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Date: Mon, 10 Apr 2023 23:27:15 +0200
From: Samuel Thibault <samuel.thibault@gnu.org>
To: Sergey Bugaev <bugaevc@gmail.com>
Cc: libc-alpha@sourceware.org, bug-hurd@gnu.org
Subject: Re: [RFC PATCH 00/34] The rest of the x86_64-gnu port
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Sergey Bugaev, le mar. 11 avril 2023 00:24:55 +0300, a ecrit:
> On Mon, Apr 10, 2023 at 10:20 PM Samuel Thibault
> <samuel.thibault@gnu.org> wrote:
> >
> > Sergey Bugaev, le dim. 19 mars 2023 18:09:43 +0300, a ecrit:
> > > As for sigreturn specifically: I'm concerned about the possibility that
> > > putting the register dump onto the user's stack (or at %rsp - 128, on x86_64)
> > > may clobber the data trampoline.c puts there (unless an altstack is used),
> > > including the very sigcontext.
> >
> > I guess we could make sure that the offset of ctx in stackframe is not
> > hit by data written by sigreturn.c.
> 
> Right; it would be easiest to reserve enough space for the register
> dump at the end of 'struct stackframe', i.e. right after the user's
> stack.

Indeed.

Samuel