102 lines
2.3 KiB
C
102 lines
2.3 KiB
C
#include <fcntl.h>
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#include <inttypes.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#if __LP64__
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#define strtoptr strtoull
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#else
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#define strtoptr strtoul
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#endif
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static int usage()
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{
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fprintf(stderr,"r [-b|-s] <address> [<value>]\n");
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return -1;
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}
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int main(int argc, char *argv[])
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{
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if(argc < 2) return usage();
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int width = 4;
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if(!strcmp(argv[1], "-b")) {
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width = 1;
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argc--;
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argv++;
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} else if(!strcmp(argv[1], "-s")) {
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width = 2;
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argc--;
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argv++;
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}
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if(argc < 2) return usage();
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uintptr_t addr = strtoptr(argv[1], 0, 16);
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uintptr_t endaddr = 0;
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char* end = strchr(argv[1], '-');
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if (end)
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endaddr = strtoptr(end + 1, 0, 16);
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if (!endaddr)
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endaddr = addr + width - 1;
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if (endaddr <= addr) {
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fprintf(stderr, "end address <= start address\n");
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return -1;
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}
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bool set = false;
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uint32_t value = 0;
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if(argc > 2) {
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set = true;
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value = strtoul(argv[2], 0, 16);
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}
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int fd = open("/dev/mem", O_RDWR | O_SYNC);
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if(fd < 0) {
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fprintf(stderr,"cannot open /dev/mem\n");
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return -1;
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}
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off64_t mmap_start = addr & ~(PAGE_SIZE - 1);
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size_t mmap_size = endaddr - mmap_start + 1;
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mmap_size = (mmap_size + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1);
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void* page = mmap64(0, mmap_size, PROT_READ | PROT_WRITE,
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MAP_SHARED, fd, mmap_start);
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if(page == MAP_FAILED){
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fprintf(stderr,"cannot mmap region\n");
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return -1;
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}
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while (addr <= endaddr) {
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switch(width){
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case 4: {
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uint32_t* x = (uint32_t*) (((uintptr_t) page) + (addr & 4095));
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if(set) *x = value;
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fprintf(stderr,"%08"PRIxPTR": %08x\n", addr, *x);
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break;
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}
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case 2: {
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uint16_t* x = (uint16_t*) (((uintptr_t) page) + (addr & 4095));
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if(set) *x = value;
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fprintf(stderr,"%08"PRIxPTR": %04x\n", addr, *x);
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break;
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}
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case 1: {
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uint8_t* x = (uint8_t*) (((uintptr_t) page) + (addr & 4095));
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if(set) *x = value;
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fprintf(stderr,"%08"PRIxPTR": %02x\n", addr, *x);
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break;
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}
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}
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addr += width;
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}
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return 0;
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}
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