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From: Jeffrey Hugo <jhugo@codeaurora.org>
To: sudeep.holla@arm.com, gregkh@linuxfoundation.org,
	rjw@rjwysocki.net, linux-acpi@vger.kernel.org,
	jeremy.linton@arm.com
Cc: linux-kernel@vger.kernel.org, vkilari@codeaurora.org,
	Jeffrey Hugo <jhugo@codeaurora.org>
Subject: [PATCH v3 1/2] drivers: base: cacheinfo: Do not populate sysfs for unknown cache types
Date: Thu, 27 Sep 2018 20:57:56 -0600	[thread overview]
Message-ID: <1538103477-15513-2-git-send-email-jhugo@codeaurora.org> (raw)
In-Reply-To: <1538103477-15513-1-git-send-email-jhugo@codeaurora.org>

If a cache has an unknown type because neither the hardware nor the
firmware told us, an entry in the sysfs tree will be made, but the type
file will not be present.  lscpu depends on the type file being present
for every entry, and will error out without printing system information
if lscpu cannot open the type file.

Presenting information about a cache without indicating its type is not
useful, therefore if we hit a cache with an unknown type, stop populating
sysfs so that userspace has the maximum amount of useful information.

This addresses the following lscpu error, which prevents any output.
lscpu: cannot open /sys/devices/system/cpu/cpu0/cache/index3/type: No such
file or directory

Suggested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
---
 drivers/base/cacheinfo.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index 5d5b598..cf78fa6 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -615,6 +615,8 @@ static int cache_add_dev(unsigned int cpu)
 		this_leaf = this_cpu_ci->info_list + i;
 		if (this_leaf->disable_sysfs)
 			continue;
+		if (this_leaf->type == CACHE_TYPE_NOCACHE)
+			break;
 		cache_groups = cache_get_attribute_groups(this_leaf);
 		ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
 					   "index%1u", i);
-- 
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.


  reply	other threads:[~2018-09-28  2:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-28  2:57 [PATCH v3 0/2] PPTT handle Handle architecturally unknown cache types Jeffrey Hugo
2018-09-28  2:57 ` Jeffrey Hugo [this message]
2018-10-02 10:49   ` [PATCH v3 1/2] drivers: base: cacheinfo: Do not populate sysfs for " Sudeep Holla
2018-10-03  9:35   ` Rafael J. Wysocki
2018-10-03 13:47     ` Jeffrey Hugo
2018-09-28  2:57 ` [PATCH v3 2/2] ACPI/PPTT: Handle architecturally " Jeffrey Hugo
2018-09-28 21:52   ` Jeremy Linton
2018-10-02 10:57   ` Sudeep Holla
2018-10-02 15:30     ` Jeffrey Hugo

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