[PATCH v5 06/10] arm64: Always enable spectrev2 vulnerability detection

From: Jeremy Linton
Date: Tue Feb 26 2019 - 20:06:13 EST


The sysfs patches need to display machine vulnerability
status regardless of kernel config. Prepare for that
by breaking out the vulnerability/mitigation detection
code from the logic which implements the mitigation.

Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
---
arch/arm64/kernel/cpu_errata.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 77f021e78a28..a27e1ee750e1 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -109,12 +109,12 @@ cpu_enable_trap_ctr_access(const struct arm64_cpu_capabilities *__unused)

atomic_t arm64_el2_vector_last_slot = ATOMIC_INIT(-1);

-#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
#include <asm/mmu_context.h>
#include <asm/cacheflush.h>

DEFINE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);

+
#ifdef CONFIG_KVM_INDIRECT_VECTORS
extern char __smccc_workaround_1_smc_start[];
extern char __smccc_workaround_1_smc_end[];
@@ -270,11 +270,11 @@ 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 */

#ifdef CONFIG_ARM64_SSBD
DEFINE_PER_CPU_READ_MOSTLY(u64, arm64_ssbd_callback_required);
@@ -513,7 +513,6 @@ cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused)
.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.
*/
@@ -545,6 +544,11 @@ 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 configuration\n");
+ return false;
+ }
+
/* forced off */
if (__nospectre_v2) {
pr_info_once("spectrev2 mitigation disabled by command line option\n");
@@ -557,8 +561,6 @@ check_branch_predictor(const struct arm64_cpu_capabilities *entry, int scope)
return (need_wa > 0);
}

-#endif
-
#ifdef CONFIG_HARDEN_EL2_VECTORS

static const struct midr_range arm64_harden_el2_vectors[] = {
@@ -732,13 +734,11 @@ 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
#ifdef CONFIG_HARDEN_EL2_VECTORS
{
.desc = "EL2 vector hardening",
--
2.20.1