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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/cpufeature.c | |
| parent | arm64: ssbs: Don't treat CPUs with SSBS as unaffected by SSB (diff) | |
| download | linux-dev-a111b7c0f20e13b54df2fa959b3dc0bdf1925ae6.tar.xz linux-dev-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/cpufeature.c')
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 703ee8564fbd..f3b32d88f165 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -25,6 +25,7 @@ #include <linux/stop_machine.h> #include <linux/types.h> #include <linux/mm.h> +#include <linux/cpu.h> #include <asm/cpu.h> #include <asm/cpufeature.h> #include <asm/cpu_ops.h> @@ -966,7 +967,7 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, MIDR_ALL_VERSIONS(MIDR_HISI_TSV110), { /* sentinel */ } }; - char const *str = "command line option"; + char const *str = "kpti command line option"; bool meltdown_safe; meltdown_safe = is_midr_in_range_list(read_cpuid_id(), kpti_safe_list); @@ -996,6 +997,11 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, } } + if (cpu_mitigations_off() && !__kpti_forced) { + str = "mitigations=off"; + __kpti_forced = -1; + } + if (!IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0)) { pr_info_once("kernel page table isolation disabled by kernel configuration\n"); return false; |