linux 读取物理寄存器

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

int main(int argc, void** argv) {
void* base;
int fd, reg;

fd = open("/dev/mem", O_RDWR | O_SYNC);
if (fd < 0) {
printf("ERR: device open failed. ");
return -1;
}

base = mmap(NULL, 0x1000, PROT_READ, MAP_SHARED, fd, 0x20E0000);
if (base == 0) {
printf("ERR: mmap failed. ");
close(fd);
return -1;
}

if (argc > 1) {
reg = strtol(argv[1], NULL, 16);
printf(">>> %08X is %08X ", 0x20E0000 + reg, *((unsigned int*)(base + reg)));
}
munmap(base, 0x1000);
close(fd);
return 0;
}