1 // SPDX-License-Identifier: GPL-2.0
19  * Will return 0 on success and -1 on failure.
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
26 int read_msr(int cpu, unsigned int idx, unsigned long long *val)  in read_msr()  argument
31 	sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);  in read_msr()
34 		return -1;  in read_msr()
35 	if (lseek(fd, idx, SEEK_CUR) == -1)  in read_msr()
37 	if (read(fd, val, sizeof *val) != sizeof *val)  in read_msr()
43 	return -1;  in read_msr()
49  * Will return 0 on success and -1 on failure.
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
55 int write_msr(int cpu, unsigned int idx, unsigned long long val)  in write_msr()  argument
60 	sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);  in write_msr()
63 		return -1;  in write_msr()
64 	if (lseek(fd, idx, SEEK_CUR) == -1)  in write_msr()
72 	return -1;  in write_msr()
75 unsigned long long msr_intel_get_turbo_ratio(unsigned int cpu)  in msr_intel_get_turbo_ratio()  argument
81 		return -1;  in msr_intel_get_turbo_ratio()
83 	ret = read_msr(cpu, MSR_NEHALEM_TURBO_RATIO_LIMIT, &val);  in msr_intel_get_turbo_ratio()