From: James Morse james.morse@arm.com
[ Upstream commit 44b3834b2eed595af07021b1c64e6f9bc396398b ]
Cortex-A57 and Cortex-A72 have an erratum where an interrupt that occurs between a pair of AES instructions in aarch32 mode may corrupt the ELR. The task will subsequently produce the wrong AES result.
The AES instructions are part of the cryptographic extensions, which are optional. User-space software will detect the support for these instructions from the hwcaps. If the platform doesn't support these instructions a software implementation should be used.
Remove the hwcap bits on affected parts to indicate user-space should not use the AES instructions.
Acked-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: James Morse james.morse@arm.com Link: https://lore.kernel.org/r/20220714161523.279570-3-james.morse@arm.com Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- Documentation/arm64/silicon-errata.rst | 4 ++++ arch/arm64/Kconfig | 16 ++++++++++++++++ arch/arm64/kernel/cpu_errata.c | 16 ++++++++++++++++ arch/arm64/kernel/cpufeature.c | 14 +++++++++++++- arch/arm64/tools/cpucaps | 1 + 5 files changed, 50 insertions(+), 1 deletion(-)
diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst index d27db84d585e..0b4235b1f8c4 100644 --- a/Documentation/arm64/silicon-errata.rst +++ b/Documentation/arm64/silicon-errata.rst @@ -82,10 +82,14 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A57 | #1319537 | ARM64_ERRATUM_1319367 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A57 | #1742098 | ARM64_ERRATUM_1742098 | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A72 | #853709 | N/A | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A72 | #1319367 | ARM64_ERRATUM_1319367 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A72 | #1655431 | ARM64_ERRATUM_1742098 | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A73 | #858921 | ARM64_ERRATUM_858921 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A76 | #1188873,1418040| ARM64_ERRATUM_1418040 | diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 1652a9800ebe..3ad734de8e49 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -503,6 +503,22 @@ config ARM64_ERRATUM_834220
If unsure, say Y.
+config ARM64_ERRATUM_1742098 + bool "Cortex-A57/A72: 1742098: ELR recorded incorrectly on interrupt taken between cryptographic instructions in a sequence" + depends on COMPAT + default y + help + This option removes the AES hwcap for aarch32 user-space to + workaround erratum 1742098 on Cortex-A57 and Cortex-A72. + + Affected parts may corrupt the AES state if an interrupt is + taken between a pair of AES instructions. These instructions + are only present if the cryptography extensions are present. + All software should have a fallback implementation for CPUs + that don't implement the cryptography extensions. + + If unsure, say Y. + config ARM64_ERRATUM_845719 bool "Cortex-A53: 845719: a load might read incorrect data" depends on COMPAT diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index c05cc3b6162e..6b92989f4cc2 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -395,6 +395,14 @@ static struct midr_range trbe_write_out_of_range_cpus[] = { }; #endif /* CONFIG_ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE */
+#ifdef CONFIG_ARM64_ERRATUM_1742098 +static struct midr_range broken_aarch32_aes[] = { + MIDR_RANGE(MIDR_CORTEX_A57, 0, 1, 0xf, 0xf), + MIDR_ALL_VERSIONS(MIDR_CORTEX_A72), + {}, +}; +#endif /* CONFIG_ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE */ + const struct arm64_cpu_capabilities arm64_errata[] = { #ifdef CONFIG_ARM64_WORKAROUND_CLEAN_CACHE { @@ -657,6 +665,14 @@ const struct arm64_cpu_capabilities arm64_errata[] = { /* Cortex-A510 r0p0 - r0p1 */ ERRATA_MIDR_REV_RANGE(MIDR_CORTEX_A510, 0, 0, 1) }, +#endif +#ifdef CONFIG_ARM64_ERRATUM_1742098 + { + .desc = "ARM erratum 1742098", + .capability = ARM64_WORKAROUND_1742098, + CAP_MIDR_RANGE_LIST(broken_aarch32_aes), + .type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, + }, #endif { } diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 8d88433de81d..90018643d424 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -79,6 +79,7 @@ #include <asm/cpufeature.h> #include <asm/cpu_ops.h> #include <asm/fpsimd.h> +#include <asm/hwcap.h> #include <asm/insn.h> #include <asm/kvm_host.h> #include <asm/mmu_context.h> @@ -1971,6 +1972,14 @@ static void cpu_enable_mte(struct arm64_cpu_capabilities const *cap) } #endif /* CONFIG_ARM64_MTE */
+static void elf_hwcap_fixup(void) +{ +#ifdef CONFIG_ARM64_ERRATUM_1742098 + if (cpus_have_const_cap(ARM64_WORKAROUND_1742098)) + compat_elf_hwcap2 &= ~COMPAT_HWCAP2_AES; +#endif /* ARM64_ERRATUM_1742098 */ +} + #ifdef CONFIG_KVM static bool is_kvm_protected_mode(const struct arm64_cpu_capabilities *entry, int __unused) { @@ -3143,8 +3152,10 @@ void __init setup_cpu_features(void) setup_system_capabilities(); setup_elf_hwcaps(arm64_elf_hwcaps);
- if (system_supports_32bit_el0()) + if (system_supports_32bit_el0()) { setup_elf_hwcaps(compat_elf_hwcaps); + elf_hwcap_fixup(); + }
if (system_uses_ttbr0_pan()) pr_info("emulated: Privileged Access Never (PAN) using TTBR0_EL1 switching\n"); @@ -3197,6 +3208,7 @@ static int enable_mismatched_32bit_el0(unsigned int cpu) cpu_active_mask); get_cpu_device(lucky_winner)->offline_disabled = true; setup_elf_hwcaps(compat_elf_hwcaps); + elf_hwcap_fixup(); pr_info("Asymmetric 32-bit EL0 support detected on CPU %u; CPU hot-unplug disabled on CPU %u\n", cpu, lucky_winner); return 0; diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index 507b20373953..8809e14cf86a 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -61,6 +61,7 @@ WORKAROUND_1418040 WORKAROUND_1463225 WORKAROUND_1508412 WORKAROUND_1542419 +WORKAROUND_1742098 WORKAROUND_1902691 WORKAROUND_2038923 WORKAROUND_2064142