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