Commit 69155794 authored by Jon Medhurst's avatar Jon Medhurst Committed by Russell King
Browse files

ARM: 7752/1: errata: LoUIS bit field in CLIDR register is incorrect 



On Cortex-A9 before version r1p0, the LoUIS bit field of the CLIDR
register returns zero when it should return one. This leads to cache
maintenance operations which rely on this value to not function as
intended, causing data corruption.

The workaround for this errata is to detect affected CPUs and correct
the LoUIS value read.

Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Acked-by: default avatarNicolas Pitre <nico@linaro.org>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJon Medhurst <tixy@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 509eb76e

arch/arm/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -1189,6 +1189,16 @@ config PL310_ERRATA_588369 
	   is not correctly implemented in PL310 as clean lines are not

	   invalidated as a result of these operations.



config ARM_ERRATA_643719

	bool "ARM errata: LoUIS bit field in CLIDR register is incorrect"

	depends on CPU_V7 && SMP

	help

	  This option enables the workaround for the 643719 Cortex-A9 (prior to

	  r1p0) erratum. On affected cores the LoUIS bit field of the CLIDR

	  register returns zero when it should return one. The workaround

	  corrects this value, ensuring cache maintenance operations which use

	  it behave as intended and avoiding data corruption.



config ARM_ERRATA_720789

	bool "ARM errata: TLBIASIDIS and TLBIMVAIS operations can broadcast a faulty ASID"

	depends on CPU_V7

arch/arm/mm/cache-v7.S

+8 −0
Original line number Diff line number Diff line
@@ -92,6 +92,14 @@ ENTRY(v7_flush_dcache_louis) 
	mrc	p15, 1, r0, c0, c0, 1		@ read clidr, r0 = clidr

	ALT_SMP(ands	r3, r0, #(7 << 21))	@ extract LoUIS from clidr

	ALT_UP(ands	r3, r0, #(7 << 27))	@ extract LoUU from clidr

#ifdef CONFIG_ARM_ERRATA_643719

	ALT_SMP(mrceq	p15, 0, r2, c0, c0, 0)	@ read main ID register

	ALT_UP(moveq	pc, lr)			@ LoUU is zero, so nothing to do

	ldreq	r1, =0x410fc090                 @ ID of ARM Cortex A9 r0p?

	biceq	r2, r2, #0x0000000f             @ clear minor revision number

	teqeq	r2, r1                          @ test for errata affected core and if so...

	orreqs	r3, #(1 << 21)			@   fix LoUIS value (and set flags state to 'ne')

#endif

	ALT_SMP(mov	r3, r3, lsr #20)	@ r3 = LoUIS * 2

	ALT_UP(mov	r3, r3, lsr #26)	@ r3 = LoUU * 2

	moveq	pc, lr				@ return if level == 0

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