From: Jeremy Linton jeremy.linton@arm.com
[ Upstream commit 8c1e3d2bb44cbb998cb28ff9a18f105fee7f1eb3 ]
Ensure we are always able to detect whether or not the CPU is affected by Spectre-v2, so that we can later advertise this to userspace.
Signed-off-by: Jeremy Linton jeremy.linton@arm.com Reviewed-by: Andre Przywara andre.przywara@arm.com Reviewed-by: Catalin Marinas catalin.marinas@arm.com Tested-by: Stefan Wahren stefan.wahren@i2se.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/kernel/cpu_errata.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-)
--- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -87,7 +87,6 @@ cpu_enable_trap_ctr_access(const struct
atomic_t arm64_el2_vector_last_slot = ATOMIC_INIT(-1);
-#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR #include <asm/mmu_context.h> #include <asm/cacheflush.h>
@@ -225,11 +224,11 @@ static int detect_harden_bp_fw(void) ((midr & MIDR_CPU_MODEL_MASK) == MIDR_QCOM_FALKOR_V1)) cb = qcom_link_stack_sanitization;
- install_bp_hardening_cb(cb, smccc_start, smccc_end); + if (IS_ENABLED(CONFIG_HARDEN_BRANCH_PREDICTOR)) + install_bp_hardening_cb(cb, smccc_start, smccc_end);
return 1; } -#endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */
DEFINE_PER_CPU_READ_MOSTLY(u64, arm64_ssbd_callback_required);
@@ -513,7 +512,6 @@ multi_entry_cap_cpu_enable(const struct caps->cpu_enable(caps); }
-#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR /* * List of CPUs that do not need any Spectre-v2 mitigation at all. */ @@ -545,6 +543,12 @@ check_branch_predictor(const struct arm6 if (!need_wa) return false;
+ if (!IS_ENABLED(CONFIG_HARDEN_BRANCH_PREDICTOR)) { + pr_warn_once("spectrev2 mitigation disabled by kernel configuration\n"); + __hardenbp_enab = false; + return false; + } + /* forced off */ if (__nospectre_v2) { pr_info_once("spectrev2 mitigation disabled by command line option\n"); @@ -556,7 +560,6 @@ check_branch_predictor(const struct arm6
return (need_wa > 0); } -#endif
#ifdef CONFIG_HARDEN_EL2_VECTORS
@@ -715,13 +718,11 @@ const struct arm64_cpu_capabilities arm6 ERRATA_MIDR_ALL_VERSIONS(MIDR_CORTEX_A73), }, #endif -#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR { .capability = ARM64_HARDEN_BRANCH_PREDICTOR, .type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, .matches = check_branch_predictor, }, -#endif #ifdef CONFIG_HARDEN_EL2_VECTORS { .desc = "EL2 vector hardening",