Re: nios2: is the ptrace ABI correct?

From: Ley Foon Tan
Date: Wed Mar 11 2015 - 03:48:37 EST


On Tue, Mar 10, 2015 at 2:17 PM, Chung-Lin Tang <cltang@xxxxxxxxxxxxxxxx> wrote:
> On 2015/3/10 10:54 AM, Ley Foon Tan wrote:
>> On Tue, Mar 10, 2015 at 1:05 AM, Ezequiel Garcia
>> <ezequiel@xxxxxxxxxxxxxxxxxxxx> wrote:
>>>
>>>
>>> On 03/09/2015 02:02 PM, Chung-Lin Tang wrote:
>>>> On 2015/3/10 12:54 AM, Chung-Lin Tang wrote:
>>>>> It appears that some of the ways nios2 has organized the
>>>>> ucontext/pt_regs/etc. are remnants of the pre-generic code, some
>>>>> basically because the port was based off m68k.
>>>>>
>>>>> I've re-organized the headers a bit: nios2/include/asm/ucontext.h is
>>>>> deleted, and re-definition of struct sigcontext now allows use of
>>>>> uapi/asm-generic/ucontext.h directly. Note that the reorg, despite
>>>>> effectively renaming some fields, is still binary compatible. I'll
>>>>> probably update the corresponding glibc definitions later.
>>>>>
>>>>> struct pt_regs is now not exported, and all exported register sets are
>>>>> now supposed to follow the 49 register set defined as in GDB now.
>>>>>
>>>>> Tobias, Ley Foon, how do you think this looks?
>>>>
>>>> Sorry, accidentally attached unrelated GCC patch instead, this one's the
>>>> correct one.
>>>>
>>>
>>> Looks good. I'm wondering if...
>>>
>>> +/* User structures for general purpose registers. */
>>> +struct user_pt_regs {
>>> + __u32 regs[49];
>>> };
>>>
>>> Can we expose the registers explicitly here? Like this:
>>>
>>> struct user_pt_regs {
>>> __u32 r0;
>>> __u32 r1;
>>> ...
>>> __u32 sp;
>>> __u32 gp;
>>> __u32 estatus;
>>> };
>>>
>>> It looks self-documenting and thus easier to use.
>>
>> Hi Chung-Lin,
>>
>> Your patch look good to me.
>> Do you have any problem to change the struct user_pt_regs based on
>> Ezequiel's suggestion?
>
> Well, exposing the register names like that sort of defeats the purpose of
> the PTR_* defines.
>
> Judging from the overall trend of style in arch/*/include/uapi/asm/ptrace.h
> across ports, I would prefer to stay with the array field.
>
Okay, I will include your patch.

Regards
Ley Foon
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