[PATCH 11/12] RISC-V: Linux ABI

[Florian Weimer]

On 06/20/2017 11:29 PM, Palmer Dabbelt wrote:
> On Wed, 14 Jun 2017 13:39:50 PDT (-0700), fweimer@redhat.com wrote:
>> Palmer Dabbelt <palmer@dabbelt.com> writes:
>>
>>> Linux-specific code that is required for maintaining ABI compatibility.
>>> This doesn't contain the actual system call interface, that is split out
>>> in order to avoid having a patch that's too big.
>>
>> You likely need to override bits/sigstack.h in one of these patches
>> because the generic MINSIGSTKSZ and SIGSTKSZ values are likely too
>> small, especially if you want to add more or broader vector registers in
>> the future.
>>
>> PTHREAD_STACK_MIN might warrant adjustment, too.
> 
> We're going to pick the most common values, which I believe are
> 
>   MINSIGSTKSZ = 4KiB (alpha, powerpc, sparc, with aarch64 setting 5KiB)

You need to check what your architecture actually needs: the amount of
data pushed by the kernel, and it's also good to take into account the
save area used by the dynamic linker trampoline.  Then maybe add a
couple of kilobytes so that there is room for some actually work
performed by the application signal handler.

Thanks,
Florian