From: Segher Boessenkool <segher@kernel.crashing.org>
To: Gabriel Paubert <paubert@iram.es>
Cc: Tejun Heo <htejun@gmail.com>,
linuxppc-dev@lists.ozlabs.org, Christoph Lameter <cl@gentwo.org>
Subject: Re: power and percpu: Could we move the paca into the percpu area?
Date: Thu, 12 Jun 2014 07:26:39 -0500 [thread overview]
Message-ID: <20140612122639.GA17838@gate.crashing.org> (raw)
In-Reply-To: <20140611210351.GA7155@visitor2.iram.es>
> Actually, from gcc/config/rs6000.h:
>
> /* 1 for registers that have pervasive standard uses
> and are not available for the register allocator.
[snip]
> So cr5, which is number 73, is never used by gcc.
Not available for RA is not the same thing at all as not used by GCC.
For example, GPR1 and XER[CA] are also fixed regs.
But, indeed, it does look like GCC doesn't use it. It seems to me that
some ABI forbade userland (or non-libraries or whatever) from using it.
I'll see what I can find out.
Segher
next prev parent reply other threads:[~2014-06-12 12:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-11 19:37 power and percpu: Could we move the paca into the percpu area? Christoph Lameter
2014-06-11 20:22 ` Benjamin Herrenschmidt
2014-06-11 21:03 ` Gabriel Paubert
2014-06-12 12:26 ` Segher Boessenkool [this message]
2014-06-12 21:57 ` Benjamin Herrenschmidt
2014-06-12 22:15 ` Segher Boessenkool
2014-06-13 11:55 ` Gabriel Paubert
2014-06-13 14:16 ` Segher Boessenkool
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