lkml.org 
[lkml]   [2020]   [Jun]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/3] glibc: Perform rseq registration at C startup and thread creation (v21)
----- On Jun 24, 2020, at 3:11 PM, Florian Weimer fweimer@redhat.com wrote:

> * Mathieu Desnoyers:
>
>>> I'm still worried that __rseq_static_assert and __rseq_alignof will show
>>> up in the UAPI with textually different definitions. (This does not
>>> apply to __rseq_tls_model_ie.)
>>
>> What makes this worry not apply to __rseq_tls_model_ie ?
>
> It's not needed by the kernel header because it doesn't contain a
> __rseq_abi declaration.
>
>>>
>>> Is my worry unfounded?
>>
>> So AFAIU you worry that eventually sys/rseq.h and linux/rseq.h carry different
>> definitions of __rseq_static_assert and __rseq_alignof.
>>
>> Indeed, I did not surround those #define with #ifndef/#endif. Maybe we should ?
>>
>> Just in case the definitions end up being different (worse case scenario), we
>> should expect their behavior to be pretty much equivalent. So going for the
>> following should address your concern I think:
>
> I think we should keep things simple on the glibc side for now and do
> this changes to the kernel headers first.

Just to be sure I understand what you mean by "keep things simple", do you
recommend removing the following lines completely for now from sys/rseq.h ?

/* Ensure the compiler supports rseq_align. */
__rseq_static_assert (__rseq_alignof (struct rseq_cs) >= 32, "alignment");
__rseq_static_assert (__rseq_alignof (struct rseq) >= 32, "alignment");

Thanks,

Mathieu


--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

\
 
 \ /
  Last update: 2020-06-24 21:17    [W:0.033 / U:0.632 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site