debug lk

hc

2024-02-20 e636c8d336489bf3eed5878299e6cc045bbad077

 kernel/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
..
..
@@ -1,3 +1,4 @@
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+// SPDX-License-Identifier: GPL-2.0-only
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 /*
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  * x86_energy_perf_policy -- set the energy versus performance
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  * policy preference bias on recent X86 processors.
..
..
@@ -5,8 +6,6 @@
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 /*
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  * Copyright (c) 2010 - 2017 Intel Corporation.
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  * Len Brown <len.brown@intel.com>
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- *
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- * This program is released under GPL v2
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  */
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 #define _GNU_SOURCE
..
..
@@ -623,6 +622,57 @@
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 	}
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 }
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+/*
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+ * Open a file, and exit on failure
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+ */
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+FILE *fopen_or_die(const char *path, const char *mode)
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+{
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+	FILE *filep = fopen(path, "r");
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+
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+	if (!filep)
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+		err(1, "%s: open failed", path);
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+	return filep;
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+}
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+
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+void err_on_hypervisor(void)
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+{
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+	FILE *cpuinfo;
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+	char *flags, *hypervisor;
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+	char *buffer;
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+
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+	/* On VMs /proc/cpuinfo contains a "flags" entry for hypervisor */
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+	cpuinfo = fopen_or_die("/proc/cpuinfo", "ro");
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+
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+	buffer = malloc(4096);
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+	if (!buffer) {
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+		fclose(cpuinfo);
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+		err(-ENOMEM, "buffer malloc fail");
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+	}
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+
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+	if (!fread(buffer, 1024, 1, cpuinfo)) {
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+		fclose(cpuinfo);
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+		free(buffer);
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+		err(1, "Reading /proc/cpuinfo failed");
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+	}
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+
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+	flags = strstr(buffer, "flags");
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+	rewind(cpuinfo);
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+	fseek(cpuinfo, flags - buffer, SEEK_SET);
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+	if (!fgets(buffer, 4096, cpuinfo)) {
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+		fclose(cpuinfo);
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+		free(buffer);
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+		err(1, "Reading /proc/cpuinfo failed");
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+	}
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+	fclose(cpuinfo);
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+
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+	hypervisor = strstr(buffer, "hypervisor");
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+
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+	free(buffer);
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+
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+	if (hypervisor)
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+		err(-1,
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+		    "not supported on this virtual machine");
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+}
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 int get_msr(int cpu, int offset, unsigned long long *msr)
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 {
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@@ -636,8 +686,10 @@
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 		err(-1, "%s open failed, try chown or chmod +r /dev/cpu/*/msr, or run as root", pathname);
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687
 
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 	retval = pread(fd, msr, sizeof(*msr), offset);
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-	if (retval != sizeof(*msr))
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+	if (retval != sizeof(*msr)) {
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+		err_on_hypervisor();
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 		err(-1, "%s offset 0x%llx read failed", pathname, (unsigned long long)offset);
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+	}
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 	if (debug > 1)
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 		fprintf(stderr, "get_msr(cpu%d, 0x%X, 0x%llX)\n", cpu, offset, *msr);
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@@ -1085,18 +1137,6 @@
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 	update_hwp_request(cpu);
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 	return 0;
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-}
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-
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-/*
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- * Open a file, and exit on failure
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- */
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-FILE *fopen_or_die(const char *path, const char *mode)
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-{
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-	FILE *filep = fopen(path, "r");
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-
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-	if (!filep)
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-		err(1, "%s: open failed", path);
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-	return filep;
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 }
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 unsigned int get_pkg_num(int cpu)