Commit f7c7bb9f authored by Andi Kleen's avatar Andi Kleen Committed by Greg Kroah-Hartman

x86: Add 1/2/4/8 byte optimization to 64bit __copy_{from,to}_user_inatomic

commit ff47ab4ff3cddfa7bc1b25b990e24abe2ae474ff upstream.

The 64bit __copy_{from,to}_user_inatomic always called
copy_from_user_generic, but skipped the special optimizations for 1/2/4/8
byte accesses.

This especially hurts the futex call, which accesses the 4 byte futex
user value with a complicated fast string operation in a function call,
instead of a single movl.

Use __copy_{from,to}_user for _inatomic instead to get the same
optimizations. The only problem was the might_fault() in those functions.
So move that to new wrapper and call __copy_{f,t}_user_nocheck()
from *_inatomic directly.

32bit already did this correctly by duplicating the code.
Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1376687844-19857-2-git-send-email-andi@firstfloor.orgSigned-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8938c105
...@@ -77,11 +77,10 @@ int copy_to_user(void __user *dst, const void *src, unsigned size) ...@@ -77,11 +77,10 @@ int copy_to_user(void __user *dst, const void *src, unsigned size)
} }
static __always_inline __must_check static __always_inline __must_check
int __copy_from_user(void *dst, const void __user *src, unsigned size) int __copy_from_user_nocheck(void *dst, const void __user *src, unsigned size)
{ {
int ret = 0; int ret = 0;
might_fault();
if (!__builtin_constant_p(size)) if (!__builtin_constant_p(size))
return copy_user_generic(dst, (__force void *)src, size); return copy_user_generic(dst, (__force void *)src, size);
switch (size) { switch (size) {
...@@ -121,11 +120,17 @@ int __copy_from_user(void *dst, const void __user *src, unsigned size) ...@@ -121,11 +120,17 @@ int __copy_from_user(void *dst, const void __user *src, unsigned size)
} }
static __always_inline __must_check static __always_inline __must_check
int __copy_to_user(void __user *dst, const void *src, unsigned size) int __copy_from_user(void *dst, const void __user *src, unsigned size)
{
might_fault();
return __copy_from_user_nocheck(dst, src, size);
}
static __always_inline __must_check
int __copy_to_user_nocheck(void __user *dst, const void *src, unsigned size)
{ {
int ret = 0; int ret = 0;
might_fault();
if (!__builtin_constant_p(size)) if (!__builtin_constant_p(size))
return copy_user_generic((__force void *)dst, src, size); return copy_user_generic((__force void *)dst, src, size);
switch (size) { switch (size) {
...@@ -164,6 +169,13 @@ int __copy_to_user(void __user *dst, const void *src, unsigned size) ...@@ -164,6 +169,13 @@ int __copy_to_user(void __user *dst, const void *src, unsigned size)
} }
} }
static __always_inline __must_check
int __copy_to_user(void __user *dst, const void *src, unsigned size)
{
might_fault();
return __copy_to_user_nocheck(dst, src, size);
}
static __always_inline __must_check static __always_inline __must_check
int __copy_in_user(void __user *dst, const void __user *src, unsigned size) int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
{ {
...@@ -220,13 +232,13 @@ int __copy_in_user(void __user *dst, const void __user *src, unsigned size) ...@@ -220,13 +232,13 @@ int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
static __must_check __always_inline int static __must_check __always_inline int
__copy_from_user_inatomic(void *dst, const void __user *src, unsigned size) __copy_from_user_inatomic(void *dst, const void __user *src, unsigned size)
{ {
return copy_user_generic(dst, (__force const void *)src, size); return __copy_from_user_nocheck(dst, (__force const void *)src, size);
} }
static __must_check __always_inline int static __must_check __always_inline int
__copy_to_user_inatomic(void __user *dst, const void *src, unsigned size) __copy_to_user_inatomic(void __user *dst, const void *src, unsigned size)
{ {
return copy_user_generic((__force void *)dst, src, size); return __copy_to_user_nocheck((__force void *)dst, src, size);
} }
extern long __copy_user_nocache(void *dst, const void __user *src, extern long __copy_user_nocache(void *dst, const void __user *src,
......
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