_subleaf(leaf, subleaf, regs) {            \
 138         static_assert(sizeof(*(regs)) == 16);           \
 139         __cpuid_read(leaf, subleaf, (u32 *)(regs));     \
 140 }
 141
 142 #define cpuid_leaf(leaf, regs) {                        \
 143         static_assert(sizeof(*(regs)) == 16);           \
 144         __cpuid_read(leaf, 0, (u32 *)(regs));           \
 145 }
 146
 147 static inline void __cpuid_read_reg(unsigned int leaf, unsigned int subleaf,
 148                                     enum cpuid_regs_idx regidx, u32 *reg)
 149 {
 150         u32 regs[4];
 151
 152         __cpuid_read(leaf, subleaf, regs);
 153         *reg = regs[regidx];
 154 }
 155
 156 #define cpuid_subleaf_reg(leaf, subleaf, regidx, reg) {         \
 157         static_assert(sizeof(*(reg)) == 4);                     \
 158         __cpuid_read_reg(leaf, subleaf, regidx, (u32 *)(reg));  \
 159 }
 160
 161 #define cpuid_leaf_reg(leaf, regidx, reg) {                     \
 162         static_assert(sizeof(*(reg)) == 4);                     \
 163         __cpuid_read_reg(leaf, 0, regidx, (u32 *)(reg));        \
 164 }
 165
 166 static __always_inline bool cpuid_function_is_indexed(u32 function)
 167 {
 168         switch (function) {
 169         case 4:
 170         case 7:
 171         case 0xb:
 172         case 0xd:
 173         case 0xf:
 174         case 0x10:
 175         case 0x12:
 176         case 0x14:
 177         case 0x17:
 178         case 0x18:
 179         case 0x1d:
 180         case 0x1e:
 181         case 0x1f:
 182         case 0x8000001d:
 183                 return true;
 184         }
 185
 186         return false;
 187 }
 188
 189 #define for_each_possible_hypervisor_cpuid_base(function) \
 190         for (function = 0x40000000; function < 0x40010000; function += 0x100)
 191
 192 static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves)
 193 {
 194         uint32_t base, eax, signature[3];
 195
 196         for_each_possible_hypervisor_cpuid_base(base) {
 197                 cpuid(base, &eax, &signature[0], &signature[1], &signature[2]);
 198
 199                 if (!memcmp(sig, signature, 12) &&
 200                     (leaves == 0 || ((eax - base) >= leaves)))
 201                         return base;
 202         }
 203
 204         return 0;
 205 }
 206
 207 #endif /* _ASM_X86_CPUID_H */