rdmsr.c

/* ----------------------------------------------------------------------- *
 *
 *   Copyright 2000 Transmeta Corporation - All Rights Reserved
 *   Copyright 2004-2008 H. Peter Anvin - All Rights Reserved
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 *   Boston MA 02110-1301, USA; either version 2 of the License, or
 *   (at your option) any later version; incorporated herein by reference.
 *
 * ----------------------------------------------------------------------- */

/*
 * rdmsr.c
 *
 * Utility to read an MSR.
 */

#include <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>

#include "rdmsr.h"

//#include "version.h"

/* Number of decimal digits for a certain number of bits */
/* (int) ceil(log(2^n)/log(10)) */
int decdigits[] = {1,  1,  1,  1,  2,  2,  2,  3,  3,  3,  4,  4,  4,
                   4,  5,  5,  5,  6,  6,  6,  7,  7,  7,  7,  8,  8,
                   8,  9,  9,  9,  10, 10, 10, 10, 11, 11, 11, 12, 12,
                   12, 13, 13, 13, 13, 14, 14, 14, 15, 15, 15, 16, 16,
                   16, 16, 17, 17, 17, 18, 18, 18, 19, 19, 19, 19, 20};

#define mo_hex 0x01
#define mo_dec 0x02
#define mo_oct 0x03
#define mo_raw 0x04
#define mo_uns 0x05
#define mo_chx 0x06
#define mo_mask 0x0f
#define mo_fill 0x40
#define mo_c 0x80

/*void usage(void)*/
/*{*/
/*	fprintf(stderr,*/
/*		"Usage: %s [options] regno\n"*/
/*		"  --help         -h  Print this help\n"*/
/*		"  --version      -V  Print current version\n"*/
/*		"  --hexadecimal  -x  Hexadecimal output (lower case)\n"*/
/*		"  --capital-hex  -X  Hexadecimal output (upper case)\n"*/
/*		"  --decimal      -d  Signed decimal output\n"*/
/*		"  --unsigned     -u  Unsigned decimal output\n"*/
/*		"  --octal        -o  Octal output\n"*/
/*		"  --c-language   -c  Format output as a C language
 * constant\n"*/
/*		"  --zero-pad     -0  Output leading zeroes\n"*/
/*		"  --raw          -r  Raw binary output\n"*/
/*		"  --all          -a  all processors\n"*/
/*		"  --processor #  -p  Select processor number (default 0)\n"*/
/*		"  --bitfield h:l -f  Output bits [h:l] only\n", program);*/
/*}*/

uint64_t rdmsr_on_cpu(uint32_t reg, int cpu);

/*/ * filter out ".", "..", "microcode" in /dev/cpu * /*/
int dir_filter(const struct dirent *dirp);

/*	if (isdigit(dirp->d_name[0]))*/
/*		return 1;*/
/*	else*/
/*		return 0;*/
/*}*/

void rdmsr_on_all_cpus(uint32_t reg) {
    struct dirent **namelist;
    int dir_entries;

    dir_entries = scandir("/dev/cpu", &namelist, dir_filter, 0);
    while (dir_entries--) {
        rdmsr_on_cpu(reg, atoi(namelist[dir_entries]->d_name));
        free(namelist[dir_entries]);
    }
    free(namelist);
}

/*unsigned int highbit = 63, lowbit = 0;*/
/*int mode = mo_hex;*/

/*int main(int argc, char *argv[])*/
/*{*/
/*	uint32_t reg;*/
/*	int c;*/
/*	int cpu = 0;*/
/*	unsigned long arg;*/
/*	char *endarg;*/

/*	program = argv[0];*/

/*	while ((c =*/
/*		getopt_long(argc, argv, short_options, long_options,*/
/*			    NULL)) != -1) {*/
/*		switch (c) {*/
/*		case 'h':*/
/*			usage();*/
/*			exit(0);*/
/*		case 'V':*/
/*			fprintf(stderr, "%s: version %s\n", program,*/
/*				VERSION_STRING);*/
/*			exit(0);*/
/*		case 'x':*/
/*			mode = (mode & ~mo_mask) | mo_hex;*/
/*			break;*/
/*		case 'X':*/
/*			mode = (mode & ~mo_mask) | mo_chx;*/
/*			break;*/
/*		case 'o':*/
/*			mode = (mode & ~mo_mask) | mo_oct;*/
/*			break;*/
/*		case 'd':*/
/*			mode = (mode & ~mo_mask) | mo_dec;*/
/*			break;*/
/*		case 'r':*/
/*			mode = (mode & ~mo_mask) | mo_raw;*/
/*			break;*/
/*		case 'u':*/
/*			mode = (mode & ~mo_mask) | mo_uns;*/
/*			break;*/
/*		case 'c':*/
/*			mode |= mo_c;*/
/*			break;*/
/*		case '0':*/
/*			mode |= mo_fill;*/
/*			break;*/
/*		case 'a':*/
/*			cpu = -1;*/
/*			break;*/
/*		case 'p':*/
/*			arg = strtoul(optarg, &endarg, 0);*/
/*			if (*endarg || arg > 255) {*/
/*				usage();*/
/*				exit(127);*/
/*			}*/
/*			cpu = (int)arg;*/
/*			break;*/
/*		case 'f':*/
/*			if (sscanf(optarg, "%u:%u", &highbit, &lowbit) != 2 ||*/
/*			    highbit > 63 || lowbit > highbit) {*/
/*				usage();*/
/*				exit(127);*/
/*			}*/
/*			break;*/
/*		default:*/
/*			usage();*/
/*			exit(127);*/
/*		}*/
/*	}*/

/*	if (optind != argc - 1) {*/
/*		/ * Should have exactly one argument * /*/
/*		usage();*/
/*		exit(127);*/
/*	}*/

/*	reg = strtoul(argv[optind], NULL, 0);*/

/*	if (cpu == -1) {*/
/*		rdmsr_on_all_cpus(reg);*/
/*	}*/
/*	else*/
/*		rdmsr_on_cpu(reg, cpu);*/
/*	exit(0);*/
/*}*/

uint64_t rdmsr_on_cpu(uint32_t reg, int cpu) {
    uint64_t data;
    int fd;
    // char *pat;
    // int width;
    char msr_file_name[64];
    /*	unsigned int bits;*/

    sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);
    fd = open(msr_file_name, O_RDONLY);
    if (fd < 0) {
        if (errno == ENXIO) {
            fprintf(stderr, "rdmsr: No CPU %d\n", cpu);
            exit(2);
        } else if (errno == EIO) {
            fprintf(stderr, "rdmsr: CPU %d doesn't support MSRs\n", cpu);
            exit(3);
        } else {
            perror("rdmsr: open");
            exit(127);
        }
    }

    if (pread(fd, &data, sizeof data, reg) != sizeof data) {
        if (errno == EIO) {
            fprintf(stderr,
                    "rdmsr: CPU %d cannot read "
                    "MSR 0x%08" PRIx32 "\n",
                    cpu, reg);
            exit(4);
        } else {
            perror("rdmsr: pread");
            exit(127);
        }
    }

    close(fd);

    return data;
}

uint64_t rdmsr_on_cpu_0(uint32_t reg) {
    uint64_t data;
    int cpu = 0;

    // char *pat;
    // int width;
    char *msr_file_name = "/dev/cpu/0/msr";
    /*	unsigned int bits;*/

    // sprintf(msr_file_name, "/dev/cpu/%d/msr", cpu);

    static int fd = -1;

    if (fd < 0) {
        fd = open(msr_file_name, O_RDONLY);
        if (fd < 0) {
            if (errno == ENXIO) {
                fprintf(stderr, "rdmsr: No CPU %d\n", cpu);
                exit(2);
            } else if (errno == EIO) {
                fprintf(stderr, "rdmsr: CPU %d doesn't support MSRs\n", cpu);
                exit(3);
            } else {
                perror("rdmsr: open");
                exit(127);
            }
        }
    }

    if (pread(fd, &data, sizeof data, reg) != sizeof data) {
        if (errno == EIO) {
            fprintf(stderr,
                    "rdmsr: CPU %d cannot read "
                    "MSR 0x%08" PRIx32 "\n",
                    cpu, reg);
            exit(4);
        } else {
            perror("rdmsr: pread");
            exit(127);
        }
    }

    // close(fd);

    return data;
}