Messages in this thread |  | | From | Florian Weimer <> | Subject | Re: [RFC PATCH glibc 09/13] glibc: Perform rseq(2) registration at C startup and thread creation (v13) | Date | Tue, 07 Jan 2020 13:23:59 +0100 |
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* Mathieu Desnoyers:
> Register rseq(2) TLS for each thread (including main), and unregister > for each thread (excluding main). "rseq" stands for Restartable > Sequences. > > See the rseq(2) man page proposed here: > https://lkml.org/lkml/2018/9/19/647 > > This patch is based on glibc-2.30. The rseq(2) system call was merged > into Linux 4.18.
This patch needs to be updated for some be/le abilist splits. Big-endian ABI lists for arm, microblaze, sh, appear to be missing. This is something that can be checked with build-many-glibcs.py.
> diff --git a/manual/threads.texi b/manual/threads.texi > index 0858ef8f92..059f781120 100644 > --- a/manual/threads.texi > +++ b/manual/threads.texi > @@ -881,3 +881,20 @@ Behaves like @code{pthread_timedjoin_np} except that the absolute time in > @c pthread_spin_unlock > @c pthread_testcancel > @c pthread_yield > + > +@node Restartable Sequences > +@section Restartable Sequences > +@cindex rseq > + > +This section describes the @glibcadj{} Restartable Sequences integration. > + > +The @glibcadj{} implements a __rseq_abi TLS symbol to interact with the @Theglibc{} @code{__rseq_abi}
> +Restartable Sequences system call (Linux-specific). The layout of this > +structure is defined by the Linux kernel rseq.h UAPI. Registration of each > +thread's __rseq_abi is performed by @glibcadj{} at libc initialization and @theglibc{} @code{__rseq_abi} > +pthread creation.
> +Each supported architecture provide a RSEQ_SIG signature in sys/rseq.h. That @code{RSEQ_SIG} @file{sys/rseq.h}
> +signature is expected to be present in the code before each Restartable > +Sequences abort handler. Failure to provide the expected signature may > +terminate the process with a Segmentation fault.
Two spaces at the end of setences, please.
The manual should use @deftypevar to create an index entry etc. for __rseq_abi. See argp_program_version for an example of how to do this.
I think current policy is to have documentation for at least the minimum functionality in the manual. I understand that it makes it a lot of work to write patches which add system call wrappers.
Thanks, Florian
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