cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

powernow-k8-decode.c (1849B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 *  (C) 2004 Bruno Ducrot <ducrot@poupinou.org>
      4 *
      5 * Based on code found in
      6 * linux/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
      7 * and originally developed by Paul Devriendt
      8 */
      9
     10#include <stdio.h>
     11#include <stdlib.h>
     12#include <stdint.h>
     13#include <unistd.h>
     14#include <errno.h>
     15#include <fcntl.h>
     16
     17#include <sys/types.h>
     18#include <sys/stat.h>
     19
     20#define MCPU 32
     21
     22#define MSR_FIDVID_STATUS	0xc0010042
     23
     24#define MSR_S_HI_CURRENT_VID	0x0000001f
     25#define MSR_S_LO_CURRENT_FID	0x0000003f
     26
     27static int get_fidvid(uint32_t cpu, uint32_t *fid, uint32_t *vid)
     28{
     29	int err = 1;
     30	uint64_t msr = 0;
     31	int fd;
     32	char file[20];
     33
     34	if (cpu > MCPU)
     35		goto out;
     36
     37	sprintf(file, "/dev/cpu/%d/msr", cpu);
     38
     39	fd = open(file, O_RDONLY);
     40	if (fd < 0)
     41		goto out;
     42	lseek(fd, MSR_FIDVID_STATUS, SEEK_CUR);
     43	if (read(fd, &msr, 8) != 8)
     44		goto err1;
     45
     46	*fid = ((uint32_t )(msr & 0xffffffffull)) & MSR_S_LO_CURRENT_FID;
     47	*vid = ((uint32_t )(msr>>32 & 0xffffffffull)) & MSR_S_HI_CURRENT_VID;
     48	err = 0;
     49err1:
     50	close(fd);
     51out:
     52	return err;
     53}
     54
     55
     56/* Return a frequency in MHz, given an input fid */
     57static uint32_t find_freq_from_fid(uint32_t fid)
     58{
     59	return 800 + (fid * 100);
     60}
     61
     62/* Return a voltage in miliVolts, given an input vid */
     63static uint32_t find_millivolts_from_vid(uint32_t vid)
     64{
     65	return 1550-vid*25;
     66}
     67
     68int main (int argc, char *argv[])
     69{
     70	int err;
     71	int cpu;
     72	uint32_t fid, vid;
     73
     74	if (argc < 2)
     75		cpu = 0;
     76	else
     77		cpu = strtoul(argv[1], NULL, 0);
     78
     79	err = get_fidvid(cpu, &fid, &vid);
     80
     81	if (err) {
     82		printf("can't get fid, vid from MSR\n");
     83		printf("Possible trouble: you don't run a powernow-k8 capable cpu\n");
     84		printf("or you are not root, or the msr driver is not present\n");
     85		exit(1);
     86	}
     87
     88	
     89	printf("cpu %d currently at %d MHz and %d mV\n",
     90			cpu,
     91			find_freq_from_fid(fid),
     92			find_millivolts_from_vid(vid));
     93	
     94	return 0;
     95}