Re: [PATCH v4 16/36] nds32: System calls handling

[Vincent Chen]

2017-12-18 19:19 GMT+08:00 Arnd Bergmann <arnd@xxxxxxxx>:
> On Mon, Dec 18, 2017 at 7:46 AM, Greentime Hu <green.hu@xxxxxxxxx> wrote:
>
>
>> new file mode 100644
>> index 0000000..90da745
>> --- /dev/null
>> +++ b/arch/nds32/include/uapi/asm/unistd.h
>> @@ -0,0 +1,12 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +// Copyright (C) 2005-2017 Andes Technology Corporation
>> +
>> +#define __ARCH_WANT_SYNC_FILE_RANGE2
>> +
>> +/* Use the standard ABI for syscalls */
>> +#include <asm-generic/unistd.h>
>> +
>> +/* Additional NDS32 specific syscalls. */
>> +#define __NR_cacheflush                (__NR_arch_specific_syscall)
>> +#define __NR__llseek             __NR_llseek
>> +__SYSCALL(__NR_cacheflush, sys_cacheflush)
>
> I'm still confused by __NR__llseek here, why do you need that one?
>

Dear Arnd:
We hoped to solve  ABI register alignment problem for llseek in glibc
by __NR__llseek.
After checking glibc again, I find glibc has same __NR__llseek macro
and It's better to solve this problem.
So, I will remove this definition in the next version patch.


>> +SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
>> +              unsigned long, prot, unsigned long, flags,
>> +              unsigned long, fd, unsigned long, pgoff)
>> +{
>> +       if (pgoff & (~PAGE_MASK >> 12))
>> +               return -EINVAL;
>> +
>> +       return sys_mmap_pgoff(addr, len, prot, flags, fd,
>> +                             pgoff >> (PAGE_SHIFT - 12));
>> +}
>> +
>> +SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
>> +              unsigned long, prot, unsigned long, flags,
>> +              unsigned long, fd, unsigned long, pgoff)
>> +{
>> +       if (unlikely(pgoff & ~PAGE_MASK))
>> +               return -EINVAL;
>> +
>> +       return sys_mmap_pgoff(addr, len, prot, flags, fd,
>> +                             pgoff >> PAGE_SHIFT);
>> +}
>
> And I don't see why you define sys_mmap() in addition to sys_mmap2().
>
This is my mistake. I will remove it in the next version patch.

> The rest of the syscall handling looks good now.
>
>          Arnd


Thanks
Vincent