1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_CPUFEATURE_H
3 #define _ASM_X86_CPUFEATURE_H
5 #include <asm/processor.h>
7 #if defined(__KERNEL__) && !defined(__ASSEMBLY__)
10 #include <linux/bitops.h>
11 #include <asm/alternative.h>
40 #define X86_CAP_FMT_NUM "%d:%d"
41 #define x86_cap_flag_num(flag) ((flag) >> 5), ((flag) & 31)
43 #ifdef CONFIG_X86_FEATURE_NAMES
44 extern const char * const x86_cap_flags[NCAPINTS*32];
45 extern const char * const x86_power_flags[32];
46 #define X86_CAP_FMT "%s"
47 #define x86_cap_flag(flag) x86_cap_flags[flag]
49 #define X86_CAP_FMT X86_CAP_FMT_NUM
50 #define x86_cap_flag x86_cap_flag_num
54 * In order to save room, we index into this array by doing
55 * X86_BUG_<name> - NCAPINTS*32.
57 extern const char * const x86_bug_flags[NBUGINTS*32];
59 #define test_cpu_cap(c, bit) \
60 arch_test_bit(bit, (unsigned long *)((c)->x86_capability))
63 * There are 32 bits/features in each mask word. The high bits
64 * (selected with (bit>>5) give us the word number and the low 5
65 * bits give us the bit/feature number inside the word.
66 * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can
67 * see if it is set in the mask word.
69 #define CHECK_BIT_IN_MASK_WORD(maskname, word, bit) \
70 (((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word ))
73 * {REQUIRED,DISABLED}_MASK_CHECK below may seem duplicated with the
74 * following BUILD_BUG_ON_ZERO() check but when NCAPINTS gets changed, all
75 * header macros which use NCAPINTS need to be changed. The duplicated macro
76 * use causes the compiler to issue errors for all headers so that all usage
77 * sites can be corrected.
79 #define REQUIRED_MASK_BIT_SET(feature_bit) \
80 ( CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 0, feature_bit) || \
81 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 1, feature_bit) || \
82 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 2, feature_bit) || \
83 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 3, feature_bit) || \
84 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 4, feature_bit) || \
85 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 5, feature_bit) || \
86 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 6, feature_bit) || \
87 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 7, feature_bit) || \
88 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 8, feature_bit) || \
89 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 9, feature_bit) || \
90 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 10, feature_bit) || \
91 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 11, feature_bit) || \
92 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 12, feature_bit) || \
93 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 13, feature_bit) || \
94 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 14, feature_bit) || \
95 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 15, feature_bit) || \
96 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 16, feature_bit) || \
97 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) || \
98 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) || \
99 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 19, feature_bit) || \
100 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 20, feature_bit) || \
101 CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 21, feature_bit) || \
102 REQUIRED_MASK_CHECK || \
103 BUILD_BUG_ON_ZERO(NCAPINTS != 22))
105 #define DISABLED_MASK_BIT_SET(feature_bit) \
106 ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 0, feature_bit) || \
107 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 1, feature_bit) || \
108 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 2, feature_bit) || \
109 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 3, feature_bit) || \
110 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 4, feature_bit) || \
111 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 5, feature_bit) || \
112 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 6, feature_bit) || \
113 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 7, feature_bit) || \
114 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 8, feature_bit) || \
115 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 9, feature_bit) || \
116 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 10, feature_bit) || \
117 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 11, feature_bit) || \
118 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 12, feature_bit) || \
119 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 13, feature_bit) || \
120 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 14, feature_bit) || \
121 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 15, feature_bit) || \
122 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 16, feature_bit) || \
123 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) || \
124 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) || \
125 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 19, feature_bit) || \
126 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 20, feature_bit) || \
127 CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 21, feature_bit) || \
128 DISABLED_MASK_CHECK || \
129 BUILD_BUG_ON_ZERO(NCAPINTS != 22))
131 #define cpu_has(c, bit) \
132 (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \
133 test_cpu_cap(c, bit))
135 #define this_cpu_has(bit) \
136 (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \
137 x86_this_cpu_test_bit(bit, \
138 (unsigned long __percpu *)&cpu_info.x86_capability))
141 * This macro is for detection of features which need kernel
142 * infrastructure to be used. It may *not* directly test the CPU
143 * itself. Use the cpu_has() family if you want true runtime
144 * testing of CPU features, like in hypervisor code where you are
145 * supporting a possible guest feature where host support for it
148 #define cpu_feature_enabled(bit) \
149 (__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
151 #define boot_cpu_has(bit) cpu_has(&boot_cpu_data, bit)
153 #define set_cpu_cap(c, bit) set_bit(bit, (unsigned long *)((c)->x86_capability))
155 extern void setup_clear_cpu_cap(unsigned int bit);
156 extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit);
158 #define setup_force_cpu_cap(bit) do { \
159 set_cpu_cap(&boot_cpu_data, bit); \
160 set_bit(bit, (unsigned long *)cpu_caps_set); \
163 #define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
166 * Static testing of CPU features. Used the same as boot_cpu_has(). It
167 * statically patches the target code for additional performance. Use
168 * static_cpu_has() only in fast paths, where every cycle counts. Which
169 * means that the boot_cpu_has() variant is already fast enough for the
170 * majority of cases and you should stick to using it as it is generally
171 * only two instructions: a RIP-relative MOV and a TEST.
173 * Do not use an "m" constraint for [cap_byte] here: gcc doesn't know
174 * that this is only used on a fallback path and will sometimes cause
175 * it to manifest the address of boot_cpu_data in a register, fouling
176 * the mainline (post-initialization) code.
178 static __always_inline bool _static_cpu_has(u16 bit)
181 ALTERNATIVE_TERNARY("jmp 6f", %P[feature], "", "jmp %l[t_no]")
182 ".pushsection .altinstr_aux,\"ax\"\n"
184 " testb %[bitnum]," _ASM_RIP(%P[cap_byte]) "\n"
188 : : [feature] "i" (bit),
189 [bitnum] "i" (1 << (bit & 7)),
190 [cap_byte] "i" (&((const char *)boot_cpu_data.x86_capability)[bit >> 3])
198 #define static_cpu_has(bit) \
200 __builtin_constant_p(boot_cpu_has(bit)) ? \
201 boot_cpu_has(bit) : \
202 _static_cpu_has(bit) \
205 #define cpu_has_bug(c, bit) cpu_has(c, (bit))
206 #define set_cpu_bug(c, bit) set_cpu_cap(c, (bit))
207 #define clear_cpu_bug(c, bit) clear_cpu_cap(c, (bit))
209 #define static_cpu_has_bug(bit) static_cpu_has((bit))
210 #define boot_cpu_has_bug(bit) cpu_has_bug(&boot_cpu_data, (bit))
211 #define boot_cpu_set_bug(bit) set_cpu_cap(&boot_cpu_data, (bit))
213 #define MAX_CPU_FEATURES (NCAPINTS * 32)
214 #define cpu_have_feature boot_cpu_has
216 #define CPU_FEATURE_TYPEFMT "x86,ven%04Xfam%04Xmod%04X"
217 #define CPU_FEATURE_TYPEVAL boot_cpu_data.x86_vendor, boot_cpu_data.x86, \
218 boot_cpu_data.x86_model
220 #endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
221 #endif /* _ASM_X86_CPUFEATURE_H */