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From: James Morse <james.morse@arm.com>
To: linux-acpi@vger.kernel.org
Cc: Rafael Wysocki <rjw@rjwysocki.net>,
	Tony Luck <tony.luck@intel.com>, Xie XiuQi <xiexiuqi@huawei.com>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Christoffer Dall <christoffer.dall@arm.com>,
	Dongjiu Geng <gengdongjiu@huawei.com>,
	linux-mm@kvack.org, Borislav Petkov <bp@alien8.de>,
	james.morse@arm.com, Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org, Len Brown <lenb@kernel.org>
Subject: [PATCH v8 09/26] ACPI / APEI: Generalise the estatus queue's notify code
Date: Tue, 29 Jan 2019 18:48:45 +0000
Message-ID: <20190129184902.102850-10-james.morse@arm.com> (raw)
In-Reply-To: <20190129184902.102850-1-james.morse@arm.com>

Refactor the estatus queue's pool notification routine from
NOTIFY_NMI's handlers. This will allow another notification
method to use the estatus queue without duplicating this code.

Add 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.

in_nmi_queue_one_entry() is separate from the rcu-list walker for a
later caller that doesn't need to walk a list.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Punit Agrawal <punit.agrawal@arm.com>
Tested-by: Tyler Baicar <tbaicar@codeaurora.org>

---
Changes since v7:
 * Moved err= onto a separate line to make this more readable
 * Dropped ghes_ prefix on new static functions
 * Renamed stuff, 'notify' has an overloaded meaning,

Changes since v6:
 * Removed pool grow/remove code as this is no longer necessary.

Changes since v3:
 * Removed duplicate or redundant paragraphs in commit message.
 * Fixed the style of a zero check.
Changes since v1:
   * Tidied up _in_nmi_notify_one().
---
 drivers/acpi/apei/ghes.c | 65 ++++++++++++++++++++++++++--------------
 1 file changed, 43 insertions(+), 22 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index af3c10f47f20..cb3d88de711f 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -912,37 +912,58 @@ static void __process_error(struct ghes *ghes)
 #endif
 }
 
-static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
+static int ghes_in_nmi_queue_one_entry(struct ghes *ghes)
 {
 	u64 buf_paddr;
-	struct ghes *ghes;
-	int sev, ret = NMI_DONE;
+	int sev;
 
-	if (!atomic_add_unless(&ghes_in_nmi, 1, 1))
-		return ret;
+	if (ghes_read_estatus(ghes, &buf_paddr)) {
+		ghes_clear_estatus(ghes, buf_paddr);
+		return -ENOENT;
+	}
 
-	list_for_each_entry_rcu(ghes, &ghes_nmi, list) {
-		if (ghes_read_estatus(ghes, &buf_paddr)) {
-			ghes_clear_estatus(ghes, buf_paddr);
-			continue;
-		} else {
-			ret = NMI_HANDLED;
-		}
+	sev = ghes_severity(ghes->estatus->error_severity);
+	if (sev >= GHES_SEV_PANIC) {
+		ghes_print_queued_estatus();
+		__ghes_panic(ghes, buf_paddr);
+	}
 
-		sev = ghes_severity(ghes->estatus->error_severity);
-		if (sev >= GHES_SEV_PANIC) {
-			ghes_print_queued_estatus();
-			__ghes_panic(ghes, buf_paddr);
-		}
+	__process_error(ghes);
+	ghes_clear_estatus(ghes, buf_paddr);
 
-		__process_error(ghes);
-		ghes_clear_estatus(ghes, buf_paddr);
+	return 0;
+}
+
+static int ghes_in_nmi_spool_from_list(struct list_head *rcu_list)
+{
+	int err, ret = -ENOENT;
+	struct ghes *ghes;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(ghes, rcu_list, list) {
+		err = ghes_in_nmi_queue_one_entry(ghes);
+		if (!err)
+			ret = 0;
 	}
+	rcu_read_unlock();
 
-#ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
-	if (ret == NMI_HANDLED)
+	if (IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG) && !ret)
 		irq_work_queue(&ghes_proc_irq_work);
-#endif
+
+	return ret;
+}
+
+static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
+{
+	int err, ret = NMI_DONE;
+
+	if (!atomic_add_unless(&ghes_in_nmi, 1, 1))
+		return ret;
+
+	err = ghes_in_nmi_spool_from_list(&ghes_nmi);
+	if (!err)
+		ret = NMI_HANDLED;
+
 	atomic_dec(&ghes_in_nmi);
 	return ret;
 }
-- 
2.20.1


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  parent reply index

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-29 18:48 [PATCH v8 00/26] APEI in_nmi() rework and SDEI wire-up James Morse
2019-01-29 18:48 ` [PATCH v8 01/26] ACPI / APEI: Don't wait to serialise with oops messages when panic()ing James Morse
2019-01-29 18:48 ` [PATCH v8 02/26] ACPI / APEI: Remove silent flag from ghes_read_estatus() James Morse
2019-01-29 18:48 ` [PATCH v8 03/26] ACPI / APEI: Switch estatus pool to use vmalloc memory James Morse
2019-01-29 18:48 ` [PATCH v8 04/26] ACPI / APEI: Make hest.c manage the estatus memory pool James Morse
2019-02-01 13:20   ` Borislav Petkov
2019-01-29 18:48 ` [PATCH v8 05/26] ACPI / APEI: Make estatus pool allocation a static size James Morse
2019-01-29 18:48 ` [PATCH v8 06/26] ACPI / APEI: Don't store CPER records physical address in struct ghes James Morse
2019-01-29 18:48 ` [PATCH v8 07/26] ACPI / APEI: Remove spurious GHES_TO_CLEAR check James Morse
2019-01-29 18:48 ` [PATCH v8 08/26] ACPI / APEI: Don't update struct ghes' flags in read/clear estatus James Morse
2019-01-29 18:48 ` James Morse [this message]
2019-02-01 13:46   ` [PATCH v8 09/26] ACPI / APEI: Generalise the estatus queue's notify code Borislav Petkov
2019-01-29 18:48 ` [PATCH v8 10/26] ACPI / APEI: Don't allow ghes_ack_error() to mask earlier errors James Morse
2019-01-29 18:48 ` [PATCH v8 11/26] ACPI / APEI: Move NOTIFY_SEA between the estatus-queue and NOTIFY_NMI James Morse
2019-01-29 18:48 ` [PATCH v8 12/26] ACPI / APEI: Switch NOTIFY_SEA to use the estatus queue James Morse
2019-01-29 18:48 ` [PATCH v8 13/26] KVM: arm/arm64: Add kvm_ras.h to collect kvm specific RAS plumbing James Morse
2019-01-29 18:48 ` [PATCH v8 14/26] arm64: KVM/mm: Move SEA handling behind a single 'claim' interface James Morse
2019-01-29 18:48 ` [PATCH v8 15/26] ACPI / APEI: Move locking to the notification helper James Morse
2019-01-29 18:48 ` [PATCH v8 16/26] ACPI / APEI: Let the notification helper specify the fixmap slot James Morse
2019-01-29 18:48 ` [PATCH v8 17/26] ACPI / APEI: Pass ghes and estatus separately to avoid a later copy James Morse
2019-01-29 18:48 ` [PATCH v8 18/26] ACPI / APEI: Make GHES estatus header validation more user friendly James Morse
2019-02-01 14:30   ` Borislav Petkov
2019-01-29 18:48 ` [PATCH v8 19/26] ACPI / APEI: Split ghes_read_estatus() to allow a peek at the CPER length James Morse
2019-01-29 18:48 ` [PATCH v8 20/26] ACPI / APEI: Only use queued estatus entry during in_nmi_queue_one_entry() James Morse
2019-01-29 18:48 ` [PATCH v8 21/26] ACPI / APEI: Use separate fixmap pages for arm64 NMI-like notifications James Morse
2019-01-29 18:48 ` [PATCH v8 22/26] mm/memory-failure: Add memory_failure_queue_kick() James Morse
2019-01-29 18:48 ` [PATCH v8 23/26] ACPI / APEI: Kick the memory_failure() queue for synchronous errors James Morse
2019-01-29 18:49 ` [PATCH v8 24/26] arm64: acpi: Make apei_claim_sea() synchronise with APEI's irq work James Morse
2019-01-30  8:56   ` Julien Thierry
2019-01-29 18:49 ` [PATCH v8 25/26] firmware: arm_sdei: Add ACPI GHES registration helper James Morse
2019-01-29 18:49 ` [PATCH v8 26/26] ACPI / APEI: Add support for the SDEI GHES Notification type James Morse
2019-02-08 11:40 ` [PATCH v8 00/26] APEI in_nmi() rework and SDEI wire-up Rafael J. Wysocki
2019-02-08 14:13   ` James Morse
2019-02-11 11:05     ` Rafael J. Wysocki
2019-02-11 18:35       ` James Morse
2019-02-12 22:14         ` Rafael J. Wysocki

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