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 };
37 
38 #define X86_CAP_FMT_NUM "%d:%d"
39 #define x86_cap_flag_num(flag) ((flag) >> 5), ((flag) & 31)
40 
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 
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 	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 19, feature_bit) ||	\
93 	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 20, feature_bit) ||	\
94 	   REQUIRED_MASK_CHECK					  ||	\
95 	   BUILD_BUG_ON_ZERO(NCAPINTS != 21))
96 
97 #define DISABLED_MASK_BIT_SET(feature_bit)				\
98 	 ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  0, feature_bit) ||	\
99 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  1, feature_bit) ||	\
100 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  2, feature_bit) ||	\
101 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  3, feature_bit) ||	\
102 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  4, feature_bit) ||	\
103 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  5, feature_bit) ||	\
104 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  6, feature_bit) ||	\
105 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  7, feature_bit) ||	\
106 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  8, feature_bit) ||	\
107 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  9, feature_bit) ||	\
108 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 10, feature_bit) ||	\
109 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 11, feature_bit) ||	\
110 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 12, feature_bit) ||	\
111 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 13, feature_bit) ||	\
112 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 14, feature_bit) ||	\
113 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 15, feature_bit) ||	\
114 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 16, feature_bit) ||	\
115 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) ||	\
116 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) ||	\
117 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 19, feature_bit) ||	\
118 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 20, feature_bit) ||	\
119 	   DISABLED_MASK_CHECK					  ||	\
120 	   BUILD_BUG_ON_ZERO(NCAPINTS != 21))
121 
122 #define cpu_has(c, bit)							\
123 	(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :	\
124 	 test_cpu_cap(c, bit))
125 
126 #define this_cpu_has(bit)						\
127 	(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :	\
128 	 x86_this_cpu_test_bit(bit,					\
129 		(unsigned long __percpu *)&cpu_info.x86_capability))
130 
131 /*
132  * This macro is for detection of features which need kernel
133  * infrastructure to be used.  It may *not* directly test the CPU
134  * itself.  Use the cpu_has() family if you want true runtime
135  * testing of CPU features, like in hypervisor code where you are
136  * supporting a possible guest feature where host support for it
137  * is not relevant.
138  */
139 #define cpu_feature_enabled(bit)	\
140 	(__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
141 
142 #define boot_cpu_has(bit)	cpu_has(&boot_cpu_data, bit)
143 
144 #define set_cpu_cap(c, bit)	set_bit(bit, (unsigned long *)((c)->x86_capability))
145 
146 extern void setup_clear_cpu_cap(unsigned int bit);
147 extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit);
148 
149 #define setup_force_cpu_cap(bit) do { \
150 	set_cpu_cap(&boot_cpu_data, bit);	\
151 	set_bit(bit, (unsigned long *)cpu_caps_set);	\
152 } while (0)
153 
154 #define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
155 
156 /*
157  * Static testing of CPU features. Used the same as boot_cpu_has(). It
158  * statically patches the target code for additional performance. Use
159  * static_cpu_has() only in fast paths, where every cycle counts. Which
160  * means that the boot_cpu_has() variant is already fast enough for the
161  * majority of cases and you should stick to using it as it is generally
162  * only two instructions: a RIP-relative MOV and a TEST.
163  *
164  * Do not use an "m" constraint for [cap_byte] here: gcc doesn't know
165  * that this is only used on a fallback path and will sometimes cause
166  * it to manifest the address of boot_cpu_data in a register, fouling
167  * the mainline (post-initialization) code.
168  */
_static_cpu_has(u16 bit)169 static __always_inline bool _static_cpu_has(u16 bit)
170 {
171 	asm goto(
172 		ALTERNATIVE_TERNARY("jmp 6f", %P[feature], "", "jmp %l[t_no]")
173 		".pushsection .altinstr_aux,\"ax\"\n"
174 		"6:\n"
175 		" testb %[bitnum]," _ASM_RIP(%P[cap_byte]) "\n"
176 		" jnz %l[t_yes]\n"
177 		" jmp %l[t_no]\n"
178 		".popsection\n"
179 		 : : [feature]  "i" (bit),
180 		     [bitnum]   "i" (1 << (bit & 7)),
181 		     [cap_byte] "i" (&((const char *)boot_cpu_data.x86_capability)[bit >> 3])
182 		 : : t_yes, t_no);
183 t_yes:
184 	return true;
185 t_no:
186 	return false;
187 }
188 
189 #define static_cpu_has(bit)					\
190 (								\
191 	__builtin_constant_p(boot_cpu_has(bit)) ?		\
192 		boot_cpu_has(bit) :				\
193 		_static_cpu_has(bit)				\
194 )
195 
196 #define cpu_has_bug(c, bit)		cpu_has(c, (bit))
197 #define set_cpu_bug(c, bit)		set_cpu_cap(c, (bit))
198 #define clear_cpu_bug(c, bit)		clear_cpu_cap(c, (bit))
199 
200 #define static_cpu_has_bug(bit)		static_cpu_has((bit))
201 #define boot_cpu_has_bug(bit)		cpu_has_bug(&boot_cpu_data, (bit))
202 #define boot_cpu_set_bug(bit)		set_cpu_cap(&boot_cpu_data, (bit))
203 
204 #define MAX_CPU_FEATURES		(NCAPINTS * 32)
205 #define cpu_have_feature		boot_cpu_has
206 
207 #define CPU_FEATURE_TYPEFMT		"x86,ven%04Xfam%04Xmod%04X"
208 #define CPU_FEATURE_TYPEVAL		boot_cpu_data.x86_vendor, boot_cpu_data.x86, \
209 					boot_cpu_data.x86_model
210 
211 #endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
212 #endif /* _ASM_X86_CPUFEATURE_H */
213