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firmware: arm_scmi: fix divide by zero when sustained_perf_level is zero 

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: a9e3fbfaa0 ("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>
Signed-off-by: Olof Johansson <olof@lixom.net>
This commit is contained in:
Sudeep Holla 2018-09-06 16:10:39 +01:00 committed by Olof Johansson
parent a72b44a871
commit 96d529bac5
1 changed files with 7 additions and 1 deletions
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8
drivers/firmware/arm_scmi/perf.c
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@ -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);
}