[PATCH] ARM: Convert bitops to use ARMv6 ldrex/strex instructions

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 31 insertions, 0 deletions

diff --git a/arch/arm/lib/bitops.h b/arch/arm/lib/bitops.h
index 4a83ab6cd565..6976e60e47cb 100644
--- a/arch/arm/lib/bitops.h
+++ b/arch/arm/lib/bitops.h
@@ -1,3 +1,33 @@
+#if __LINUX_ARM_ARCH__ >= 6
+        .macro  bitop, instr
+        mov     r2, #1
+        and     r3, r0, #7              @ Get bit offset
+        add     r1, r1, r0, lsr #3      @ Get byte offset
+        mov     r3, r2, lsl r3
+1:      ldrexb  r2, [r1]
+        \instr  r2, r2, r3
+        strexb  r0, r2, [r1]
+        cmpne   r0, #0
+        bne     1b
+        mov     pc, lr
+        .endm
+
+        .macro  testop, instr, store
+        and     r3, r0, #7              @ Get bit offset
+        mov     r2, #1
+        add     r1, r1, r0, lsr #3      @ Get byte offset
+        mov     r3, r2, lsl r3          @ create mask
+1:      ldrexb  r2, [r1]
+        ands    r0, r2, r3              @ save old value of bit
+        \instr  ip, r2, r3                      @ toggle bit
+        strexb  r2, ip, [r1]
+        cmp     r2, #0
+        bne     1b
+        cmp     r0, #0
+        movne   r0, #1
+2:      mov     pc, lr
+        .endm
+#else
         .macro  bitop, instr
         and     r2, r0, #7
         mov     r3, #1
@@ -31,3 +61,4 @@
         moveq   r0, #0
         mov     pc, lr
         .endm
+#endif