/*
 * Taken from the linux kernel file of the same name
 *
 * (C) Copyright 2012
 * Graeme Russ, <graeme.russ@gmail.com>
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

#ifndef _ASM_X86_MSR_H
#define _ASM_X86_MSR_H

#include <asm/msr-index.h>

#ifndef __ASSEMBLY__

#include <linux/types.h>
#include <linux/ioctl.h>

#define X86_IOC_RDMSR_REGS      _IOWR('c', 0xA0, __u32[8])
#define X86_IOC_WRMSR_REGS      _IOWR('c', 0xA1, __u32[8])

#ifdef __KERNEL__

#include <linux/errno.h>

struct msr {
        union {
                struct {
                        u32 l;
                        u32 h;
                };
                u64 q;
        };
};

struct msr_info {
        u32 msr_no;
        struct msr reg;
        struct msr *msrs;
        int err;
};

struct msr_regs_info {
        u32 *regs;
        int err;
};

static inline unsigned long long native_read_tscp(unsigned int *aux)
{
        unsigned long low, high;
        asm volatile(".byte 0x0f,0x01,0xf9"
                     : "=a" (low), "=d" (high), "=c" (*aux));
        return low | ((u64)high << 32);
}

/*
 * both i386 and x86_64 returns 64-bit value in edx:eax, but gcc's "A"
 * constraint has different meanings. For i386, "A" means exactly
 * edx:eax, while for x86_64 it doesn't mean rdx:rax or edx:eax. Instead,
 * it means rax *or* rdx.
 */
#ifdef CONFIG_X86_64
#define DECLARE_ARGS(val, low, high)    unsigned low, high
#define EAX_EDX_VAL(val, low, high)     ((low) | ((u64)(high) << 32))
#define EAX_EDX_ARGS(val, low, high)    "a" (low), "d" (high)
#define EAX_EDX_RET(val, low, high)     "=a" (low), "=d" (high)
#else
#define DECLARE_ARGS(val, low, high)    unsigned long long val
#define EAX_EDX_VAL(val, low, high)     (val)
#define EAX_EDX_ARGS(val, low, high)    "A" (val)
#define EAX_EDX_RET(val, low, high)     "=A" (val)
#endif

static inline __attribute__((no_instrument_function))
        unsigned long long native_read_msr(unsigned int msr)
{
        DECLARE_ARGS(val, low, high);

        asm volatile("rdmsr" : EAX_EDX_RET(val, low, high) : "c" (msr));
        return EAX_EDX_VAL(val, low, high);
}

static inline void native_write_msr(unsigned int msr,
                                    unsigned low, unsigned high)
{
        asm volatile("wrmsr" : : "c" (msr), "a"(low), "d" (high) : "memory");
}

extern unsigned long long native_read_tsc(void);

extern int native_rdmsr_safe_regs(u32 regs[8]);
extern int native_wrmsr_safe_regs(u32 regs[8]);

static inline unsigned long long native_read_pmc(int counter)
{
        DECLARE_ARGS(val, low, high);

        asm volatile("rdpmc" : EAX_EDX_RET(val, low, high) : "c" (counter));
        return EAX_EDX_VAL(val, low, high);
}

#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#else
#include <errno.h>
/*
 * Access to machine-specific registers (available on 586 and better only)
 * Note: the rd* operations modify the parameters directly (without using
 * pointer indirection), this allows gcc to optimize better
 */

#define rdmsr(msr, val1, val2)                                  \
do {                                                            \
        u64 __val = native_read_msr((msr));                     \
        (void)((val1) = (u32)__val);                            \
        (void)((val2) = (u32)(__val >> 32));                    \
} while (0)

static inline void wrmsr(unsigned msr, unsigned low, unsigned high)
{
        native_write_msr(msr, low, high);
}

#define rdmsrl(msr, val)                        \
        ((val) = native_read_msr((msr)))

#define wrmsrl(msr, val)                                                \
        native_write_msr((msr), (u32)((u64)(val)), (u32)((u64)(val) >> 32))

static inline void msr_clrsetbits_64(unsigned msr, u64 clear, u64 set)
{
        u64 val;

        val = native_read_msr(msr);
        val &= ~clear;
        val |= set;
        wrmsrl(msr, val);
}

static inline void msr_setbits_64(unsigned msr, u64 set)
{
        u64 val;

        val = native_read_msr(msr);
        val |= set;
        wrmsrl(msr, val);
}

static inline void msr_clrbits_64(unsigned msr, u64 clear)
{
        u64 val;

        val = native_read_msr(msr);
        val &= ~clear;
        wrmsrl(msr, val);
}

/* rdmsr with exception handling */
#define rdmsr_safe(msr, p1, p2)                                 \
({                                                              \
        int __err;                                              \
        u64 __val = native_read_msr_safe((msr), &__err);        \
        (*p1) = (u32)__val;                                     \
        (*p2) = (u32)(__val >> 32);                             \
        __err;                                                  \
})

static inline int rdmsrl_amd_safe(unsigned msr, unsigned long long *p)
{
        u32 gprs[8] = { 0 };
        int err;

        gprs[1] = msr;
        gprs[7] = 0x9c5a203a;

        err = native_rdmsr_safe_regs(gprs);

        *p = gprs[0] | ((u64)gprs[2] << 32);

        return err;
}

static inline int wrmsrl_amd_safe(unsigned msr, unsigned long long val)
{
        u32 gprs[8] = { 0 };

        gprs[0] = (u32)val;
        gprs[1] = msr;
        gprs[2] = val >> 32;
        gprs[7] = 0x9c5a203a;

        return native_wrmsr_safe_regs(gprs);
}

static inline int rdmsr_safe_regs(u32 regs[8])
{
        return native_rdmsr_safe_regs(regs);
}

static inline int wrmsr_safe_regs(u32 regs[8])
{
        return native_wrmsr_safe_regs(regs);
}

typedef struct msr_t {
        uint32_t lo;
        uint32_t hi;
} msr_t;

static inline struct msr_t msr_read(unsigned msr_num)
{
        struct msr_t msr;

        rdmsr(msr_num, msr.lo, msr.hi);

        return msr;
}

static inline void msr_write(unsigned msr_num, msr_t msr)
{
        wrmsr(msr_num, msr.lo, msr.hi);
}

#define rdtscl(low)                                             \
        ((low) = (u32)__native_read_tsc())

#define rdtscll(val)                                            \
        ((val) = __native_read_tsc())

#define rdpmc(counter, low, high)                       \
do {                                                    \
        u64 _l = native_read_pmc((counter));            \
        (low)  = (u32)_l;                               \
        (high) = (u32)(_l >> 32);                       \
} while (0)

#define rdtscp(low, high, aux)                                  \
do {                                                            \
        unsigned long long _val = native_read_tscp(&(aux));     \
        (low) = (u32)_val;                                      \
        (high) = (u32)(_val >> 32);                             \
} while (0)

#define rdtscpll(val, aux) (val) = native_read_tscp(&(aux))

#endif  /* !CONFIG_PARAVIRT */


#define checking_wrmsrl(msr, val) wrmsr_safe((msr), (u32)(val),         \
                                             (u32)((val) >> 32))

#define write_tsc(val1, val2) wrmsr(MSR_IA32_TSC, (val1), (val2))

#define write_rdtscp_aux(val) wrmsr(MSR_TSC_AUX, (val), 0)

struct msr *msrs_alloc(void);
void msrs_free(struct msr *msrs);

#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_MSR_H */