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From:   Jeshua Smith <jeshuas@nvidia.com>
To:     "keescook@chromium.org" <keescook@chromium.org>,
        "tony.luck@intel.com" <tony.luck@intel.com>,
        "gpiccoli@igalia.com" <gpiccoli@igalia.com>,
        "rafael@kernel.org" <rafael@kernel.org>,
        "lenb@kernel.org" <lenb@kernel.org>,
        "james.morse@arm.com" <james.morse@arm.com>,
        "bp@alien8.de" <bp@alien8.de>
CC:     "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
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        "linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
        Thierry Reding <treding@nvidia.com>,
        Jonathan Hunter <jonathanh@nvidia.com>
Subject: RE: [PATCH V2] ACPI: APEI: Use ERST timeout for slow devices
Thread-Topic: [PATCH V2] ACPI: APEI: Use ERST timeout for slow devices
Thread-Index: AQHZtREytrmSwIEvT06Ibqr95x6guq/abXNg
Date:   Fri, 4 Aug 2023 15:55:07 +0000
Message-ID: <DM6PR12MB3371BA50E3B76D2266273901DB09A@DM6PR12MB3371.namprd12.prod.outlook.com>
References: <20230712223448.145079-1-jeshuas@nvidia.com>
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Can the maintainers please respond to my patch?

-----Original Message-----
From: Jeshua Smith <jeshuas@nvidia.com>=20
Sent: Wednesday, July 12, 2023 4:35 PM
To: keescook@chromium.org; tony.luck@intel.com; gpiccoli@igalia.com; rafael=
@kernel.org; lenb@kernel.org; james.morse@arm.com; bp@alien8.de
Cc: linux-acpi@vger.kernel.org; linux-kernel@vger.kernel.org; linux-hardeni=
ng@vger.kernel.org; linux-tegra@vger.kernel.org; Thierry Reding <treding@nv=
idia.com>; Jonathan Hunter <jonathanh@nvidia.com>; Jeshua Smith <jeshuas@nv=
idia.com>
Subject: [PATCH V2] ACPI: APEI: Use ERST timeout for slow devices

Slow devices such as flash may not meet the default 1ms timeout value, so u=
se the ERST max execution time value that they provide as the timeout if it=
 is larger.

Signed-off-by: Jeshua Smith <jeshuas@nvidia.com>
---
v2:
* no longer add copyright.
* no longer add unused ERST_EXEC_TIMING_TYPICAL defines.
* set timings to 0 if the ACPI_ERST_EXECUTE_TIMINGS operation isn't support=
ed,
  which will result in the default timeout being used.

 drivers/acpi/apei/erst.c | 41 ++++++++++++++++++++++++++++++++++++----
 1 file changed, 37 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c index 2479=
89060e29..bf65e3461531 100644
--- a/drivers/acpi/apei/erst.c
+++ b/drivers/acpi/apei/erst.c
@@ -59,6 +59,10 @@ static struct acpi_table_erst *erst_tab;
 #define ERST_RANGE_NVRAM	0x0002
 #define ERST_RANGE_SLOW		0x0004
=20
+/* ERST Exec max timings */
+#define ERST_EXEC_TIMING_MAX_MASK      0xFFFFFFFF00000000
+#define ERST_EXEC_TIMING_MAX_SHIFT     32
+
 /*
  * ERST Error Log Address Range, used as buffer for reading/writing
  * error records.
@@ -68,6 +72,7 @@ static struct erst_erange {
 	u64 size;
 	void __iomem *vaddr;
 	u32 attr;
+	u64 timings;
 } erst_erange;
=20
 /*
@@ -97,6 +102,19 @@ static inline int erst_errno(int command_status)
 	}
 }
=20
+static inline u64 erst_get_timeout(void) {
+	u64 timeout =3D FIRMWARE_TIMEOUT;
+
+	if (erst_erange.attr & ERST_RANGE_SLOW) {
+		timeout =3D ((erst_erange.timings & ERST_EXEC_TIMING_MAX_MASK) >>
+			ERST_EXEC_TIMING_MAX_SHIFT) * NSEC_PER_MSEC;
+		if (timeout < FIRMWARE_TIMEOUT)
+			timeout =3D FIRMWARE_TIMEOUT;
+	}
+	return timeout;
+}
+
 static int erst_timedout(u64 *t, u64 spin_unit)  {
 	if ((s64)*t < spin_unit) {
@@ -191,9 +209,11 @@ static int erst_exec_stall_while_true(struct apei_exec=
_context *ctx,  {
 	int rc;
 	u64 val;
-	u64 timeout =3D FIRMWARE_TIMEOUT;
+	u64 timeout;
 	u64 stall_time;
=20
+	timeout =3D erst_get_timeout();
+
 	if (ctx->var1 > FIRMWARE_MAX_STALL) {
 		if (!in_nmi())
 			pr_warn(FW_WARN
@@ -389,6 +409,13 @@ static int erst_get_erange(struct erst_erange *range)
 	if (rc)
 		return rc;
 	range->attr =3D apei_exec_ctx_get_output(&ctx);
+	rc =3D apei_exec_run(&ctx, ACPI_ERST_EXECUTE_TIMINGS);
+	if (rc =3D=3D 0)
+		range->timings =3D apei_exec_ctx_get_output(&ctx);
+	else if (rc =3D=3D -ENOENT)
+		range->timings =3D 0;
+	else
+		return rc;
=20
 	return 0;
 }
@@ -621,10 +648,12 @@ EXPORT_SYMBOL_GPL(erst_get_record_id_end);
 static int __erst_write_to_storage(u64 offset)  {
 	struct apei_exec_context ctx;
-	u64 timeout =3D FIRMWARE_TIMEOUT;
+	u64 timeout;
 	u64 val;
 	int rc;
=20
+	timeout =3D erst_get_timeout();
+
 	erst_exec_ctx_init(&ctx);
 	rc =3D apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_WRITE);
 	if (rc)
@@ -660,10 +689,12 @@ static int __erst_write_to_storage(u64 offset)  stati=
c int __erst_read_from_storage(u64 record_id, u64 offset)  {
 	struct apei_exec_context ctx;
-	u64 timeout =3D FIRMWARE_TIMEOUT;
+	u64 timeout;
 	u64 val;
 	int rc;
=20
+	timeout =3D erst_get_timeout();
+
 	erst_exec_ctx_init(&ctx);
 	rc =3D apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_READ);
 	if (rc)
@@ -703,10 +734,12 @@ static int __erst_read_from_storage(u64 record_id, u6=
4 offset)  static int __erst_clear_from_storage(u64 record_id)  {
 	struct apei_exec_context ctx;
-	u64 timeout =3D FIRMWARE_TIMEOUT;
+	u64 timeout;
 	u64 val;
 	int rc;
=20
+	timeout =3D erst_get_timeout();
+
 	erst_exec_ctx_init(&ctx);
 	rc =3D apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_CLEAR);
 	if (rc)
--
2.25.1