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| author | Liu Song <liusong@linux.alibaba.com> | 2022-08-26 19:40:50 +0800 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2022-09-09 19:02:22 +0100 |
| commit | 877ace9eab7de032f954533afd5d1ecd0cf62eaf (patch) | |
| tree | 8bf06a8f23f1aeb42a3f1a2c1867d22b5da34466 /arch/arm64/kernel | |
| parent | 8eb858c44b98e0326bb32fca34ae671995cd73bb (diff) | |
| download | linux-877ace9eab7de032f954533afd5d1ecd0cf62eaf.tar.bz2 | |
arm64: spectre: increase parameters that can be used to turn off bhb mitigation individually
In our environment, it was found that the mitigation BHB has a great
impact on the benchmark performance. For example, in the lmbench test,
the "process fork && exit" test performance drops by 20%.
So it is necessary to have the ability to turn off the mitigation
individually through cmdline, thus avoiding having to compile the
kernel by adjusting the config.
Signed-off-by: Liu Song <liusong@linux.alibaba.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/1661514050-22263-1-git-send-email-liusong@linux.alibaba.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/proton-pack.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c index 40be3a7c2c53..bd1690335bb9 100644 --- a/arch/arm64/kernel/proton-pack.c +++ b/arch/arm64/kernel/proton-pack.c @@ -988,6 +988,14 @@ static void this_cpu_set_vectors(enum arm64_bp_harden_el1_vectors slot) isb(); } +static bool __read_mostly __nospectre_bhb; +static int __init parse_spectre_bhb_param(char *str) +{ + __nospectre_bhb = true; + return 0; +} +early_param("nospectre_bhb", parse_spectre_bhb_param); + void spectre_bhb_enable_mitigation(const struct arm64_cpu_capabilities *entry) { bp_hardening_cb_t cpu_cb; @@ -1001,7 +1009,7 @@ void spectre_bhb_enable_mitigation(const struct arm64_cpu_capabilities *entry) /* No point mitigating Spectre-BHB alone. */ } else if (!IS_ENABLED(CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY)) { pr_info_once("spectre-bhb mitigation disabled by compile time option\n"); - } else if (cpu_mitigations_off()) { + } else if (cpu_mitigations_off() || __nospectre_bhb) { pr_info_once("spectre-bhb mitigation disabled by command line option\n"); } else if (supports_ecbhb(SCOPE_LOCAL_CPU)) { state = SPECTRE_MITIGATED; |