From: "H.J. Lu" <hjl.tools@gmail.com>
To: Ramana Radhakrishnan <ramana.gcc@googlemail.com>
Cc: Jeff Law <law@redhat.com>, Cary Coutant <ccoutant@gmail.com>,
Joe Groff <jgroff@apple.com>, Alan Modra <amodra@gmail.com>,
Binutils <binutils@sourceware.org>,
Szabolcs Nagy <szabolcs.nagy@arm.com>
Subject: Re: Preventing preemption of 'protected' symbols in GNU ld 2.26
Date: Thu, 31 Mar 2016 15:05:00 -0000 [thread overview]
Message-ID: <CAMe9rOqTerV+ePFM+PNj+2cBzRf5C0hXmmF4him_bQfkNqp-1g@mail.gmail.com> (raw)
In-Reply-To: <CAJA7tRYqr_8QyjRZ=N5WCxNZ_owoBN_HB0r_F7CigstG-esZKg@mail.gmail.com>
On Thu, Mar 31, 2016 at 6:26 AM, Ramana Radhakrishnan
<ramana.gcc@googlemail.com> wrote:
> On Thu, Mar 31, 2016 at 1:52 AM, Jeff Law <law@redhat.com> wrote:
>> On 03/30/2016 06:40 PM, Cary Coutant wrote:
>>>>
>>>> It would help me immensely on the GCC side if things if you and Alan
>>>> could
>>>> easily summarize correct behavior and the impact if we were to just
>>>> revert
>>>> HJ's change. A testcase would be amazingly helpful too.
>>>
>>>
>>> It looks like it's not just the one change. There's this patch:
>>>
>>> https://gcc.gnu.org/ml/gcc-patches/2015-07/msg01871.html
>>>
>>> which took the idea that protected can still be pre-empted by a COPY
>>> relocation and extended it to three more targets that use COPY
>>> relocations.
>>>
>>> I wonder how many other patches have been based on the same
>>> misunderstanding?
>>
>> I don't think it was many -- I certainly recall the arm/aarch64 variant.
>> There may have been one other varasm.c change in this space or I might be
>> conflating it with the arm/aarch64 change. Tracking those down is naturally
>> part of this work.
>
> The glibc tests elf/tst-protected1{a,b}.c also need to be reviewed at
> the same time. IIUC, the reason the patch above went in were to fix
> failures on arm / aarch64 with those tests. I haven't yet worked out
> whether all this is the same issue.
>
These testcases show the problem between copy relocation and
protected data symbol. I updated my program property extension
to GNU ABI to prevent copy relocation against protected data symbol:
https://sourceware.org/ml/gnu-gabi/2016-q1/msg00041.html
--
H.J.
next prev parent reply other threads:[~2016-03-31 15:05 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <AB592ABD-D6D7-4D2F-A0D6-45738F168DC4@apple.com>
2016-03-29 19:31 ` Fwd: " Joe Groff
2016-03-29 19:33 ` H.J. Lu
2016-03-29 19:36 ` Joe Groff
2016-03-29 19:43 ` H.J. Lu
2016-03-29 19:51 ` Joe Groff
2016-03-29 19:54 ` H.J. Lu
2016-03-29 22:05 ` H.J. Lu
2016-03-30 1:44 ` Alan Modra
2016-03-30 1:46 ` Cary Coutant
2016-03-30 4:04 ` Jeff Law
2016-03-30 7:20 ` Cary Coutant
2016-03-30 7:34 ` Cary Coutant
2016-03-30 14:44 ` Alan Modra
2016-03-31 0:45 ` Cary Coutant
2016-04-15 21:49 ` Preventing preemption of 'protected' symbols in GNU ld 2.26 [aka should we revert the fix for 65248] Jeff Law
2016-04-15 21:56 ` H.J. Lu
2016-04-18 9:02 ` Richard Biener
2016-04-18 14:49 ` Alan Modra
2016-04-18 14:59 ` H.J. Lu
2016-04-18 17:04 ` Maciej W. Rozycki
2016-04-18 17:09 ` H.J. Lu
2016-04-18 17:24 ` Michael Matz
2016-04-18 17:27 ` H.J. Lu
2016-04-18 18:52 ` Jakub Jelinek
2016-04-18 19:28 ` H.J. Lu
2016-04-18 17:55 ` Cary Coutant
2016-04-25 17:24 ` Jeff Law
2016-04-25 17:31 ` H.J. Lu
2016-04-18 17:57 ` Maciej W. Rozycki
2016-04-19 5:08 ` Alan Modra
2016-04-19 8:20 ` Richard Biener
2016-04-19 9:53 ` Szabolcs Nagy
2016-04-19 14:06 ` Michael Matz
2016-04-19 15:37 ` Cary Coutant
2016-04-19 15:44 ` H.J. Lu
2016-04-19 15:52 ` H.J. Lu
2016-04-19 15:54 ` H.J. Lu
2016-04-19 15:58 ` Cary Coutant
2016-04-19 16:00 ` H.J. Lu
2016-04-19 15:54 ` Cary Coutant
2016-04-19 19:11 ` H.J. Lu
2016-04-19 20:17 ` Rich Felker
2016-04-19 21:03 ` Cary Coutant
2016-04-20 17:45 ` anonymous
2016-04-19 15:46 ` Alan Modra
2016-04-25 17:35 ` Jeff Law
2016-04-26 5:55 ` Alan Modra
2016-04-26 8:13 ` Jakub Jelinek
2016-04-18 17:05 ` Cary Coutant
2016-03-31 0:40 ` Preventing preemption of 'protected' symbols in GNU ld 2.26 Cary Coutant
2016-03-31 0:53 ` Jeff Law
2016-03-31 13:27 ` Ramana Radhakrishnan
2016-03-31 15:05 ` H.J. Lu [this message]
2016-04-15 16:10 ` Szabolcs Nagy
2016-04-01 19:51 ` Jeff Law
2016-04-02 2:53 ` Alan Modra
2016-04-19 19:47 ` Fwd: " Rich Felker
2016-04-15 16:16 H.J. Lu
2016-04-15 16:36 ` Jeff Law
2016-04-15 16:45 ` H.J. Lu
2016-04-15 16:43 ` Szabolcs Nagy
2016-04-15 23:59 ` Maciej W. Rozycki
2016-04-16 1:08 ` Szabolcs Nagy
-- strict thread matches above, loose matches on Subject: below --
2016-03-24 0:00 Joe Groff
2016-03-24 0:45 ` H.J. Lu
2016-03-24 0:52 ` Joe Groff
2016-03-24 1:25 ` H.J. Lu
2016-03-24 15:01 ` Cary Coutant
2016-03-24 15:07 ` H.J. Lu
2016-03-24 16:06 ` Cary Coutant
2016-03-24 16:42 ` H.J. Lu
2016-03-24 16:56 ` Cary Coutant
2016-03-24 17:05 ` H.J. Lu
2016-03-24 17:06 ` Joe Groff
2016-03-24 17:09 ` H.J. Lu
2016-03-24 18:31 ` Cary Coutant
2016-03-27 16:26 ` Rafael Espíndola
2016-03-28 12:12 ` H.J. Lu
[not found] ` <BC969B3B-87A2-4238-90C8-DA2E166707AF@apple.com>
2016-03-28 17:03 ` Joe Groff
2016-03-28 17:17 ` H.J. Lu
2016-03-28 22:22 ` Cary Coutant
2016-03-28 22:24 ` Joe Groff
2016-03-28 22:38 ` Cary Coutant
2016-03-28 22:41 ` Joe Groff
2016-03-28 23:21 ` Alan Modra
2016-03-29 0:29 ` Cary Coutant
2016-03-29 15:44 ` H.J. Lu
2016-03-28 22:12 ` Cary Coutant
2016-03-29 12:40 ` Maciej W. Rozycki
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