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 CPUID_8000_001F_EAX,
35 };
36
37 #define X86_CAP_FMT_NUM "%d:%d"
38 #define x86_cap_flag_num(flag) ((flag) >> 5), ((flag) & 31)
39
40 #ifdef CONFIG_X86_FEATURE_NAMES
41 extern const char * const x86_cap_flags[NCAPINTS*32];
42 extern const char * const x86_power_flags[32];
43 #define X86_CAP_FMT "%s"
44 #define x86_cap_flag(flag) x86_cap_flags[flag]
45 #else
46 #define X86_CAP_FMT X86_CAP_FMT_NUM
47 #define x86_cap_flag x86_cap_flag_num
48 #endif
49
50 /*
51 * In order to save room, we index into this array by doing
52 * X86_BUG_<name> - NCAPINTS*32.
53 */
54 extern const char * const x86_bug_flags[NBUGINTS*32];
55
56 #define test_cpu_cap(c, bit) \
57 arch_test_bit(bit, (unsigned long *)((c)->x86_capability))
58
59 /*
60 * There are 32 bits/features in each mask word. The high bits
61 * (selected with (bit>>5) give us the word number and the low 5
62 * bits give us the bit/feature number inside the word.
63 * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can
64 * see if it is set in the mask word.
65 */
66 #define CHECK_BIT_IN_MASK_WORD(maskname, word, bit) \
67 (((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word ))
68
69 /*
70 * {REQUIRED,DISABLED}_MASK_CHECK below may seem duplicated with the
71 * following BUILD_BUG_ON_ZERO() check but when NCAPINTS gets changed, all
72 * header macros which use NCAPINTS need to be changed. The duplicated macro
73 * use causes the compiler to issue errors for all headers so that all usage
74 * sites can be corrected.
75 */
76 #define REQUIRED_MASK_BIT_SET(feature_bit) \
77 ( CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 0, feature_bit) || \
78 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 1, feature_bit) || \
79 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 2, feature_bit) || \
80 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 3, feature_bit) || \
81 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 4, feature_bit) || \
82 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 5, feature_bit) || \
83 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 6, feature_bit) || \
84 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 7, feature_bit) || \
85 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 8, feature_bit) || \
86 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 9, feature_bit) || \
87 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 10, feature_bit) || \
88 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 11, feature_bit) || \
89 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 12, feature_bit) || \
90 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 13, feature_bit) || \
91 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 14, feature_bit) || \
92 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 15, feature_bit) || \
93 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 16, feature_bit) || \
94 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) || \
95 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) || \
96 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 19, feature_bit) || \
97 REQUIRED_MASK_CHECK || \
98 BUILD_BUG_ON_ZERO(NCAPINTS != 20))
99
100 #define DISABLED_MASK_BIT_SET(feature_bit) \
101 ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 0, feature_bit) || \
102 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 1, feature_bit) || \
103 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 2, feature_bit) || \
104 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 3, feature_bit) || \
105 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 4, feature_bit) || \
106 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 5, feature_bit) || \
107 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 6, feature_bit) || \
108 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 7, feature_bit) || \
109 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 8, feature_bit) || \
110 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 9, feature_bit) || \
111 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 10, feature_bit) || \
112 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 11, feature_bit) || \
113 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 12, feature_bit) || \
114 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 13, feature_bit) || \
115 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 14, feature_bit) || \
116 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 15, feature_bit) || \
117 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 16, feature_bit) || \
118 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) || \
119 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) || \
120 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 19, feature_bit) || \
121 DISABLED_MASK_CHECK || \
122 BUILD_BUG_ON_ZERO(NCAPINTS != 20))
123
124 #define cpu_has(c, bit) \
125 (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \
126 test_cpu_cap(c, bit))
127
128 #define this_cpu_has(bit) \
129 (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \
130 x86_this_cpu_test_bit(bit, \
131 (unsigned long __percpu *)&cpu_info.x86_capability))
132
133 /*
134 * This macro is for detection of features which need kernel
135 * infrastructure to be used. It may *not* directly test the CPU
136 * itself. Use the cpu_has() family if you want true runtime
137 * testing of CPU features, like in hypervisor code where you are
138 * supporting a possible guest feature where host support for it
139 * is not relevant.
140 */
141 #define cpu_feature_enabled(bit) \
142 (__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
143
144 #define boot_cpu_has(bit) cpu_has(&boot_cpu_data, bit)
145
146 #define set_cpu_cap(c, bit) set_bit(bit, (unsigned long *)((c)->x86_capability))
147
148 extern void setup_clear_cpu_cap(unsigned int bit);
149 extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit);
150
151 #define setup_force_cpu_cap(bit) do { \
152 set_cpu_cap(&boot_cpu_data, bit); \
153 set_bit(bit, (unsigned long *)cpu_caps_set); \
154 } while (0)
155
156 #define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
157
158 /*
159 * Static testing of CPU features. Used the same as boot_cpu_has(). It
160 * statically patches the target code for additional performance. Use
161 * static_cpu_has() only in fast paths, where every cycle counts. Which
162 * means that the boot_cpu_has() variant is already fast enough for the
163 * majority of cases and you should stick to using it as it is generally
164 * only two instructions: a RIP-relative MOV and a TEST.
165 *
166 * Do not use an "m" constraint for [cap_byte] here: gcc doesn't know
167 * that this is only used on a fallback path and will sometimes cause
168 * it to manifest the address of boot_cpu_data in a register, fouling
169 * the mainline (post-initialization) code.
170 */
_static_cpu_has(u16 bit)171 static __always_inline bool _static_cpu_has(u16 bit)
172 {
173 asm_volatile_goto(
174 ALTERNATIVE_TERNARY("jmp 6f", %P[feature], "", "jmp %l[t_no]")
175 ".pushsection .altinstr_aux,\"ax\"\n"
176 "6:\n"
177 " testb %[bitnum]," _ASM_RIP(%P[cap_byte]) "\n"
178 " jnz %l[t_yes]\n"
179 " jmp %l[t_no]\n"
180 ".popsection\n"
181 : : [feature] "i" (bit),
182 [bitnum] "i" (1 << (bit & 7)),
183 [cap_byte] "i" (&((const char *)boot_cpu_data.x86_capability)[bit >> 3])
184 : : t_yes, t_no);
185 t_yes:
186 return true;
187 t_no:
188 return false;
189 }
190
191 #define static_cpu_has(bit) \
192 ( \
193 __builtin_constant_p(boot_cpu_has(bit)) ? \
194 boot_cpu_has(bit) : \
195 _static_cpu_has(bit) \
196 )
197
198 #define cpu_has_bug(c, bit) cpu_has(c, (bit))
199 #define set_cpu_bug(c, bit) set_cpu_cap(c, (bit))
200 #define clear_cpu_bug(c, bit) clear_cpu_cap(c, (bit))
201
202 #define static_cpu_has_bug(bit) static_cpu_has((bit))
203 #define boot_cpu_has_bug(bit) cpu_has_bug(&boot_cpu_data, (bit))
204 #define boot_cpu_set_bug(bit) set_cpu_cap(&boot_cpu_data, (bit))
205
206 #define MAX_CPU_FEATURES (NCAPINTS * 32)
207 #define cpu_have_feature boot_cpu_has
208
209 #define CPU_FEATURE_TYPEFMT "x86,ven%04Xfam%04Xmod%04X"
210 #define CPU_FEATURE_TYPEVAL boot_cpu_data.x86_vendor, boot_cpu_data.x86, \
211 boot_cpu_data.x86_model
212
213 #endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
214 #endif /* _ASM_X86_CPUFEATURE_H */
215