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-rw-r--r--arch/arm64/kernel/cpufeature.c34
-rw-r--r--arch/arm64/kernel/suspend.c4
2 files changed, 38 insertions, 0 deletions
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index f15e2fb97011..237f8822a391 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -20,6 +20,7 @@
#include <linux/bsearch.h>
#include <linux/cpumask.h>
+#include <linux/crash_dump.h>
#include <linux/sort.h>
#include <linux/stop_machine.h>
#include <linux/types.h>
@@ -117,6 +118,7 @@ EXPORT_SYMBOL(cpu_hwcap_keys);
static bool __maybe_unused
cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused);
+static void cpu_enable_cnp(struct arm64_cpu_capabilities const *cap);
/*
* NOTE: Any changes to the visibility of features should be kept in
@@ -863,6 +865,20 @@ static bool has_cache_dic(const struct arm64_cpu_capabilities *entry,
return read_sanitised_ftr_reg(SYS_CTR_EL0) & BIT(CTR_DIC_SHIFT);
}
+static bool __maybe_unused
+has_useable_cnp(const struct arm64_cpu_capabilities *entry, int scope)
+{
+ /*
+ * Kdump isn't guaranteed to power-off all secondary CPUs, CNP
+ * may share TLB entries with a CPU stuck in the crashed
+ * kernel.
+ */
+ if (is_kdump_kernel())
+ return false;
+
+ return has_cpuid_feature(entry, scope);
+}
+
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
static int __kpti_forced; /* 0: not forced, >0: forced on, <0: forced off */
@@ -1312,6 +1328,19 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.cpu_enable = cpu_enable_ssbs,
},
#endif
+#ifdef CONFIG_ARM64_CNP
+ {
+ .desc = "Common not Private translations",
+ .capability = ARM64_HAS_CNP,
+ .type = ARM64_CPUCAP_SYSTEM_FEATURE,
+ .matches = has_useable_cnp,
+ .sys_reg = SYS_ID_AA64MMFR2_EL1,
+ .sign = FTR_UNSIGNED,
+ .field_pos = ID_AA64MMFR2_CNP_SHIFT,
+ .min_field_value = 1,
+ .cpu_enable = cpu_enable_cnp,
+ },
+#endif
{},
};
@@ -1749,6 +1778,11 @@ cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused)
return (cpus_have_const_cap(ARM64_HAS_PAN) && !cpus_have_const_cap(ARM64_HAS_UAO));
}
+static void __maybe_unused cpu_enable_cnp(struct arm64_cpu_capabilities const *cap)
+{
+ cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
+}
+
/*
* We emulate only the following system register space.
* Op0 = 0x3, CRn = 0x0, Op1 = 0x0, CRm = [0, 4 - 7]
diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c
index 70c283368b64..9405d1b7f4b0 100644
--- a/arch/arm64/kernel/suspend.c
+++ b/arch/arm64/kernel/suspend.c
@@ -48,6 +48,10 @@ void notrace __cpu_suspend_exit(void)
*/
cpu_uninstall_idmap();
+ /* Restore CnP bit in TTBR1_EL1 */
+ if (system_supports_cnp())
+ cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
+
/*
* PSTATE was not saved over suspend/resume, re-enable any detected
* features that might not have been set correctly.