/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_UM_CPUFEATURE_H
#define _ASM_UM_CPUFEATURE_H

#include <asm/processor.h>

#if defined(__KERNEL__) && !defined(__ASSEMBLER__)

#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, 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 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(__ASSEMBLER__) */
#endif /* _ASM_UM_CPUFEATURE_H */