uaccess_64.h

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#ifndef _ASM_X86_UACCESS_64_H
#define _ASM_X86_UACCESS_64_H

/*
 * User space memory access functions
 */
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/lockdep.h>
#include <asm/alternative.h>
#include <asm/cpufeature.h>
#include <asm/page.h>

/*
 * Copy To/From Userspace
 */

/* Handles exceptions in both to and from, but doesn't do access_ok */
__must_check unsigned long
copy_user_enhanced_fast_string(void *to, const void *from, unsigned len);
__must_check unsigned long
copy_user_generic_string(void *to, const void *from, unsigned len);
__must_check unsigned long
copy_user_generic_unrolled(void *to, const void *from, unsigned len);

static __always_inline __must_check unsigned long
copy_user_generic(void *to, const void *from, unsigned len)
{
    unsigned ret;

    /*
     * If CPU has ERMS feature, use copy_user_enhanced_fast_string.
     * Otherwise, if CPU has rep_good feature, use copy_user_generic_string.
     * Otherwise, use copy_user_generic_unrolled.
     */
    alternative_call_2(copy_user_generic_unrolled,
             copy_user_generic_string,
             X86_FEATURE_REP_GOOD,
             copy_user_enhanced_fast_string,
             X86_FEATURE_ERMS,
             ASM_OUTPUT2("=a" (ret), "=D" (to), "=S" (from),
                     "=d" (len)),
             "1" (to), "2" (from), "3" (len)
             : "memory", "rcx", "r8", "r9", "r10", "r11");
    return ret;
}

__must_check unsigned long
_copy_to_user(void __user *to, const void *from, unsigned len);
__must_check unsigned long
_copy_from_user(void *to, const void __user *from, unsigned len);
__must_check unsigned long
copy_in_user(void __user *to, const void __user *from, unsigned len);

static inline unsigned long __must_check copy_from_user(void *to,
                      const void __user *from,
                      unsigned long n)
{
    int sz = __compiletime_object_size(to);

    might_fault();
    if (likely(sz == -1 || sz >= n))
        n = _copy_from_user(to, from, n);
#ifdef CONFIG_DEBUG_VM
    else
        WARN(1, "Buffer overflow detected!\n");
#endif
    return n;
}

static __always_inline __must_check
int copy_to_user(void __user *dst, const void *src, unsigned size)
{
    might_fault();

    return _copy_to_user(dst, src, size);
}

static __always_inline __must_check
int __copy_from_user(void *dst, const void __user *src, unsigned size)
{
    int ret = 0;

    might_fault();
    if (!__builtin_constant_p(size))
        return copy_user_generic(dst, (__force void *)src, size);
    switch (size) {
    case 1:__get_user_asm(*(u8 *)dst, (u8 __user *)src,
                  ret, "b", "b", "=q", 1);
        return ret;
    case 2:__get_user_asm(*(u16 *)dst, (u16 __user *)src,
                  ret, "w", "w", "=r", 2);
        return ret;
    case 4:__get_user_asm(*(u32 *)dst, (u32 __user *)src,
                  ret, "l", "k", "=r", 4);
        return ret;
    case 8:__get_user_asm(*(u64 *)dst, (u64 __user *)src,
                  ret, "q", "", "=r", 8);
        return ret;
    case 10:
        __get_user_asm(*(u64 *)dst, (u64 __user *)src,
                   ret, "q", "", "=r", 10);
        if (unlikely(ret))
            return ret;
        __get_user_asm(*(u16 *)(8 + (char *)dst),
                   (u16 __user *)(8 + (char __user *)src),
                   ret, "w", "w", "=r", 2);
        return ret;
    case 16:
        __get_user_asm(*(u64 *)dst, (u64 __user *)src,
                   ret, "q", "", "=r", 16);
        if (unlikely(ret))
            return ret;
        __get_user_asm(*(u64 *)(8 + (char *)dst),
                   (u64 __user *)(8 + (char __user *)src),
                   ret, "q", "", "=r", 8);
        return ret;
    default:
        return copy_user_generic(dst, (__force void *)src, size);
    }
}

static __always_inline __must_check
int __copy_to_user(void __user *dst, const void *src, unsigned size)
{
    int ret = 0;

    might_fault();
    if (!__builtin_constant_p(size))
        return copy_user_generic((__force void *)dst, src, size);
    switch (size) {
    case 1:__put_user_asm(*(u8 *)src, (u8 __user *)dst,
                  ret, "b", "b", "iq", 1);
        return ret;
    case 2:__put_user_asm(*(u16 *)src, (u16 __user *)dst,
                  ret, "w", "w", "ir", 2);
        return ret;
    case 4:__put_user_asm(*(u32 *)src, (u32 __user *)dst,
                  ret, "l", "k", "ir", 4);
        return ret;
    case 8:__put_user_asm(*(u64 *)src, (u64 __user *)dst,
                  ret, "q", "", "er", 8);
        return ret;
    case 10:
        __put_user_asm(*(u64 *)src, (u64 __user *)dst,
                   ret, "q", "", "er", 10);
        if (unlikely(ret))
            return ret;
        asm("":::"memory");
        __put_user_asm(4[(u16 *)src], 4 + (u16 __user *)dst,
                   ret, "w", "w", "ir", 2);
        return ret;
    case 16:
        __put_user_asm(*(u64 *)src, (u64 __user *)dst,
                   ret, "q", "", "er", 16);
        if (unlikely(ret))
            return ret;
        asm("":::"memory");
        __put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst,
                   ret, "q", "", "er", 8);
        return ret;
    default:
        return copy_user_generic((__force void *)dst, src, size);
    }
}

static __always_inline __must_check
int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
{
    int ret = 0;

    might_fault();
    if (!__builtin_constant_p(size))
        return copy_user_generic((__force void *)dst,
                     (__force void *)src, size);
    switch (size) {
    case 1: {
        u8 tmp;
        __get_user_asm(tmp, (u8 __user *)src,
                   ret, "b", "b", "=q", 1);
        if (likely(!ret))
            __put_user_asm(tmp, (u8 __user *)dst,
                       ret, "b", "b", "iq", 1);
        return ret;
    }
    case 2: {
        u16 tmp;
        __get_user_asm(tmp, (u16 __user *)src,
                   ret, "w", "w", "=r", 2);
        if (likely(!ret))
            __put_user_asm(tmp, (u16 __user *)dst,
                       ret, "w", "w", "ir", 2);
        return ret;
    }

    case 4: {
        u32 tmp;
        __get_user_asm(tmp, (u32 __user *)src,
                   ret, "l", "k", "=r", 4);
        if (likely(!ret))
            __put_user_asm(tmp, (u32 __user *)dst,
                       ret, "l", "k", "ir", 4);
        return ret;
    }
    case 8: {
        u64 tmp;
        __get_user_asm(tmp, (u64 __user *)src,
                   ret, "q", "", "=r", 8);
        if (likely(!ret))
            __put_user_asm(tmp, (u64 __user *)dst,
                       ret, "q", "", "er", 8);
        return ret;
    }
    default:
        return copy_user_generic((__force void *)dst,
                     (__force void *)src, size);
    }
}

static __must_check __always_inline int
__copy_from_user_inatomic(void *dst, const void __user *src, unsigned size)
{
    return copy_user_generic(dst, (__force const void *)src, size);
}

static __must_check __always_inline int
__copy_to_user_inatomic(void __user *dst, const void *src, unsigned size)
{
    return copy_user_generic((__force void *)dst, src, size);
}

extern long __copy_user_nocache(void *dst, const void __user *src,
                unsigned size, int zerorest);

static inline int
__copy_from_user_nocache(void *dst, const void __user *src, unsigned size)
{
    might_sleep();
    return __copy_user_nocache(dst, src, size, 1);
}

static inline int
__copy_from_user_inatomic_nocache(void *dst, const void __user *src,
                  unsigned size)
{
    return __copy_user_nocache(dst, src, size, 0);
}

unsigned long
copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest);

#endif /* _ASM_X86_UACCESS_64_H */