LXR linux/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
  12enum 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_F_0_EDX,
  26        CPUID_F_1_EDX,
  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
  36extern const char * const x86_cap_flags[NCAPINTS*32];
  37extern 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 */
  49extern 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#define REQUIRED_MASK_BIT_SET(feature_bit)              \
  65         ( CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  0, feature_bit) ||    \
  66           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  1, feature_bit) ||    \
  67           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  2, feature_bit) ||    \
  68           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  3, feature_bit) ||    \
  69           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  4, feature_bit) ||    \
  70           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  5, feature_bit) ||    \
  71           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  6, feature_bit) ||    \
  72           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  7, feature_bit) ||    \
  73           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  8, feature_bit) ||    \
  74           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  9, feature_bit) ||    \
  75           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 10, feature_bit) ||    \
  76           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 11, feature_bit) ||    \
  77           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 12, feature_bit) ||    \
  78           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 13, feature_bit) ||    \
  79           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 14, feature_bit) ||    \
  80           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 15, feature_bit) ||    \
  81           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 16, feature_bit) ||    \
  82           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) ||    \
  83           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) ||    \
  84           REQUIRED_MASK_CHECK                                    ||    \
  85           BUILD_BUG_ON_ZERO(NCAPINTS != 19))
  86
  87#define DISABLED_MASK_BIT_SET(feature_bit)                              \
  88         ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  0, feature_bit) ||    \
  89           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  1, feature_bit) ||    \
  90           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  2, feature_bit) ||    \
  91           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  3, feature_bit) ||    \
  92           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  4, feature_bit) ||    \
  93           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  5, feature_bit) ||    \
  94           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  6, feature_bit) ||    \
  95           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  7, feature_bit) ||    \
  96           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  8, feature_bit) ||    \
  97           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  9, feature_bit) ||    \
  98           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 10, feature_bit) ||    \
  99           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 11, feature_bit) ||    \
 100           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 12, feature_bit) ||    \
 101           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 13, feature_bit) ||    \
 102           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 14, feature_bit) ||    \
 103           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 15, feature_bit) ||    \
 104           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 16, feature_bit) ||    \
 105           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) ||    \
 106           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) ||    \
 107           DISABLED_MASK_CHECK                                    ||    \
 108           BUILD_BUG_ON_ZERO(NCAPINTS != 19))
 109
 110#define cpu_has(c, bit)                                                 \
 111        (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :  \
 112         test_cpu_cap(c, bit))
 113
 114#define this_cpu_has(bit)                                               \
 115        (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :  \
 116         x86_this_cpu_test_bit(bit, (unsigned long *)&cpu_info.x86_capability))
 117
 118/*
 119 * This macro is for detection of features which need kernel
 120 * infrastructure to be used.  It may *not* directly test the CPU
 121 * itself.  Use the cpu_has() family if you want true runtime
 122 * testing of CPU features, like in hypervisor code where you are
 123 * supporting a possible guest feature where host support for it
 124 * is not relevant.
 125 */
 126#define cpu_feature_enabled(bit)        \
 127        (__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
 128
 129#define boot_cpu_has(bit)       cpu_has(&boot_cpu_data, bit)
 130
 131#define set_cpu_cap(c, bit)     set_bit(bit, (unsigned long *)((c)->x86_capability))
 132
 133extern void setup_clear_cpu_cap(unsigned int bit);
 134extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit);
 135
 136#define setup_force_cpu_cap(bit) do { \
 137        set_cpu_cap(&boot_cpu_data, bit);       \
 138        set_bit(bit, (unsigned long *)cpu_caps_set);    \
 139} while (0)
 140
 141#define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
 142
 143#if defined(__clang__) && !defined(CC_HAVE_ASM_GOTO)
 144
 145/*
 146 * Workaround for the sake of BPF compilation which utilizes kernel
 147 * headers, but clang does not support ASM GOTO and fails the build.
 148 */
 149#ifndef __BPF_TRACING__
 150#warning "Compiler lacks ASM_GOTO support. Add -D __BPF_TRACING__ to your compiler arguments"
 151#endif
 152
 153#define static_cpu_has(bit)            boot_cpu_has(bit)
 154
 155#else
 156
 157/*
 158 * Static testing of CPU features.  Used the same as boot_cpu_has().
 159 * These will statically patch the target code for additional
 160 * performance.
 161 */
 162static __always_inline __pure bool _static_cpu_has(u16 bit)
 163{
 164        asm_volatile_goto("1: jmp 6f\n"
 165                 "2:\n"
 166                 ".skip -(((5f-4f) - (2b-1b)) > 0) * "
 167                         "((5f-4f) - (2b-1b)),0x90\n"
 168                 "3:\n"
 169                 ".section .altinstructions,\"a\"\n"
 170                 " .long 1b - .\n"              /* src offset */
 171                 " .long 4f - .\n"              /* repl offset */
 172                 " .word %P[always]\n"          /* always replace */
 173                 " .byte 3b - 1b\n"             /* src len */
 174                 " .byte 5f - 4f\n"             /* repl len */
 175                 " .byte 3b - 2b\n"             /* pad len */
 176                 ".previous\n"
 177                 ".section .altinstr_replacement,\"ax\"\n"
 178                 "4: jmp %l[t_no]\n"
 179                 "5:\n"
 180                 ".previous\n"
 181                 ".section .altinstructions,\"a\"\n"
 182                 " .long 1b - .\n"              /* src offset */
 183                 " .long 0\n"                   /* no replacement */
 184                 " .word %P[feature]\n"         /* feature bit */
 185                 " .byte 3b - 1b\n"             /* src len */
 186                 " .byte 0\n"                   /* repl len */
 187                 " .byte 0\n"                   /* pad len */
 188                 ".previous\n"
 189                 ".section .altinstr_aux,\"ax\"\n"
 190                 "6:\n"
 191                 " testb %[bitnum],%[cap_byte]\n"
 192                 " jnz %l[t_yes]\n"
 193                 " jmp %l[t_no]\n"
 194                 ".previous\n"
 195                 : : [feature]  "i" (bit),
 196                     [always]   "i" (X86_FEATURE_ALWAYS),
 197                     [bitnum]   "i" (1 << (bit & 7)),
 198                     [cap_byte] "m" (((const char *)boot_cpu_data.x86_capability)[bit >> 3])
 199                 : : t_yes, t_no);
 200t_yes:
 201        return true;
 202t_no:
 203        return false;
 204}
 205
 206#define static_cpu_has(bit)                                     \
 207(                                                               \
 208        __builtin_constant_p(boot_cpu_has(bit)) ?               \
 209                boot_cpu_has(bit) :                             \
 210                _static_cpu_has(bit)                            \
 211)
 212#endif
 213
 214#define cpu_has_bug(c, bit)             cpu_has(c, (bit))
 215#define set_cpu_bug(c, bit)             set_cpu_cap(c, (bit))
 216#define clear_cpu_bug(c, bit)           clear_cpu_cap(c, (bit))
 217
 218#define static_cpu_has_bug(bit)         static_cpu_has((bit))
 219#define boot_cpu_has_bug(bit)           cpu_has_bug(&boot_cpu_data, (bit))
 220#define boot_cpu_set_bug(bit)           set_cpu_cap(&boot_cpu_data, (bit))
 221
 222#define MAX_CPU_FEATURES                (NCAPINTS * 32)
 223#define cpu_have_feature                boot_cpu_has
 224
 225#define CPU_FEATURE_TYPEFMT             "x86,ven%04Xfam%04Xmod%04X"
 226#define CPU_FEATURE_TYPEVAL             boot_cpu_data.x86_vendor, boot_cpu_data.x86, \
 227                                        boot_cpu_data.x86_model
 228
 229#endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
 230#endif /* _ASM_X86_CPUFEATURE_H */
 231