Re: [PATCH 1/2] drivers/edac: Add L1 and L2 error detection for A53 and A57

Hi Boris,

Sorry for the long delay, your mail was buried in my inbox.

On Wed, Aug 26, 2020 at 10:41:35AM +0200, Borislav Petkov wrote:

On Thu, Aug 13, 2020 at 09:57:20AM +0200, Sascha Hauer wrote:

quoted

The Cortex A53 and A57 cores have error detection capabilities for the
L1/L2 Caches, this patch adds a driver for them.

Unfortunately there is no robust way to inject errors into the caches,
so this driver doesn't contain any code to actually test it. It has
been tested though with code taken from an older version of this driver
found here: https://lkml.org/lkml/2018/3/14/1203. For reasons stated
in this thread the error injection code is not suitable for mainline,
so it is removed from the driver.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 .../bindings/edac/arm,cortex-a5x-edac.yaml    |  32 +++
 drivers/edac/Kconfig                          |   6 +
 drivers/edac/Makefile                         |   1 +
 drivers/edac/cortex_arm64_l1_l2.c             | 208 ++++++++++++++++++
 4 files changed, 247 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/edac/arm,cortex-a5x-edac.yaml
 create mode 100644 drivers/edac/cortex_arm64_l1_l2.c

Just nitpicks below. James'd need to look at this too before it goes
anywhere.

Checkpatch is trying to tell me something here:

WARNING: DT compatible string "arm,cortex-a53-edac" appears un-documented -- check ./Documentation/devicetree/bindings/
#296: FILE: drivers/edac/cortex_arm64_l1_l2.c:190:
+       { .compatible = "arm,cortex-a53-edac" },

WARNING: DT compatible string "arm,cortex-a57-edac" appears un-documented -- check ./Documentation/devicetree/bindings/
#297: FILE: drivers/edac/cortex_arm64_l1_l2.c:191:
+       { .compatible = "arm,cortex-a57-edac" },

for 2/2 too:

WARNING: DT compatible string "arm,cortex-a53-edac" appears un-documented -- check ./Documentation/devicetree/bindings/
#39: FILE: arch/arm64/boot/dts/freescale/fsl-ls1043a.dtsi:842:
+               compatible = "arm,cortex-a53-edac";

WARNING: DT compatible string "arm,cortex-a57-edac" appears un-documented -- check ./Documentation/devicetree/bindings/
#56: FILE: arch/arm64/boot/dts/freescale/fsl-ls1046a.dtsi:805:
+               compatible = "arm,cortex-a57-edac";


False positive or valid?

Have you run checkpatch on a tree with this patch applied? If not, then
yes, it's undocumented as the docs are added with this patch.

...

quoted

+static void read_errors(void *data)
+{
+	u64 cpumerr, l2merr;
+	int cpu = smp_processor_id();
+	char msg[MESSAGE_SIZE];
+	struct edac_device_ctl_info *edac_ctl = data;

Please sort function local variables declaration in a reverse christmas
tree order:

	<type A> longest_variable_name;
	<type B> shorter_var_name;
	<type C> even_shorter;
	<type D> i;

I never heard of such a requirement. How is the length defined? Is it
only the length of the variable name or is it the length of the name
including the type? Including the array braces [] or not? What if a
variable shall be initialized with the value of an earlier declared
variable, do I have to make up variable names with a suitable length in
that case?  What if shorter_var_name and even_shorter are of same type,
can I still write them in a single line? Finally, Is this documented
somewhere?

I hope that was a joke from you that I didn't understand.

Check your other functions too pls.

quoted

+	/* cpumerrsr_el1 */
+	asm volatile("mrs %0, s3_1_c15_c2_2" : "=r" (cpumerr));
+	asm volatile("msr s3_1_c15_c2_2, %0" :: "r" (0));
+
+	if (cpumerr & CPUMERRSR_EL1_VALID) {
+		const char *str;
+		int fatal = (cpumerr & CPUMERRSR_EL1_FATAL) != 0;

Don't need "!= 0" and fatal can be bool.

Ok.

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel