内存验证小程序

简单的验证写入内存和值与读出来的是否相同
64位编译需要加上gcc -D_LARGEFILE64_SOURCE=1， 否则会有编译warning导致后续运行段错误

/* this program write mem with rand numbers,
then read to check it, can be used to check resv mem is ok or not*/

#include <stdio.h>
#include <sys/mman.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>

int main(int argc,char* argv[])
{
    unsigned char* addrbase;
    volatile unsigned char reg_val;
    int memfd = -1;
    errno = 0;
    int i = 0;
    int j = 0;

    if (argc < 5)
        printf("./test phystart(0x800xx) phy_len(0x100000) 1/0(0-read all and print, 1-write and read and check) 5(default wait 5 to check)\n");

    unsigned long start = strtoul(argv[1], NULL, 16);
    unsigned long len = strtoul(argv[2], NULL, 16);
    unsigned long end = start + len;

    int set_flag = atoi(argv[3]);
    int wait_s = atoi(argv[4]);

    printf("phy start=0x%x, end==0x%x, len=0x%x\n", start, end, len);

    srand( (unsigned)time( NULL ) );
    unsigned int rand_base = rand();
    printf("rand() = 0x%x\n", rand_base);

    if ((memfd = open("/dev/mem", O_RDWR )) < 0)
    {
        printf("open /dev/mem error\n");
        return -1;
    }
    if (sizeof(unsigned long) == 4){
        printf("mmap !!!\n");
        addrbase = (unsigned char*)mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, memfd, start);//0x3a800000 start is absolute phy address
    } else {
        printf("mmap64 !!!\n");
        addrbase = (unsigned char*)mmap64(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, memfd, start);
    }
    printf("addrbase=0x%lx\n", addrbase);

    if (set_flag == 0) {
        for (i = 0; i < len ; i++) {
            reg_val = *(addrbase+i);
            printf("[read] i=%d, reg_val=0x%x\n", i, reg_val);
        }
    }



    if (set_flag == 1) {
        printf("before memset, addrbase=0x%lx\n", addrbase);
        for (i = 0; i < 10 ; i++) {
            reg_val = *(addrbase+i);
            printf("[before] i=%d, reg_val=0x%x\n", i, reg_val);
        }
        printf("in memset, addrbase=0x%lx\n", addrbase);
        for (i = 0; i < len; i++) {
            if (i%(1024*1024) == 0) {
                printf(".");
                fflush ( stdout );
            }
            memset((addrbase+i), (rand_base*i)%255, 1);
        }
        printf("waiting %d s to scan mem\n", wait_s);
        sleep(wait_s);
        printf("to scan...\n");
        for (i = 0; i < len ; i++) {
            if (i%(1024*1024) == 0) {
                printf(".");
                fflush ( stdout );
            }
            reg_val = *(addrbase + i);
            if (reg_val != (rand_base*i)%255)
                 printf("[*** after check fail ***] i=%d, reg_val=0x%x, (rand_base*i)%255=0x%x\n", i, reg_val, (rand_base*i)%255);
        }
        printf("check sucess=0x%lx\n", addrbase);
    }
    sleep(1);
    printf("over=0x%lx\n", addrbase);

    if (munmap((void*)addrbase, len))
    {
        printf("munmap fail errno:%d\n", errno);
    }

    close(memfd);

    printf("return sucess!\n");

    return 0;
}