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