From a111b7c0f20e13b54df2fa959b3dc0bdf1925ae6 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Fri, 12 Apr 2019 15:39:32 -0500 Subject: arm64/speculation: Support 'mitigations=' cmdline option Configure arm64 runtime CPU speculation bug mitigations in accordance with the 'mitigations=' cmdline option. This affects Meltdown, Spectre v2, and Speculative Store Bypass. The default behavior is unchanged. Signed-off-by: Josh Poimboeuf [will: reorder checks so KASLR implies KPTI and SSBS is affected by cmdline] Signed-off-by: Will Deacon --- arch/arm64/kernel/cpu_errata.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'arch/arm64/kernel/cpu_errata.c') diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 44ef98be001e..1b9ce0fdd81d 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -386,6 +387,9 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry, WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible()); + if (cpu_mitigations_off()) + ssbd_state = ARM64_SSBD_FORCE_DISABLE; + /* delay setting __ssb_safe until we get a firmware response */ if (is_midr_in_range_list(read_cpuid_id(), entry->midr_range_list)) this_cpu_safe = true; @@ -589,7 +593,7 @@ check_branch_predictor(const struct arm64_cpu_capabilities *entry, int scope) } /* forced off */ - if (__nospectre_v2) { + if (__nospectre_v2 || cpu_mitigations_off()) { pr_info_once("spectrev2 mitigation disabled by command line option\n"); __hardenbp_enab = false; return false; -- cgit v1.2.3