Re: [PATCH 2/2] gcc: Avoid non-aligned access for ARM5e

[Khem Raj <raj.khem@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 1548 bytes --]


> On Oct 8, 2015, at 9:07 AM, Jens Rehsack <rehsack@gmail.com> wrote:
> 
> 
>> Am 08.10.2015 um 16:46 schrieb Khem Raj <raj.khem@gmail.com>:
>> 
>> 
>>> On Oct 8, 2015, at 7:33 AM, Jens Rehsack <rehsack@gmail.com> wrote:
>>> 
>>> 
>>> [Icedtee Ticket #2153] -- see http://icedtea.classpath.org/bugzilla/show_bug.cgi?id=2153
>>> 
>>> This patch prevents gcc generate code on ARM5e accessing 64 bit values, because gcc doesn't ensure they're 64 bit aligned.
>>> Accessing a 64 bit value from a 32 bit alignment causes segmentation faults.
>>> 
>>> Patch is taken from https://github.com/archlinuxarm/PKGBUILDs/blob/master/core/gcc/0001-ARMv5-disable-LDRD-STRD.patch
>> 
>> Can you try using -mfix-cortex-m3-ldrd, does that help ?
> 
> Well, I have a marvel-kirkwood - I'll give it a shot but don't know whether it works at all.
> 
>> The patch is a workaround to gcc, as it seems real problem is in defining instruction constraints
>> please open a gcc bug for this.
> 
> Dunno whether I want to have all that stress. When neither ARCH linux guys did that nor Icedtea
> maintainers, how could I succeed there?
> 
> Best I can do is (if -mfix-cortex-m3-ldrd doesn't help), keep it private. When -mfix-cortex-m3-ldrd
> helps, is adding it to ./meta/conf/machine/include/tune-arm926ejs.inc a sane approach?

This might be OK. Although I would like to see it fixed in right way in gcc, we don’t want to carry patches
that are not accepted upstream. We already have 60 odd patches and we should reduce them if possible.

[-- Attachment #2: Message signed with OpenPGP using GPGMail --]
[-- Type: application/pgp-signature, Size: 211 bytes --]