Subject: [merged] x86-add-1-2-4-8-byte-optimization-to-64bit-__copy_fromto_user_inatomic.patch removed from -mm tree
To: ak@xxxxxxxxxxxxxxx,a.p.zijlstra@xxxxxxxxx,hpa@xxxxxxxxx,mingo@xxxxxxx,tglx@xxxxxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 16 Sep 2013 12:50:21 -0700
The patch titled
Subject: x86: add 1/2/4/8 byte optimization to 64bit __copy_{from,to}_user_inatomic
has been removed from the -mm tree. Its filename was
x86-add-1-2-4-8-byte-optimization-to-64bit-__copy_fromto_user_inatomic.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Subject: x86: add 1/2/4/8 byte optimization to 64bit __copy_{from,to}_user_inatomic
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: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/uaccess_64.h | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
diff -puN arch/x86/include/asm/uaccess_64.h~x86-add-1-2-4-8-byte-optimization-to-64bit-__copy_fromto_user_inatomic arch/x86/include/asm/uaccess_64.h
--- a/arch/x86/include/asm/uaccess_64.h~x86-add-1-2-4-8-byte-optimization-to-64bit-__copy_fromto_user_inatomic
+++ a/arch/x86/include/asm/uaccess_64.h
@@ -77,11 +77,10 @@ int copy_to_user(void __user *dst, const
}
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;
- might_fault();
if (!__builtin_constant_p(size))
return copy_user_generic(dst, (__force void *)src, size);
switch (size) {
@@ -121,11 +120,17 @@ int __copy_from_user(void *dst, const vo
}
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;
- might_fault();
if (!__builtin_constant_p(size))
return copy_user_generic((__force void *)dst, src, size);
switch (size) {
@@ -165,6 +170,13 @@ int __copy_to_user(void __user *dst, con
}
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
int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
{
int ret = 0;
@@ -220,13 +232,13 @@ int __copy_in_user(void __user *dst, con
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);
+ return __copy_from_user_nocheck(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);
+ return __copy_to_user_nocheck((__force void *)dst, src, size);
}
extern long __copy_user_nocache(void *dst, const void __user *src,
_
Patches currently in -mm which might be from ak@xxxxxxxxxxxxxxx are
origin.patch
linux-next.patch
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