Le 05/04/2023 à 13:21, Ding, Shenghao a écrit :
Hi Both
I wrote a test code to verify the be32_to_cpu & be32_to_cpup,
static int __init lkm_init(void)
{
char test_buf[]={0x12, 0x34, 0xab, 0xbc, 0x56, 0x78, 0xef};
unsigned int *k, p, q;
int i;
printk("Hello, Shanghai!\n");
for (i = 0; i < 4; i ++) {
k = (unsigned int *)&test_buf[i];
p = be32_to_cpup((__be32 *)k);
q = be32_to_cpu(test_buf[i]);
printk("%d: *k = 0x%08x p = 0x%08x q = 0x%08x %ld\n",
i, *k, p, q, sizeof(unsigned int));
}
return 0;
}
The output is:
[ 9109.722548] Hello, Shanghai!
[ 9109.726287] 0: *k = 0xbcab3412 p = 0x1234abbc q = 0x12000000 4
[ 9109.727665] 1: *k = 0x56bcab34 p = 0x34abbc56 q = 0x34000000 4
[ 9109.728553] 2: *k = 0x7856bcab p = 0xabbc5678 q = 0xabffffff 4
[ 9109.729308] 3: *k = 0xef7856bc p = 0xbc5678ef q = 0xbcffffff 4
Apparently, be32_to_cpup's output is what I expected.
Looking forward to your comments. Thanks.
Hi,
thanks for the clarification and code sample.
You are right.
I had in mind that something like: be32_to_cpu((__be32 *)data);
would make it. (thanks to the cast)
But because of the need of "&" and "[offset]", it would just make the
code unnecessarily complex.
I think that your approach is better.
CJ
