From patchwork Tue Jan 29 18:48:59 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Morse X-Patchwork-Id: 10786971 X-Patchwork-Delegate: rjw@sisk.pl Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2A0851399 for ; Tue, 29 Jan 2019 18:50:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1A0EC2D741 for ; Tue, 29 Jan 2019 18:50:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0E88F2D7E4; Tue, 29 Jan 2019 18:50:48 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 398EF2D741 for ; Tue, 29 Jan 2019 18:50:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727245AbfA2Suq (ORCPT ); Tue, 29 Jan 2019 13:50:46 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:42486 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727165AbfA2Suq (ORCPT ); Tue, 29 Jan 2019 13:50:46 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E7D8B15AB; Tue, 29 Jan 2019 10:50:45 -0800 (PST) Received: from eglon.cambridge.arm.com (eglon.cambridge.arm.com [10.1.196.105]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 46AB93F557; Tue, 29 Jan 2019 10:50:43 -0800 (PST) From: James Morse 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 , james.morse@arm.com Subject: [PATCH v8 23/26] ACPI / APEI: Kick the memory_failure() queue for synchronous errors Date: Tue, 29 Jan 2019 18:48:59 +0000 Message-Id: <20190129184902.102850-24-james.morse@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190129184902.102850-1-james.morse@arm.com> References: <20190129184902.102850-1-james.morse@arm.com> MIME-Version: 1.0 Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP memory_failure() offlines or repairs pages of memory that have been discovered to be corrupt. These may be detected by an external component, (e.g. the memory controller), and notified via an IRQ. In this case the work is queued as not all of memory_failure()s work can happen in IRQ context. If the error was detected as a result of user-space accessing a corrupt memory location the CPU may take an abort instead. On arm64 this is a 'synchronous external abort', and on a firmware first system it is replayed using NOTIFY_SEA. This notification has NMI like properties, (it can interrupt IRQ-masked code), so the memory_failure() work is queued. If we return to user-space before the queued memory_failure() work is processed, we will take the fault again. This loop may cause platform firmware to exceed some threshold and reboot when Linux could have recovered from this error. For NMIlike notifications keep track of whether memory_failure() work was queued, and make task_work pending to flush out the queue. To save memory allocations, the task_work is allocated as part of the ghes_estatus_node, and free()ing it back to the pool is deferred. Signed-off-by: James Morse --- current->mm == &init_mm ? I couldn't find a helper for this. The intent is not to set TIF flags on kernel threads. What happens if a kernel-thread takes on of these? Its just one of the many not-handled-very-well cases we have already, as memory_failure() puts it: "try to be lucky". I assume that if NOTIFY_NMI is coming from SMM it must suffer from this problem too. Changes since v7: * Don't allocate memory, stuff it in estatus_node. This means passing back a 'queued' flag to ghes_proc_in_irq() which holds the estatus_node. --- drivers/acpi/apei/ghes.c | 68 +++++++++++++++++++++++++++++++++------- include/acpi/ghes.h | 3 ++ 2 files changed, 60 insertions(+), 11 deletions(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index e6f0d176b245..dfa8f155f964 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -47,6 +47,7 @@ #include #include #include +#include #include #include @@ -399,23 +400,46 @@ static void ghes_clear_estatus(struct ghes *ghes, ghes_ack_error(ghes->generic_v2); } -static void ghes_handle_memory_failure(struct acpi_hest_generic_data *gdata, int sev) +/* + * Called as task_work before returning to user-space. + * Ensure any queued work has been done before we return to the context that + * triggered the notification. + */ +static void ghes_kick_task_work(struct callback_head *head) +{ + struct acpi_hest_generic_status *estatus; + struct ghes_estatus_node *estatus_node; + u32 node_len; + + estatus_node = container_of(head, struct ghes_estatus_node, task_work); + memory_failure_queue_kick(estatus_node->task_work_cpu); + + estatus = GHES_ESTATUS_FROM_NODE(estatus_node); + node_len = GHES_ESTATUS_NODE_LEN(cper_estatus_len(estatus)); + gen_pool_free(ghes_estatus_pool, (unsigned long)estatus_node, node_len); +} + +static bool ghes_handle_memory_failure(struct ghes *ghes, + struct acpi_hest_generic_data *gdata, + int sev) { -#ifdef CONFIG_ACPI_APEI_MEMORY_FAILURE unsigned long pfn; int flags = -1; int sec_sev = ghes_severity(gdata->error_severity); struct cper_sec_mem_err *mem_err = acpi_hest_get_payload(gdata); + if (!IS_ENABLED(CONFIG_ACPI_APEI_MEMORY_FAILURE)) + return false; + if (!(mem_err->validation_bits & CPER_MEM_VALID_PA)) - return; + return false; pfn = mem_err->physical_addr >> PAGE_SHIFT; if (!pfn_valid(pfn)) { pr_warn_ratelimited(FW_WARN GHES_PFX "Invalid address in generic error data: %#llx\n", mem_err->physical_addr); - return; + return false; } /* iff following two events can be handled properly by now */ @@ -425,9 +449,12 @@ static void ghes_handle_memory_failure(struct acpi_hest_generic_data *gdata, int if (sev == GHES_SEV_RECOVERABLE && sec_sev == GHES_SEV_RECOVERABLE) flags = 0; - if (flags != -1) + if (flags != -1) { memory_failure_queue(pfn, flags); -#endif + return true; + } + + return false; } /* @@ -475,11 +502,12 @@ static void ghes_handle_aer(struct acpi_hest_generic_data *gdata) #endif } -static void ghes_do_proc(struct ghes *ghes, +static bool ghes_do_proc(struct ghes *ghes, const struct acpi_hest_generic_status *estatus) { int sev, sec_sev; struct acpi_hest_generic_data *gdata; + bool work_queued = false; guid_t *sec_type; guid_t *fru_id = &NULL_UUID_LE; char *fru_text = ""; @@ -500,7 +528,8 @@ static void ghes_do_proc(struct ghes *ghes, ghes_edac_report_mem_error(sev, mem_err); arch_apei_report_mem_error(sev, mem_err); - ghes_handle_memory_failure(gdata, sev); + if (ghes_handle_memory_failure(ghes, gdata, sev)) + work_queued = true; } else if (guid_equal(sec_type, &CPER_SEC_PCIE)) { ghes_handle_aer(gdata); @@ -517,6 +546,8 @@ static void ghes_do_proc(struct ghes *ghes, gdata->error_data_length); } } + + return work_queued; } static void __ghes_print_estatus(const char *pfx, @@ -812,7 +843,9 @@ static void ghes_proc_in_irq(struct irq_work *irq_work) struct ghes_estatus_node *estatus_node; struct acpi_hest_generic *generic; struct acpi_hest_generic_status *estatus; + bool task_work_pending; u32 len, node_len; + int ret; llnode = llist_del_all(&ghes_estatus_llist); /* @@ -827,14 +860,26 @@ static void ghes_proc_in_irq(struct irq_work *irq_work) estatus = GHES_ESTATUS_FROM_NODE(estatus_node); len = cper_estatus_len(estatus); node_len = GHES_ESTATUS_NODE_LEN(len); - ghes_do_proc(estatus_node->ghes, estatus); + task_work_pending = ghes_do_proc(estatus_node->ghes, estatus); if (!ghes_estatus_cached(estatus)) { generic = estatus_node->generic; if (ghes_print_estatus(NULL, generic, estatus)) ghes_estatus_cache_add(generic, estatus); } - gen_pool_free(ghes_estatus_pool, (unsigned long)estatus_node, - node_len); + + if (task_work_pending && current->mm != &init_mm) { + estatus_node->task_work.func = ghes_kick_task_work; + estatus_node->task_work_cpu = smp_processor_id(); + ret = task_work_add(current, &estatus_node->task_work, + true); + if (ret) + estatus_node->task_work.func = NULL; + } + + if (!estatus_node->task_work.func) + gen_pool_free(ghes_estatus_pool, + (unsigned long)estatus_node, node_len); + llnode = next; } } @@ -894,6 +939,7 @@ static int ghes_in_nmi_queue_one_entry(struct ghes *ghes, estatus_node->ghes = ghes; estatus_node->generic = ghes->generic; + estatus_node->task_work.func = NULL; estatus = GHES_ESTATUS_FROM_NODE(estatus_node); if (__ghes_read_estatus(estatus, buf_paddr, fixmap_idx, len)) { diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h index e3f1cddb4ac8..517a5231cc1b 100644 --- a/include/acpi/ghes.h +++ b/include/acpi/ghes.h @@ -33,6 +33,9 @@ struct ghes_estatus_node { struct llist_node llnode; struct acpi_hest_generic *generic; struct ghes *ghes; + + int task_work_cpu; + struct callback_head task_work; }; struct ghes_estatus_cache {