6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mark Rutland <mark.rutland@xxxxxxx> [ 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@xxxxxxx> Cc: James Morse <james.morse@xxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Link: https://lore.kernel.org/r/20240603111812.1514101-5-mark.rutland@xxxxxxx Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx> [ Mark: fix conflicts, drop unneeded cpucaps.h ] Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- Documentation/arch/arm64/silicon-errata.rst | 2 +- arch/arm64/Kconfig | 29 +++------------------ arch/arm64/kernel/cpu_errata.c | 8 ++---- arch/arm64/kernel/proton-pack.c | 2 +- 4 files changed, 8 insertions(+), 33 deletions(-) diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst index f8e49ff9ab0d4..e7fc5e1664265 100644 --- a/Documentation/arch/arm64/silicon-errata.rst +++ b/Documentation/arch/arm64/silicon-errata.rst @@ -147,7 +147,7 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2253138 | ARM64_ERRATUM_2253138 | +----------------+-----------------+-----------------+-----------------------------+ -| 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 db5560300df84..d9d84f716228b 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1068,34 +1068,14 @@ config ARM64_ERRATUM_3117295 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. + This option adds the workaround for the following errata: - 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. - - 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 @@ -1109,7 +1089,6 @@ config ARM64_ERRATUM_3312417 If unsure, say Y. - config CAVIUM_ERRATUM_22375 bool "Cavium erratum 22375, 24313" default y diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 3e1554a58209b..36d3f894f8637 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -448,14 +448,10 @@ static const struct midr_range erratum_spec_unpriv_load_list[] = { }; #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 @@ -758,7 +754,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = { .cpu_enable = cpu_clear_bf16_from_user_emulation, }, #endif -#ifdef CONFIG_ARM64_WORKAROUND_SPECULATIVE_SSBS +#ifdef CONFIG_ARM64_ERRATUM_3194386 { .desc = "ARM errata 3194386, 3312417", .capability = ARM64_WORKAROUND_SPECULATIVE_SSBS, diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c index e662c4d2856b6..57503dc4b22fa 100644 --- a/arch/arm64/kernel/proton-pack.c +++ b/arch/arm64/kernel/proton-pack.c @@ -567,7 +567,7 @@ static enum mitigation_state spectre_v4_enable_hw_mitigation(void) * Mitigate this with an unconditional speculation barrier, as 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 SPECTRE_MITIGATED; -- 2.43.0
