Commit 84b6504f authored by Will Deacon's avatar Will Deacon Committed by Russell King
Browse files

ARM: 7823/1: errata: workaround Cortex-A15 erratum 773022 



On Cortex-A15 CPUs up to and including r0p4, in certain rare sequences
of code, the loop buffer may deliver incorrect instructions. This
workaround disables the loop buffer to avoid the erratum.

Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 2afd0a05

arch/arm/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -1373,6 +1373,15 @@ config ARM_ERRATA_798181 
	  which sends an IPI to the CPUs that are running the same ASID

	  as the one being invalidated.



config ARM_ERRATA_773022

	bool "ARM errata: incorrect instructions may be executed from loop buffer"

	depends on CPU_V7

	help

	  This option enables the workaround for the 773022 Cortex-A15

	  (up to r0p4) erratum. In certain rare sequences of code, the

	  loop buffer may deliver incorrect instructions. This

	  workaround disables the loop buffer to avoid the erratum.



endmenu



source "arch/arm/common/Kconfig"

arch/arm/mm/proc-v7.S

+13 −1
Original line number Diff line number Diff line
@@ -329,7 +329,19 @@ __v7_setup: 
1:

#endif



3:	mov	r10, #0

	/* Cortex-A15 Errata */

3:	ldr	r10, =0x00000c0f		@ Cortex-A15 primary part number

	teq	r0, r10

	bne	4f



#ifdef CONFIG_ARM_ERRATA_773022

	cmp	r6, #0x4			@ only present up to r0p4

	mrcle	p15, 0, r10, c1, c0, 1		@ read aux control register

	orrle	r10, r10, #1 << 1		@ disable loop buffer

	mcrle	p15, 0, r10, c1, c0, 1		@ write aux control register

#endif



4:	mov	r10, #0

	mcr	p15, 0, r10, c7, c5, 0		@ I+BTB cache invalidate

	dsb

#ifdef CONFIG_MMU

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