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ARM: 6388/1: errata: DMB operation may be faulty

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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>
This commit is contained in:
Will Deacon 2010-09-14 09:51:43 +01:00 committed by Russell King
parent 6491848d1a
commit 9f05027c7c
2 changed files with 26 additions and 2 deletions
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12
arch/arm/Kconfig
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@ -1051,6 +1051,18 @@ config ARM_ERRATA_460075
ACTLR register. Note that setting specific bits in the ACTLR register
may not be available in non-secure mode.
config ARM_ERRATA_742230
bool "ARM errata: DMB operation may be faulty"
depends on CPU_V7 && SMP
help
This option enables the workaround for the 742230 Cortex-A9
(r1p0..r2p2) erratum. Under rare circumstances, a DMB instruction
between two write operations may not ensure the correct visibility
ordering of the two writes. This workaround sets a specific bit in
the diagnostic register of the Cortex-A9 which causes the DMB
instruction to behave as a DSB, ensuring the correct behaviour of
the two writes.
config PL310_ERRATA_588369
bool "Clean & Invalidate maintenance operations do not invalidate clean lines"
depends on CACHE_L2X0 && ARCH_OMAP4

16
arch/arm/mm/proc-v7.S
View File

@ -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
2: mov r10, #0
/* 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
3: mov r10, #0
#ifdef HARVARD_CACHE
mcr p15, 0, r10, c7, c5, 0 @ I+BTB cache invalidate
#endif