1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_UM_CPUFEATURE_H 3 #define _ASM_UM_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 12 extern const char * const x86_cap_flags[NCAPINTS*32]; 13 extern const char * const x86_power_flags[32]; 14 #define X86_CAP_FMT "%s" 15 #define x86_cap_flag(flag) x86_cap_flags[flag] 16 17 /* 18 * In order to save room, we index into this array by doing 19 * X86_BUG_<name> - NCAPINTS*32. 20 */ 21 extern const char * const x86_bug_flags[NBUGINTS*32]; 22 23 #define test_cpu_cap(c, bit) \ 24 test_bit(bit, (unsigned long *)((c)->x86_capability)) 25 26 /* 27 * There are 32 bits/features in each mask word. The high bits 28 * (selected with (bit>>5) give us the word number and the low 5 29 * bits give us the bit/feature number inside the word. 30 * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can 31 * see if it is set in the mask word. 32 */ 33 #define CHECK_BIT_IN_MASK_WORD(maskname, word, bit) \ 34 (((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word )) 35 36 #define cpu_has(c, bit) \ 37 test_cpu_cap(c, bit) 38 39 #define this_cpu_has(bit) \ 40 (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \ 41 x86_this_cpu_test_bit(bit, cpu_info.x86_capability)) 42 43 /* 44 * This macro is for detection of features which need kernel 45 * infrastructure to be used. It may *not* directly test the CPU 46 * itself. Use the cpu_has() family if you want true runtime 47 * testing of CPU features, like in hypervisor code where you are 48 * supporting a possible guest feature where host support for it 49 * is not relevant. 50 */ 51 #define cpu_feature_enabled(bit) \ 52 (__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit)) 53 54 #define boot_cpu_has(bit) cpu_has(&boot_cpu_data, bit) 55 56 #define set_cpu_cap(c, bit) set_bit(bit, (unsigned long *)((c)->x86_capability)) 57 58 extern void setup_clear_cpu_cap(unsigned int bit); 59 60 #define setup_force_cpu_cap(bit) do { \ 61 set_cpu_cap(&boot_cpu_data, bit); \ 62 set_bit(bit, (unsigned long *)cpu_caps_set); \ 63 } while (0) 64 65 #define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit) 66 67 /* 68 * Static testing of CPU features. Used the same as boot_cpu_has(). It 69 * statically patches the target code for additional performance. Use 70 * static_cpu_has() only in fast paths, where every cycle counts. Which 71 * means that the boot_cpu_has() variant is already fast enough for the 72 * majority of cases and you should stick to using it as it is generally 73 * only two instructions: a RIP-relative MOV and a TEST. 74 */ 75 static __always_inline bool _static_cpu_has(u16 bit) 76 { 77 asm goto("1: jmp 6f\n" 78 "2:\n" 79 ".skip -(((5f-4f) - (2b-1b)) > 0) * " 80 "((5f-4f) - (2b-1b)),0x90\n" 81 "3:\n" 82 ".section .altinstructions,\"a\"\n" 83 " .long 1b - .\n" /* src offset */ 84 " .long 4f - .\n" /* repl offset */ 85 " .word %P[always]\n" /* always replace */ 86 " .byte 3b - 1b\n" /* src len */ 87 " .byte 5f - 4f\n" /* repl len */ 88 " .byte 3b - 2b\n" /* pad len */ 89 ".previous\n" 90 ".section .altinstr_replacement,\"ax\"\n" 91 "4: jmp %l[t_no]\n" 92 "5:\n" 93 ".previous\n" 94 ".section .altinstructions,\"a\"\n" 95 " .long 1b - .\n" /* src offset */ 96 " .long 0\n" /* no replacement */ 97 " .word %P[feature]\n" /* feature bit */ 98 " .byte 3b - 1b\n" /* src len */ 99 " .byte 0\n" /* repl len */ 100 " .byte 0\n" /* pad len */ 101 ".previous\n" 102 ".section .altinstr_aux,\"ax\"\n" 103 "6:\n" 104 " testb %[bitnum],%[cap_byte]\n" 105 " jnz %l[t_yes]\n" 106 " jmp %l[t_no]\n" 107 ".previous\n" 108 : : [feature] "i" (bit), 109 [always] "i" (X86_FEATURE_ALWAYS), 110 [bitnum] "i" (1 << (bit & 7)), 111 [cap_byte] "m" (((const char *)boot_cpu_data.x86_capability)[bit >> 3]) 112 : : t_yes, t_no); 113 t_yes: 114 return true; 115 t_no: 116 return false; 117 } 118 119 #define static_cpu_has(bit) \ 120 ( \ 121 __builtin_constant_p(boot_cpu_has(bit)) ? \ 122 boot_cpu_has(bit) : \ 123 _static_cpu_has(bit) \ 124 ) 125 126 #define cpu_has_bug(c, bit) cpu_has(c, (bit)) 127 #define set_cpu_bug(c, bit) set_cpu_cap(c, (bit)) 128 129 #define static_cpu_has_bug(bit) static_cpu_has((bit)) 130 #define boot_cpu_has_bug(bit) cpu_has_bug(&boot_cpu_data, (bit)) 131 #define boot_cpu_set_bug(bit) set_cpu_cap(&boot_cpu_data, (bit)) 132 133 #define MAX_CPU_FEATURES (NCAPINTS * 32) 134 #define cpu_have_feature boot_cpu_has 135 136 #define CPU_FEATURE_TYPEFMT "x86,ven%04Xfam%04Xmod%04X" 137 #define CPU_FEATURE_TYPEVAL boot_cpu_data.x86_vendor, boot_cpu_data.x86, \ 138 boot_cpu_data.x86_model 139 140 #endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */ 141 #endif /* _ASM_UM_CPUFEATURE_H */ 142