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| author |   James Morse <james.morse@arm.com> | 2024-08-19 14:15:53 +0100 |
|---|---|---|
| committer | James Morse <james.morse@arm.com> | 2025-05-08 15:28:35 +0100 |
| commit | e7956c92f396a44eeeb6eaf7a5b5e1ad24db6748 (patch) | |
| tree | a99b3aedea743ec12f0fe1d56309870fe506ec8b | |
| parent | arm64: insn: Add support for encoding DSB (diff) | |
| download | wireguard-linux-e7956c92f396a44eeeb6eaf7a5b5e1ad24db6748.tar.xz wireguard-linux-e7956c92f396a44eeeb6eaf7a5b5e1ad24db6748.zip | |
arm64: proton-pack: Expose whether the platform is mitigated by firmware
is_spectre_bhb_fw_affected() allows the caller to determine if the CPU
is known to need a firmware mitigation. CPUs are either on the list
of CPUs we know about, or firmware has been queried and reported that
the platform is affected - and mitigated by firmware.
This helper is not useful to determine if the platform is mitigated
by firmware. A CPU could be on the know list, but the firmware may
not be implemented. Its affected but not mitigated.
spectre_bhb_enable_mitigation() handles this distinction by checking
the firmware state before enabling the mitigation.
Add a helper to expose this state. This will be used by the BPF JIT
to determine if calling firmware for a mitigation is necessary and
supported.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/include/asm/spectre.h | 1 | ||||
| -rw-r--r-- | arch/arm64/kernel/proton-pack.c | 5 |
2 files changed, 6 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/spectre.h b/arch/arm64/include/asm/spectre.h index f1524cdeacf1..78fb720987fb 100644 --- a/arch/arm64/include/asm/spectre.h +++ b/arch/arm64/include/asm/spectre.h @@ -97,6 +97,7 @@ enum mitigation_state arm64_get_meltdown_state(void); enum mitigation_state arm64_get_spectre_bhb_state(void); bool is_spectre_bhb_affected(const struct arm64_cpu_capabilities *entry, int scope); +bool is_spectre_bhb_fw_mitigated(void); void spectre_bhb_enable_mitigation(const struct arm64_cpu_capabilities *__unused); bool try_emulate_el1_ssbs(struct pt_regs *regs, u32 instr); diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c index b607f6dfc5e6..355f1f3098a2 100644 --- a/arch/arm64/kernel/proton-pack.c +++ b/arch/arm64/kernel/proton-pack.c @@ -1094,6 +1094,11 @@ void spectre_bhb_enable_mitigation(const struct arm64_cpu_capabilities *entry) update_mitigation_state(&spectre_bhb_state, state); } +bool is_spectre_bhb_fw_mitigated(void) +{ + return test_bit(BHB_FW, &system_bhb_mitigations); +} + /* Patched to NOP when enabled */ void noinstr spectre_bhb_patch_loop_mitigation_enable(struct alt_instr *alt, __le32 *origptr, |