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_APX, X86_FEATURE_XSAVE },
32 { X86_FEATURE_CMOV, X86_FEATURE_FXSR },
33 { X86_FEATURE_MMX, X86_FEATURE_FXSR },
34 { X86_FEATURE_MMXEXT, X86_FEATURE_MMX },
35 { X86_FEATURE_FXSR_OPT, X86_FEATURE_FXSR },
36 { X86_FEATURE_XSAVE, X86_FEATURE_FXSR },
37 { X86_FEATURE_XMM, X86_FEATURE_FXSR },
38 { X86_FEATURE_XMM2, X86_FEATURE_XMM },
39 { X86_FEATURE_XMM3, X86_FEATURE_XMM2 },
40 { X86_FEATURE_XMM4_1, X86_FEATURE_XMM2 },
41 { X86_FEATURE_XMM4_2, X86_FEATURE_XMM2 },
42 { X86_FEATURE_XMM3, X86_FEATURE_XMM2 },
43 { X86_FEATURE_PCLMULQDQ, X86_FEATURE_XMM2 },
44 { X86_FEATURE_SSSE3, X86_FEATURE_XMM2, },
45 { X86_FEATURE_F16C, X86_FEATURE_XMM2, },
46 { X86_FEATURE_AES, X86_FEATURE_XMM2 },
47 { X86_FEATURE_SHA_NI, X86_FEATURE_XMM2 },
48 { X86_FEATURE_GFNI, X86_FEATURE_XMM2 },
49 { X86_FEATURE_AVX_VNNI, X86_FEATURE_AVX },
50 { X86_FEATURE_FMA, X86_FEATURE_AVX },
51 { X86_FEATURE_VAES, X86_FEATURE_AVX },
52 { X86_FEATURE_VPCLMULQDQ, X86_FEATURE_AVX },
53 { X86_FEATURE_AVX2, X86_FEATURE_AVX, },
54 { X86_FEATURE_AVX512F, X86_FEATURE_AVX, },
55 { X86_FEATURE_AVX512IFMA, X86_FEATURE_AVX512F },
56 { X86_FEATURE_AVX512PF, X86_FEATURE_AVX512F },
57 { X86_FEATURE_AVX512ER, X86_FEATURE_AVX512F },
58 { X86_FEATURE_AVX512CD, X86_FEATURE_AVX512F },
59 { X86_FEATURE_AVX512DQ, X86_FEATURE_AVX512F },
60 { X86_FEATURE_AVX512BW, X86_FEATURE_AVX512F },
61 { X86_FEATURE_AVX512VL, X86_FEATURE_AVX512F },
62 { X86_FEATURE_AVX512VBMI, X86_FEATURE_AVX512F },
63 { X86_FEATURE_AVX512_VBMI2, X86_FEATURE_AVX512VL },
64 { X86_FEATURE_AVX512_VNNI, X86_FEATURE_AVX512VL },
65 { X86_FEATURE_AVX512_BITALG, X86_FEATURE_AVX512VL },
66 { X86_FEATURE_AVX512_4VNNIW, X86_FEATURE_AVX512F },
67 { X86_FEATURE_AVX512_4FMAPS, X86_FEATURE_AVX512F },
68 { X86_FEATURE_AVX512_VPOPCNTDQ, X86_FEATURE_AVX512F },
69 { X86_FEATURE_AVX512_VP2INTERSECT, X86_FEATURE_AVX512VL },
70 { X86_FEATURE_CQM_OCCUP_LLC, X86_FEATURE_CQM_LLC },
71 { X86_FEATURE_CQM_MBM_TOTAL, X86_FEATURE_CQM_LLC },
72 { X86_FEATURE_CQM_MBM_LOCAL, X86_FEATURE_CQM_LLC },
73 { X86_FEATURE_BMEC, X86_FEATURE_CQM_MBM_TOTAL },
74 { X86_FEATURE_BMEC, X86_FEATURE_CQM_MBM_LOCAL },
75 { X86_FEATURE_AVX512_BF16, X86_FEATURE_AVX512VL },
76 { X86_FEATURE_AVX512_FP16, X86_FEATURE_AVX512BW },
77 { X86_FEATURE_ENQCMD, X86_FEATURE_XSAVES },
78 { X86_FEATURE_PER_THREAD_MBA, X86_FEATURE_MBA },
79 { X86_FEATURE_SGX_LC, X86_FEATURE_SGX },
80 { X86_FEATURE_SGX1, X86_FEATURE_SGX },
81 { X86_FEATURE_SGX2, X86_FEATURE_SGX1 },
82 { X86_FEATURE_SGX_EDECCSSA, X86_FEATURE_SGX1 },
83 { X86_FEATURE_XFD, X86_FEATURE_XSAVES },
84 { X86_FEATURE_XFD, X86_FEATURE_XGETBV1 },
85 { X86_FEATURE_AMX_TILE, X86_FEATURE_XFD },
86 { X86_FEATURE_AMX_FP16, X86_FEATURE_AMX_TILE },
87 { X86_FEATURE_AMX_BF16, X86_FEATURE_AMX_TILE },
88 { X86_FEATURE_AMX_INT8, X86_FEATURE_AMX_TILE },
89 { X86_FEATURE_SHSTK, X86_FEATURE_XSAVES },
90 { X86_FEATURE_FRED, X86_FEATURE_LKGS },
91 { X86_FEATURE_SPEC_CTRL_SSBD, X86_FEATURE_SPEC_CTRL },
92 {}
93};
94
95static inline void clear_feature(struct cpuinfo_x86 *c, unsigned int feature)
96{
97 /*
98 * Note: This could use the non atomic __*_bit() variants, but the
99 * rest of the cpufeature code uses atomics as well, so keep it for
100 * consistency. Cleanup all of it separately.
101 */
102 if (!c) {
103 clear_cpu_cap(c: &boot_cpu_data, bit: feature);
104 set_bit(nr: feature, addr: (unsigned long *)cpu_caps_cleared);
105 } else {
106 clear_bit(nr: feature, addr: (unsigned long *)c->x86_capability);
107 }
108}
109
110/* Take the capabilities and the BUG bits into account */
111#define MAX_FEATURE_BITS ((NCAPINTS + NBUGINTS) * sizeof(u32) * 8)
112
113static void do_clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
114{
115 DECLARE_BITMAP(disable, MAX_FEATURE_BITS);
116 const struct cpuid_dep *d;
117 bool changed;
118
119 if (WARN_ON(feature >= MAX_FEATURE_BITS))
120 return;
121
122 if (boot_cpu_has(feature))
123 WARN_ON(alternatives_patched);
124
125 clear_feature(c, feature);
126
127 /* Collect all features to disable, handling dependencies */
128 memset(s: disable, c: 0, n: sizeof(disable));
129 __set_bit(feature, disable);
130
131 /* Loop until we get a stable state. */
132 do {
133 changed = false;
134 for (d = cpuid_deps; d->feature; d++) {
135 if (!test_bit(d->depends, disable))
136 continue;
137 if (__test_and_set_bit(d->feature, disable))
138 continue;
139
140 changed = true;
141 clear_feature(c, feature: d->feature);
142 }
143 } while (changed);
144}
145
146void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
147{
148 do_clear_cpu_cap(c, feature);
149}
150
151void setup_clear_cpu_cap(unsigned int feature)
152{
153 do_clear_cpu_cap(NULL, feature);
154}
155
156/*
157 * Return the feature "name" if available, otherwise return
158 * the X86_FEATURE_* numerals to make it easier to identify
159 * the feature.
160 */
161static const char *x86_feature_name(unsigned int feature, char *buf)
162{
163 if (x86_cap_flags[feature])
164 return x86_cap_flags[feature];
165
166 snprintf(buf, size: 16, fmt: "%d*32+%2d", feature / 32, feature % 32);
167
168 return buf;
169}
170
171void check_cpufeature_deps(struct cpuinfo_x86 *c)
172{
173 char feature_buf[16], depends_buf[16];
174 const struct cpuid_dep *d;
175
176 for (d = cpuid_deps; d->feature; d++) {
177 if (cpu_has(c, d->feature) && !cpu_has(c, d->depends)) {
178 /*
179 * Only warn about the first unmet dependency on the
180 * first CPU where it is encountered to avoid spamming
181 * the kernel log.
182 */
183 pr_warn_once("x86 CPU feature dependency check failure: CPU%d has '%s' enabled but '%s' disabled. Kernel might be fine, but no guarantees.\n",
184 smp_processor_id(),
185 x86_feature_name(d->feature, feature_buf),
186 x86_feature_name(d->depends, depends_buf));
187 }
188 }
189}
190