* [PATCH 0/2] RFC only - allow arches to over-ride unit sized user copies
@ 2012-11-20 14:38 Vineet.Gupta1
2012-11-20 14:38 ` [PATCH 1/2] asm-generic: uaccess: allow arch to over-ride __get_user_fn() Vineet.Gupta1
2012-11-20 14:38 ` [PATCH 2/2] ARC: provide optimal __get_user_fn() Vineet.Gupta1
0 siblings, 2 replies; 10+ messages in thread
From: Vineet.Gupta1 @ 2012-11-20 14:38 UTC (permalink / raw)
To: arnd; +Cc: linux-arch, linux-kernel, Vineet Gupta
From: Vineet Gupta <vgupta@synopsys.com>
Hi Arnd,
The current asm-generic/uaccess unit copy interface __{get,put}_user( )
defaults to using __copy_{to,from}_user( ). For archs which don't support
unaligned access, latter typically involves generated code for alignment
checks.
It is expected that arch will provide a fast path in __copy_{to,from}_user( )
for such unit sized copies - probably using __builtin_const_p( ) etc -
however the alignment checks still can't be eliminated altogether using that.
Even if they could, it woudl make the implementation messier IMHO.
However given that 2 separate interfaces already exist form beginning
(i.e. __get_user vs. __copy_from_user) will it make sense to allow arch to
provide alternate implementation of former w/o having to mess with latter.
I did a quick hack to that end and I can see that savings are more than
just "noise".
bloat-o-meter vmlinux_pre_uaccess vmlinux_uaccess_part1 | head
add/remove: 0/1 grow/shrink: 10/62 up/down: 1502/-7256 (-5754)
The patch which converts just __get_user follows. I've not
done the full/clean version yet as this is just to gather feedback.
Thx,
-Vineet
Vineet Gupta (2):
asm-generic: uaccess: allow arch to over-ride __get_user_fn()
ARC: provide optimal __get_user_fn()
arch/arc/include/asm/uaccess.h | 51 ++++++++++++++++++++++++++++++++++++++++
include/asm-generic/uaccess.h | 5 ++++
2 files changed, 56 insertions(+), 0 deletions(-)
--
1.7.4.1
^ permalink raw reply [flat|nested] 10+ messages in thread* [PATCH 1/2] asm-generic: uaccess: allow arch to over-ride __get_user_fn() 2012-11-20 14:38 [PATCH 0/2] RFC only - allow arches to over-ride unit sized user copies Vineet.Gupta1 @ 2012-11-20 14:38 ` Vineet.Gupta1 2012-11-20 14:38 ` Vineet.Gupta1 ` (2 more replies) 2012-11-20 14:38 ` [PATCH 2/2] ARC: provide optimal __get_user_fn() Vineet.Gupta1 1 sibling, 3 replies; 10+ messages in thread From: Vineet.Gupta1 @ 2012-11-20 14:38 UTC (permalink / raw) To: arnd; +Cc: linux-arch, linux-kernel, Vineet Gupta From: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> --- include/asm-generic/uaccess.h | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h index 5f6ee61..432d55f 100644 --- a/include/asm-generic/uaccess.h +++ b/include/asm-generic/uaccess.h @@ -225,12 +225,17 @@ extern int __put_user_bad(void) __attribute__((noreturn)); -EFAULT; \ }) +#ifndef __get_user_fn static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) { size = __copy_from_user(x, ptr, size); return size ? -EFAULT : size; } +#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k) + +#endif + extern int __get_user_bad(void) __attribute__((noreturn)); #ifndef __copy_from_user_inatomic -- 1.7.4.1 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 1/2] asm-generic: uaccess: allow arch to over-ride __get_user_fn() 2012-11-20 14:38 ` [PATCH 1/2] asm-generic: uaccess: allow arch to over-ride __get_user_fn() Vineet.Gupta1 @ 2012-11-20 14:38 ` Vineet.Gupta1 2012-11-20 15:55 ` Arnd Bergmann 2012-12-21 19:43 ` Arnd Bergmann 2 siblings, 0 replies; 10+ messages in thread From: Vineet.Gupta1 @ 2012-11-20 14:38 UTC (permalink / raw) To: arnd; +Cc: linux-arch, linux-kernel, Vineet Gupta From: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> --- include/asm-generic/uaccess.h | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h index 5f6ee61..432d55f 100644 --- a/include/asm-generic/uaccess.h +++ b/include/asm-generic/uaccess.h @@ -225,12 +225,17 @@ extern int __put_user_bad(void) __attribute__((noreturn)); -EFAULT; \ }) +#ifndef __get_user_fn static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) { size = __copy_from_user(x, ptr, size); return size ? -EFAULT : size; } +#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k) + +#endif + extern int __get_user_bad(void) __attribute__((noreturn)); #ifndef __copy_from_user_inatomic -- 1.7.4.1 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH 1/2] asm-generic: uaccess: allow arch to over-ride __get_user_fn() 2012-11-20 14:38 ` [PATCH 1/2] asm-generic: uaccess: allow arch to over-ride __get_user_fn() Vineet.Gupta1 2012-11-20 14:38 ` Vineet.Gupta1 @ 2012-11-20 15:55 ` Arnd Bergmann 2012-12-21 19:43 ` Arnd Bergmann 2 siblings, 0 replies; 10+ messages in thread From: Arnd Bergmann @ 2012-11-20 15:55 UTC (permalink / raw) To: Vineet.Gupta1; +Cc: linux-arch, linux-kernel On Tuesday 20 November 2012, Vineet.Gupta1@synopsys.com wrote: > +#ifndef __get_user_fn > static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) > { > size = __copy_from_user(x, ptr, size); > return size ? -EFAULT : size; > } > > +#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k) > + > +#endif This is ok as well. The idea with the asm-generic __copy_from_user() implementation is to separate out the cases where you have just a few bytes and handle them efficiently inline. If you don't want to do that for some reason, overriding __get_user_fn works as well. The resulting object code should be the same. Arnd ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 1/2] asm-generic: uaccess: allow arch to over-ride __get_user_fn() 2012-11-20 14:38 ` [PATCH 1/2] asm-generic: uaccess: allow arch to over-ride __get_user_fn() Vineet.Gupta1 2012-11-20 14:38 ` Vineet.Gupta1 2012-11-20 15:55 ` Arnd Bergmann @ 2012-12-21 19:43 ` Arnd Bergmann 2012-12-24 5:50 ` Vineet Gupta 2 siblings, 1 reply; 10+ messages in thread From: Arnd Bergmann @ 2012-12-21 19:43 UTC (permalink / raw) To: Vineet.Gupta1; +Cc: linux-arch, linux-kernel On Tuesday 20 November 2012, Vineet.Gupta1@synopsys.com wrote: > From: Vineet Gupta <vgupta@synopsys.com> > > Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Acked-by: Arnd Bergmann <arnd@arndb.de> ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 1/2] asm-generic: uaccess: allow arch to over-ride __get_user_fn() 2012-12-21 19:43 ` Arnd Bergmann @ 2012-12-24 5:50 ` Vineet Gupta 0 siblings, 0 replies; 10+ messages in thread From: Vineet Gupta @ 2012-12-24 5:50 UTC (permalink / raw) To: Arnd Bergmann; +Cc: linux-arch, linux-kernel On Saturday 22 December 2012 01:13 AM, Arnd Bergmann wrote: > On Tuesday 20 November 2012, Vineet.Gupta1@synopsys.com wrote: >> From: Vineet Gupta <vgupta@synopsys.com> >> >> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> > Acked-by: Arnd Bergmann <arnd@arndb.de> Thx, -Vineet ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH 2/2] ARC: provide optimal __get_user_fn() 2012-11-20 14:38 [PATCH 0/2] RFC only - allow arches to over-ride unit sized user copies Vineet.Gupta1 2012-11-20 14:38 ` [PATCH 1/2] asm-generic: uaccess: allow arch to over-ride __get_user_fn() Vineet.Gupta1 @ 2012-11-20 14:38 ` Vineet.Gupta1 2012-11-20 14:38 ` Vineet.Gupta1 2012-11-20 15:51 ` Arnd Bergmann 1 sibling, 2 replies; 10+ messages in thread From: Vineet.Gupta1 @ 2012-11-20 14:38 UTC (permalink / raw) To: arnd; +Cc: linux-arch, linux-kernel, Vineet Gupta From: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> --- arch/arc/include/asm/uaccess.h | 51 ++++++++++++++++++++++++++++++++++++++++ 1 files changed, 51 insertions(+), 0 deletions(-) diff --git a/arch/arc/include/asm/uaccess.h b/arch/arc/include/asm/uaccess.h index 503c98d..d9cbae4 100644 --- a/arch/arc/include/asm/uaccess.h +++ b/arch/arc/include/asm/uaccess.h @@ -35,6 +35,57 @@ #define __access_ok(addr, sz) (unlikely(__kernel_ok) || \ likely(__user_ok((addr), (sz)))) +/*********** Single byte/s-word/word copies ******************/ + +#define __get_user_fn(sz, u, k) \ +({ \ + long __ret = 0; /* success by default */ \ + switch (sz) { \ + case 1: __arc_get_user_one(*(k), u, "ldb", __ret); break; \ + case 2: __arc_get_user_one(*(k), u, "ldw", __ret); break; \ + case 4: __arc_get_user_one(*(k), u, "ld", __ret); break; \ + case 8: __arc_get_user_one_64(*(k), u, __ret); break; \ + } \ + __ret; \ +}) + +#define __arc_get_user_one(dst, src, op, ret) \ + __asm__ __volatile__( \ + "1: "op" %1,[%2]\n" \ + "2: ;nop\n" \ + " .section .fixup, \"ax\"\n" \ + " .align 4\n" \ + "3: mov %0, %3\n" \ + " j 2b\n" \ + " .previous\n" \ + " .section __ex_table, \"a\"\n" \ + " .align 4\n" \ + " .word 1b,3b\n" \ + " .previous\n" \ + \ + : "+r" (ret), "=r" (dst) \ + : "r" (src), "i" (-EFAULT)) + +#define __arc_get_user_one_64(dst, src, ret) \ + __asm__ __volatile__( \ + "1: ld %1,[%2]\n" \ + "4: ld %R1,[%2, 4]\n" \ + "2: ;nop\n" \ + " .section .fixup, \"ax\"\n" \ + " .align 4\n" \ + "3: mov %0, %3\n" \ + " j 2b\n" \ + " .previous\n" \ + " .section __ex_table, \"a\"\n" \ + " .align 4\n" \ + " .word 1b,3b\n" \ + " .word 4b,3b\n" \ + " .previous\n" \ + \ + : "+r" (ret), "=r" (dst) \ + : "r" (src), "i" (-EFAULT)) + + static inline unsigned long __arc_copy_from_user(void *to, const void __user *from, unsigned long n) { -- 1.7.4.1 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 2/2] ARC: provide optimal __get_user_fn() 2012-11-20 14:38 ` [PATCH 2/2] ARC: provide optimal __get_user_fn() Vineet.Gupta1 @ 2012-11-20 14:38 ` Vineet.Gupta1 2012-11-20 15:51 ` Arnd Bergmann 1 sibling, 0 replies; 10+ messages in thread From: Vineet.Gupta1 @ 2012-11-20 14:38 UTC (permalink / raw) To: arnd; +Cc: linux-arch, linux-kernel, Vineet Gupta From: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> --- arch/arc/include/asm/uaccess.h | 51 ++++++++++++++++++++++++++++++++++++++++ 1 files changed, 51 insertions(+), 0 deletions(-) diff --git a/arch/arc/include/asm/uaccess.h b/arch/arc/include/asm/uaccess.h index 503c98d..d9cbae4 100644 --- a/arch/arc/include/asm/uaccess.h +++ b/arch/arc/include/asm/uaccess.h @@ -35,6 +35,57 @@ #define __access_ok(addr, sz) (unlikely(__kernel_ok) || \ likely(__user_ok((addr), (sz)))) +/*********** Single byte/s-word/word copies ******************/ + +#define __get_user_fn(sz, u, k) \ +({ \ + long __ret = 0; /* success by default */ \ + switch (sz) { \ + case 1: __arc_get_user_one(*(k), u, "ldb", __ret); break; \ + case 2: __arc_get_user_one(*(k), u, "ldw", __ret); break; \ + case 4: __arc_get_user_one(*(k), u, "ld", __ret); break; \ + case 8: __arc_get_user_one_64(*(k), u, __ret); break; \ + } \ + __ret; \ +}) + +#define __arc_get_user_one(dst, src, op, ret) \ + __asm__ __volatile__( \ + "1: "op" %1,[%2]\n" \ + "2: ;nop\n" \ + " .section .fixup, \"ax\"\n" \ + " .align 4\n" \ + "3: mov %0, %3\n" \ + " j 2b\n" \ + " .previous\n" \ + " .section __ex_table, \"a\"\n" \ + " .align 4\n" \ + " .word 1b,3b\n" \ + " .previous\n" \ + \ + : "+r" (ret), "=r" (dst) \ + : "r" (src), "i" (-EFAULT)) + +#define __arc_get_user_one_64(dst, src, ret) \ + __asm__ __volatile__( \ + "1: ld %1,[%2]\n" \ + "4: ld %R1,[%2, 4]\n" \ + "2: ;nop\n" \ + " .section .fixup, \"ax\"\n" \ + " .align 4\n" \ + "3: mov %0, %3\n" \ + " j 2b\n" \ + " .previous\n" \ + " .section __ex_table, \"a\"\n" \ + " .align 4\n" \ + " .word 1b,3b\n" \ + " .word 4b,3b\n" \ + " .previous\n" \ + \ + : "+r" (ret), "=r" (dst) \ + : "r" (src), "i" (-EFAULT)) + + static inline unsigned long __arc_copy_from_user(void *to, const void __user *from, unsigned long n) { -- 1.7.4.1 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH 2/2] ARC: provide optimal __get_user_fn() 2012-11-20 14:38 ` [PATCH 2/2] ARC: provide optimal __get_user_fn() Vineet.Gupta1 2012-11-20 14:38 ` Vineet.Gupta1 @ 2012-11-20 15:51 ` Arnd Bergmann 2012-12-21 4:33 ` Vineet Gupta 1 sibling, 1 reply; 10+ messages in thread From: Arnd Bergmann @ 2012-11-20 15:51 UTC (permalink / raw) To: Vineet.Gupta1; +Cc: linux-arch, linux-kernel On Tuesday 20 November 2012, Vineet.Gupta1@synopsys.com wrote: > From: Vineet Gupta <vgupta@synopsys.com> > > Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Yes, this looks good to me. Acked-by: Arnd Bergmann <arnd@arndb.de> ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 2/2] ARC: provide optimal __get_user_fn() 2012-11-20 15:51 ` Arnd Bergmann @ 2012-12-21 4:33 ` Vineet Gupta 0 siblings, 0 replies; 10+ messages in thread From: Vineet Gupta @ 2012-12-21 4:33 UTC (permalink / raw) To: Arnd Bergmann; +Cc: linux-arch, linux-kernel On Tuesday 20 November 2012 09:21 PM, Arnd Bergmann wrote: > On Tuesday 20 November 2012, Vineet.Gupta1@synopsys.com wrote: >> From: Vineet Gupta <vgupta@synopsys.com> >> >> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> > > Yes, this looks good to me. > > Acked-by: Arnd Bergmann <arnd@arndb.de> > Can you please also ACK the asm-generic bits of this series [PATCH 1/2] Thx, -Vineet ^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2012-12-24 5:50 UTC | newest] Thread overview: 10+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2012-11-20 14:38 [PATCH 0/2] RFC only - allow arches to over-ride unit sized user copies Vineet.Gupta1 2012-11-20 14:38 ` [PATCH 1/2] asm-generic: uaccess: allow arch to over-ride __get_user_fn() Vineet.Gupta1 2012-11-20 14:38 ` Vineet.Gupta1 2012-11-20 15:55 ` Arnd Bergmann 2012-12-21 19:43 ` Arnd Bergmann 2012-12-24 5:50 ` Vineet Gupta 2012-11-20 14:38 ` [PATCH 2/2] ARC: provide optimal __get_user_fn() Vineet.Gupta1 2012-11-20 14:38 ` Vineet.Gupta1 2012-11-20 15:51 ` Arnd Bergmann 2012-12-21 4:33 ` Vineet Gupta
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