95108fa34a
Impact: make more types of copies non-temporal
This change makes the following simple fix:
30d697f: x86: fix performance regression in write() syscall
A bit more sophisticated: we check the 'total' number of bytes
written to decide whether to copy in a cached or a non-temporal
way.
This will for example cause the tail (modulo 4096 bytes) chunk
of a large write() to be non-temporal too - not just the page-sized
chunks.
Cc: Salman Qazi <sqazi@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
220 lines
6.1 KiB
C
220 lines
6.1 KiB
C
#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/prefetch.h>
|
|
#include <linux/lockdep.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_generic(void *to, const void *from, unsigned len);
|
|
|
|
__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 __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", "", "ir", 8);
|
|
return ret;
|
|
case 10:
|
|
__put_user_asm(*(u64 *)src, (u64 __user *)dst,
|
|
ret, "q", "", "ir", 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", "", "ir", 16);
|
|
if (unlikely(ret))
|
|
return ret;
|
|
asm("":::"memory");
|
|
__put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst,
|
|
ret, "q", "", "ir", 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", "", "ir", 8);
|
|
return ret;
|
|
}
|
|
default:
|
|
return copy_user_generic((__force void *)dst,
|
|
(__force void *)src, size);
|
|
}
|
|
}
|
|
|
|
__must_check long
|
|
strncpy_from_user(char *dst, const char __user *src, long count);
|
|
__must_check long
|
|
__strncpy_from_user(char *dst, const char __user *src, long count);
|
|
__must_check long strnlen_user(const char __user *str, long n);
|
|
__must_check long __strnlen_user(const char __user *str, long n);
|
|
__must_check long strlen_user(const char __user *str);
|
|
__must_check unsigned long clear_user(void __user *mem, unsigned long len);
|
|
__must_check unsigned long __clear_user(void __user *mem, unsigned long len);
|
|
|
|
__must_check long __copy_from_user_inatomic(void *dst, const void __user *src,
|
|
unsigned 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, unsigned long total)
|
|
{
|
|
might_sleep();
|
|
/*
|
|
* In practice this limit means that large file write()s
|
|
* which get chunked to 4K copies get handled via
|
|
* non-temporal stores here. Smaller writes get handled
|
|
* via regular __copy_from_user():
|
|
*/
|
|
if (likely(total >= PAGE_SIZE))
|
|
return __copy_user_nocache(dst, src, size, 1);
|
|
else
|
|
return __copy_from_user(dst, src, size);
|
|
}
|
|
|
|
static inline int __copy_from_user_inatomic_nocache(void *dst,
|
|
const void __user *src, unsigned size, unsigned total)
|
|
{
|
|
if (likely(total >= PAGE_SIZE))
|
|
return __copy_user_nocache(dst, src, size, 0);
|
|
else
|
|
return __copy_from_user_inatomic(dst, src, size);
|
|
}
|
|
|
|
unsigned long
|
|
copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest);
|
|
|
|
#endif /* _ASM_X86_UACCESS_64_H */
|