We expect all CPUs to be running at the same EL inside the kernel
with or without VHE enabled and we have strict checks to ensure
that any mismatch triggers a kernel panic. If VHE is enabled,
we use the feature based on the boot CPU and all other CPUs
should follow. This makes it a perfect candidate for a cpability
based on the boot CPU, which should be matched by all the CPUs
(both when is ON and OFF). This saves us some not-so-pretty
hooks and special code, just for verifying the conflict.
Cc: Marc Zyngier <marc.zyng...@arm.com>
Cc: Dave Martin <dave.mar...@arm.com>
Cc: Will Deacon <will.dea...@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poul...@arm.com>
---
arch/arm64/include/asm/cpufeature.h | 7 +++++++
arch/arm64/include/asm/virt.h | 6 ------
arch/arm64/kernel/cpufeature.c | 3 +--
arch/arm64/kernel/smp.c | 38 -------------------------------------
4 files changed, 8 insertions(+), 46 deletions(-)
diff --git a/arch/arm64/include/asm/cpufeature.h
b/arch/arm64/include/asm/cpufeature.h
index 04161aac0f06..42292a0b93a4 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -260,6 +260,13 @@ extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0;
(ARM64_CPUCAP_SCOPE_LOCAL_CPU | \
ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU)
+/*
+ * Critical CPU feature used early in the boot based on the boot CPU.
+ * The feature should be matched by all booting CPU (both miss and hit
+ * cases).
+ */
+#define ARM64_CPUCAP_CRITICAL_BOOT_CPU_FEATURE ARM64_CPUCAP_SCOPE_BOOT_CPU
+
struct arm64_cpu_capabilities {
const char *desc;
u16 capability;
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index c5f89442785c..9d1e24e030b3 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -102,12 +102,6 @@ static inline bool has_vhe(void)
return false;
}
-#ifdef CONFIG_ARM64_VHE
-extern void verify_cpu_run_el(void);
-#else
-static inline void verify_cpu_run_el(void) {}
-#endif
-
#endif /* __ASSEMBLY__ */
#endif /* ! __ASM__VIRT_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 6d759f068de1..247d34ea6b5e 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -982,7 +982,7 @@ static const struct arm64_cpu_capabilities arm64_features[]
= {
{
.desc = "Virtualization Host Extensions",
.capability = ARM64_HAS_VIRT_HOST_EXTN,
- .type = ARM64_CPUCAP_SYSTEM_FEATURE,
+ .type = ARM64_CPUCAP_CRITICAL_BOOT_CPU_FEATURE,
.matches = runs_at_el2,
.cpu_enable = cpu_copy_el2regs,
},
@@ -1322,7 +1322,6 @@ static bool verify_local_cpu_caps(u16 scope_mask)
*/
static void check_early_cpu_features(void)
{
- verify_cpu_run_el();
verify_cpu_asid_bits();
/*
* Early features are used by the kernel already. If there
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 5cef11450183..f3e2e3aec0b0 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -85,43 +85,6 @@ enum ipi_msg_type {
IPI_WAKEUP
};
-#ifdef CONFIG_ARM64_VHE
-
-/* Whether the boot CPU is running in HYP mode or not*/
-static bool boot_cpu_hyp_mode;
-
-static inline void save_boot_cpu_run_el(void)
-{
- boot_cpu_hyp_mode = is_kernel_in_hyp_mode();
-}
-
-static inline bool is_boot_cpu_in_hyp_mode(void)
-{
- return boot_cpu_hyp_mode;
-}
-
-/*
- * Verify that a secondary CPU is running the kernel at the same
- * EL as that of the boot CPU.
- */
-void verify_cpu_run_el(void)
-{
- bool in_el2 = is_kernel_in_hyp_mode();
- bool boot_cpu_el2 = is_boot_cpu_in_hyp_mode();
-
- if (in_el2 ^ boot_cpu_el2) {
- pr_crit("CPU%d: mismatched Exception Level(EL%d) with boot
CPU(EL%d)\n",
- smp_processor_id(),
- in_el2 ? 2 : 1,
- boot_cpu_el2 ? 2 : 1);
- cpu_panic_kernel();
- }
-}
-
-#else
-static inline void save_boot_cpu_run_el(void) {}
-#endif
-
#ifdef CONFIG_HOTPLUG_CPU
static int op_cpu_kill(unsigned int cpu);
#else
@@ -447,7 +410,6 @@ void __init smp_prepare_boot_cpu(void)
*/
jump_label_init();
cpuinfo_store_boot_cpu();
- save_boot_cpu_run_el();
}
static u64 __init of_get_cpu_mpidr(struct device_node *dn)
--
2.14.3
