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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/arm64/kernel | |
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/arm64/kernel')
-rw-r--r-- | arch/arm64/kernel/acpi.c | 31 |
1 files changed, 31 insertions, 0 deletions
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; +} |