From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ot1-f70.google.com (mail-ot1-f70.google.com [209.85.210.70]) by kanga.kvack.org (Postfix) with ESMTP id 11DDC6B6A9B for ; Mon, 3 Dec 2018 13:08:01 -0500 (EST) Received: by mail-ot1-f70.google.com with SMTP id t13so5994522otk.4 for ; Mon, 03 Dec 2018 10:08:01 -0800 (PST) Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id l78si6508323oih.207.2018.12.03.10.07.59 for ; Mon, 03 Dec 2018 10:07:59 -0800 (PST) From: James Morse Subject: [PATCH v7 23/25] arm64: acpi: Make apei_claim_sea() synchronise with APEI's irq work Date: Mon, 3 Dec 2018 18:06:11 +0000 Message-Id: <20181203180613.228133-24-james.morse@arm.com> In-Reply-To: <20181203180613.228133-1-james.morse@arm.com> References: <20181203180613.228133-1-james.morse@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 , Dongjiu Geng , Xie XiuQi , Fan Wu , 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 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 Reviewed-by: Punit Agrawal Tested-by: Tyler Baicar CC: Xie XiuQi CC: gengdongjiu --- 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 | 22 +++++++++++++++++++++- arch/arm64/mm/fault.c | 9 ++++----- 2 files changed, 25 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index 803f0494dd3e..421331157e8f 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -268,13 +269,17 @@ pgprot_t __acpi_get_mem_attribute(phys_addr_t addr) int apei_claim_sea(struct pt_regs *regs) { int err = -ENOENT; - unsigned long current_flags; + unsigned long current_flags, interrupted_flags; if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES)) return err; current_flags = arch_local_save_flags(); + interrupted_flags = current_flags; + if (regs) + interrupted_flags = regs->pstate; + /* * SEA can interrupt SError, mask it and describe this as an NMI so * that APEI defers the handling. @@ -283,6 +288,21 @@ 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 { + 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 956afc7d932a..c26ee1f1cc36 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -629,11 +629,10 @@ 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; -- 2.19.2