arch/x86/include/asm/cpufeature.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_X86_CPUFEATURE_H
   3 #define _ASM_X86_CPUFEATURE_H
   4
   5 #include <asm/processor.h>
   6
   7 #if defined(__KERNEL__) && !defined(__ASSEMBLY__)
   8
   9 #include <asm/asm.h>
  10 #include <linux/bitops.h>
  11
  12 enum cpuid_leafs
  13 {
  14         CPUID_1_EDX             = 0,
  15         CPUID_8000_0001_EDX,
  16         CPUID_8086_0001_EDX,
  17         CPUID_LNX_1,
  18         CPUID_1_ECX,
  19         CPUID_C000_0001_EDX,
  20         CPUID_8000_0001_ECX,
  21         CPUID_LNX_2,
  22         CPUID_LNX_3,
  23         CPUID_7_0_EBX,
  24         CPUID_D_1_EAX,
  25         CPUID_LNX_4,
  26         CPUID_7_1_EAX,
  27         CPUID_8000_0008_EBX,
  28         CPUID_6_EAX,
  29         CPUID_8000_000A_EDX,
  30         CPUID_7_ECX,
  31         CPUID_8000_0007_EBX,
  32         CPUID_7_EDX,
  33 };
  34
  35 #ifdef CONFIG_X86_FEATURE_NAMES
  36 extern const char * const x86_cap_flags[NCAPINTS*32];
  37 extern const char * const x86_power_flags[32];
  38 #define X86_CAP_FMT "%s"
  39 #define x86_cap_flag(flag) x86_cap_flags[flag]
  40 #else
  41 #define X86_CAP_FMT "%d:%d"
  42 #define x86_cap_flag(flag) ((flag) >> 5), ((flag) & 31)
  43 #endif
  44
  45 /*
  46  * In order to save room, we index into this array by doing
  47  * X86_BUG_<name> - NCAPINTS*32.
  48  */
  49 extern const char * const x86_bug_flags[NBUGINTS*32];
  50
  51 #define test_cpu_cap(c, bit)                                            \
  52          test_bit(bit, (unsigned long *)((c)->x86_capability))
  53
  54 /*
  55  * There are 32 bits/features in each mask word.  The high bits
  56  * (selected with (bit>>5) give us the word number and the low 5
  57  * bits give us the bit/feature number inside the word.
  58  * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can
  59  * see if it is set in the mask word.
  60  */
  61 #define CHECK_BIT_IN_MASK_WORD(maskname, word, bit)     \
  62         (((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word ))
  63
  64 /*
  65  * {REQUIRED,DISABLED}_MASK_CHECK below may seem duplicated with the
  66  * following BUILD_BUG_ON_ZERO() check but when NCAPINTS gets changed, all
  67  * header macros which use NCAPINTS need to be changed. The duplicated macro
  68  * use causes the compiler to issue errors for all headers so that all usage
  69  * sites can be corrected.
  70  */
  71 #define REQUIRED_MASK_BIT_SET(feature_bit)              \
  72          ( CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  0, feature_bit) ||    \
  73            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  1, feature_bit) ||    \
  74            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  2, feature_bit) ||    \
  75            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  3, feature_bit) ||    \
  76            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  4, feature_bit) ||    \
  77            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  5, feature_bit) ||    \
  78            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  6, feature_bit) ||    \
  79            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  7, feature_bit) ||    \
  80            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  8, feature_bit) ||    \
  81            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  9, feature_bit) ||    \
  82            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 10, feature_bit) ||    \
  83            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 11, feature_bit) ||    \
  84            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 12, feature_bit) ||    \
  85            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 13, feature_bit) ||    \
  86            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 14, feature_bit) ||    \
  87            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 15, feature_bit) ||    \
  88            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 16, feature_bit) ||    \
  89            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) ||    \
  90            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) ||    \
  91            REQUIRED_MASK_CHECK                                    ||    \
  92            BUILD_BUG_ON_ZERO(NCAPINTS != 19))
  93
  94 #define DISABLED_MASK_BIT_SET(feature_bit)                              \
  95          ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  0, feature_bit) ||    \
  96            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  1, feature_bit) ||    \
  97            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  2, feature_bit) ||    \
  98            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  3, feature_bit) ||    \
  99            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  4, feature_bit) ||    \
 100            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  5, feature_bit) ||    \
 101            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  6, feature_bit) ||    \
 102            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  7, feature_bit) ||    \
 103            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  8, feature_bit) ||    \
 104            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  9, feature_bit) ||    \
 105            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 10, feature_bit) ||    \
 106            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 11, feature_bit) ||    \
 107            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 12, feature_bit) ||    \
 108            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 13, feature_bit) ||    \
 109            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 14, feature_bit) ||    \
 110            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 15, feature_bit) ||    \
 111            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 16, feature_bit) ||    \
 112            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) ||    \
 113            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) ||    \
 114            DISABLED_MASK_CHECK                                    ||    \
 115            BUILD_BUG_ON_ZERO(NCAPINTS != 19))
 116
 117 #define cpu_has(c, bit)                                                 \
 118         (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :  \
 119          test_cpu_cap(c, bit))
 120
 121 #define this_cpu_has(bit)                                               \
 122         (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :  \
 123          x86_this_cpu_test_bit(bit,                                     \
 124                 (unsigned long __percpu *)&cpu_info.x86_capability))
 125
 126 /*
 127  * This macro is for detection of features which need kernel
 128  * infrastructure to be used.  It may *not* directly test the CPU
 129  * itself.  Use the cpu_has() family if you want true runtime
 130  * testing of CPU features, like in hypervisor code where you are
 131  * supporting a possible guest feature where host support for it
 132  * is not relevant.
 133  */
 134 #define cpu_feature_enabled(bit)        \
 135         (__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
 136
 137 #define boot_cpu_has(bit)       cpu_has(&boot_cpu_data, bit)
 138
 139 #define set_cpu_cap(c, bit)     set_bit(bit, (unsigned long *)((c)->x86_capability))
 140
 141 extern void setup_clear_cpu_cap(unsigned int bit);
 142 extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit);
 143
 144 #define setup_force_cpu_cap(bit) do { \
 145         set_cpu_cap(&boot_cpu_data, bit);       \
 146         set_bit(bit, (unsigned long *)cpu_caps_set);    \
 147 } while (0)
 148
 149 #define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
 150
 151 #if defined(__clang__) && !defined(CONFIG_CC_HAS_ASM_GOTO)
 152
 153 /*
 154  * Workaround for the sake of BPF compilation which utilizes kernel
 155  * headers, but clang does not support ASM GOTO and fails the build.
 156  */
 157 #ifndef __BPF_TRACING__
 158 #warning "Compiler lacks ASM_GOTO support. Add -D __BPF_TRACING__ to your compiler arguments"
 159 #endif
 160
 161 #define static_cpu_has(bit)            boot_cpu_has(bit)
 162
 163 #else
 164
 165 /*
 166  * Static testing of CPU features. Used the same as boot_cpu_has(). It
 167  * statically patches the target code for additional performance. Use
 168  * static_cpu_has() only in fast paths, where every cycle counts. Which
 169  * means that the boot_cpu_has() variant is already fast enough for the
 170  * majority of cases and you should stick to using it as it is generally
 171  * only two instructions: a RIP-relative MOV and a TEST.
 172  */
 173 static __always_inline bool _static_cpu_has(u16 bit)
 174 {
 175         asm_volatile_goto("1: jmp 6f\n"
 176                  "2:\n"
 177                  ".skip -(((5f-4f) - (2b-1b)) > 0) * "
 178                          "((5f-4f) - (2b-1b)),0x90\n"
 179                  "3:\n"
 180                  ".section .altinstructions,\"a\"\n"
 181                  " .long 1b - .\n"              /* src offset */
 182                  " .long 4f - .\n"              /* repl offset */
 183                  " .word %P[always]\n"          /* always replace */
 184                  " .byte 3b - 1b\n"             /* src len */
 185                  " .byte 5f - 4f\n"             /* repl len */
 186                  " .byte 3b - 2b\n"             /* pad len */
 187                  ".previous\n"
 188                  ".section .altinstr_replacement,\"ax\"\n"
 189                  "4: jmp %l[t_no]\n"
 190                  "5:\n"
 191                  ".previous\n"
 192                  ".section .altinstructions,\"a\"\n"
 193                  " .long 1b - .\n"              /* src offset */
 194                  " .long 0\n"                   /* no replacement */
 195                  " .word %P[feature]\n"         /* feature bit */
 196                  " .byte 3b - 1b\n"             /* src len */
 197                  " .byte 0\n"                   /* repl len */
 198                  " .byte 0\n"                   /* pad len */
 199                  ".previous\n"
 200                  ".section .altinstr_aux,\"ax\"\n"
 201                  "6:\n"
 202                  " testb %[bitnum],%[cap_byte]\n"
 203                  " jnz %l[t_yes]\n"
 204                  " jmp %l[t_no]\n"
 205                  ".previous\n"
 206                  : : [feature]  "i" (bit),
 207                      [always]   "i" (X86_FEATURE_ALWAYS),
 208                      [bitnum]   "i" (1 << (bit & 7)),
 209                      [cap_byte] "m" (((const char *)boot_cpu_data.x86_capability)[bit >> 3])
 210                  : : t_yes, t_no);
 211 t_yes:
 212         return true;
 213 t_no:
 214         return false;
 215 }
 216
 217 #define static_cpu_has(bit)                                     \
 218 (                                                               \
 219         __builtin_constant_p(boot_cpu_has(bit)) ?               \
 220                 boot_cpu_has(bit) :                             \
 221                 _static_cpu_has(bit)                            \
 222 )
 223 #endif
 224
 225 #define cpu_has_bug(c, bit)             cpu_has(c, (bit))
 226 #define set_cpu_bug(c, bit)             set_cpu_cap(c, (bit))
 227 #define clear_cpu_bug(c, bit)           clear_cpu_cap(c, (bit))
 228
 229 #define static_cpu_has_bug(bit)         static_cpu_has((bit))
 230 #define boot_cpu_has_bug(bit)           cpu_has_bug(&boot_cpu_data, (bit))
 231 #define boot_cpu_set_bug(bit)           set_cpu_cap(&boot_cpu_data, (bit))
 232
 233 #define MAX_CPU_FEATURES                (NCAPINTS * 32)
 234 #define cpu_have_feature                boot_cpu_has
 235
 236 #define CPU_FEATURE_TYPEFMT             "x86,ven%04Xfam%04Xmod%04X"
 237 #define CPU_FEATURE_TYPEVAL             boot_cpu_data.x86_vendor, boot_cpu_data.x86, \
 238                                         boot_cpu_data.x86_model
 239
 240 #endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
 241 #endif /* _ASM_X86_CPUFEATURE_H */