From: Jeremy Linton <jeremy.linton@xxxxxxx>
[ 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@xxxxxxx>
Reviewed-by: Andre Przywara <andre.przywara@xxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Tested-by: Stefan Wahren <stefan.wahren@xxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
arch/arm64/kernel/cpu_errata.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index bf6d8aa9b45a..647c533cfd90 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -76,7 +76,6 @@ cpu_enable_trap_ctr_access(const struct arm64_cpu_capabilities *__unused)
config_sctlr_el1(SCTLR_EL1_UCT, 0);
}
-#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
#include <asm/mmu_context.h>
#include <asm/cacheflush.h>
@@ -217,11 +216,11 @@ 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);
@@ -457,7 +456,6 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, \
CAP_MIDR_RANGE_LIST(midr_list)
-#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
/*
* List of CPUs that do not need any Spectre-v2 mitigation at all.
*/
@@ -489,6 +487,12 @@ check_branch_predictor(const struct arm64_cpu_capabilities *entry, int scope)
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");
@@ -500,7 +504,6 @@ check_branch_predictor(const struct arm64_cpu_capabilities *entry, int scope)
return (need_wa > 0);
}
-#endif
const struct arm64_cpu_capabilities arm64_errata[] = {
#if defined(CONFIG_ARM64_ERRATUM_826319) || \
@@ -640,13 +643,11 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
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
{
.desc = "Speculative Store Bypass Disable",
.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
--
2.20.1
