From a1152be30a043d2d4dcb1683415f328bf3c51978 Mon Sep 17 00:00:00 2001 From: James Morse Date: Tue, 29 Apr 2025 13:55:17 +0100 Subject: [PATCH] arm64: proton-pack: Expose whether the branchy loop k value Add a helper to expose the k value of the branchy loop. This is needed by the BPF JIT to generate the mitigation sequence in BPF programs. Signed-off-by: James Morse Reviewed-by: Catalin Marinas --- arch/arm64/include/asm/spectre.h | 1 + arch/arm64/kernel/proton-pack.c | 5 +++++ 2 files changed, 6 insertions(+) diff --git a/arch/arm64/include/asm/spectre.h b/arch/arm64/include/asm/spectre.h index 78fb720987fb4..bca12134245c6 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); +u8 get_spectre_bhb_loop_value(void); 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 355f1f3098a24..3154094a9e33d 100644 --- a/arch/arm64/kernel/proton-pack.c +++ b/arch/arm64/kernel/proton-pack.c @@ -999,6 +999,11 @@ bool is_spectre_bhb_affected(const struct arm64_cpu_capabilities *entry, return true; } +u8 get_spectre_bhb_loop_value(void) +{ + return max_bhb_k; +} + static void this_cpu_set_vectors(enum arm64_bp_harden_el1_vectors slot) { const char *v = arm64_get_bp_hardening_vector(slot); -- 2.39.5