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| author | Will Deacon <will.deacon@arm.com> | 2010-09-14 09:51:43 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-09-17 10:16:51 +0100 |
| commit | 9f05027c7cb3cfe56a31892bd83391138d41a667 (patch) | |
| tree | efe9361be8e1b8d78ff44ef13a1e46e1a4b9b23a /arch/arm/mm/proc-v7.S | |
| parent | 6491848d1ab246f6d243ddef25085fc1d836ff2c (diff) | |
| download | lwn-9f05027c7cb3cfe56a31892bd83391138d41a667.tar.gz lwn-9f05027c7cb3cfe56a31892bd83391138d41a667.zip | |
ARM: 6388/1: errata: DMB operation may be faulty
On versions of the Cortex-A9 up to and including r2p2, under rare
circumstances, a DMB instruction between 2 write operations may not
ensure the correct visibility ordering of the 2 writes.
This workaround sets a bit in the diagnostic register of the Cortex-A9,
causing the DMB instruction to behave like a DSB, which functions
correctly on the affected cores.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mm/proc-v7.S')
| -rw-r--r-- | arch/arm/mm/proc-v7.S | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index 1f16f9e3f441..945f36341fa6 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -201,7 +201,7 @@ __v7_setup: mrc p15, 0, r0, c0, c0, 0 @ read main ID register and r10, r0, #0xff000000 @ ARM? teq r10, #0x41000000 - bne 2f + bne 3f and r5, r0, #0x00f00000 @ variant and r6, r0, #0x0000000f @ revision orr r6, r6, r5, lsr #20-4 @ combine variant and revision @@ -231,8 +231,20 @@ __v7_setup: orreq r10, r10, #(1 << 22) @ set the Write Allocate disable bit mcreq p15, 1, r10, c9, c0, 2 @ write the L2 cache aux ctrl register #endif + b 3f + + /* Cortex-A9 Errata */ +2: ldr r10, =0x00000c09 @ Cortex-A9 primary part number + teq r0, r10 + bne 3f +#ifdef CONFIG_ARM_ERRATA_742230 + cmp r6, #0x22 @ only present up to r2p2 + mrcle p15, 0, r10, c15, c0, 1 @ read diagnostic register + orrle r10, r10, #1 << 4 @ set bit #4 + mcrle p15, 0, r10, c15, c0, 1 @ write diagnostic register +#endif -2: mov r10, #0 +3: mov r10, #0 #ifdef HARVARD_CACHE mcr p15, 0, r10, c7, c5, 0 @ I+BTB cache invalidate #endif |