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| author | Mark Nelson <markn@au1.ibm.com> | 2008-11-11 03:53:34 +0300 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2008-11-19 08:04:54 +0300 |
| commit | a4e22f02f5b6518c1484faea1f88d81802b9feac (patch) | |
| tree | 62652cde79d43420b8587344cb27ae8f9f1d12ef /arch/powerpc/lib | |
| parent | 7526ff76f84178f8c926de7e590e4c5f9d4a2e62 (diff) | |
| download | linux-a4e22f02f5b6518c1484faea1f88d81802b9feac.tar.xz | |
powerpc: Update 64bit __copy_tofrom_user() using CPU_FTR_UNALIGNED_LD_STD
In exactly the same way that we updated memcpy() with new feature
sections in commit 25d6e2d7c58ddc4a3b614fc5381591c0cfe66556 ("powerpc:
Update 64bit memcpy() using CPU_FTR_UNALIGNED_LD_STD"), we do the same
thing here for __copy_tofrom_user(). Once again this is purely a
performance tweak for Cell and Power6 - this has no effect on all the
other 64bit powerpc chips.
We can make these same changes to __copy_tofrom_user() because the
basic copy algorithm is the same as in memcpy() - this version just
has all the exception handling logic needed when copying to or from
userspace as well as a special case for copying whole 4K pages that
are page aligned.
CPU_FTR_UNALIGNED_LD_STD CPU was added in commit
4ec577a28980a0790df3c3dfe9c81f6e2222acfb ("powerpc: Add new CPU
feature: CPU_FTR_UNALIGNED_LD_STD").
We also make the same simple one line change from cmpldi r1,... to
cmpldi cr1,... for consistency.
Signed-off-by: Mark Nelson <markn@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/lib')
| -rw-r--r-- | arch/powerpc/lib/copyuser_64.S | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/arch/powerpc/lib/copyuser_64.S b/arch/powerpc/lib/copyuser_64.S index 25ec5378afa4..70693a5c12a1 100644 --- a/arch/powerpc/lib/copyuser_64.S +++ b/arch/powerpc/lib/copyuser_64.S @@ -26,11 +26,24 @@ _GLOBAL(__copy_tofrom_user) andi. r6,r6,7 PPC_MTOCRF 0x01,r5 blt cr1,.Lshort_copy +/* Below we want to nop out the bne if we're on a CPU that has the + * CPU_FTR_UNALIGNED_LD_STD bit set and the CPU_FTR_CP_USE_DCBTZ bit + * cleared. + * At the time of writing the only CPU that has this combination of bits + * set is Power6. + */ +BEGIN_FTR_SECTION + nop +FTR_SECTION_ELSE bne .Ldst_unaligned +ALT_FTR_SECTION_END(CPU_FTR_UNALIGNED_LD_STD | CPU_FTR_CP_USE_DCBTZ, \ + CPU_FTR_UNALIGNED_LD_STD) .Ldst_aligned: - andi. r0,r4,7 addi r3,r3,-16 +BEGIN_FTR_SECTION + andi. r0,r4,7 bne .Lsrc_unaligned +END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD) srdi r7,r5,4 20: ld r9,0(r4) addi r4,r4,-8 @@ -138,7 +151,7 @@ _GLOBAL(__copy_tofrom_user) PPC_MTOCRF 0x01,r6 /* put #bytes to 8B bdry into cr7 */ subf r5,r6,r5 li r7,0 - cmpldi r1,r5,16 + cmpldi cr1,r5,16 bf cr7*4+3,1f 35: lbz r0,0(r4) 81: stb r0,0(r3) |