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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_UACCESS_64_H
#define _ASM_X86_UACCESS_64_H
/*
* User space memory access functions
*/
#include <linux/compiler.h>
#include <linux/lockdep.h>
#include <linux/kasan-checks.h>
#include <asm/alternative.h>
#include <asm/cpufeatures.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;
}
static __always_inline __must_check unsigned long
raw_copy_from_user(void *dst, const void __user *src, unsigned long size)
{
return copy_user_generic(dst, (__force void *)src, size);
}
static __always_inline __must_check unsigned long
raw_copy_to_user(void __user *dst, const void *src, unsigned long 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);
extern long __copy_user_flushcache(void *dst, const void __user *src, unsigned size);
extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
size_t len);
static inline int
__copy_from_user_inatomic_nocache(void *dst, const void __user *src,
unsigned size)
{
kasan_check_write(dst, size);
return __copy_user_nocache(dst, src, size, 0);
}
static inline int
__copy_from_user_flushcache(void *dst, const void __user *src, unsigned size)
{
kasan_check_write(dst, size);
return __copy_user_flushcache(dst, src, size);
}
/*
* Zero Userspace.
*/
__must_check unsigned long
clear_user_original(void __user *addr, unsigned long len);
__must_check unsigned long
clear_user_rep_good(void __user *addr, unsigned long len);
__must_check unsigned long
clear_user_erms(void __user *addr, unsigned long len);
static __always_inline __must_check unsigned long __clear_user(void __user *addr, unsigned long size)
{
might_fault();
stac();
/*
* No memory constraint because it doesn't change any memory gcc
* knows about.
*/
asm volatile(
"1:\n\t"
ALTERNATIVE_3("rep stosb",
"call clear_user_erms", ALT_NOT(X86_FEATURE_FSRM),
"call clear_user_rep_good", ALT_NOT(X86_FEATURE_ERMS),
"call clear_user_original", ALT_NOT(X86_FEATURE_REP_GOOD))
"2:\n"
_ASM_EXTABLE_UA(1b, 2b)
: "+c" (size), "+D" (addr), ASM_CALL_CONSTRAINT
: "a" (0)
/* rep_good clobbers %rdx */
: "rdx");
clac();
return size;
}
static __always_inline unsigned long clear_user(void __user *to, unsigned long n)
{
if (access_ok(to, n))
return __clear_user(to, n);
return n;
}
#endif /* _ASM_X86_UACCESS_64_H */
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