diff options
author | James Morse <james.morse@arm.com> | 2019-01-29 18:48:50 +0000 |
---|---|---|
committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2019-02-07 23:10:45 +0100 |
commit | d44f1b8dd7e66d80cc4205809e5ace866bd851da (patch) | |
tree | 102c993327b0f620c9d1aefcc95ad3d7819fd68c /arch | |
parent | 0db5e0223035b2c84e6186831fc27511270af812 (diff) | |
download | linux-d44f1b8dd7e66d80cc4205809e5ace866bd851da.tar.bz2 |
arm64: KVM/mm: Move SEA handling behind a single 'claim' interface
To split up APEIs in_nmi() path, the caller needs to always be
in_nmi(). Add a helper to do the work and claim the notification.
When KVM or the arch code takes an exception that might be a RAS
notification, it asks the APEI firmware-first code whether it wants
to claim the exception. A future kernel-first mechanism may be queried
afterwards, and claim the notification, otherwise we fall through
to the existing default behaviour.
The NOTIFY_SEA code was merged before considering multiple, possibly
interacting, NMI-like notifications and the need to consider kernel
first in the future. Make the 'claiming' behaviour explicit.
Restructuring the APEI code to allow multiple NMI-like notifications
means any notification that might interrupt interrupts-masked
code must always be wrapped in nmi_enter()/nmi_exit(). This will
allow APEI to use in_nmi() to use the right fixmap entries.
Mask SError over this window to prevent an asynchronous RAS error
arriving and tripping 'nmi_enter()'s BUG_ON(in_nmi()).
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Tyler Baicar <tbaicar@codeaurora.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/arm64/include/asm/acpi.h | 4 | ||||
-rw-r--r-- | arch/arm64/include/asm/daifflags.h | 1 | ||||
-rw-r--r-- | arch/arm64/include/asm/kvm_ras.h | 16 | ||||
-rw-r--r-- | arch/arm64/kernel/acpi.c | 31 | ||||
-rw-r--r-- | arch/arm64/mm/fault.c | 24 |
5 files changed, 55 insertions, 21 deletions
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h index 2def77ec14be..7628efbe6c12 100644 --- a/arch/arm64/include/asm/acpi.h +++ b/arch/arm64/include/asm/acpi.h @@ -18,6 +18,7 @@ #include <asm/cputype.h> #include <asm/io.h> +#include <asm/ptrace.h> #include <asm/smp_plat.h> #include <asm/tlbflush.h> @@ -110,9 +111,10 @@ static inline u32 get_acpi_id_for_cpu(unsigned int cpu) static inline void arch_fix_phys_package_id(int num, u32 slot) { } void __init acpi_init_cpus(void); - +int apei_claim_sea(struct pt_regs *regs); #else static inline void acpi_init_cpus(void) { } +static inline int apei_claim_sea(struct pt_regs *regs) { return -ENOENT; } #endif /* CONFIG_ACPI */ #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL diff --git a/arch/arm64/include/asm/daifflags.h b/arch/arm64/include/asm/daifflags.h index 8d91f2233135..fa90779fc752 100644 --- a/arch/arm64/include/asm/daifflags.h +++ b/arch/arm64/include/asm/daifflags.h @@ -20,6 +20,7 @@ #define DAIF_PROCCTX 0 #define DAIF_PROCCTX_NOIRQ PSR_I_BIT +#define DAIF_ERRCTX (PSR_I_BIT | PSR_A_BIT) /* mask/save/unmask/restore all exceptions, including interrupts. */ static inline void local_daif_mask(void) diff --git a/arch/arm64/include/asm/kvm_ras.h b/arch/arm64/include/asm/kvm_ras.h index 6096f0251812..8ac6ee77437c 100644 --- a/arch/arm64/include/asm/kvm_ras.h +++ b/arch/arm64/include/asm/kvm_ras.h @@ -4,8 +4,22 @@ #ifndef __ARM64_KVM_RAS_H__ #define __ARM64_KVM_RAS_H__ +#include <linux/acpi.h> +#include <linux/errno.h> #include <linux/types.h> -int kvm_handle_guest_sea(phys_addr_t addr, unsigned int esr); +#include <asm/acpi.h> + +/* + * Was this synchronous external abort a RAS notification? + * Returns '0' for errors handled by some RAS subsystem, or -ENOENT. + */ +static inline int kvm_handle_guest_sea(phys_addr_t addr, unsigned int esr) +{ + /* apei_claim_sea(NULL) expects to mask interrupts itself */ + lockdep_assert_irqs_enabled(); + + return apei_claim_sea(NULL); +} #endif /* __ARM64_KVM_RAS_H__ */ diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index 44e3c351e1ea..803f0494dd3e 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -27,8 +27,10 @@ #include <linux/smp.h> #include <linux/serial_core.h> +#include <acpi/ghes.h> #include <asm/cputype.h> #include <asm/cpu_ops.h> +#include <asm/daifflags.h> #include <asm/pgtable.h> #include <asm/smp_plat.h> @@ -256,3 +258,32 @@ pgprot_t __acpi_get_mem_attribute(phys_addr_t addr) return __pgprot(PROT_NORMAL_NC); return __pgprot(PROT_DEVICE_nGnRnE); } + +/* + * Claim Synchronous External Aborts as a firmware first notification. + * + * Used by KVM and the arch do_sea handler. + * @regs may be NULL when called from process context. + */ +int apei_claim_sea(struct pt_regs *regs) +{ + int err = -ENOENT; + unsigned long current_flags; + + if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES)) + return err; + + current_flags = arch_local_save_flags(); + + /* + * SEA can interrupt SError, mask it and describe this as an NMI so + * that APEI defers the handling. + */ + local_daif_restore(DAIF_ERRCTX); + nmi_enter(); + err = ghes_notify_sea(); + nmi_exit(); + local_daif_restore(current_flags); + + return err; +} diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index c76dc981e3fc..e1c84c2e1cab 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -18,6 +18,7 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#include <linux/acpi.h> #include <linux/extable.h> #include <linux/signal.h> #include <linux/mm.h> @@ -33,6 +34,7 @@ #include <linux/preempt.h> #include <linux/hugetlb.h> +#include <asm/acpi.h> #include <asm/bug.h> #include <asm/cmpxchg.h> #include <asm/cpufeature.h> @@ -47,8 +49,6 @@ #include <asm/tlbflush.h> #include <asm/traps.h> -#include <acpi/ghes.h> - struct fault_info { int (*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs); @@ -643,19 +643,10 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) inf = esr_to_fault_info(esr); /* - * Synchronous aborts may interrupt code which had interrupts masked. - * Before calling out into the wider kernel tell the interested - * subsystems. + * Return value ignored as we rely on signal merging. + * Future patches will make this more robust. */ - if (IS_ENABLED(CONFIG_ACPI_APEI_SEA)) { - if (interrupts_enabled(regs)) - nmi_enter(); - - ghes_notify_sea(); - - if (interrupts_enabled(regs)) - nmi_exit(); - } + apei_claim_sea(regs); if (esr & ESR_ELx_FnV) siaddr = NULL; @@ -733,11 +724,6 @@ static const struct fault_info fault_info[] = { { do_bad, SIGKILL, SI_KERNEL, "unknown 63" }, }; -int kvm_handle_guest_sea(phys_addr_t addr, unsigned int esr) -{ - return ghes_notify_sea(); -} - asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs) { |