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