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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 19/26] ACPI / APEI: Split ghes_read_estatus() to allow a peek at the CPER length
Date: Tue, 29 Jan 2019 18:48:55 +0000
Message-ID: <20190129184902.102850-20-james.morse@arm.com> (raw)
In-Reply-To: <20190129184902.102850-1-james.morse@arm.com>

ghes_read_estatus() reads the record address, then the record's
header, then performs some sanity checks before reading the
records into the provided estatus buffer.

To provide this estatus buffer the caller must know the size of the
records in advance, or always provide a worst-case sized buffer as
happens today for the non-NMI notifications.

Add a function to peek at the record's header to find the size. This
will let the NMI path allocate the right amount of memory before reading
the records, instead of using the worst-case size, and having to copy
the records.

Split ghes_read_estatus() to create __ghes_peek_estatus() which
returns the address and size of the CPER records.

Signed-off-by: James Morse <james.morse@arm.com>

Changes since v7:
 * Grammar
 * concistent argument ordering

Changes since v6:
 * Additional buf_addr = 0 error handling
 * Moved checking out of peek-estatus
 * Reworded an error message so we can tell them apart
---
 drivers/acpi/apei/ghes.c | 40 +++++++++++++++++++++++++++++-----------
 1 file changed, 29 insertions(+), 11 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 9391fff71344..12375a82fa03 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -317,12 +317,12 @@ int __ghes_check_estatus(struct ghes *ghes,
 	return 0;
 }
 
-static int ghes_read_estatus(struct ghes *ghes,
-			     struct acpi_hest_generic_status *estatus,
-			     u64 *buf_paddr, enum fixed_addresses fixmap_idx)
+/* Read the CPER block, returning its address, and header in estatus. */
+static int __ghes_peek_estatus(struct ghes *ghes,
+			       struct acpi_hest_generic_status *estatus,
+			       u64 *buf_paddr, enum fixed_addresses fixmap_idx)
 {
 	struct acpi_hest_generic *g = ghes->generic;
-	u32 len;
 	int rc;
 
 	rc = apei_read(buf_paddr, &g->error_status_address);
@@ -343,14 +343,14 @@ static int ghes_read_estatus(struct ghes *ghes,
 		return -ENOENT;
 	}
 
-	rc = __ghes_check_estatus(ghes, estatus);
-	if (rc)
-		return rc;
+	return __ghes_check_estatus(ghes, estatus);
+}
 
-	len = cper_estatus_len(estatus);
-	ghes_copy_tofrom_phys(estatus + 1,
-			      *buf_paddr + sizeof(*estatus),
-			      len - sizeof(*estatus), 1, fixmap_idx);
+static int __ghes_read_estatus(struct acpi_hest_generic_status *estatus,
+			       u64 buf_paddr, enum fixed_addresses fixmap_idx,
+			       size_t buf_len)
+{
+	ghes_copy_tofrom_phys(estatus, buf_paddr, buf_len, 1, fixmap_idx);
 	if (cper_estatus_check(estatus)) {
 		pr_warn_ratelimited(FW_WARN GHES_PFX
 				    "Failed to read error status block!\n");
@@ -360,6 +360,24 @@ static int ghes_read_estatus(struct ghes *ghes,
 	return 0;
 }
 
+static int ghes_read_estatus(struct ghes *ghes,
+			     struct acpi_hest_generic_status *estatus,
+			     u64 *buf_paddr, enum fixed_addresses fixmap_idx)
+{
+	int rc;
+
+	rc = __ghes_peek_estatus(ghes, estatus, buf_paddr, fixmap_idx);
+	if (rc)
+		return rc;
+
+	rc = __ghes_check_estatus(ghes, estatus);
+	if (rc)
+		return rc;
+
+	return __ghes_read_estatus(estatus, *buf_paddr, fixmap_idx,
+				   cper_estatus_len(estatus));
+}
+
 static void ghes_clear_estatus(struct ghes *ghes,
 			       struct acpi_hest_generic_status *estatus,
 			       u64 buf_paddr, enum fixed_addresses fixmap_idx)
-- 
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 ` [PATCH v8 09/26] ACPI / APEI: Generalise the estatus queue's notify code James Morse
2019-02-01 13:46   ` 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 ` James Morse [this message]
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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