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
   7 struct 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  */
  22 const static struct cpuid_dep cpuid_deps[] = {
  23         { X86_FEATURE_XSAVEOPT,         X86_FEATURE_XSAVE     },
  24         { X86_FEATURE_XSAVEC,           X86_FEATURE_XSAVE     },
  25         { X86_FEATURE_XSAVES,           X86_FEATURE_XSAVE     },
  26         { X86_FEATURE_AVX,              X86_FEATURE_XSAVE     },
  27         { X86_FEATURE_PKU,              X86_FEATURE_XSAVE     },
  28         { X86_FEATURE_MPX,              X86_FEATURE_XSAVE     },
  29         { X86_FEATURE_XGETBV1,          X86_FEATURE_XSAVE     },
  30         { X86_FEATURE_FXSR_OPT,         X86_FEATURE_FXSR      },
  31         { X86_FEATURE_XMM,              X86_FEATURE_FXSR      },
  32         { X86_FEATURE_XMM2,             X86_FEATURE_XMM       },
  33         { X86_FEATURE_XMM3,             X86_FEATURE_XMM2      },
  34         { X86_FEATURE_XMM4_1,           X86_FEATURE_XMM2      },
  35         { X86_FEATURE_XMM4_2,           X86_FEATURE_XMM2      },
  36         { X86_FEATURE_XMM3,             X86_FEATURE_XMM2      },
  37         { X86_FEATURE_PCLMULQDQ,        X86_FEATURE_XMM2      },
  38         { X86_FEATURE_SSSE3,            X86_FEATURE_XMM2,     },
  39         { X86_FEATURE_F16C,             X86_FEATURE_XMM2,     },
  40         { X86_FEATURE_AES,              X86_FEATURE_XMM2      },
  41         { X86_FEATURE_SHA_NI,           X86_FEATURE_XMM2      },
  42         { X86_FEATURE_FMA,              X86_FEATURE_AVX       },
  43         { X86_FEATURE_AVX2,             X86_FEATURE_AVX,      },
  44         { X86_FEATURE_AVX512F,          X86_FEATURE_AVX,      },
  45         { X86_FEATURE_AVX512IFMA,       X86_FEATURE_AVX512F   },
  46         { X86_FEATURE_AVX512PF,         X86_FEATURE_AVX512F   },
  47         { X86_FEATURE_AVX512ER,         X86_FEATURE_AVX512F   },
  48         { X86_FEATURE_AVX512CD,         X86_FEATURE_AVX512F   },
  49         { X86_FEATURE_AVX512DQ,         X86_FEATURE_AVX512F   },
  50         { X86_FEATURE_AVX512BW,         X86_FEATURE_AVX512F   },
  51         { X86_FEATURE_AVX512VL,         X86_FEATURE_AVX512F   },
  52         { X86_FEATURE_AVX512VBMI,       X86_FEATURE_AVX512F   },
  53         { X86_FEATURE_AVX512_VBMI2,     X86_FEATURE_AVX512VL  },
  54         { X86_FEATURE_GFNI,             X86_FEATURE_AVX512VL  },
  55         { X86_FEATURE_VAES,             X86_FEATURE_AVX512VL  },
  56         { X86_FEATURE_VPCLMULQDQ,       X86_FEATURE_AVX512VL  },
  57         { X86_FEATURE_AVX512_VNNI,      X86_FEATURE_AVX512VL  },
  58         { X86_FEATURE_AVX512_BITALG,    X86_FEATURE_AVX512VL  },
  59         { X86_FEATURE_AVX512_4VNNIW,    X86_FEATURE_AVX512F   },
  60         { X86_FEATURE_AVX512_4FMAPS,    X86_FEATURE_AVX512F   },
  61         { X86_FEATURE_AVX512_VPOPCNTDQ, X86_FEATURE_AVX512F   },
  62         {}
  63 };
  64
  65 static inline void clear_feature(struct cpuinfo_x86 *c, unsigned int feature)
  66 {
  67         /*
  68          * Note: This could use the non atomic __*_bit() variants, but the
  69          * rest of the cpufeature code uses atomics as well, so keep it for
  70          * consistency. Cleanup all of it separately.
  71          */
  72         if (!c) {
  73                 clear_cpu_cap(&boot_cpu_data, feature);
  74                 set_bit(feature, (unsigned long *)cpu_caps_cleared);
  75         } else {
  76                 clear_bit(feature, (unsigned long *)c->x86_capability);
  77         }
  78 }
  79
  80 /* Take the capabilities and the BUG bits into account */
  81 #define MAX_FEATURE_BITS ((NCAPINTS + NBUGINTS) * sizeof(u32) * 8)
  82
  83 static void do_clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
  84 {
  85         DECLARE_BITMAP(disable, MAX_FEATURE_BITS);
  86         const struct cpuid_dep *d;
  87         bool changed;
  88
  89         if (WARN_ON(feature >= MAX_FEATURE_BITS))
  90                 return;
  91
  92         clear_feature(c, feature);
  93
  94         /* Collect all features to disable, handling dependencies */
  95         memset(disable, 0, sizeof(disable));
  96         __set_bit(feature, disable);
  97
  98         /* Loop until we get a stable state. */
  99         do {
 100                 changed = false;
 101                 for (d = cpuid_deps; d->feature; d++) {
 102                         if (!test_bit(d->depends, disable))
 103                                 continue;
 104                         if (__test_and_set_bit(d->feature, disable))
 105                                 continue;
 106
 107                         changed = true;
 108                         clear_feature(c, d->feature);
 109                 }
 110         } while (changed);
 111 }
 112
 113 void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
 114 {
 115         do_clear_cpu_cap(c, feature);
 116 }
 117
 118 void setup_clear_cpu_cap(unsigned int feature)
 119 {
 120         do_clear_cpu_cap(NULL, feature);
 121 }