This is a note to let you know that I've just added the patch titled
arm64: errata: Remove AES hwcap for COMPAT tasks
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm64-errata-remove-aes-hwcap-for-compat-tasks.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 44b3834b2eed595af07021b1c64e6f9bc396398b Mon Sep 17 00:00:00 2001
From: James Morse <james.morse@xxxxxxx>
Date: Thu, 14 Jul 2022 17:15:23 +0100
Subject: arm64: errata: Remove AES hwcap for COMPAT tasks
From: James Morse <james.morse@xxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: James Morse <james.morse@xxxxxxx>
Link: https://lore.kernel.org/r/20220714161523.279570-3-james.morse@xxxxxxx
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
[florian: resolved conflicts in arch/arm64/tools/cpucaps and cpu_errata.c]
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -70,8 +70,12 @@ stable kernels.
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A57 | #834220 | ARM64_ERRATUM_834220 |
+----------------+-----------------+-----------------+-----------------------------+
+| ARM | Cortex-A57 | #1742098 | ARM64_ERRATUM_1742098 |
++----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A72 | #853709 | N/A |
+----------------+-----------------+-----------------+-----------------------------+
+| ARM | Cortex-A72 | #1655431 | ARM64_ERRATUM_1742098 |
++----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A73 | #858921 | ARM64_ERRATUM_858921 |
+----------------+-----------------+-----------------+-----------------------------+
| ARM | Cortex-A55 | #1024718 | ARM64_ERRATUM_1024718 |
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -574,6 +574,22 @@ config ARM64_ERRATUM_1542419
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 CAVIUM_ERRATUM_22375
bool "Cavium erratum 22375, 24313"
default y
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -56,7 +56,8 @@
#define ARM64_WORKAROUND_CAVIUM_TX2_219_PRFM 46
#define ARM64_WORKAROUND_1542419 47
#define ARM64_SPECTRE_BHB 48
+#define ARM64_WORKAROUND_1742098 49
-#define ARM64_NCAPS 49
+#define ARM64_NCAPS 50
#endif /* __ASM_CPUCAPS_H */
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -817,6 +817,14 @@ static const struct arm64_cpu_capabiliti
};
#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
{
@@ -998,6 +1006,14 @@ const struct arm64_cpu_capabilities arm6
.cpu_enable = cpu_enable_trap_ctr_access,
},
#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
@@ -21,6 +21,7 @@
#include <asm/cpufeature.h>
#include <asm/cpu_ops.h>
#include <asm/fpsimd.h>
+#include <asm/hwcap.h>
#include <asm/mmu_context.h>
#include <asm/processor.h>
#include <asm/sysreg.h>
@@ -1280,6 +1281,14 @@ static bool can_use_gic_priorities(const
}
#endif
+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 */
+}
+
static const struct arm64_cpu_capabilities arm64_features[] = {
{
.desc = "GIC system register CPU interface",
@@ -2103,8 +2112,10 @@ void __init setup_cpu_features(void)
mark_const_caps_ready();
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");
Patches currently in stable-queue which might be from james.morse@xxxxxxx are
queue-5.4/arm64-errata-remove-aes-hwcap-for-compat-tasks.patch
