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TOMOYO Linux Cross Reference
Linux/arch/x86/include/asm/cpufeature.h

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  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         CPUID_8000_0021_EAX,
 36         CPUID_LNX_5,
 37         NR_CPUID_WORDS,
 38 };
 39 
 40 #define X86_CAP_FMT_NUM "%d:%d"
 41 #define x86_cap_flag_num(flag) ((flag) >> 5), ((flag) & 31)
 42 
 43 extern const char * const x86_cap_flags[NCAPINTS*32];
 44 extern const char * const x86_power_flags[32];
 45 #define X86_CAP_FMT "%s"
 46 #define x86_cap_flag(flag) x86_cap_flags[flag]
 47 
 48 /*
 49  * In order to save room, we index into this array by doing
 50  * X86_BUG_<name> - NCAPINTS*32.
 51  */
 52 extern const char * const x86_bug_flags[NBUGINTS*32];
 53 
 54 #define test_cpu_cap(c, bit)                                            \
 55          arch_test_bit(bit, (unsigned long *)((c)->x86_capability))
 56 
 57 /*
 58  * There are 32 bits/features in each mask word.  The high bits
 59  * (selected with (bit>>5) give us the word number and the low 5
 60  * bits give us the bit/feature number inside the word.
 61  * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can
 62  * see if it is set in the mask word.
 63  */
 64 #define CHECK_BIT_IN_MASK_WORD(maskname, word, bit)     \
 65         (((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word ))
 66 
 67 /*
 68  * {REQUIRED,DISABLED}_MASK_CHECK below may seem duplicated with the
 69  * following BUILD_BUG_ON_ZERO() check but when NCAPINTS gets changed, all
 70  * header macros which use NCAPINTS need to be changed. The duplicated macro
 71  * use causes the compiler to issue errors for all headers so that all usage
 72  * sites can be corrected.
 73  */
 74 #define REQUIRED_MASK_BIT_SET(feature_bit)              \
 75          ( CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  0, feature_bit) ||    \
 76            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  1, feature_bit) ||    \
 77            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  2, feature_bit) ||    \
 78            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  3, feature_bit) ||    \
 79            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  4, feature_bit) ||    \
 80            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  5, feature_bit) ||    \
 81            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  6, feature_bit) ||    \
 82            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  7, feature_bit) ||    \
 83            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  8, feature_bit) ||    \
 84            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  9, feature_bit) ||    \
 85            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 10, feature_bit) ||    \
 86            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 11, feature_bit) ||    \
 87            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 12, feature_bit) ||    \
 88            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 13, feature_bit) ||    \
 89            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 14, feature_bit) ||    \
 90            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 15, feature_bit) ||    \
 91            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 16, feature_bit) ||    \
 92            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) ||    \
 93            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) ||    \
 94            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 19, feature_bit) ||    \
 95            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 20, feature_bit) ||    \
 96            CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 21, feature_bit) ||    \
 97            REQUIRED_MASK_CHECK                                    ||    \
 98            BUILD_BUG_ON_ZERO(NCAPINTS != 22))
 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            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 20, feature_bit) ||    \
122            CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 21, feature_bit) ||    \
123            DISABLED_MASK_CHECK                                    ||    \
124            BUILD_BUG_ON_ZERO(NCAPINTS != 22))
125 
126 #define cpu_has(c, bit)                                                 \
127         (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :  \
128          test_cpu_cap(c, bit))
129 
130 #define this_cpu_has(bit)                                               \
131         (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :  \
132          x86_this_cpu_test_bit(bit, cpu_info.x86_capability))
133 
134 /*
135  * This macro is for detection of features which need kernel
136  * infrastructure to be used.  It may *not* directly test the CPU
137  * itself.  Use the cpu_has() family if you want true runtime
138  * testing of CPU features, like in hypervisor code where you are
139  * supporting a possible guest feature where host support for it
140  * is not relevant.
141  */
142 #define cpu_feature_enabled(bit)        \
143         (__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
144 
145 #define boot_cpu_has(bit)       cpu_has(&boot_cpu_data, bit)
146 
147 #define set_cpu_cap(c, bit)     set_bit(bit, (unsigned long *)((c)->x86_capability))
148 
149 extern void setup_clear_cpu_cap(unsigned int bit);
150 extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit);
151 
152 #define setup_force_cpu_cap(bit) do {                   \
153                                                         \
154         if (!boot_cpu_has(bit))                         \
155                 WARN_ON(alternatives_patched);          \
156                                                         \
157         set_cpu_cap(&boot_cpu_data, bit);               \
158         set_bit(bit, (unsigned long *)cpu_caps_set);    \
159 } while (0)
160 
161 #define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
162 
163 /*
164  * Static testing of CPU features. Used the same as boot_cpu_has(). It
165  * statically patches the target code for additional performance. Use
166  * static_cpu_has() only in fast paths, where every cycle counts. Which
167  * means that the boot_cpu_has() variant is already fast enough for the
168  * majority of cases and you should stick to using it as it is generally
169  * only two instructions: a RIP-relative MOV and a TEST.
170  *
171  * Do not use an "m" constraint for [cap_byte] here: gcc doesn't know
172  * that this is only used on a fallback path and will sometimes cause
173  * it to manifest the address of boot_cpu_data in a register, fouling
174  * the mainline (post-initialization) code.
175  */
176 static __always_inline bool _static_cpu_has(u16 bit)
177 {
178         asm goto(ALTERNATIVE_TERNARY("jmp 6f", %c[feature], "", "jmp %l[t_no]")
179                 ".pushsection .altinstr_aux,\"ax\"\n"
180                 "6:\n"
181                 " testb %[bitnum], %a[cap_byte]\n"
182                 " jnz %l[t_yes]\n"
183                 " jmp %l[t_no]\n"
184                 ".popsection\n"
185                  : : [feature]  "i" (bit),
186                      [bitnum]   "i" (1 << (bit & 7)),
187                      [cap_byte] "i" (&((const char *)boot_cpu_data.x86_capability)[bit >> 3])
188                  : : t_yes, t_no);
189 t_yes:
190         return true;
191 t_no:
192         return false;
193 }
194 
195 #define static_cpu_has(bit)                                     \
196 (                                                               \
197         __builtin_constant_p(boot_cpu_has(bit)) ?               \
198                 boot_cpu_has(bit) :                             \
199                 _static_cpu_has(bit)                            \
200 )
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 

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