设定： 一个运行busybox-Linux的ARM-CPU（A9）。这个与网络对话并获得预编译的静态链接精灵。 第二个CPU运行裸机应用程序。我在那个上面有newlib，整个“OS”只是执行那个基本程序而在内存中。 两者都分享OCM。
我成功地使两个处理器“对话”。我可以从linux中将十六进制值写入内存，另一个处理器读取它，反之亦然。 现在我想解析前面提到的精灵，将它发送到OCM，让裸机读入它的内存，通过asm设置程序计数器并执行所述elf（也可以使用.o文件）。 我已经陷入了解析精灵的问题......
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <byteswap.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <errno.h>
#include <sys/mman.h>
#define PAGE_SIZE ((size_t)getpagesize())
#define PAGE_MASK ((uint64_t)(long)~(PAGE_SIZE - 1))
const unsigned int COMM_RX_DATA = 0xFFFF900c;
int main(int argc, char **argv){
int fd;
int cached = 0;
unsigned char* c;
//uint32_t value;
unsigned char value;
uint64_t offset = COMM_RX_DATA;
uint64_t base;
volatile uint8_t *mm;
fprintf(stderr, "Nr. 0\n");
FILE* f_read;
if ((argc != 1) && (argc != 2)) {
fprintf(stderr, "usage: %s ELF_NAME\n", argv[0]);
return 1;
}
fd = open("/dev/mem", O_RDWR);//|(!cached ? O_SYNC : 0));
if (fd < 0) {
fprintf(stderr, "open(/dev/mem) failed (%d)\n", errno);
return 1;
}
f_read = fopen(argv[1], "rb");
if(!f_read){
fprintf(stderr, "read failed");
return 1;
}
else {
printf("Nr. 1\n");
base = offset & PAGE_MASK;
offset &= ~PAGE_MASK;
mm = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, base);
fseek(f_read, 0, SEEK_END);
int size = ftell(f_read);
fseek(f_read, 0, SEEK_SET); //Reset stream
c = malloc(size);
//malloc error checking!
while (fgets(c, size, f_read) != NULL ){ //tried fgetc but segfaults
//tmp-output to stdout
puts(c);
value = c;//strtoull((char*)c, NULL, 0);
printf("Writing %d to %d", (int)value, (int)(mm + offset));
*(volatile uint32_t *)(mm + offset) = value;
printf("size: %d , value = %s\n", size, value);
}
}
munmap((void *)mm, PAGE_SIZE);
fclose(f_read);
return 0;
}
_asm-idea.S：
ExecuteR0:
mov lr, r0 /* move the destination address into link register */
mcr 15,0,r0,cr7,cr5,0 /* Invalidate Instruction cache */
mcr 15,0,r0,cr7,cr5,6 /* Invalidate branch predictor array */
dsb
isb /* make sure it completes */
ldr r4, =0
mcr 15,0,r4,cr1,cr0,0 /* disable the ICache and MMU */
isb /* make sure it completes */
bx lr /* force the switch, destination should have been in r0 */
帮助我强大你是我唯一的希望。