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 09:59:12 +1000 [thread overview]
Message-ID: <1378079952.3978.15.camel@pasglop> (raw)
In-Reply-To: <20130827071235.GQ3430@bubble.grove.modra.org>
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.
The pointer has been cast to an integer before the addition, it's no
longer an object pointer and gcc shouldn't treat it as such, at which
point we are in the domain of normal integer arithmetics.
Cheers,
Ben.
next prev parent reply other threads:[~2013-09-01 23:59 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 [this message]
2013-09-02 2:31 ` Alan Modra
2013-09-02 5:06 ` Benjamin Herrenschmidt
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