svn commit: r212076 - head/lib/libthr/thread
David Xu
davidxu at freebsd.org
Thu Sep 2 12:51:58 UTC 2010
John Baldwin wrote:
> 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.
>
>
Thanks for clarifying, I am really confused when Kostik Belousov mailed me,
I wish I had not made the mistake, after all it was 4 years 10 months
ago, so I
can not remember exactly what had happened at that time.
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