[PATCH 5.4 36/72] arm64: Allow CPUs unffected by ARM erratum 1418040 to come in late

Greg Kroah-Hartman
2020-09-21T16:49:08Z

From: Marc Zyngier <maz@kernel.org>

[ Upstream commit ed888cb0d1ebce69f12794e89fbd5e2c86d40b8d ]

Now that we allow CPUs affected by erratum 1418040 to come in late,
this prevents their unaffected sibblings from coming in late (or
coming back after a suspend or hotplug-off, which amounts to the
same thing).

To allow this, we need to add ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU,
which amounts to set .type to ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE.

Fixes: bf87bb0881d0 ("arm64: Allow booting of late CPUs affected by erratum 1418040")
Reported-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200911181611.2073183-1-maz@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm64/kernel/cpu_errata.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 51462c59ab5da..d2e738c455566 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -917,8 +917,12 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
.desc = "ARM erratum 1418040",
.capability = ARM64_WORKAROUND_1418040,
ERRATA_MIDR_RANGE_LIST(erratum_1418040_list),
- .type = (ARM64_CPUCAP_SCOPE_LOCAL_CPU |
- ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU),
+ /*
+ * We need to allow affected CPUs to come in late, but
+ * also need the non-affected CPUs to be able to come
+ * in at any point in time. Wonderful.
+ */
+ .type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
},
#endif
#ifdef CONFIG_ARM64_ERRATUM_1165522
--
2.25.1