From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f70.google.com (mail-oi0-f70.google.com [209.85.218.70]) by kanga.kvack.org (Postfix) with ESMTP id 762156B0268 for ; Thu, 22 Mar 2018 14:18:21 -0400 (EDT) Received: by mail-oi0-f70.google.com with SMTP id 129-v6so4941377oid.12 for ; Thu, 22 Mar 2018 11:18:21 -0700 (PDT) Received: from foss.arm.com (foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id r82si32021oia.276.2018.03.22.11.18.20 for ; Thu, 22 Mar 2018 11:18:20 -0700 (PDT) From: James Morse Subject: [PATCH v2 11/11] arm64: acpi: Make apei_claim_sea() synchronise with APEI's irq work Date: Thu, 22 Mar 2018 18:14:45 +0000 Message-Id: <20180322181445.23298-12-james.morse@arm.com> In-Reply-To: <20180322181445.23298-1-james.morse@arm.com> References: <20180322181445.23298-1-james.morse@arm.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-acpi@vger.kernel.org Cc: kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, Borislav Petkov , Marc Zyngier , Christoffer Dall , Will Deacon , Catalin Marinas , Naoya Horiguchi , Rafael Wysocki , Len Brown , Tony Luck , Tyler Baicar , Dongjiu Geng , Xie XiuQi , Punit Agrawal , James Morse 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 Reviewed-by: Punit Agrawal CC: Xie XiuQi CC: gengdongjiu --- 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 6a4823a3eb5e..a51a7abd98e0 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -275,10 +276,14 @@ 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; + /* * APEI expects an NMI-like notification to always be called * in NMI context. @@ -287,6 +292,20 @@ 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 303c8b425c82..e218e291a17a 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -580,11 +580,10 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) inf->name, esr, addr); if (IS_ENABLED(CONFIG_ACPI_APEI_SEA)) { - /* - * 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; + } } info.si_signo = SIGBUS; -- 2.16.2