Re: x86_64 system call entry points II

Andi Kleen
2006-06-06T05:30:09Z

Martin Bisson <bissonm@discreet.com> writes:
>
> - int $0x80/64 bits: All system calls return -1 (EINTR). Is there
> something wrong in the way I call it:
> pid_t getpid64()
> {
> pid_t resultvar;
>
> asm volatile (
> "int $0x80\n\t"
> : "=a" (resultvar) : "0" (__NR_getpid)
> : "memory");
>
> return resultvar;
> }

I tested it now. Since it ends up as a 32bit syscall you're not
actually calling 64bit getpid() - but 32bit mkdir(). That is because 32bit and 64bit
have different syscall numbers. For me it returns -14, which is EFAULT.
Expected for a random argument to mkdir()

-Andi