linux-kernel - [PATCH 2/2] cpufreq: cppc: cppc_cpufreq_get_rate() returns zero in all error cases.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20230815014018.4132350-1-liaochang1@huawei.com>
Date:   Tue, 15 Aug 2023 09:40:17 +0800
From:   Liao Chang <liaochang1@...wei.com>
To:     <rafael@...nel.org>, <viresh.kumar@...aro.org>
CC:     <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] cpufreq: cppc: cppc_cpufreq_get_rate() returns zero in all error cases.

The cpufreq framework used to use the zero of return value to reflect
the cppc_cpufreq_get_rate() had failed to get current frequecy and treat
all positive integer to be succeed. Since cppc_get_perf_ctrs() returns a
negative integer in error case, so it is better to convert the value to
zero as the return value of cppc_cpufreq_get_rate().

Signed-off-by: Liao Chang <liaochang1@...wei.com>
---
 drivers/cpufreq/cppc_cpufreq.c | 4 ++--
 include/linux/cpufreq.h        | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 796bc3e19f77..1cdef2da1ea4 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -854,13 +854,13 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpu)

 	ret = cppc_get_perf_ctrs(cpu, &fb_ctrs_t0);
 	if (ret)
-		return ret;
+		return 0;

 	udelay(2); /* 2usec delay between sampling */

 	ret = cppc_get_perf_ctrs(cpu, &fb_ctrs_t1);
 	if (ret)
-		return ret;
+		return 0;

 	delivered_perf = cppc_perf_from_fbctrs(cpu_data, &fb_ctrs_t0,
 					       &fb_ctrs_t1);
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 172ff51c1b2a..99da27466b8f 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -370,7 +370,7 @@ struct cpufreq_driver {
 	int		(*target_intermediate)(struct cpufreq_policy *policy,
 					       unsigned int index);

-	/* should be defined, if possible */
+	/* should be defined, if possible, return 0 on error */
 	unsigned int	(*get)(unsigned int cpu);

 	/* Called to update policy limits on firmware notifications. */
-- 
2.25.1