1 #if defined(__i386__) || defined(__x86_64__) 2 3 #include <fcntl.h> 4 #include <stdio.h> 5 #include <unistd.h> 6 #include <stdint.h> 7 8 #include "helpers/helpers.h" 9 10 /* Intel specific MSRs */ 11 #define MSR_IA32_PERF_STATUS 0x198 12 #define MSR_IA32_MISC_ENABLES 0x1a0 13 #define MSR_IA32_ENERGY_PERF_BIAS 0x1b0 14 #define MSR_NEHALEM_TURBO_RATIO_LIMIT 0x1ad 15 16 /* 17 * read_msr 18 * 19 * Will return 0 on success and -1 on failure. 20 * Possible errno values could be: 21 * EFAULT -If the read/write did not fully complete 22 * EIO -If the CPU does not support MSRs 23 * ENXIO -If the CPU does not exist 24 */ 25 26 int read_msr(int cpu, unsigned int idx, unsigned long long *val) 27 { 28 int fd; 29 char msr_file_name[64]; 30 31 sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu); 32 fd = open(msr_file_name, O_RDONLY); 33 if (fd < 0) 34 return -1; 35 if (lseek(fd, idx, SEEK_CUR) == -1) 36 goto err; 37 if (read(fd, val, sizeof *val) != sizeof *val) 38 goto err; 39 close(fd); 40 return 0; 41 err: 42 close(fd); 43 return -1; 44 } 45 46 /* 47 * write_msr 48 * 49 * Will return 0 on success and -1 on failure. 50 * Possible errno values could be: 51 * EFAULT -If the read/write did not fully complete 52 * EIO -If the CPU does not support MSRs 53 * ENXIO -If the CPU does not exist 54 */ 55 int write_msr(int cpu, unsigned int idx, unsigned long long val) 56 { 57 int fd; 58 char msr_file_name[64]; 59 60 sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu); 61 fd = open(msr_file_name, O_WRONLY); 62 if (fd < 0) 63 return -1; 64 if (lseek(fd, idx, SEEK_CUR) == -1) 65 goto err; 66 if (write(fd, &val, sizeof val) != sizeof val) 67 goto err; 68 close(fd); 69 return 0; 70 err: 71 close(fd); 72 return -1; 73 } 74 75 int msr_intel_get_perf_bias(unsigned int cpu) 76 { 77 unsigned long long val; 78 int ret; 79 80 if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS)) 81 return -1; 82 83 ret = read_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, &val); 84 if (ret) 85 return ret; 86 return val; 87 } 88 89 int msr_intel_set_perf_bias(unsigned int cpu, unsigned int val) 90 { 91 int ret; 92 93 if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS)) 94 return -1; 95 96 ret = write_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, val); 97 if (ret) 98 return ret; 99 return 0; 100 } 101 102 unsigned long long msr_intel_get_turbo_ratio(unsigned int cpu) 103 { 104 unsigned long long val; 105 int ret; 106 107 if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_HAS_TURBO_RATIO)) 108 return -1; 109 110 ret = read_msr(cpu, MSR_NEHALEM_TURBO_RATIO_LIMIT, &val); 111 if (ret) 112 return ret; 113 return val; 114 } 115 #endif 116