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| author | Will Deacon <will.deacon@arm.com> | 2015-06-02 15:18:38 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2015-07-27 11:08:39 +0100 |
| commit | 23e94994464a7281838785675e09c8ed1055f62f (patch) | |
| tree | ecf1beb8f744ec2b7e13625bdbcf34afb0da5e80 /arch/arm64/lib/copy_from_user.S | |
| parent | 5d220ff9420f8b1689805ba2d938bedf9e0860a4 (diff) | |
| download | lwn-23e94994464a7281838785675e09c8ed1055f62f.tar.gz lwn-23e94994464a7281838785675e09c8ed1055f62f.zip | |
arm64: lib: use pair accessors for copy_*_user routines
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>
Diffstat (limited to 'arch/arm64/lib/copy_from_user.S')
| -rw-r--r-- | arch/arm64/lib/copy_from_user.S | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S index 5e27add9d362..47c3fa5ae4ae 100644 --- a/arch/arm64/lib/copy_from_user.S +++ b/arch/arm64/lib/copy_from_user.S @@ -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 |