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arm64: lib: use pair accessors for copy_*_user routines

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The AArch64 instruction set contains load/store pair memory accessors,
so use these in our copy_*_user routines to transfer 16 bytes per
iteration.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Will Deacon 2015-06-02 15:18:38 +01:00
parent 5d220ff942
commit 23e9499446
3 changed files with 33 additions and 18 deletions
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17
arch/arm64/lib/copy_from_user.S
View File

@ -28,14 +28,19 @@
* x0 - bytes not copied
*/
ENTRY(__copy_from_user)
add x4, x1, x2 // upper user buffer boundary
subs x2, x2, #8
add x5, x1, x2 // upper user buffer boundary
subs x2, x2, #16
b.mi 1f
0:
USER(9f, ldp x3, x4, [x1], #16)
subs x2, x2, #16
stp x3, x4, [x0], #16
b.pl 0b
1: adds x2, x2, #8
b.mi 2f
1:
USER(9f, ldr x3, [x1], #8 )
subs x2, x2, #8
sub x2, x2, #8
str x3, [x0], #8
b.pl 1b
2: adds x2, x2, #4
b.mi 3f
USER(9f, ldr w3, [x1], #4 )
@ -56,7 +61,7 @@ ENDPROC(__copy_from_user)
.section .fixup,"ax"
.align 2
9: sub x2, x4, x1
9: sub x2, x5, x1
mov x3, x2
10: strb wzr, [x0], #1 // zero remaining buffer space
subs x3, x3, #1

17
arch/arm64/lib/copy_in_user.S
View File

@ -30,14 +30,19 @@
* x0 - bytes not copied
*/
ENTRY(__copy_in_user)
add x4, x0, x2 // upper user buffer boundary
subs x2, x2, #8
add x5, x0, x2 // upper user buffer boundary
subs x2, x2, #16
b.mi 1f
0:
USER(9f, ldp x3, x4, [x1], #16)
subs x2, x2, #16
USER(9f, stp x3, x4, [x0], #16)
b.pl 0b
1: adds x2, x2, #8
b.mi 2f
1:
USER(9f, ldr x3, [x1], #8 )
subs x2, x2, #8
sub x2, x2, #8
USER(9f, str x3, [x0], #8 )
b.pl 1b
2: adds x2, x2, #4
b.mi 3f
USER(9f, ldr w3, [x1], #4 )
@ -58,6 +63,6 @@ ENDPROC(__copy_in_user)
.section .fixup,"ax"
.align 2
9: sub x0, x4, x0 // bytes not copied
9: sub x0, x5, x0 // bytes not copied
ret
.previous

17
arch/arm64/lib/copy_to_user.S
View File

@ -28,14 +28,19 @@
* x0 - bytes not copied
*/
ENTRY(__copy_to_user)
add x4, x0, x2 // upper user buffer boundary
subs x2, x2, #8
add x5, x0, x2 // upper user buffer boundary
subs x2, x2, #16
b.mi 1f
0:
ldp x3, x4, [x1], #16
subs x2, x2, #16
USER(9f, stp x3, x4, [x0], #16)
b.pl 0b
1: adds x2, x2, #8
b.mi 2f
1:
ldr x3, [x1], #8
subs x2, x2, #8
sub x2, x2, #8
USER(9f, str x3, [x0], #8 )
b.pl 1b
2: adds x2, x2, #4
b.mi 3f
ldr w3, [x1], #4
@ -56,6 +61,6 @@ ENDPROC(__copy_to_user)
.section .fixup,"ax"
.align 2
9: sub x0, x4, x0 // bytes not copied
9: sub x0, x5, x0 // bytes not copied
ret
.previous