From 54ea06f6afe85aaf419e51343d4e4b5599197113 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sat, 16 Jul 2005 15:21:51 +0100 Subject: [PATCH] ARM: Convert bitops to use ARMv6 ldrex/strex instructions Signed-off-by: Russell King --- arch/arm/lib/bitops.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'arch/arm/lib/bitops.h') 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 -- cgit v1.2.2 From 614d73edae68836f7659ee8efec90878e6215fb1 Mon Sep 17 00:00:00 2001 From: Russell King Date: Wed, 27 Jul 2005 23:00:05 +0100 Subject: [ARM SMP] Fix data corruption in test_* bitops If we found that the bit was already in the desired state, we would skip performing the operation, and write random data back. Signed-off-by: Russell King --- arch/arm/lib/bitops.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/arm/lib/bitops.h') diff --git a/arch/arm/lib/bitops.h b/arch/arm/lib/bitops.h index 6976e60e47cb..5382a3023602 100644 --- a/arch/arm/lib/bitops.h +++ b/arch/arm/lib/bitops.h @@ -19,9 +19,9 @@ 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 + \instr r2, r2, r3 @ toggle bit + strexb ip, r2, [r1] + cmp ip, #0 bne 1b cmp r0, #0 movne r0, #1 -- cgit v1.2.2 From e7ec02938dbe8ca35b750f29eaa4b12de0b52754 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 28 Jul 2005 20:36:26 +0100 Subject: [ARM SMP] Fix another ARMv6 bitop problem We sometimes forgot to check whether the exclusive store succeeded. Ensure that we always check. Also ensure that we always use the out of line versions, since the inline versions are not SMP safe. Signed-off-by: Russell King --- arch/arm/lib/bitops.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arm/lib/bitops.h') diff --git a/arch/arm/lib/bitops.h b/arch/arm/lib/bitops.h index 5382a3023602..2036ff15bda9 100644 --- a/arch/arm/lib/bitops.h +++ b/arch/arm/lib/bitops.h @@ -7,7 +7,7 @@ 1: ldrexb r2, [r1] \instr r2, r2, r3 strexb r0, r2, [r1] - cmpne r0, #0 + cmp r0, #0 bne 1b mov pc, lr .endm -- cgit v1.2.2