From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Alan Modra <amodra@gmail.com>
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, 02 Sep 2013 15:06:16 +1000 [thread overview]
Message-ID: <1378098376.3978.17.camel@pasglop> (raw)
In-Reply-To: <20130902023110.GV3430@bubble.grove.modra.org>
On Mon, 2013-09-02 at 12:01 +0930, Alan Modra wrote:
> > 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.
Ah that is nice indeed :-) In that case I assume we can't have the offset
itself be part of the TOC :-) Chicken or egg ?
Not sure what's the right fix here is, we don't want to always reserve
enough instructions "space" to do a full 64-bit offset load...
Ben.
prev parent reply other threads:[~2013-09-02 5:06 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
2013-09-02 5:06 ` Benjamin Herrenschmidt [this message]
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