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| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2019-04-12 15:39:32 -0500 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2019-05-01 14:48:07 +0100 |
| commit | a111b7c0f20e13b54df2fa959b3dc0bdf1925ae6 (patch) | |
| tree | fb21c31d9d66a71ece8f4a9b8138002ca5eacb6d /arch/arm64/kernel/cpu_errata.c | |
| parent | eb337cdfcd5dd3b10522c2f34140a73a4c285c30 (diff) | |
| download | lwn-a111b7c0f20e13b54df2fa959b3dc0bdf1925ae6.tar.gz lwn-a111b7c0f20e13b54df2fa959b3dc0bdf1925ae6.zip | |
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 <jpoimboe@redhat.com>
[will: reorder checks so KASLR implies KPTI and SSBS is affected by cmdline]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/kernel/cpu_errata.c')
| -rw-r--r-- | arch/arm64/kernel/cpu_errata.c | 6 |
1 files changed, 5 insertions, 1 deletions
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 <linux/arm-smccc.h> #include <linux/psci.h> #include <linux/types.h> +#include <linux/cpu.h> #include <asm/cpu.h> #include <asm/cputype.h> #include <asm/cpufeature.h> @@ -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; |