[LTP] [PATCH] stime: Only o32 system calls require 32-bit programs on mips

[zhanglianjie <zhanglianjie@uniontech.com>]

On 2021-07-20 15:56, Petr Vorel wrote:
> Hi zhanglianjie,
> 
>> The stime() system call is only o32, not n32 and n64. If you do not
>> specify that the current program is compiled to 32-bit when compiling
>> the program on mips, the stime() system call will fail when the
>> program is running.
> You're right that stime() is only on o32. But tst_syscall() should catch that.
> Or does it set different errno than ENOSYS?

The returned errno is EFAULT. The o32 system call of stime is 
implemented on mips, so ENOSYS will not be returned.

COMPAT_SYSCALL_DEFINE1(stime, compat_time_t __user *, tptr)
{
     ...
     if (get_user(tv.tv_sec, tptr))
         return -EFAULT;
     ...
}

The tptr address is in the user space 0x120010da0, and after the system 
call, it is 0x20010da0 in the kernel state, and the upper 32 bits are 
set to 0, resulting in a failure to copy data from the user space to the 
kernel space.

This patch needs to be modified and cannot affect other architectures.

> 
> ...
>> +#if defined(__mips__) && _MIPS_SZLONG == 32
>>   		return tst_syscall(__NR_stime, ntime);
>> +#else
>> +		tst_brk(TCONF, "the stime() syscall only o32 ABI in mips, make sure the current program is 32-bit");
>> +#endif
> 

-- 
Regards,
Zhang Lianjie