From: Suzuki K Poulose suzuki.poulose@arm.com

commit c0b15c25d25171db4b70cc0b7dbc1130ee94017d upstream.

The erratum 1024718 affects Cortex-A55 r0p0 to r2p0. However we apply the work around for r0p0 - r1p0. Unfortunately this won't be fixed for the future revisions for the CPU. Thus extend the work around for all versions of A55, to cover for r2p0 and any future revisions.

Cc: stable@vger.kernel.org #v4.4 v4.9 v4.14 Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will@kernel.org Cc: James Morse james.morse@arm.com Cc: Kunihiko Hayashi hayashi.kunihiko@socionext.com Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com Link: https://lore.kernel.org/r/20210203230057.3961239-1-suzuki.poulose@arm.com [will: Update Kconfig help text] Signed-off-by: Will Deacon will@kernel.org [Nanyon: adjust for stable version below v4.16, which set TCR_HD earlier in assembly code] Signed-off-by: Nanyong Sun sunnanyong@huawei.com --- arch/arm64/Kconfig | 2 +- arch/arm64/mm/proc.S | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index e296ae3e20f4..e76f74874a42 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -450,7 +450,7 @@ config ARM64_ERRATUM_1024718 help This option adds work around for Arm Cortex-A55 Erratum 1024718.

- Affected Cortex-A55 cores (r0p0, r0p1, r1p0) could cause incorrect + Affected Cortex-A55 cores (all revisions) could cause incorrect update of the hardware dirty bit when the DBM/AP bits are updated without a break-before-make. The work around is to disable the usage of hardware DBM locally on the affected cores. CPUs not affected by diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index ecbc060807d2..a9ff7fb41832 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -455,8 +455,8 @@ ENTRY(__cpu_setup) cmp x9, #2 b.lt 1f #ifdef CONFIG_ARM64_ERRATUM_1024718 - /* Disable hardware DBM on Cortex-A55 r0p0, r0p1 & r1p0 */ - cpu_midr_match MIDR_CORTEX_A55, MIDR_CPU_VAR_REV(0, 0), MIDR_CPU_VAR_REV(1, 0), x1, x2, x3, x4 + /* Disable hardware DBM on Cortex-A55 all versions */ + cpu_midr_match MIDR_CORTEX_A55, MIDR_CPU_VAR_REV(0, 0), MIDR_CPU_VAR_REV(0xf, 0xf), x1, x2, x3, x4 cbnz x1, 1f #endif orr x10, x10, #TCR_HD // hardware Dirty flag update