| Message ID | 20190129184902.102850-25-james.morse@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | APEI in_nmi() rework and SDEI wire-up | expand |
Hi James, On 29/01/2019 18:49, James Morse wrote: > APEI is unable to do all of its error handling work in nmi-context, so > it defers non-fatal work onto the irq_work queue. arch_irq_work_raise() > sends an IPI to the calling cpu, but this is not guaranteed to be taken > before returning to user-space. > > Unless the exception interrupted a context with irqs-masked, > irq_work_run() can run immediately. Otherwise return -EINPROGRESS to > indicate ghes_notify_sea() found some work to do, but it hasn't > finished yet. > > With this apei_claim_sea() returning '0' means this external-abort was > also notification of a firmware-first RAS error, and that APEI has > processed the CPER records. > > Signed-off-by: James Morse <james.morse@arm.com> > Reviewed-by: Punit Agrawal <punit.agrawal@arm.com> > Tested-by: Tyler Baicar <tbaicar@codeaurora.org> > Acked-by: Catalin Marinas <catalin.marinas@arm.com> > CC: Xie XiuQi <xiexiuqi@huawei.com> > CC: gengdongjiu <gengdongjiu@huawei.com> > > --- > Changes since v7: > * Added Catalin's ack, then: > * Added __irq_enter()/exit() calls so if we interrupted preemptible code, the > preempt count matches what other irq-work expects. > * Changed the 'if (!arch_irqs_disabled_flags(interrupted_flags))' test to be > safe before/after Julien's PMR series. > > Changes since v6: > * Added pr_warn() for the EINPROGRESS case so panic-tracebacks show > 'APEI was here'. > * Tinkered with the commit message > > Changes since v2: > * Removed IS_ENABLED() check, done by the caller unless we have a dummy > definition. > --- > arch/arm64/kernel/acpi.c | 23 +++++++++++++++++++++++ > arch/arm64/mm/fault.c | 9 ++++----- > 2 files changed, 27 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c > index 803f0494dd3e..8288ae0c8f3b 100644 > --- a/arch/arm64/kernel/acpi.c > +++ b/arch/arm64/kernel/acpi.c > @@ -22,6 +22,7 @@ > #include <linux/init.h> > #include <linux/irq.h> > #include <linux/irqdomain.h> > +#include <linux/irq_work.h> > #include <linux/memblock.h> > #include <linux/of_fdt.h> > #include <linux/smp.h> > @@ -268,12 +269,17 @@ pgprot_t __acpi_get_mem_attribute(phys_addr_t addr) > int apei_claim_sea(struct pt_regs *regs) > { > int err = -ENOENT; > + bool return_to_irqs_enabled; > unsigned long current_flags; > > if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES)) > return err; > > current_flags = arch_local_save_flags(); > + return_to_irqs_enabled = !irqs_disabled_flags(current_flags); > + > + if (regs) > + return_to_irqs_enabled = interrupts_enabled(regs); > > /* > * SEA can interrupt SError, mask it and describe this as an NMI so > @@ -283,6 +289,23 @@ int apei_claim_sea(struct pt_regs *regs) > nmi_enter(); > err = ghes_notify_sea(); > nmi_exit(); > + > + /* > + * APEI NMI-like notifications are deferred to irq_work. Unless > + * we interrupted irqs-masked code, we can do that now. > + */ > + if (!err) { > + if (return_to_irqs_enabled) { > + local_daif_restore(DAIF_PROCCTX_NOIRQ); > + __irq_enter(); > + irq_work_run(); > + __irq_exit(); > + } else { > + pr_warn("APEI work queued but not completed"); > + err = -EINPROGRESS; > + } > + } > + Reviewed-by: Julien Thierry <julien.thierry@arm.com> Cheers,
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index 803f0494dd3e..8288ae0c8f3b 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -22,6 +22,7 @@ #include <linux/init.h> #include <linux/irq.h> #include <linux/irqdomain.h> +#include <linux/irq_work.h> #include <linux/memblock.h> #include <linux/of_fdt.h> #include <linux/smp.h> @@ -268,12 +269,17 @@ pgprot_t __acpi_get_mem_attribute(phys_addr_t addr) int apei_claim_sea(struct pt_regs *regs) { int err = -ENOENT; + bool return_to_irqs_enabled; unsigned long current_flags; if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES)) return err; current_flags = arch_local_save_flags(); + return_to_irqs_enabled = !irqs_disabled_flags(current_flags); + + if (regs) + return_to_irqs_enabled = interrupts_enabled(regs); /* * SEA can interrupt SError, mask it and describe this as an NMI so @@ -283,6 +289,23 @@ int apei_claim_sea(struct pt_regs *regs) nmi_enter(); err = ghes_notify_sea(); nmi_exit(); + + /* + * APEI NMI-like notifications are deferred to irq_work. Unless + * we interrupted irqs-masked code, we can do that now. + */ + if (!err) { + if (return_to_irqs_enabled) { + local_daif_restore(DAIF_PROCCTX_NOIRQ); + __irq_enter(); + irq_work_run(); + __irq_exit(); + } else { + pr_warn("APEI work queued but not completed"); + err = -EINPROGRESS; + } + } + local_daif_restore(current_flags); return err; diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index e1c84c2e1cab..1611714f8333 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -642,11 +642,10 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) inf = esr_to_fault_info(esr); - /* - * Return value ignored as we rely on signal merging. - * Future patches will make this more robust. - */ - apei_claim_sea(regs); + if (apei_claim_sea(regs) == 0) { + /* APEI claimed this as a firmware-first notification */ + return 0; + } if (esr & ESR_ELx_FnV) siaddr = NULL;