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88 lines
1.8 KiB
88 lines
1.8 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#if defined(__i386__) || defined(__x86_64__) |
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#include <fcntl.h> |
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#include <stdio.h> |
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#include <unistd.h> |
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#include <stdint.h> |
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#include "helpers/helpers.h" |
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/* Intel specific MSRs */ |
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#define MSR_IA32_PERF_STATUS 0x198 |
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#define MSR_IA32_MISC_ENABLES 0x1a0 |
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#define MSR_NEHALEM_TURBO_RATIO_LIMIT 0x1ad |
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/* |
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* read_msr |
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* |
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* Will return 0 on success and -1 on failure. |
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* Possible errno values could be: |
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* EFAULT -If the read/write did not fully complete |
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* EIO -If the CPU does not support MSRs |
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* ENXIO -If the CPU does not exist |
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*/ |
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int read_msr(int cpu, unsigned int idx, unsigned long long *val) |
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{ |
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int fd; |
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char msr_file_name[64]; |
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sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu); |
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fd = open(msr_file_name, O_RDONLY); |
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if (fd < 0) |
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return -1; |
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if (lseek(fd, idx, SEEK_CUR) == -1) |
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goto err; |
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if (read(fd, val, sizeof *val) != sizeof *val) |
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goto err; |
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close(fd); |
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return 0; |
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err: |
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close(fd); |
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return -1; |
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} |
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/* |
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* write_msr |
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* |
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* Will return 0 on success and -1 on failure. |
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* Possible errno values could be: |
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* EFAULT -If the read/write did not fully complete |
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* EIO -If the CPU does not support MSRs |
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* ENXIO -If the CPU does not exist |
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*/ |
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int write_msr(int cpu, unsigned int idx, unsigned long long val) |
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{ |
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int fd; |
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char msr_file_name[64]; |
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sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu); |
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fd = open(msr_file_name, O_WRONLY); |
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if (fd < 0) |
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return -1; |
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if (lseek(fd, idx, SEEK_CUR) == -1) |
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goto err; |
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if (write(fd, &val, sizeof val) != sizeof val) |
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goto err; |
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close(fd); |
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return 0; |
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err: |
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close(fd); |
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return -1; |
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} |
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unsigned long long msr_intel_get_turbo_ratio(unsigned int cpu) |
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{ |
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unsigned long long val; |
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int ret; |
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if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_HAS_TURBO_RATIO)) |
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return -1; |
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ret = read_msr(cpu, MSR_NEHALEM_TURBO_RATIO_LIMIT, &val); |
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if (ret) |
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return ret; |
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return val; |
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} |
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#endif
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