From patchwork Thu Mar 22 18:14:36 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Morse X-Patchwork-Id: 10302085 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 2C50C600F6 for ; Thu, 22 Mar 2018 18:18:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1D6162882F for ; Thu, 22 Mar 2018 18:18:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 11F562883B; Thu, 22 Mar 2018 18:18:00 +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=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 80DA12882F for ; Thu, 22 Mar 2018 18:17:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=G3vre3fX6u+Z6ujOS+LaH+enKpTieTOA5MPRkROvmCs=; b=bOdaWsxS3wwk/2vxDnxJ2M7V9M JYAAjrZiYVUg5yCAjD10TATT9E030BUMMhVogNWjTMdd8KogG7XE+Qgj1enjCHDPCX2u8xn+47rXZ Ouo1WyZ8nNQmhbsfCVvtCYKDZsm5kCyu6uFquzPMmstQSGXGNDoTLbPFzwPzIDZXxGb4Uji6l+hgr kA+Dnzwis2HwD4SLSIeJOv4hOMDY/RoH88cYojKT7YqaFGXEe/n4V0CCgPyjGGFZPtAaALQD0GVsB wFsisdFSPK3d54DEqquTOsAfexQVbOxslN5oi2hG3UGTa+CG+oN53y8iVpY1eI5d2rFkuTb8ZSAFv I6+Trntw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ez4mf-00048M-Qa; Thu, 22 Mar 2018 18:17:53 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ez4ma-00046E-Gm for linux-arm-kernel@lists.infradead.org; Thu, 22 Mar 2018 18:17:50 +0000 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 03E20165C; Thu, 22 Mar 2018 11:17:45 -0700 (PDT) Received: from melchizedek.cambridge.arm.com (melchizedek.cambridge.arm.com [10.1.207.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 0B3E23F487; Thu, 22 Mar 2018 11:17:41 -0700 (PDT) From: James Morse To: linux-acpi@vger.kernel.org Subject: [PATCH v2 02/11] ACPI / APEI: Generalise the estatus queue's add/remove and notify code Date: Thu, 22 Mar 2018 18:14:36 +0000 Message-Id: <20180322181445.23298-3-james.morse@arm.com> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180322181445.23298-1-james.morse@arm.com> References: <20180322181445.23298-1-james.morse@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180322_111748_692929_FF2770A5 X-CRM114-Status: GOOD ( 16.80 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rafael Wysocki , Tony Luck , Christoffer Dall , Punit Agrawal , Xie XiuQi , Marc Zyngier , Catalin Marinas , Tyler Baicar , Will Deacon , Dongjiu Geng , linux-mm@kvack.org, Borislav Petkov , James Morse , Naoya Horiguchi , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, Len Brown MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP To support asynchronous NMI-like notifications on arm64 we need to use the estatus-queue. These patches refactor it to allow multiple APEI notification types to use it. Refactor the estatus queue's pool grow/shrink code and notification routine from NOTIFY_NMI's handlers. This will allow another notification method to use the estatus queue without duplicating this code. This patch adds rcu_read_lock()/rcu_read_unlock() around the list list_for_each_entry_rcu() walker. These aren't strictly necessary as the whole nmi_enter/nmi_exit() window is a spooky RCU read-side critical section. Keep the oops_begin() call for x86, arm64 doesn't have one of these, and APEI is the only thing outside arch code calling this.. The existing ghes_estatus_pool_shrink() is folded into the new ghes_estatus_queue_shrink_pool() as only the queue uses it. _in_nmi_notify_one() is separate from the rcu-list walker for a later caller that doesn't need to walk a list. Signed-off-by: James Morse Reviewed-by: Punit Agrawal --- Changes since v1: * Tidied up _in_nmi_notify_one(). Unchanged since v1: * oops_begin() is still x86 only. For arm64 this would be an APEI specific callback that doesn't quite stop log messages from other CPUs being interleaved. drivers/acpi/apei/ghes.c | 100 ++++++++++++++++++++++++++++++----------------- 1 file changed, 65 insertions(+), 35 deletions(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index e2af91c92135..c8a6c5b0516e 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -747,6 +747,51 @@ static void __process_error(struct ghes *ghes) #endif } +static int _in_nmi_notify_one(struct ghes *ghes) +{ + int sev; + + if (ghes_read_estatus(ghes, 1)) { + ghes_clear_estatus(ghes); + return -ENOENT; + } + + sev = ghes_severity(ghes->estatus->error_severity); + if (sev >= GHES_SEV_PANIC) { +#ifdef CONFIG_X86 + oops_begin(); +#endif + ghes_print_queued_estatus(); + __ghes_panic(ghes); + } + + if (!(ghes->flags & GHES_TO_CLEAR)) + return 0; + + __process_error(ghes); + ghes_clear_estatus(ghes); + + return 0; +} + +static int ghes_estatus_queue_notified(struct list_head *rcu_list) +{ + int ret = -ENOENT; + struct ghes *ghes; + + rcu_read_lock(); + list_for_each_entry_rcu(ghes, rcu_list, list) { + if (!_in_nmi_notify_one(ghes)) + ret = 0; + } + rcu_read_unlock(); + + if (IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG) && ret == 0) + irq_work_queue(&ghes_proc_irq_work); + + return ret; +} + static unsigned long ghes_esource_prealloc_size( const struct acpi_hest_generic *generic) { @@ -762,11 +807,24 @@ static unsigned long ghes_esource_prealloc_size( return prealloc_size; } -static void ghes_estatus_pool_shrink(unsigned long len) +/* After removing a queue user, we can shrink the pool */ +static void ghes_estatus_queue_shrink_pool(struct ghes *ghes) { + unsigned long len; + + len = ghes_esource_prealloc_size(ghes->generic); ghes_estatus_pool_size_request -= PAGE_ALIGN(len); } +/* Before adding a queue user, grow the pool */ +static void ghes_estatus_queue_grow_pool(struct ghes *ghes) +{ + unsigned long len; + + len = ghes_esource_prealloc_size(ghes->generic); + ghes_estatus_pool_expand(len); +} + static void ghes_proc_in_irq(struct irq_work *irq_work) { struct llist_node *llnode, *next; @@ -965,48 +1023,22 @@ static LIST_HEAD(ghes_nmi); static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs) { - struct ghes *ghes; - int sev, ret = NMI_DONE; + int ret = NMI_DONE; if (!atomic_add_unless(&ghes_in_nmi, 1, 1)) return ret; - list_for_each_entry_rcu(ghes, &ghes_nmi, list) { - if (ghes_read_estatus(ghes, 1)) { - ghes_clear_estatus(ghes); - continue; - } else { - ret = NMI_HANDLED; - } - - sev = ghes_severity(ghes->estatus->error_severity); - if (sev >= GHES_SEV_PANIC) { - oops_begin(); - ghes_print_queued_estatus(); - __ghes_panic(ghes); - } + if (!ghes_estatus_queue_notified(&ghes_nmi)) + ret = NMI_HANDLED; - if (!(ghes->flags & GHES_TO_CLEAR)) - continue; - - __process_error(ghes); - ghes_clear_estatus(ghes); - } - -#ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG - if (ret == NMI_HANDLED) - irq_work_queue(&ghes_proc_irq_work); -#endif atomic_dec(&ghes_in_nmi); return ret; } static void ghes_nmi_add(struct ghes *ghes) { - unsigned long len; + ghes_estatus_queue_grow_pool(ghes); - len = ghes_esource_prealloc_size(ghes->generic); - ghes_estatus_pool_expand(len); mutex_lock(&ghes_list_mutex); if (list_empty(&ghes_nmi)) register_nmi_handler(NMI_LOCAL, ghes_notify_nmi, 0, "ghes"); @@ -1016,8 +1048,6 @@ static void ghes_nmi_add(struct ghes *ghes) static void ghes_nmi_remove(struct ghes *ghes) { - unsigned long len; - mutex_lock(&ghes_list_mutex); list_del_rcu(&ghes->list); if (list_empty(&ghes_nmi)) @@ -1028,8 +1058,8 @@ static void ghes_nmi_remove(struct ghes *ghes) * freed after NMI handler finishes. */ synchronize_rcu(); - len = ghes_esource_prealloc_size(ghes->generic); - ghes_estatus_pool_shrink(len); + + ghes_estatus_queue_shrink_pool(ghes); } #else /* CONFIG_HAVE_ACPI_APEI_NMI */