linux-kernel - [PATCH v6 1/9] cpufreq: CPPC: Add generic helpers for sysfs show/store

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

Message-ID: <20260120145623.2959636-2-sumitg@nvidia.com>
Date: Tue, 20 Jan 2026 20:26:15 +0530
From: Sumit Gupta <sumitg@...dia.com>
To: <rafael@...nel.org>, <viresh.kumar@...aro.org>, <pierre.gondois@....com>,
	<zhenglifeng1@...wei.com>, <ionela.voinescu@....com>, <lenb@...nel.org>,
	<robert.moore@...el.com>, <corbet@....net>, <rdunlap@...radead.org>,
	<ray.huang@....com>, <gautham.shenoy@....com>, <mario.limonciello@....com>,
	<perry.yuan@....com>, <zhanjie9@...ilicon.com>, <linux-pm@...r.kernel.org>,
	<linux-acpi@...r.kernel.org>, <linux-doc@...r.kernel.org>,
	<acpica-devel@...ts.linux.dev>, <linux-kernel@...r.kernel.org>
CC: <linux-tegra@...r.kernel.org>, <treding@...dia.com>,
	<jonathanh@...dia.com>, <vsethi@...dia.com>, <ksitaraman@...dia.com>,
	<sanjayc@...dia.com>, <nhartman@...dia.com>, <bbasu@...dia.com>,
	<sumitg@...dia.com>
Subject: [PATCH v6 1/9] cpufreq: CPPC: Add generic helpers for sysfs show/store

Add generic helper functions for u64 sysfs attributes that follow the
common pattern of calling CPPC get/set APIs:
- cppc_cpufreq_sysfs_show_u64(): reads value and handles -EOPNOTSUPP
- cppc_cpufreq_sysfs_store_u64(): parses input and calls set function

Add CPPC_CPUFREQ_ATTR_RW_U64() macro to generate show/store functions
using these helpers, reducing boilerplate for simple attributes.

Convert auto_act_window and energy_performance_preference_val to use
the new macro.

No functional changes.

Signed-off-by: Sumit Gupta <sumitg@...dia.com>
---
 drivers/cpufreq/cppc_cpufreq.c | 69 ++++++++++++----------------------
 1 file changed, 25 insertions(+), 44 deletions(-)

diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 36e8a75a37f1..c95dcd7719c3 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -863,73 +863,54 @@ static ssize_t store_auto_select(struct cpufreq_policy *policy,
 	return count;
 }
 
-static ssize_t show_auto_act_window(struct cpufreq_policy *policy, char *buf)
+static ssize_t cppc_cpufreq_sysfs_show_u64(unsigned int cpu,
+					   int (*get_func)(int, u64 *),
+					   char *buf)
 {
 	u64 val;
-	int ret;
-
-	ret = cppc_get_auto_act_window(policy->cpu, &val);
+	int ret = get_func((int)cpu, &val);
 
-	/* show "<unsupported>" when this register is not supported by cpc */
 	if (ret == -EOPNOTSUPP)
 		return sysfs_emit(buf, "<unsupported>\n");
-
 	if (ret)
 		return ret;
 
 	return sysfs_emit(buf, "%llu\n", val);
 }
 
-static ssize_t store_auto_act_window(struct cpufreq_policy *policy,
-				     const char *buf, size_t count)
+static ssize_t cppc_cpufreq_sysfs_store_u64(unsigned int cpu,
+					    int (*set_func)(int, u64),
+					    const char *buf, size_t count)
 {
-	u64 usec;
+	u64 val;
 	int ret;
 
-	ret = kstrtou64(buf, 0, &usec);
+	ret = kstrtou64(buf, 0, &val);
 	if (ret)
 		return ret;
 
-	ret = cppc_set_auto_act_window(policy->cpu, usec);
-	if (ret)
-		return ret;
+	ret = set_func((int)cpu, val);
 
-	return count;
+	return ret ? ret : count;
 }
 
-static ssize_t show_energy_performance_preference_val(struct cpufreq_policy *policy, char *buf)
-{
-	u64 val;
-	int ret;
-
-	ret = cppc_get_epp_perf(policy->cpu, &val);
-
-	/* show "<unsupported>" when this register is not supported by cpc */
-	if (ret == -EOPNOTSUPP)
-		return sysfs_emit(buf, "<unsupported>\n");
-
-	if (ret)
-		return ret;
-
-	return sysfs_emit(buf, "%llu\n", val);
+#define CPPC_CPUFREQ_ATTR_RW_U64(_name, _get_func, _set_func)		\
+static ssize_t show_##_name(struct cpufreq_policy *policy, char *buf)	\
+{									\
+	return cppc_cpufreq_sysfs_show_u64(policy->cpu, _get_func, buf);\
+}									\
+static ssize_t store_##_name(struct cpufreq_policy *policy,		\
+			     const char *buf, size_t count)		\
+{									\
+	return cppc_cpufreq_sysfs_store_u64(policy->cpu, _set_func,	\
+					    buf, count);		\
 }
 
-static ssize_t store_energy_performance_preference_val(struct cpufreq_policy *policy,
-						       const char *buf, size_t count)
-{
-	u64 val;
-	int ret;
+CPPC_CPUFREQ_ATTR_RW_U64(auto_act_window, cppc_get_auto_act_window,
+			 cppc_set_auto_act_window)
 
-	ret = kstrtou64(buf, 0, &val);
-	if (ret)
-		return ret;
-
-	ret = cppc_set_epp(policy->cpu, val);
-	if (ret)
-		return ret;
-
-	return count;
-}
+CPPC_CPUFREQ_ATTR_RW_U64(energy_performance_preference_val,
+			 cppc_get_epp_perf, cppc_set_epp)
 
 cpufreq_freq_attr_ro(freqdomain_cpus);
 cpufreq_freq_attr_rw(auto_select);
-- 
2.34.1