From: Alan Modra <amodra@gmail.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH] powerpc: Work around gcc miscompilation of __pa() on 64-bit
Date: Mon, 2 Sep 2013 12:01:10 +0930 [thread overview]
Message-ID: <20130902023110.GV3430@bubble.grove.modra.org> (raw)
In-Reply-To: <1378079952.3978.15.camel@pasglop>
On Mon, Sep 02, 2013 at 09:59:12AM +1000, Benjamin Herrenschmidt wrote:
> On Tue, 2013-08-27 at 16:42 +0930, Alan Modra wrote:
> > The proper fix is to define a whole slew of new relocations and reloc
> > specifiers, and modify everything to use them, but that seems like too
> > much bother. I had ideas once upon a time to implement gas and ld
> > options that makes @ha and _HA report overflows, but haven't found one
> > of those round tuits.
>
> No, if you don't have a reloc that can represent this, then the proper
> fix is to use the existing relocs to load the original symbol address
> into a register, then *generate* the appropriate 64-bit addition on top
> of it.
I already have a gcc fix to do exactly that. My "proper fix" comment
was more to do with the general case. For example, when linking a
huge object that overflows _HA relocs right now we silently generate
bad code.
--
Alan Modra
Australia Development Lab, IBM
next prev parent reply other threads:[~2013-09-02 2:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-27 6:07 [PATCH] powerpc: Work around gcc miscompilation of __pa() on 64-bit Paul Mackerras
2013-08-27 7:12 ` Alan Modra
2013-08-27 9:03 ` Paul Mackerras
2013-09-01 23:59 ` Benjamin Herrenschmidt
2013-09-02 2:31 ` Alan Modra [this message]
2013-09-02 5:06 ` Benjamin Herrenschmidt
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