From: James Morse james.morse@arm.com
commit 44b3834b2eed595af07021b1c64e6f9bc396398b upstream.
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 [florian: removed arch/arm64/tools/cpucaps and fixup cpufeature.c] Signed-off-by: Florian Fainelli f.fainelli@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- Documentation/arm64/silicon-errata.rst | 4 ++++ arch/arm64/Kconfig | 16 ++++++++++++++++ arch/arm64/include/asm/cpucaps.h | 3 ++- arch/arm64/kernel/cpu_errata.c | 16 ++++++++++++++++ arch/arm64/kernel/cpufeature.c | 13 ++++++++++++- 5 files changed, 50 insertions(+), 2 deletions(-)
--- a/Documentation/arm64/silicon-errata.rst +++ b/Documentation/arm64/silicon-errata.rst @@ -76,10 +76,14 @@ 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 | --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -481,6 +481,22 @@ 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 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -68,7 +68,8 @@ #define ARM64_WORKAROUND_1508412 58 #define ARM64_SPECTRE_BHB 59 #define ARM64_WORKAROUND_2457168 60 +#define ARM64_WORKAROUND_1742098 61
-#define ARM64_NCAPS 61 +#define ARM64_NCAPS 62
#endif /* __ASM_CPUCAPS_H */ --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -356,6 +356,14 @@ static const struct midr_range erratum_1 }; #endif
+#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 + const struct arm64_cpu_capabilities arm64_errata[] = { #ifdef CONFIG_ARM64_WORKAROUND_CLEAN_CACHE { @@ -555,6 +563,14 @@ const struct arm64_cpu_capabilities arm6 CAP_MIDR_RANGE(MIDR_CORTEX_A510, 0, 0, 1, 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 { } }; --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -76,6 +76,7 @@ #include <asm/cpufeature.h> #include <asm/cpu_ops.h> #include <asm/fpsimd.h> +#include <asm/hwcap.h> #include <asm/mmu_context.h> #include <asm/mte.h> #include <asm/processor.h> @@ -1730,6 +1731,14 @@ static void cpu_enable_mte(struct arm64_ } #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 */ +} + /* Internal helper functions to match cpu capability type */ static bool cpucap_late_cpu_optional(const struct arm64_cpu_capabilities *cap) @@ -2735,8 +2744,10 @@ 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");