From: Namhyung Kim <namhyung@gmail.com>
To: Stuart Menefy <stuart.menefy@st.com>
Cc: Paul Mundt <lethal@linux-sh.org>,
"linux-sh@vger.kernel.org" <linux-sh@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sh: remove RELOC_HIDE on exception handlers and
Date: Tue, 10 Aug 2010 03:09:43 +0000 [thread overview]
Message-ID: <1281409783.1670.14.camel@leonhard> (raw)
In-Reply-To: <4C601ECD.2070503@st.com>
2010-08-09 (ì›”), 16:29 +0100, Stuart Menefy:
> Unfortunately these are necessary, although it is nothing to do with linker
> relocation. These functions take a struct pt_regs as a parameter (not a
> pointer), and modify some of the fields of that structure. We needed a way
> to ensure that gcc didn't optimise away those assignments - to gcc
> they appear to be assignments to a local variable, so quite legitimately
> get optimised away. So we used RELOC_HIDE() as a way of doing that.
>
Oh, I didn't know that. Thank you for the comments.
> A clearer way to do this would be to pass in a struct pt_regs pointer,
> but that would require going via a stub function which loads up the
> pointer.
>
> Stuart
>
So is it worth if I'm gonna work on it?
--
Regards,
Namhyung Kim
WARNING: multiple messages have this Message-ID (diff)
From: Namhyung Kim <namhyung@gmail.com>
To: Stuart Menefy <stuart.menefy@st.com>
Cc: Paul Mundt <lethal@linux-sh.org>,
"linux-sh@vger.kernel.org" <linux-sh@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sh: remove RELOC_HIDE on exception handlers and syscall routines
Date: Tue, 10 Aug 2010 12:09:43 +0900 [thread overview]
Message-ID: <1281409783.1670.14.camel@leonhard> (raw)
In-Reply-To: <4C601ECD.2070503@st.com>
2010-08-09 (월), 16:29 +0100, Stuart Menefy:
> Unfortunately these are necessary, although it is nothing to do with linker
> relocation. These functions take a struct pt_regs as a parameter (not a
> pointer), and modify some of the fields of that structure. We needed a way
> to ensure that gcc didn't optimise away those assignments - to gcc
> they appear to be assignments to a local variable, so quite legitimately
> get optimised away. So we used RELOC_HIDE() as a way of doing that.
>
Oh, I didn't know that. Thank you for the comments.
> A clearer way to do this would be to pass in a struct pt_regs pointer,
> but that would require going via a stub function which loads up the
> pointer.
>
> Stuart
>
So is it worth if I'm gonna work on it?
--
Regards,
Namhyung Kim
next prev parent reply other threads:[~2010-08-10 3:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-08 20:53 [PATCH] sh: remove RELOC_HIDE on exception handlers and syscall routines Namhyung Kim
2010-08-08 20:53 ` Namhyung Kim
2010-08-09 15:29 ` [PATCH] sh: remove RELOC_HIDE on exception handlers and syscall Stuart Menefy
2010-08-09 15:29 ` [PATCH] sh: remove RELOC_HIDE on exception handlers and syscall routines Stuart Menefy
2010-08-10 3:09 ` Namhyung Kim [this message]
2010-08-10 3:09 ` Namhyung Kim
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