5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mark Rutland mark.rutland@arm.com
[ Upstream commit ec768766608092087dfb5c1fc45a16a6f524dee2 ]
Cortex-X4 erratum 3194386 and Neoverse-V3 erratum 3312417 are identical, with duplicate Kconfig text and some unsightly ifdeffery. While we try to share code behind CONFIG_ARM64_WORKAROUND_SPECULATIVE_SSBS, having separate options results in a fair amount of boilerplate code, and this will only get worse as we expand the set of affected CPUs.
To reduce this boilerplate, unify the two behind a common Kconfig option. This removes the duplicate text and Kconfig logic, and removes the need for the intermediate ARM64_WORKAROUND_SPECULATIVE_SSBS option. The set of affected CPUs is described as a list so that this can easily be extended.
I've used ARM64_ERRATUM_3194386 (matching the Neoverse-V3 erratum ID) as the common option, matching the way we use ARM64_ERRATUM_1319367 to cover Cortex-A57 erratum 1319537 and Cortex-A72 erratum 1319367.
Signed-off-by: Mark Rutland mark.rutland@arm.com Cc: James Morse james.morse@arm.com Cc: Will Deacon will@kernel.org Link: https://lore.kernel.org/r/20240603111812.1514101-5-mark.rutland@arm.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com [ Mark: fix conflicts & renames, drop unneeded cpucaps.h ] Signed-off-by: Mark Rutland mark.rutland@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- Documentation/arm64/silicon-errata.rst | 2 +- arch/arm64/Kconfig | 28 ++++---------------------- arch/arm64/kernel/cpu_errata.c | 10 +++------ 3 files changed, 8 insertions(+), 32 deletions(-)
diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst index 003424286dda4..b2db2492bd131 100644 --- a/Documentation/arm64/silicon-errata.rst +++ b/Documentation/arm64/silicon-errata.rst @@ -96,7 +96,7 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1542419 | ARM64_ERRATUM_1542419 | +----------------+-----------------+-----------------+-----------------------------+ -| ARM | Neoverse-V3 | #3312417 | ARM64_ERRATUM_3312417 | +| ARM | Neoverse-V3 | #3312417 | ARM64_ERRATUM_3194386 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-500 | #841119,826419 | N/A | +----------------+-----------------+-----------------+-----------------------------+ diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 122f2b068e28d..1455a81ee8687 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -590,34 +590,14 @@ config ARM64_ERRATUM_1742098
If unsure, say Y.
-config ARM64_WORKAROUND_SPECULATIVE_SSBS - bool - config ARM64_ERRATUM_3194386 - bool "Cortex-X4: 3194386: workaround for MSR SSBS not self-synchronizing" - select ARM64_WORKAROUND_SPECULATIVE_SSBS + bool "Cortex-X4/Neoverse-V3: workaround for MSR SSBS not self-synchronizing" default y help - This option adds the workaround for ARM Cortex-X4 erratum 3194386. - - On affected cores "MSR SSBS, #0" instructions may not affect - subsequent speculative instructions, which may permit unexepected - speculative store bypassing. - - Work around this problem by placing a speculation barrier after - kernel changes to SSBS. The presence of the SSBS special-purpose - register is hidden from hwcaps and EL0 reads of ID_AA64PFR1_EL1, such - that userspace will use the PR_SPEC_STORE_BYPASS prctl to change - SSBS. + This option adds the workaround for the following errata:
- If unsure, say Y. - -config ARM64_ERRATUM_3312417 - bool "Neoverse-V3: 3312417: workaround for MSR SSBS not self-synchronizing" - select ARM64_WORKAROUND_SPECULATIVE_SSBS - default y - help - This option adds the workaround for ARM Neoverse-V3 erratum 3312417. + * ARM Cortex-X4 erratum 3194386 + * ARM Neoverse-V3 erratum 3312417
On affected cores "MSR SSBS, #0" instructions may not affect subsequent speculative instructions, which may permit unexepected diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index dd8be391e595d..5e77a7595059b 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -382,7 +382,7 @@ void arm64_set_ssbd_mitigation(bool state) * CPUs could mis-speculate branches and bypass a conditional * barrier. */ - if (IS_ENABLED(CONFIG_ARM64_WORKAROUND_SPECULATIVE_SSBS)) + if (IS_ENABLED(CONFIG_ARM64_ERRATUM_3194386)) spec_bar();
return; @@ -841,14 +841,10 @@ static struct midr_range broken_aarch32_aes[] = { }; #endif
-#ifdef CONFIG_ARM64_WORKAROUND_SPECULATIVE_SSBS -static const struct midr_range erratum_spec_ssbs_list[] = { #ifdef CONFIG_ARM64_ERRATUM_3194386 +static const struct midr_range erratum_spec_ssbs_list[] = { MIDR_ALL_VERSIONS(MIDR_CORTEX_X4), -#endif -#ifdef CONFIG_ARM64_ERRATUM_3312417 MIDR_ALL_VERSIONS(MIDR_NEOVERSE_V3), -#endif {} }; #endif @@ -1042,7 +1038,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = { .type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, }, #endif -#ifdef CONFIG_ARM64_WORKAROUND_SPECULATIVE_SSBS +#ifdef CONFIG_ARM64_ERRATUM_3194386 { .desc = "ARM errata 3194386, 3312417", .capability = ARM64_WORKAROUND_SPECULATIVE_SSBS,