--- /dev/null
+/*
+ * (C) 2004-2009 Dominik Brodowski <linux@dominikbrodowski.de>
+ * (C) 2011 Thomas Renninger <trenn@novell.com> Novell Inc.
+ *
+ * Licensed under the terms of the GNU GPL License version 2.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "helpers/sysfs.h"
+
+unsigned int sysfs_read_file(const char *path, char *buf, size_t buflen)
+{
+ int fd;
+ ssize_t numread;
+
+ fd = open(path, O_RDONLY);
+ if (fd == -1)
+ return 0;
+
+ numread = read(fd, buf, buflen - 1);
+ if (numread < 1) {
+ close(fd);
+ return 0;
+ }
+
+ buf[numread] = '\0';
+ close(fd);
+
+ return (unsigned int) numread;
+}
+
+/*
+ * Detect whether a CPU is online
+ *
+ * Returns:
+ * 1 -> if CPU is online
+ * 0 -> if CPU is offline
+ * negative errno values in error case
+ */
+int sysfs_is_cpu_online(unsigned int cpu)
+{
+ char path[SYSFS_PATH_MAX];
+ int fd;
+ ssize_t numread;
+ unsigned long long value;
+ char linebuf[MAX_LINE_LEN];
+ char *endp;
+ struct stat statbuf;
+
+ snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u", cpu);
+
+ if (stat(path, &statbuf) != 0)
+ return 0;
+
+ /*
+ * kernel without CONFIG_HOTPLUG_CPU
+ * -> cpuX directory exists, but not cpuX/online file
+ */
+ snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/online", cpu);
+ if (stat(path, &statbuf) != 0)
+ return 1;
+
+ fd = open(path, O_RDONLY);
+ if (fd == -1)
+ return -errno;
+
+ numread = read(fd, linebuf, MAX_LINE_LEN - 1);
+ if (numread < 1) {
+ close(fd);
+ return -EIO;
+ }
+ linebuf[numread] = '\0';
+ close(fd);
+
+ value = strtoull(linebuf, &endp, 0);
+ if (value > 1)
+ return -EINVAL;
+
+ return value;
+}
+
+/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */
+
+
+/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */
+
+/*
+ * helper function to check whether a file under "../cpuX/cpuidle/stateX/" dir
+ * exists.
+ * For example the functionality to disable c-states was introduced in later
+ * kernel versions, this function can be used to explicitly check for this
+ * feature.
+ *
+ * returns 1 if the file exists, 0 otherwise.
+ */
+unsigned int sysfs_idlestate_file_exists(unsigned int cpu,
+ unsigned int idlestate,
+ const char *fname)
+{
+ char path[SYSFS_PATH_MAX];
+ struct stat statbuf;
+
+
+ snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",
+ cpu, idlestate, fname);
+ if (stat(path, &statbuf) != 0)
+ return 0;
+ return 1;
+}
+
+/*
+ * helper function to read file from /sys into given buffer
+ * fname is a relative path under "cpuX/cpuidle/stateX/" dir
+ * cstates starting with 0, C0 is not counted as cstate.
+ * This means if you want C1 info, pass 0 as idlestate param
+ */
+unsigned int sysfs_idlestate_read_file(unsigned int cpu, unsigned int idlestate,
+ const char *fname, char *buf, size_t buflen)
+{
+ char path[SYSFS_PATH_MAX];
+ int fd;
+ ssize_t numread;
+
+ snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",
+ cpu, idlestate, fname);
+
+ fd = open(path, O_RDONLY);
+ if (fd == -1)
+ return 0;
+
+ numread = read(fd, buf, buflen - 1);
+ if (numread < 1) {
+ close(fd);
+ return 0;
+ }
+
+ buf[numread] = '\0';
+ close(fd);
+
+ return (unsigned int) numread;
+}
+
+/*
+ * helper function to write a new value to a /sys file
+ * fname is a relative path under "../cpuX/cpuidle/cstateY/" dir
+ *
+ * Returns the number of bytes written or 0 on error
+ */
+static
+unsigned int sysfs_idlestate_write_file(unsigned int cpu,
+ unsigned int idlestate,
+ const char *fname,
+ const char *value, size_t len)
+{
+ char path[SYSFS_PATH_MAX];
+ int fd;
+ ssize_t numwrite;
+
+ snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",
+ cpu, idlestate, fname);
+
+ fd = open(path, O_WRONLY);
+ if (fd == -1)
+ return 0;
+
+ numwrite = write(fd, value, len);
+ if (numwrite < 1) {
+ close(fd);
+ return 0;
+ }
+
+ close(fd);
+
+ return (unsigned int) numwrite;
+}
+
+/* read access to files which contain one numeric value */
+
+enum idlestate_value {
+ IDLESTATE_USAGE,
+ IDLESTATE_POWER,
+ IDLESTATE_LATENCY,
+ IDLESTATE_TIME,
+ IDLESTATE_DISABLE,
+ MAX_IDLESTATE_VALUE_FILES
+};
+
+static const char *idlestate_value_files[MAX_IDLESTATE_VALUE_FILES] = {
+ [IDLESTATE_USAGE] = "usage",
+ [IDLESTATE_POWER] = "power",
+ [IDLESTATE_LATENCY] = "latency",
+ [IDLESTATE_TIME] = "time",
+ [IDLESTATE_DISABLE] = "disable",
+};
+
+static unsigned long long sysfs_idlestate_get_one_value(unsigned int cpu,
+ unsigned int idlestate,
+ enum idlestate_value which)
+{
+ unsigned long long value;
+ unsigned int len;
+ char linebuf[MAX_LINE_LEN];
+ char *endp;
+
+ if (which >= MAX_IDLESTATE_VALUE_FILES)
+ return 0;
+
+ len = sysfs_idlestate_read_file(cpu, idlestate,
+ idlestate_value_files[which],
+ linebuf, sizeof(linebuf));
+ if (len == 0)
+ return 0;
+
+ value = strtoull(linebuf, &endp, 0);
+
+ if (endp == linebuf || errno == ERANGE)
+ return 0;
+
+ return value;
+}
+
+/* read access to files which contain one string */
+
+enum idlestate_string {
+ IDLESTATE_DESC,
+ IDLESTATE_NAME,
+ MAX_IDLESTATE_STRING_FILES
+};
+
+static const char *idlestate_string_files[MAX_IDLESTATE_STRING_FILES] = {
+ [IDLESTATE_DESC] = "desc",
+ [IDLESTATE_NAME] = "name",
+};
+
+
+static char *sysfs_idlestate_get_one_string(unsigned int cpu,
+ unsigned int idlestate,
+ enum idlestate_string which)
+{
+ char linebuf[MAX_LINE_LEN];
+ char *result;
+ unsigned int len;
+
+ if (which >= MAX_IDLESTATE_STRING_FILES)
+ return NULL;
+
+ len = sysfs_idlestate_read_file(cpu, idlestate,
+ idlestate_string_files[which],
+ linebuf, sizeof(linebuf));
+ if (len == 0)
+ return NULL;
+
+ result = strdup(linebuf);
+ if (result == NULL)
+ return NULL;
+
+ if (result[strlen(result) - 1] == '\n')
+ result[strlen(result) - 1] = '\0';
+
+ return result;
+}
+
+/*
+ * Returns:
+ * 1 if disabled
+ * 0 if enabled
+ * -1 if idlestate is not available
+ * -2 if disabling is not supported by the kernel
+ */
+int sysfs_is_idlestate_disabled(unsigned int cpu,
+ unsigned int idlestate)
+{
+ if (sysfs_get_idlestate_count(cpu) <= idlestate)
+ return -1;
+
+ if (!sysfs_idlestate_file_exists(cpu, idlestate,
+ idlestate_value_files[IDLESTATE_DISABLE]))
+ return -2;
+ return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_DISABLE);
+}
+
+/*
+ * Pass 1 as last argument to disable or 0 to enable the state
+ * Returns:
+ * 0 on success
+ * negative values on error, for example:
+ * -1 if idlestate is not available
+ * -2 if disabling is not supported by the kernel
+ * -3 No write access to disable/enable C-states
+ */
+int sysfs_idlestate_disable(unsigned int cpu,
+ unsigned int idlestate,
+ unsigned int disable)
+{
+ char value[SYSFS_PATH_MAX];
+ int bytes_written;
+
+ if (sysfs_get_idlestate_count(cpu) <= idlestate)
+ return -1;
+
+ if (!sysfs_idlestate_file_exists(cpu, idlestate,
+ idlestate_value_files[IDLESTATE_DISABLE]))
+ return -2;
+
+ snprintf(value, SYSFS_PATH_MAX, "%u", disable);
+
+ bytes_written = sysfs_idlestate_write_file(cpu, idlestate, "disable",
+ value, sizeof(disable));
+ if (bytes_written)
+ return 0;
+ return -3;
+}
+
+unsigned long sysfs_get_idlestate_latency(unsigned int cpu,
+ unsigned int idlestate)
+{
+ return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_LATENCY);
+}
+
+unsigned long sysfs_get_idlestate_usage(unsigned int cpu,
+ unsigned int idlestate)
+{
+ return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_USAGE);
+}
+
+unsigned long long sysfs_get_idlestate_time(unsigned int cpu,
+ unsigned int idlestate)
+{
+ return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_TIME);
+}
+
+char *sysfs_get_idlestate_name(unsigned int cpu, unsigned int idlestate)
+{
+ return sysfs_idlestate_get_one_string(cpu, idlestate, IDLESTATE_NAME);
+}
+
+char *sysfs_get_idlestate_desc(unsigned int cpu, unsigned int idlestate)
+{
+ return sysfs_idlestate_get_one_string(cpu, idlestate, IDLESTATE_DESC);
+}
+
+/*
+ * Returns number of supported C-states of CPU core cpu
+ * Negativ in error case
+ * Zero if cpuidle does not export any C-states
+ */
+unsigned int sysfs_get_idlestate_count(unsigned int cpu)
+{
+ char file[SYSFS_PATH_MAX];
+ struct stat statbuf;
+ int idlestates = 1;
+
+
+ snprintf(file, SYSFS_PATH_MAX, PATH_TO_CPU "cpuidle");
+ if (stat(file, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode))
+ return 0;
+
+ snprintf(file, SYSFS_PATH_MAX, PATH_TO_CPU "cpu%u/cpuidle/state0", cpu);
+ if (stat(file, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode))
+ return 0;
+
+ while (stat(file, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
+ snprintf(file, SYSFS_PATH_MAX, PATH_TO_CPU
+ "cpu%u/cpuidle/state%d", cpu, idlestates);
+ idlestates++;
+ }
+ idlestates--;
+ return idlestates;
+}
+
+/* CPUidle general /sys/devices/system/cpu/cpuidle/ sysfs access ********/
+
+/*
+ * helper function to read file from /sys into given buffer
+ * fname is a relative path under "cpu/cpuidle/" dir
+ */
+static unsigned int sysfs_cpuidle_read_file(const char *fname, char *buf,
+ size_t buflen)
+{
+ char path[SYSFS_PATH_MAX];
+
+ snprintf(path, sizeof(path), PATH_TO_CPU "cpuidle/%s", fname);
+
+ return sysfs_read_file(path, buf, buflen);
+}
+
+
+
+/* read access to files which contain one string */
+
+enum cpuidle_string {
+ CPUIDLE_GOVERNOR,
+ CPUIDLE_GOVERNOR_RO,
+ CPUIDLE_DRIVER,
+ MAX_CPUIDLE_STRING_FILES
+};
+
+static const char *cpuidle_string_files[MAX_CPUIDLE_STRING_FILES] = {
+ [CPUIDLE_GOVERNOR] = "current_governor",
+ [CPUIDLE_GOVERNOR_RO] = "current_governor_ro",
+ [CPUIDLE_DRIVER] = "current_driver",
+};
+
+
+static char *sysfs_cpuidle_get_one_string(enum cpuidle_string which)
+{
+ char linebuf[MAX_LINE_LEN];
+ char *result;
+ unsigned int len;
+
+ if (which >= MAX_CPUIDLE_STRING_FILES)
+ return NULL;
+
+ len = sysfs_cpuidle_read_file(cpuidle_string_files[which],
+ linebuf, sizeof(linebuf));
+ if (len == 0)
+ return NULL;
+
+ result = strdup(linebuf);
+ if (result == NULL)
+ return NULL;
+
+ if (result[strlen(result) - 1] == '\n')
+ result[strlen(result) - 1] = '\0';
+
+ return result;
+}
+
+char *sysfs_get_cpuidle_governor(void)
+{
+ char *tmp = sysfs_cpuidle_get_one_string(CPUIDLE_GOVERNOR_RO);
+ if (!tmp)
+ return sysfs_cpuidle_get_one_string(CPUIDLE_GOVERNOR);
+ else
+ return tmp;
+}
+
+char *sysfs_get_cpuidle_driver(void)
+{
+ return sysfs_cpuidle_get_one_string(CPUIDLE_DRIVER);
+}
+/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */
+
+/*
+ * Get sched_mc or sched_smt settings
+ * Pass "mc" or "smt" as argument
+ *
+ * Returns negative value on failure
+ */
+int sysfs_get_sched(const char *smt_mc)
+{
+ return -ENODEV;
+}
+
+/*
+ * Get sched_mc or sched_smt settings
+ * Pass "mc" or "smt" as argument
+ *
+ * Returns negative value on failure
+ */
+int sysfs_set_sched(const char *smt_mc, int val)
+{
+ return -ENODEV;
+}
Code Review / kvmfornfv.git / blobdiff