tools/power x86_energy_perf_policy: Enhances SoC Slider related checks

When processor_thermal_soc_slider is loaded, its slider
and offset modparams are visible.  Check that the driver
actually registered the profile named "SoC Slider" before
reading or writing these modparams.

n.b. This utility allows writing the Slider and Offset modparams
even if the driver policy is not "balanced".  Currently the
processor_thermal_soc_slider consults those modparams
only in "balanced" mode.

Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 104 insertions, 38 deletions

diff --git a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
index 1f330c82d7c1..83e5adbcda69 100644
--- a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
+++ b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
@@ -104,9 +104,14 @@ char platform_profile[64];
 #define PATH_SOC_SLIDER_BALANCE "/sys/module/processor_thermal_soc_slider/parameters/slider_balance"
 #define PATH_SOC_SLIDER_OFFSET "/sys/module/processor_thermal_soc_slider/parameters/slider_offset"
 #define PATH_PLATFORM_PROFILE "/sys/class/platform-profile/platform-profile-0/profile"
+#define PATH_PLATFORM_PROFILE_NAME "/sys/class/platform-profile/platform-profile-0/name"
+#define POWER_SLIDER_NAME "SoC Power Slider"
 
 static int use_android_msr_path;
 
+static unsigned int read_sysfs(const char *, char *, size_t);
+static int sysfs_read_string(const char *, char *, size_t);
+
 /*
  * maintain compatibility with original implementation, but don't document it:
  */
@@ -551,39 +556,91 @@ void print_version(void)
 	printf("x86_energy_perf_policy 2025.11.22 Len Brown <lenb@kernel.org>\n");
 }
 
+static int platform_profile_access(int mode)
+{
+	if (access(PATH_PLATFORM_PROFILE, mode)) {
+		if (debug)
+			fprintf(stderr, "Can not access %s\n", PATH_PLATFORM_PROFILE);
+		return 0;
+	}
+
+	return 1;
+}
+
+static int platform_profile_name_is(char *name)
+{
+	char buf[64];
+
+	if (sysfs_read_string(PATH_PLATFORM_PROFILE_NAME, buf, sizeof(buf)) != 0) {
+		if (debug)
+			fprintf(stderr, "Can not read %s\n", PATH_PLATFORM_PROFILE_NAME);
+		return 0;
+	}
+
+	if (strncmp(buf, name, 16)) {
+		if (debug)
+			fprintf(stderr, "%s does not match '%s'\n", PATH_PLATFORM_PROFILE_NAME, name);
+		return 0;
+	}
+
+	return 1;
+}
+
+static int soc_slider_access(int mode)
+{
+	if (!platform_profile_access(R_OK))
+		return 0;
+
+	if (!platform_profile_name_is(POWER_SLIDER_NAME))
+		return 0;
+
+	if (access(PATH_SOC_SLIDER_BALANCE, mode)) {
+		if (debug)
+			fprintf(stderr, "Can not access %s\n", PATH_SOC_SLIDER_BALANCE);
+		return 0;
+	}
+
+	if (access(PATH_SOC_SLIDER_OFFSET, mode)) {
+		if (debug)
+			fprintf(stderr, "Can not access %s\n", PATH_SOC_SLIDER_OFFSET);
+		return 0;
+	}
+
+	return 1;
+}
+
 void cmdline(int argc, char **argv)
 {
 	int opt;
 	int option_index = 0;
 
 	static struct option long_options[] = {
-		{"all",		required_argument,	0, 'a'},
-		{"cpu",		required_argument,	0, 'c'},
-		{"pkg",		required_argument,	0, 'p'},
-		{"debug",	no_argument,		0, 'd'},
-		{"hwp-desired",	required_argument,	0, 'D'},
-		{"epb",	required_argument,	0, 'B'},
-		{"force",	no_argument,	0, 'f'},
-		{"hwp-enable",	no_argument,	0, 'e'},
-		{"help",	no_argument,	0, 'h'},
-		{"hwp-epp",	required_argument,	0, 'P'},
-		{"hwp-min",	required_argument,	0, 'm'},
-		{"hwp-max",	required_argument,	0, 'M'},
-		{"read",	no_argument,		0, 'r'},
-		{"turbo-enable",	required_argument,	0, 't'},
-		{"hwp-use-pkg",	required_argument,	0, 'u'},
-		{"version",	no_argument,		0, 'v'},
-		{"hwp-window",	required_argument,	0, 'w'},
-		{"soc-slider-balance", required_argument, 0, 'S'},
-		{"soc-slider-offset",  required_argument, 0, 'O'},
-		{"platform-profile",   required_argument, 0, 'F'},
-		{0,		0,			0, 0 }
+		{ "all", required_argument, 0, 'a' },
+		{ "cpu", required_argument, 0, 'c' },
+		{ "pkg", required_argument, 0, 'p' },
+		{ "debug", no_argument, 0, 'd' },
+		{ "hwp-desired", required_argument, 0, 'D' },
+		{ "epb", required_argument, 0, 'B' },
+		{ "force", no_argument, 0, 'f' },
+		{ "hwp-enable", no_argument, 0, 'e' },
+		{ "help", no_argument, 0, 'h' },
+		{ "hwp-epp", required_argument, 0, 'P' },
+		{ "hwp-min", required_argument, 0, 'm' },
+		{ "hwp-max", required_argument, 0, 'M' },
+		{ "read", no_argument, 0, 'r' },
+		{ "turbo-enable", required_argument, 0, 't' },
+		{ "hwp-use-pkg", required_argument, 0, 'u' },
+		{ "version", no_argument, 0, 'v' },
+		{ "hwp-window", required_argument, 0, 'w' },
+		{ "soc-slider-balance", required_argument, 0, 'S' },
+		{ "soc-slider-offset", required_argument, 0, 'O' },
+		{ "platform-profile", required_argument, 0, 'F' },
+		{ 0, 0, 0, 0 }
 	};
 
 	progname = argv[0];
 
-	while ((opt = getopt_long_only(argc, argv, "+a:c:dD:E:e:f:m:M:rt:u:vw::S:O:F:",
-				long_options, &option_index)) != -1) {
+	while ((opt = getopt_long_only(argc, argv, "+a:c:dD:E:e:f:m:M:rt:u:vw::S:O:F:", long_options, &option_index)) != -1) {
 		switch (opt) {
 		case 'a':
 			parse_cmdline_all(optarg);
@@ -613,6 +670,8 @@ void cmdline(int argc, char **argv)
 		case 'F':
 			if (strlen(optarg) >= sizeof(platform_profile))
 				errx(1, "--platform-profile: value too long");
+			if (!platform_profile_access(W_OK))
+				errx(1, "Can not update platform-profile in '%s'", PATH_PLATFORM_PROFILE);
 			strcpy(platform_profile, optarg);
 			update_platform_profile = 1;
 			break;
@@ -625,6 +684,8 @@ void cmdline(int argc, char **argv)
 		case 'O':
 			if (parse_cmdline_int(optarg, &soc_slider_offset))
 				errx(1, "--soc-slider-offset: invalid value");
+			if (!soc_slider_access(W_OK))
+				errx(1, "Unable to write SOC Slider Offset");
 			update_soc_slider_offset = 1;
 			break;
 		case 'p':
@@ -639,6 +700,8 @@ void cmdline(int argc, char **argv)
 		case 'S':
 			if (parse_cmdline_int(optarg, &soc_slider_balance))
 				errx(1, "--soc-slider-balance: invalid value");
+			if (!soc_slider_access(W_OK))
+				errx(1, "Unable to write SOC Slider-Balance in '%s'", PATH_SOC_SLIDER_BALANCE);
 			update_soc_slider_balance = 1;
 			break;
 		case 't':
@@ -814,7 +877,8 @@ static unsigned int write_sysfs(const char *path, char *buf, size_t buflen)
 
 	numwritten = write(fd, buf, buflen - 1);
 	if (numwritten < 1) {
-		perror("write failed\n");
+		buf[strcspn(buf, "\n")] = '\0';
+		warn("Write '%s' to '%s' failed", buf, path);
 		close(fd);
 		return -1;
 	}
@@ -972,27 +1036,30 @@ static int set_epb_sysfs(int cpu, int val)
 	return (int)val;
 }
 
-static int soc_slider_available(void)
-{
-	if (access(PATH_SOC_SLIDER_BALANCE, R_OK) &&
-			access(PATH_SOC_SLIDER_OFFSET, R_OK) &&
-			access(PATH_PLATFORM_PROFILE, R_OK))
-		return 0;
-
-	return 1;
-}
-
 static void print_soc_slider(void)
 {
 	char buf[64];
 
-	if (!soc_slider_available())
+	if (!soc_slider_access(R_OK))
 		return;
 
 	if (sysfs_read_string(PATH_SOC_SLIDER_BALANCE, buf, sizeof(buf)) == 0)
 		printf("soc-slider-balance: %s\n", buf);
+
 	if (sysfs_read_string(PATH_SOC_SLIDER_OFFSET, buf, sizeof(buf)) == 0)
 		printf("soc-slider-offset: %s\n", buf);
+}
+
+static void print_platform_profile(void)
+{
+	char buf[64];
+
+	if (!platform_profile_access(R_OK))
+		return;
+
+	if (sysfs_read_string(PATH_PLATFORM_PROFILE_NAME, buf, sizeof(buf)) == 0)
+		printf("platform-profile-name: %s\n", buf);
+
 	if (sysfs_read_string(PATH_PLATFORM_PROFILE, buf, sizeof(buf)) == 0)
 		printf("platform-profile: %s\n", buf);
 }
@@ -1725,13 +1792,12 @@ int main(int argc, char **argv)
 		return -EINVAL;
 
 	/* display information only, no updates to settings */
-	if (!update_epb && !update_turbo && !hwp_update_enabled() &&
-	    !update_soc_slider_balance && !update_soc_slider_offset &&
-	    !update_platform_profile) {
+	if (!update_epb && !update_turbo && !hwp_update_enabled() && !update_soc_slider_balance && !update_soc_slider_offset && !update_platform_profile) {
 		if (cpu_selected_set)
 			for_all_cpus_in_set(cpu_setsize, cpu_selected_set, print_cpu_msrs);
 
 		print_soc_slider();
+		print_platform_profile();
 
 		if (has_hwp_request_pkg) {
 			if (pkg_selected_set == 0)