From: Sudeep Holla <sudeep.holla@arm.com>
To: arm@kernel.org
Cc: Sudeep Holla <sudeep.holla@arm.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Ionela Voinescu <ionela.voinescu@arm.com>,
Quentin Perret <quentin.perret@arm.com>,
Kevin Hilman <khilman@linaro.org>,
Olof Johansson <olof@lixom.net>, Arnd Bergmann <arnd@arndb.de>
Subject: [PATCH v2] firmware: arm_scmi: fix divide by zero when sustained_perf_level is zero
Date: Thu, 6 Sep 2018 16:10:39 +0100 [thread overview]
Message-ID: <1536246639-7420-1-git-send-email-sudeep.holla@arm.com> (raw)
In-Reply-To: <1536165491-27813-1-git-send-email-sudeep.holla@arm.com>
Firmware can provide zero as values for sustained performance level and
corresponding sustained frequency in kHz in order to hide the actual
frequencies and provide only abstract values. It may endup with divide
by zero scenario resulting in kernel panic.
Let's set the multiplication factor to one if either one or both of them
(sustained_perf_level and sustained_freq) are set to zero.
Fixes: a9e3fbfaa0ff ("firmware: arm_scmi: add initial support for performance protocol")
Reported-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
drivers/firmware/arm_scmi/perf.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
Hi ARM SoC team,
Can you pick this patch directly ?
Regards,
Sudeep
diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
index 721e6c57beae..64342944d917 100644
--- a/drivers/firmware/arm_scmi/perf.c
+++ b/drivers/firmware/arm_scmi/perf.c
@@ -166,7 +166,13 @@ scmi_perf_domain_attributes_get(const struct scmi_handle *handle, u32 domain,
le32_to_cpu(attr->sustained_freq_khz);
dom_info->sustained_perf_level =
le32_to_cpu(attr->sustained_perf_level);
- dom_info->mult_factor = (dom_info->sustained_freq_khz * 1000) /
+ if (!dom_info->sustained_freq_khz ||
+ !dom_info->sustained_perf_level)
+ /* CPUFreq converts to kHz, hence default 1000 */
+ dom_info->mult_factor = 1000;
+ else
+ dom_info->mult_factor =
+ (dom_info->sustained_freq_khz * 1000) /
dom_info->sustained_perf_level;
memcpy(dom_info->name, attr->name, SCMI_MAX_STR_SIZE);
}
--
2.7.4
next prev parent reply other threads:[~2018-09-06 15:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-05 16:38 [PATCH] firmware: arm_scmi: fix divide by zero when sustained_perf_level is zero Sudeep Holla
2018-09-06 13:17 ` Quentin Perret
2018-09-06 14:38 ` Sudeep Holla
2018-09-06 15:10 ` Sudeep Holla [this message]
2018-09-06 16:59 ` [PATCH v2] " Olof Johansson
2018-09-06 17:11 ` Sudeep Holla
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1536246639-7420-1-git-send-email-sudeep.holla@arm.com \
--to=sudeep.holla@arm.com \
--cc=arm@kernel.org \
--cc=arnd@arndb.de \
--cc=ionela.voinescu@arm.com \
--cc=khilman@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=olof@lixom.net \
--cc=quentin.perret@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).