LXR linux/arch/x86/kernel/cpu/cpuid-deps.c

   1/* Declare dependencies between CPUIDs */
   2#include <linux/kernel.h>
   3#include <linux/init.h>
   4#include <linux/module.h>
   5#include <asm/cpufeature.h>
   6
   7struct cpuid_dep {
   8        unsigned int    feature;
   9        unsigned int    depends;
  10};
  11
  12/*
  13 * Table of CPUID features that depend on others.
  14 *
  15 * This only includes dependencies that can be usefully disabled, not
  16 * features part of the base set (like FPU).
  17 *
  18 * Note this all is not __init / __initdata because it can be
  19 * called from cpu hotplug. It shouldn't do anything in this case,
  20 * but it's difficult to tell that to the init reference checker.
  21 */
  22static const struct cpuid_dep cpuid_deps[] = {
  23        { X86_FEATURE_FXSR,                     X86_FEATURE_FPU       },
  24        { X86_FEATURE_XSAVEOPT,                 X86_FEATURE_XSAVE     },
  25        { X86_FEATURE_XSAVEC,                   X86_FEATURE_XSAVE     },
  26        { X86_FEATURE_XSAVES,                   X86_FEATURE_XSAVE     },
  27        { X86_FEATURE_AVX,                      X86_FEATURE_XSAVE     },
  28        { X86_FEATURE_PKU,                      X86_FEATURE_XSAVE     },
  29        { X86_FEATURE_MPX,                      X86_FEATURE_XSAVE     },
  30        { X86_FEATURE_XGETBV1,                  X86_FEATURE_XSAVE     },
  31        { X86_FEATURE_CMOV,                     X86_FEATURE_FXSR      },
  32        { X86_FEATURE_MMX,                      X86_FEATURE_FXSR      },
  33        { X86_FEATURE_MMXEXT,                   X86_FEATURE_MMX       },
  34        { X86_FEATURE_FXSR_OPT,                 X86_FEATURE_FXSR      },
  35        { X86_FEATURE_XSAVE,                    X86_FEATURE_FXSR      },
  36        { X86_FEATURE_XMM,                      X86_FEATURE_FXSR      },
  37        { X86_FEATURE_XMM2,                     X86_FEATURE_XMM       },
  38        { X86_FEATURE_XMM3,                     X86_FEATURE_XMM2      },
  39        { X86_FEATURE_XMM4_1,                   X86_FEATURE_XMM2      },
  40        { X86_FEATURE_XMM4_2,                   X86_FEATURE_XMM2      },
  41        { X86_FEATURE_XMM3,                     X86_FEATURE_XMM2      },
  42        { X86_FEATURE_PCLMULQDQ,                X86_FEATURE_XMM2      },
  43        { X86_FEATURE_SSSE3,                    X86_FEATURE_XMM2,     },
  44        { X86_FEATURE_F16C,                     X86_FEATURE_XMM2,     },
  45        { X86_FEATURE_AES,                      X86_FEATURE_XMM2      },
  46        { X86_FEATURE_SHA_NI,                   X86_FEATURE_XMM2      },
  47        { X86_FEATURE_FMA,                      X86_FEATURE_AVX       },
  48        { X86_FEATURE_AVX2,                     X86_FEATURE_AVX,      },
  49        { X86_FEATURE_AVX512F,                  X86_FEATURE_AVX,      },
  50        { X86_FEATURE_AVX512IFMA,               X86_FEATURE_AVX512F   },
  51        { X86_FEATURE_AVX512PF,                 X86_FEATURE_AVX512F   },
  52        { X86_FEATURE_AVX512ER,                 X86_FEATURE_AVX512F   },
  53        { X86_FEATURE_AVX512CD,                 X86_FEATURE_AVX512F   },
  54        { X86_FEATURE_AVX512DQ,                 X86_FEATURE_AVX512F   },
  55        { X86_FEATURE_AVX512BW,                 X86_FEATURE_AVX512F   },
  56        { X86_FEATURE_AVX512VL,                 X86_FEATURE_AVX512F   },
  57        { X86_FEATURE_AVX512VBMI,               X86_FEATURE_AVX512F   },
  58        { X86_FEATURE_AVX512_VBMI2,             X86_FEATURE_AVX512VL  },
  59        { X86_FEATURE_GFNI,                     X86_FEATURE_AVX512VL  },
  60        { X86_FEATURE_VAES,                     X86_FEATURE_AVX512VL  },
  61        { X86_FEATURE_VPCLMULQDQ,               X86_FEATURE_AVX512VL  },
  62        { X86_FEATURE_AVX512_VNNI,              X86_FEATURE_AVX512VL  },
  63        { X86_FEATURE_AVX512_BITALG,            X86_FEATURE_AVX512VL  },
  64        { X86_FEATURE_AVX512_4VNNIW,            X86_FEATURE_AVX512F   },
  65        { X86_FEATURE_AVX512_4FMAPS,            X86_FEATURE_AVX512F   },
  66        { X86_FEATURE_AVX512_VPOPCNTDQ,         X86_FEATURE_AVX512F   },
  67        { X86_FEATURE_AVX512_VP2INTERSECT,      X86_FEATURE_AVX512VL  },
  68        { X86_FEATURE_CQM_OCCUP_LLC,            X86_FEATURE_CQM_LLC   },
  69        { X86_FEATURE_CQM_MBM_TOTAL,            X86_FEATURE_CQM_LLC   },
  70        { X86_FEATURE_CQM_MBM_LOCAL,            X86_FEATURE_CQM_LLC   },
  71        { X86_FEATURE_AVX512_BF16,              X86_FEATURE_AVX512VL  },
  72        {}
  73};
  74
  75static inline void clear_feature(struct cpuinfo_x86 *c, unsigned int feature)
  76{
  77        /*
  78         * Note: This could use the non atomic __*_bit() variants, but the
  79         * rest of the cpufeature code uses atomics as well, so keep it for
  80         * consistency. Cleanup all of it separately.
  81         */
  82        if (!c) {
  83                clear_cpu_cap(&boot_cpu_data, feature);
  84                set_bit(feature, (unsigned long *)cpu_caps_cleared);
  85        } else {
  86                clear_bit(feature, (unsigned long *)c->x86_capability);
  87        }
  88}
  89
  90/* Take the capabilities and the BUG bits into account */
  91#define MAX_FEATURE_BITS ((NCAPINTS + NBUGINTS) * sizeof(u32) * 8)
  92
  93static void do_clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
  94{
  95        DECLARE_BITMAP(disable, MAX_FEATURE_BITS);
  96        const struct cpuid_dep *d;
  97        bool changed;
  98
  99        if (WARN_ON(feature >= MAX_FEATURE_BITS))
 100                return;
 101
 102        clear_feature(c, feature);
 103
 104        /* Collect all features to disable, handling dependencies */
 105        memset(disable, 0, sizeof(disable));
 106        __set_bit(feature, disable);
 107
 108        /* Loop until we get a stable state. */
 109        do {
 110                changed = false;
 111                for (d = cpuid_deps; d->feature; d++) {
 112                        if (!test_bit(d->depends, disable))
 113                                continue;
 114                        if (__test_and_set_bit(d->feature, disable))
 115                                continue;
 116
 117                        changed = true;
 118                        clear_feature(c, d->feature);
 119                }
 120        } while (changed);
 121}
 122
 123void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
 124{
 125        do_clear_cpu_cap(c, feature);
 126}
 127
 128void setup_clear_cpu_cap(unsigned int feature)
 129{
 130        do_clear_cpu_cap(NULL, feature);
 131}
 132