From: Paul E. McKenney <paul...@linux.vnet.ibm.com>
The powerpc 64-bit __copy_tofrom_user() function uses shifts to handle
unaligned invocations. However, these shifts were designed for
big-endian systems: On little-endian systems, they must shift in the
opposite direction.
This commit relies on the C preprocessor to insert the correct shifts
into the assembly code.
[ This is a rare but nasty LE issue. Most of the time we use the POWER7
optimised __copy_tofrom_user_power7 loop, but when it hits an exception
we fall back to the base __copy_tofrom_user loop. - Anton ]
Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
Signed-off-by: Anton Blanchard <an...@samba.org>
---
diff --git a/arch/powerpc/lib/copyuser_64.S b/arch/powerpc/lib/copyuser_64.S
index d73a590..596a285 100644
--- a/arch/powerpc/lib/copyuser_64.S
+++ b/arch/powerpc/lib/copyuser_64.S
@@ -9,6 +9,14 @@
#include <asm/processor.h>
#include <asm/ppc_asm.h>
+#ifdef __BIG_ENDIAN__
+#define sLd sld /* Shift towards low-numbered address. */
+#define sHd srd /* Shift towards high-numbered address. */
+#else
+#define sLd srd /* Shift towards low-numbered address. */
+#define sHd sld /* Shift towards high-numbered address. */
+#endif
+
.align 7
_GLOBAL(__copy_tofrom_user)
BEGIN_FTR_SECTION
@@ -118,10 +126,10 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
24: ld r9,0(r4) /* 3+2n loads, 2+2n stores */
25: ld r0,8(r4)
- sld r6,r9,r10
+ sLd r6,r9,r10
26: ldu r9,16(r4)
- srd r7,r0,r11
- sld r8,r0,r10
+ sHd r7,r0,r11
+ sLd r8,r0,r10
or r7,r7,r6
blt cr6,79f
27: ld r0,8(r4)
@@ -129,35 +137,35 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
28: ld r0,0(r4) /* 4+2n loads, 3+2n stores */
29: ldu r9,8(r4)
- sld r8,r0,r10
+ sLd r8,r0,r10
addi r3,r3,-8
blt cr6,5f
30: ld r0,8(r4)
- srd r12,r9,r11
- sld r6,r9,r10
+ sHd r12,r9,r11
+ sLd r6,r9,r10
31: ldu r9,16(r4)
or r12,r8,r12
- srd r7,r0,r11
- sld r8,r0,r10
+ sHd r7,r0,r11
+ sLd r8,r0,r10
addi r3,r3,16
beq cr6,78f
1: or r7,r7,r6
32: ld r0,8(r4)
76: std r12,8(r3)
-2: srd r12,r9,r11
- sld r6,r9,r10
+2: sHd r12,r9,r11
+ sLd r6,r9,r10
33: ldu r9,16(r4)
or r12,r8,r12
77: stdu r7,16(r3)
- srd r7,r0,r11
- sld r8,r0,r10
+ sHd r7,r0,r11
+ sLd r8,r0,r10
bdnz 1b
78: std r12,8(r3)
or r7,r7,r6
79: std r7,16(r3)
-5: srd r12,r9,r11
+5: sHd r12,r9,r11
or r12,r8,r12
80: std r12,24(r3)
bne 6f
@@ -165,23 +173,38 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
blr
6: cmpwi cr1,r5,8
addi r3,r3,32
- sld r9,r9,r10
+ sLd r9,r9,r10
ble cr1,7f
34: ld r0,8(r4)
- srd r7,r0,r11
+ sHd r7,r0,r11
or r9,r7,r9
7:
bf cr7*4+1,1f
+#ifdef __BIG_ENDIAN__
rotldi r9,r9,32
+#endif
94: stw r9,0(r3)
+#ifdef __LITTLE_ENDIAN__
+ rotrdi r9,r9,32
+#endif
addi r3,r3,4
1: bf cr7*4+2,2f
+#ifdef __BIG_ENDIAN__
rotldi r9,r9,16
+#endif
95: sth r9,0(r3)
+#ifdef __LITTLE_ENDIAN__
+ rotrdi r9,r9,16
+#endif
addi r3,r3,2
2: bf cr7*4+3,3f
+#ifdef __BIG_ENDIAN__
rotldi r9,r9,8
+#endif
96: stb r9,0(r3)
+#ifdef __LITTLE_ENDIAN__
+ rotrdi r9,r9,8
+#endif
3: li r3,0
blr
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