From: Suzuki K Poulose suzuki.poulose@arm.com
[ Upstream commit 830dcc9f9a7cd26a812522a26efaacf7df6fc365 ]
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 capability 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.
The patch also makes the VHE capability entry depend on CONFIG_ARM64_VHE.
Cc: Marc Zyngier marc.zyngier@arm.com Cc: Will Deacon will.deacon@arm.com Reviewed-by: Dave Martin dave.martin@arm.com Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.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/include/asm/cpufeature.h | 6 +++++ arch/arm64/include/asm/virt.h | 6 ----- arch/arm64/kernel/cpufeature.c | 5 ++-- arch/arm64/kernel/smp.c | 38 ------------------------------------ 4 files changed, 9 insertions(+), 46 deletions(-)
--- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -283,6 +283,12 @@ extern struct arm64_ftr_reg arm64_ftr_re (ARM64_CPUCAP_SCOPE_LOCAL_CPU | \ ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU)
+/* + * CPU feature used early in the boot based on the boot CPU. All secondary + * CPUs must match the state of the capability as detected by the boot CPU. + */ +#define ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE ARM64_CPUCAP_SCOPE_BOOT_CPU + struct arm64_cpu_capabilities { const char *desc; u16 capability; --- 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 */ --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -982,13 +982,15 @@ static const struct arm64_cpu_capabiliti .matches = cpufeature_pan_not_uao, }, #endif /* CONFIG_ARM64_PAN */ +#ifdef CONFIG_ARM64_VHE { .desc = "Virtualization Host Extensions", .capability = ARM64_HAS_VIRT_HOST_EXTN, - .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .type = ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE, .matches = runs_at_el2, .cpu_enable = cpu_copy_el2regs, }, +#endif /* CONFIG_ARM64_VHE */ { .desc = "32-bit EL0 Support", .capability = ARM64_HAS_32BIT_EL0, @@ -1332,7 +1334,6 @@ static bool verify_local_cpu_caps(u16 sc */ 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 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -83,43 +83,6 @@ 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 @@ -448,7 +411,6 @@ 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)