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| author | James Morse <james.morse@arm.com> | 2021-12-10 17:32:56 +0300 |
|---|---|---|
| committer | James Morse <james.morse@arm.com> | 2022-02-24 17:02:44 +0300 |
| commit | 228a26b912287934789023b4132ba76065d9491c (patch) | |
| tree | 67a41ff4b1f85a9f72239a7f213d1ff2279af0ac /arch/arm64/include/asm/vectors.h | |
| parent | a5905d6af492ee6a4a2205f0d550b3f931b03d03 (diff) | |
| download | linux-228a26b912287934789023b4132ba76065d9491c.tar.xz | |
arm64: Use the clearbhb instruction in mitigations
Future CPUs may implement a clearbhb instruction that is sufficient
to mitigate SpectreBHB. CPUs that implement this instruction, but
not CSV2.3 must be affected by Spectre-BHB.
Add support to use this instruction as the BHB mitigation on CPUs
that support it. The instruction is in the hint space, so it will
be treated by a NOP as older CPUs.
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/vectors.h')
| -rw-r--r-- | arch/arm64/include/asm/vectors.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/vectors.h b/arch/arm64/include/asm/vectors.h index 1f65c37dc653..f64613a96d53 100644 --- a/arch/arm64/include/asm/vectors.h +++ b/arch/arm64/include/asm/vectors.h @@ -32,6 +32,12 @@ enum arm64_bp_harden_el1_vectors { * canonical vectors. */ EL1_VECTOR_BHB_FW, + + /* + * Use the ClearBHB instruction, before branching to the canonical + * vectors. + */ + EL1_VECTOR_BHB_CLEAR_INSN, #endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */ /* @@ -43,6 +49,7 @@ enum arm64_bp_harden_el1_vectors { #ifndef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY #define EL1_VECTOR_BHB_LOOP -1 #define EL1_VECTOR_BHB_FW -1 +#define EL1_VECTOR_BHB_CLEAR_INSN -1 #endif /* !CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */ /* The vectors to use on return from EL0. e.g. to remap the kernel */ |