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 we can't guarantee this will be taken before we return.
Unless we interrupted a context with irqs-masked, we can call irq_work_run() to do the work now. Otherwise return -EINPROGRESS to indicate ghes_notify_sea() found some work to do, but it hasn't finished yet. With this we can take apei_claim_sea() returning '0' to mean 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 <[email protected]> Reviewed-by: Punit Agrawal <[email protected]> Tested-by: Tyler Baicar <[email protected]> CC: Xie XiuQi <[email protected]> CC: gengdongjiu <[email protected]> --- Changes since v2: * Removed IS_ENABLED() check, done by the caller unless we have a dummy definition. --- arch/arm64/kernel/acpi.c | 19 +++++++++++++++++++ arch/arm64/mm/fault.c | 9 ++++----- 2 files changed, 23 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index a9b8bba014b5..09744e2d15a0 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -23,6 +23,7 @@ #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> @@ -270,10 +271,14 @@ int apei_claim_sea(struct pt_regs *regs) { int err = -ENOENT; unsigned long current_flags = arch_local_save_flags(); + unsigned long interrupted_flags = current_flags; if (!IS_ENABLED(CONFIG_ACPI_APEI_SEA)) return err; + if (regs) + interrupted_flags = regs->pstate; + /* * SEA can interrupt SError, mask it and describe this as an NMI so * that APEI defers the handling. @@ -282,6 +287,20 @@ 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 (!arch_irqs_disabled_flags(interrupted_flags)) { + local_daif_restore(DAIF_PROCCTX_NOIRQ); + irq_work_run(); + } else { + err = -EINPROGRESS; + } + } + local_daif_restore(current_flags); return err; diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 2c38776bb71f..97036e01522a 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -630,11 +630,10 @@ 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; + } clear_siginfo(&info); info.si_signo = inf->sig; -- 2.19.0 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
