root/arch/x86/kernel/cpu/cpuid-deps.c

DEFINITIONS

1. clear_feature
2. do_clear_cpu_cap
3. clear_cpu_cap
4. setup_clear_cpu_cap

   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 static 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 
  75 static 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 
  93 static 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 
 123 void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
 124 {
 125         do_clear_cpu_cap(c, feature);
 126 }
 127 
 128 void setup_clear_cpu_cap(unsigned int feature)
 129 {
 130         do_clear_cpu_cap(NULL, feature);
 131 }