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#include <asm/alternative.h>
  12
  13enum cpuid_leafs
  14{
  15        CPUID_1_EDX             = 0,
  16        CPUID_8000_0001_EDX,
  17        CPUID_8086_0001_EDX,
  18        CPUID_LNX_1,
  19        CPUID_1_ECX,
  20        CPUID_C000_0001_EDX,
  21        CPUID_8000_0001_ECX,
  22        CPUID_LNX_2,
  23        CPUID_LNX_3,
  24        CPUID_7_0_EBX,
  25        CPUID_D_1_EAX,
  26        CPUID_LNX_4,
  27        CPUID_7_1_EAX,
  28        CPUID_8000_0008_EBX,
  29        CPUID_6_EAX,
  30        CPUID_8000_000A_EDX,
  31        CPUID_7_ECX,
  32        CPUID_8000_0007_EBX,
  33        CPUID_7_EDX,
  34        CPUID_8000_001F_EAX,
  35};
  36
  37#ifdef CONFIG_X86_FEATURE_NAMES
  38extern const char * const x86_cap_flags[NCAPINTS*32];
  39extern const char * const x86_power_flags[32];
  40#define X86_CAP_FMT "%s"
  41#define x86_cap_flag(flag) x86_cap_flags[flag]
  42#else
  43#define X86_CAP_FMT "%d:%d"
  44#define x86_cap_flag(flag) ((flag) >> 5), ((flag) & 31)
  45#endif
  46
  47/*
  48 * In order to save room, we index into this array by doing
  49 * X86_BUG_<name> - NCAPINTS*32.
  50 */
  51extern const char * const x86_bug_flags[NBUGINTS*32];
  52
  53#define test_cpu_cap(c, bit)                                            \
  54         test_bit(bit, (unsigned long *)((c)->x86_capability))
  55
  56/*
  57 * There are 32 bits/features in each mask word.  The high bits
  58 * (selected with (bit>>5) give us the word number and the low 5
  59 * bits give us the bit/feature number inside the word.
  60 * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can
  61 * see if it is set in the mask word.
  62 */
  63#define CHECK_BIT_IN_MASK_WORD(maskname, word, bit)     \
  64        (((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word ))
  65
  66/*
  67 * {REQUIRED,DISABLED}_MASK_CHECK below may seem duplicated with the
  68 * following BUILD_BUG_ON_ZERO() check but when NCAPINTS gets changed, all
  69 * header macros which use NCAPINTS need to be changed. The duplicated macro
  70 * use causes the compiler to issue errors for all headers so that all usage
  71 * sites can be corrected.
  72 */
  73#define REQUIRED_MASK_BIT_SET(feature_bit)              \
  74         ( CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  0, feature_bit) ||    \
  75           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  1, feature_bit) ||    \
  76           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  2, feature_bit) ||    \
  77           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  3, feature_bit) ||    \
  78           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  4, feature_bit) ||    \
  79           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  5, feature_bit) ||    \
  80           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  6, feature_bit) ||    \
  81           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  7, feature_bit) ||    \
  82           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  8, feature_bit) ||    \
  83           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  9, feature_bit) ||    \
  84           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 10, feature_bit) ||    \
  85           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 11, feature_bit) ||    \
  86           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 12, feature_bit) ||    \
  87           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 13, feature_bit) ||    \
  88           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 14, feature_bit) ||    \
  89           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 15, feature_bit) ||    \
  90           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 16, feature_bit) ||    \
  91           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) ||    \
  92           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) ||    \
  93           CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 19, feature_bit) ||    \
  94           REQUIRED_MASK_CHECK                                    ||    \
  95           BUILD_BUG_ON_ZERO(NCAPINTS != 20))
  96
  97#define DISABLED_MASK_BIT_SET(feature_bit)                              \
  98         ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  0, feature_bit) ||    \
  99           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  1, feature_bit) ||    \
 100           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  2, feature_bit) ||    \
 101           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  3, feature_bit) ||    \
 102           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  4, feature_bit) ||    \
 103           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  5, feature_bit) ||    \
 104           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  6, feature_bit) ||    \
 105           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  7, feature_bit) ||    \
 106           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  8, feature_bit) ||    \
 107           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  9, feature_bit) ||    \
 108           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 10, feature_bit) ||    \
 109           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 11, feature_bit) ||    \
 110           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 12, feature_bit) ||    \
 111           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 13, feature_bit) ||    \
 112           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 14, feature_bit) ||    \
 113           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 15, feature_bit) ||    \
 114           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 16, feature_bit) ||    \
 115           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) ||    \
 116           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) ||    \
 117           CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 19, feature_bit) ||    \
 118           DISABLED_MASK_CHECK                                    ||    \
 119           BUILD_BUG_ON_ZERO(NCAPINTS != 20))
 120
 121#define cpu_has(c, bit)                                                 \
 122        (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :  \
 123         test_cpu_cap(c, bit))
 124
 125#define this_cpu_has(bit)                                               \
 126        (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :  \
 127         x86_this_cpu_test_bit(bit,                                     \
 128                (unsigned long __percpu *)&cpu_info.x86_capability))
 129
 130/*
 131 * This macro is for detection of features which need kernel
 132 * infrastructure to be used.  It may *not* directly test the CPU
 133 * itself.  Use the cpu_has() family if you want true runtime
 134 * testing of CPU features, like in hypervisor code where you are
 135 * supporting a possible guest feature where host support for it
 136 * is not relevant.
 137 */
 138#define cpu_feature_enabled(bit)        \
 139        (__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
 140
 141#define boot_cpu_has(bit)       cpu_has(&boot_cpu_data, bit)
 142
 143#define set_cpu_cap(c, bit)     set_bit(bit, (unsigned long *)((c)->x86_capability))
 144
 145extern void setup_clear_cpu_cap(unsigned int bit);
 146extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit);
 147
 148#define setup_force_cpu_cap(bit) do { \
 149        set_cpu_cap(&boot_cpu_data, bit);       \
 150        set_bit(bit, (unsigned long *)cpu_caps_set);    \
 151} while (0)
 152
 153#define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
 154
 155#if defined(__clang__) && !defined(CONFIG_CC_HAS_ASM_GOTO)
 156
 157/*
 158 * Workaround for the sake of BPF compilation which utilizes kernel
 159 * headers, but clang does not support ASM GOTO and fails the build.
 160 */
 161#ifndef __BPF_TRACING__
 162#warning "Compiler lacks ASM_GOTO support. Add -D __BPF_TRACING__ to your compiler arguments"
 163#endif
 164
 165#define static_cpu_has(bit)            boot_cpu_has(bit)
 166
 167#else
 168
 169/*
 170 * Static testing of CPU features. Used the same as boot_cpu_has(). It
 171 * statically patches the target code for additional performance. Use
 172 * static_cpu_has() only in fast paths, where every cycle counts. Which
 173 * means that the boot_cpu_has() variant is already fast enough for the
 174 * majority of cases and you should stick to using it as it is generally
 175 * only two instructions: a RIP-relative MOV and a TEST.
 176 */
 177static __always_inline bool _static_cpu_has(u16 bit)
 178{
 179        asm_volatile_goto(
 180                ALTERNATIVE_TERNARY("jmp 6f", %P[feature], "", "jmp %l[t_no]")
 181                ".section .altinstr_aux,\"ax\"\n"
 182                "6:\n"
 183                " testb %[bitnum],%[cap_byte]\n"
 184                " jnz %l[t_yes]\n"
 185                " jmp %l[t_no]\n"
 186                ".previous\n"
 187                 : : [feature]  "i" (bit),
 188                     [bitnum]   "i" (1 << (bit & 7)),
 189                     [cap_byte] "m" (((const char *)boot_cpu_data.x86_capability)[bit >> 3])
 190                 : : t_yes, t_no);
 191t_yes:
 192        return true;
 193t_no:
 194        return false;
 195}
 196
 197#define static_cpu_has(bit)                                     \
 198(                                                               \
 199        __builtin_constant_p(boot_cpu_has(bit)) ?               \
 200                boot_cpu_has(bit) :                             \
 201                _static_cpu_has(bit)                            \
 202)
 203#endif
 204
 205#define cpu_has_bug(c, bit)             cpu_has(c, (bit))
 206#define set_cpu_bug(c, bit)             set_cpu_cap(c, (bit))
 207#define clear_cpu_bug(c, bit)           clear_cpu_cap(c, (bit))
 208
 209#define static_cpu_has_bug(bit)         static_cpu_has((bit))
 210#define boot_cpu_has_bug(bit)           cpu_has_bug(&boot_cpu_data, (bit))
 211#define boot_cpu_set_bug(bit)           set_cpu_cap(&boot_cpu_data, (bit))
 212
 213#define MAX_CPU_FEATURES                (NCAPINTS * 32)
 214#define cpu_have_feature                boot_cpu_has
 215
 216#define CPU_FEATURE_TYPEFMT             "x86,ven%04Xfam%04Xmod%04X"
 217#define CPU_FEATURE_TYPEVAL             boot_cpu_data.x86_vendor, boot_cpu_data.x86, \
 218                                        boot_cpu_data.x86_model
 219
 220#endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
 221#endif /* _ASM_X86_CPUFEATURE_H */
 222