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- /* SPDX-License-Identifier: GPL-2.0 */
- #ifndef _ASM_UM_CPUFEATURE_H
- #define _ASM_UM_CPUFEATURE_H
- #include <asm/processor.h>
- #if defined(__KERNEL__) && !defined(__ASSEMBLY__)
- #include <asm/asm.h>
- #include <linux/bitops.h>
- extern const char * const x86_cap_flags[NCAPINTS*32];
- extern const char * const x86_power_flags[32];
- #define X86_CAP_FMT "%s"
- #define x86_cap_flag(flag) x86_cap_flags[flag]
- /*
- * In order to save room, we index into this array by doing
- * X86_BUG_<name> - NCAPINTS*32.
- */
- extern const char * const x86_bug_flags[NBUGINTS*32];
- #define test_cpu_cap(c, bit) \
- test_bit(bit, (unsigned long *)((c)->x86_capability))
- /*
- * There are 32 bits/features in each mask word. The high bits
- * (selected with (bit>>5) give us the word number and the low 5
- * bits give us the bit/feature number inside the word.
- * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can
- * see if it is set in the mask word.
- */
- #define CHECK_BIT_IN_MASK_WORD(maskname, word, bit) \
- (((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word ))
- #define cpu_has(c, bit) \
- test_cpu_cap(c, bit)
- #define this_cpu_has(bit) \
- (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \
- x86_this_cpu_test_bit(bit, \
- (unsigned long __percpu *)&cpu_info.x86_capability))
- /*
- * This macro is for detection of features which need kernel
- * infrastructure to be used. It may *not* directly test the CPU
- * itself. Use the cpu_has() family if you want true runtime
- * testing of CPU features, like in hypervisor code where you are
- * supporting a possible guest feature where host support for it
- * is not relevant.
- */
- #define cpu_feature_enabled(bit) \
- (__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
- #define boot_cpu_has(bit) cpu_has(&boot_cpu_data, bit)
- #define set_cpu_cap(c, bit) set_bit(bit, (unsigned long *)((c)->x86_capability))
- extern void setup_clear_cpu_cap(unsigned int bit);
- #define setup_force_cpu_cap(bit) do { \
- set_cpu_cap(&boot_cpu_data, bit); \
- set_bit(bit, (unsigned long *)cpu_caps_set); \
- } while (0)
- #define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
- /*
- * Static testing of CPU features. Used the same as boot_cpu_has(). It
- * statically patches the target code for additional performance. Use
- * static_cpu_has() only in fast paths, where every cycle counts. Which
- * means that the boot_cpu_has() variant is already fast enough for the
- * majority of cases and you should stick to using it as it is generally
- * only two instructions: a RIP-relative MOV and a TEST.
- */
- static __always_inline bool _static_cpu_has(u16 bit)
- {
- asm_volatile_goto("1: jmp 6f\n"
- "2:\n"
- ".skip -(((5f-4f) - (2b-1b)) > 0) * "
- "((5f-4f) - (2b-1b)),0x90\n"
- "3:\n"
- ".section .altinstructions,\"a\"\n"
- " .long 1b - .\n" /* src offset */
- " .long 4f - .\n" /* repl offset */
- " .word %P[always]\n" /* always replace */
- " .byte 3b - 1b\n" /* src len */
- " .byte 5f - 4f\n" /* repl len */
- " .byte 3b - 2b\n" /* pad len */
- ".previous\n"
- ".section .altinstr_replacement,\"ax\"\n"
- "4: jmp %l[t_no]\n"
- "5:\n"
- ".previous\n"
- ".section .altinstructions,\"a\"\n"
- " .long 1b - .\n" /* src offset */
- " .long 0\n" /* no replacement */
- " .word %P[feature]\n" /* feature bit */
- " .byte 3b - 1b\n" /* src len */
- " .byte 0\n" /* repl len */
- " .byte 0\n" /* pad len */
- ".previous\n"
- ".section .altinstr_aux,\"ax\"\n"
- "6:\n"
- " testb %[bitnum],%[cap_byte]\n"
- " jnz %l[t_yes]\n"
- " jmp %l[t_no]\n"
- ".previous\n"
- : : [feature] "i" (bit),
- [always] "i" (X86_FEATURE_ALWAYS),
- [bitnum] "i" (1 << (bit & 7)),
- [cap_byte] "m" (((const char *)boot_cpu_data.x86_capability)[bit >> 3])
- : : t_yes, t_no);
- t_yes:
- return true;
- t_no:
- return false;
- }
- #define static_cpu_has(bit) \
- ( \
- __builtin_constant_p(boot_cpu_has(bit)) ? \
- boot_cpu_has(bit) : \
- _static_cpu_has(bit) \
- )
- #define cpu_has_bug(c, bit) cpu_has(c, (bit))
- #define set_cpu_bug(c, bit) set_cpu_cap(c, (bit))
- #define static_cpu_has_bug(bit) static_cpu_has((bit))
- #define boot_cpu_has_bug(bit) cpu_has_bug(&boot_cpu_data, (bit))
- #define boot_cpu_set_bug(bit) set_cpu_cap(&boot_cpu_data, (bit))
- #define MAX_CPU_FEATURES (NCAPINTS * 32)
- #define cpu_have_feature boot_cpu_has
- #define CPU_FEATURE_TYPEFMT "x86,ven%04Xfam%04Xmod%04X"
- #define CPU_FEATURE_TYPEVAL boot_cpu_data.x86_vendor, boot_cpu_data.x86, \
- boot_cpu_data.x86_model
- #endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
- #endif /* _ASM_UM_CPUFEATURE_H */
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