Date: Thu, 2 Sep 2010 08:16:59 -0400 From: John Baldwin <jhb@freebsd.org> To: David Xu <davidxu@freebsd.org> Cc: Kostik Belousov <kostikbel@gmail.com>, svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r212076 - head/lib/libthr/thread Message-ID: <201009020816.59745.jhb@freebsd.org> In-Reply-To: <4C7F8C28.50309@freebsd.org> References: <201009010218.o812IX5G048257@svn.freebsd.org> <201009020639.47198.jhb@freebsd.org> <4C7F8C28.50309@freebsd.org>
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On Thursday, September 02, 2010 7:36:08 am David Xu wrote:
> John Baldwin wrote:
> > On Thursday, September 02, 2010 6:22:18 am Kostik Belousov wrote:
> >
> >> On Thu, Sep 02, 2010 at 05:35:39PM +0000, David Xu wrote:
> >>
> >>> Kostik Belousov wrote:
> >>>
> >>>
> >>>>> the tf_err may not be equal to ksi_addr! This may need to be fixed.
> >>>>>
> >>>>>
> >>>> The change was introduced by
> >>>> r151316 | davidxu | 2005-10-14
> >>>> /* Old FreeBSD-style arguments. */
> >>>> - sf.sf_siginfo = code;
> >>>> - sf.sf_addr = regs->tf_err;
> >>>> + sf.sf_siginfo = ksi->ksi_code;
> >>>> + sf.sf_addr = (register_t)ksi->ksi_addr;
> >>>> sf.sf_ahu.sf_handler = catcher;
> >>>>
> >>>>
> >>> :(
> >>>
> >> The rollback looks straightforward. I explicitely decided to not change
> >> any architecture that is not i386.
> >>
> >
> > It may not be this simple. At one point we had a "feature" where we
trashed
> > tf_err in the trapframe to store the address so it could be passed to
sendsig
> > for this purpose. I think once we started using ksi_addr here we removed
the
> > trashing of tf_err as it was no longer necessary.
> >
> >
> I saw RELENG_5 saved it at td_md.md_fault_address, but I really can not
> remember
> which version has such "feature". ;-)
> By the way, I still can not find a modern program uses this old style
> and wants to
> know the exact fault address.
> Kostik Belousov fixed the error I had made when I was implementing
> signal queue.
See revision 170688 for example:
r170688 | jhb | 2007-06-13 18:37:48 -0400 (Wed, 13 Jun 2007) | 6 lines
Don't clobber tf_err with the eva from a page fault as the page fault
address is saved in ksi_addr already.
PR: i386/101379
Submitted by: Tijl Coosemans : tijl ulyssis org
Index: trap.c
===================================================================
--- trap.c (revision 170687)
+++ trap.c (revision 170688)
@@ -785,9 +785,6 @@
return (-1);
}
- /* kludge to pass faulting virtual address to sendsig */
- frame->tf_err = eva;
-
return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
}
Given that, I think the existing code is correct and that there is no bug to
be fixed.
--
John Baldwin
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