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authorMark Nelson <markn@au1.ibm.com>2008-11-11 00:53:34 +0000
committerPaul Mackerras <paulus@samba.org>2008-11-19 16:04:54 +1100
commita4e22f02f5b6518c1484faea1f88d81802b9feac (patch)
tree62652cde79d43420b8587344cb27ae8f9f1d12ef /arch/powerpc/lib
parent7526ff76f84178f8c926de7e590e4c5f9d4a2e62 (diff)
downloadblackbird-op-linux-a4e22f02f5b6518c1484faea1f88d81802b9feac.tar.gz
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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.S17
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)
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