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Re: [PATCH 08/15] nios2: Use Linux kABI for syscall return
On 19/02/2020 18:40, Vineet Gupta wrote:
> On 2/10/20 11:20 AM, Adhemerval Zanella wrote:
>> It changes the nios INTERNAL_SYSCALL_RAW macro to return a negative
>> value instead of 'r2' register value on 'err' macro argument.
>>
>> The macro INTERNAL_SYSCALL_DECL is no longer required, and the
>> INTERNAL_SYSCALL_ERROR_P follows the other Linux kABIS.
>>
>> Checked with a build against nios2-linux-gnu.
>> ---
>> sysdeps/unix/sysv/linux/nios2/sysdep.h | 10 +++++-----
>> 1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/sysdeps/unix/sysv/linux/nios2/sysdep.h b/sysdeps/unix/sysv/linux/nios2/sysdep.h
>> index b02730bd23..eab888df32 100644
>> --- a/sysdeps/unix/sysv/linux/nios2/sysdep.h
>> +++ b/sysdeps/unix/sysv/linux/nios2/sysdep.h
>> @@ -157,13 +157,14 @@
>> (int) result_var; })
>>
>> #undef INTERNAL_SYSCALL_DECL
>> -#define INTERNAL_SYSCALL_DECL(err) unsigned int err __attribute__((unused))
>> +#define INTERNAL_SYSCALL_DECL(err) do { } while (0)
>>
>> #undef INTERNAL_SYSCALL_ERROR_P
>> -#define INTERNAL_SYSCALL_ERROR_P(val, err) ((void) (val), (unsigned int) (err))
>> +#define INTERNAL_SYSCALL_ERROR_P(val, err) \
>> + ((unsigned long) (val) >= (unsigned long) -4095)
>>
>> #undef INTERNAL_SYSCALL_ERRNO
>> -#define INTERNAL_SYSCALL_ERRNO(val, err) ((void) (err), val)
>> +#define INTERNAL_SYSCALL_ERRNO(val, err) (-(val))
>>
>> #undef INTERNAL_SYSCALL_RAW
>> #define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \
>> @@ -180,8 +181,7 @@
>> : "+r" (_r2), "=r" (_err) \
>> : ASM_ARGS_##nr \
>> : __SYSCALL_CLOBBERS); \
>> - _sys_result = _r2; \
>> - err = _err; \
>> + _sys_result = _err != 0 ? -_r2 : -_r2; \
>
> Is there a typo here ? both cases seem to be -ve
It is, thanks for catching it. I have pushed b790c8c2ed to fix and
double checked nios2 syscall handling (arch/nios2/kernel/entry.S:205)
to certify that the modification does follow nios2 kABI.