From: Segher Boessenkool <segher@kernel.crashing.org>
To: David Laight <David.Laight@ACULAB.COM>
Cc: Kees Cook <keescook@chromium.org>, Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Jinbum Park <jinb.park7@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] mm: fix RODATA_TEST failure "rodata_test: test data was not read only"
Date: Mon, 25 Sep 2017 14:41:31 -0500 [thread overview]
Message-ID: <20170925194130.GV8421@gate.crashing.org> (raw)
In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6DD007F58B@AcuExch.aculab.com>
On Mon, Sep 25, 2017 at 04:01:55PM +0000, David Laight wrote:
> From: Segher Boessenkool
> > The compiler puts this item in .sdata, for 32-bit. There is no .srodata,
> > so if it wants to use a small data section, it must use .sdata .
> >
> > Non-external, non-referenced symbols are not put in .sdata, that is the
> > difference you see with the "static".
> >
> > I don't think there is a bug here. If you think there is, please open
> > a GCC bug.
>
> The .sxxx sections are for 'small' data that can be accessed (typically)
> using small offsets from a global register.
> This means that all sections must be adjacent in the image.
> So you can't really have readonly small data.
>
> My guess is that the linker script is putting .srodata in with .sdata.
.srodata does not *exist* (in the ABI).
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: David Laight <David.Laight@ACULAB.COM>
Cc: Kees Cook <keescook@chromium.org>, Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Jinbum Park <jinb.park7@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] mm: fix RODATA_TEST failure "rodata_test: test data was not read only"
Date: Mon, 25 Sep 2017 14:41:31 -0500 [thread overview]
Message-ID: <20170925194130.GV8421@gate.crashing.org> (raw)
In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6DD007F58B@AcuExch.aculab.com>
On Mon, Sep 25, 2017 at 04:01:55PM +0000, David Laight wrote:
> From: Segher Boessenkool
> > The compiler puts this item in .sdata, for 32-bit. There is no .srodata,
> > so if it wants to use a small data section, it must use .sdata .
> >
> > Non-external, non-referenced symbols are not put in .sdata, that is the
> > difference you see with the "static".
> >
> > I don't think there is a bug here. If you think there is, please open
> > a GCC bug.
>
> The .sxxx sections are for 'small' data that can be accessed (typically)
> using small offsets from a global register.
> This means that all sections must be adjacent in the image.
> So you can't really have readonly small data.
>
> My guess is that the linker script is putting .srodata in with .sdata.
.srodata does not *exist* (in the ABI).
Segher
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next prev parent reply other threads:[~2017-09-25 19:42 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-21 9:37 [PATCH] mm: fix RODATA_TEST failure "rodata_test: test data was not read only" Christophe Leroy
2017-09-21 9:37 ` Christophe Leroy
2017-09-24 19:17 ` Kees Cook
2017-09-24 19:17 ` Kees Cook
2017-09-25 7:37 ` Segher Boessenkool
2017-09-25 7:37 ` Segher Boessenkool
2017-09-25 16:01 ` David Laight
2017-09-25 16:01 ` David Laight
2017-09-25 16:01 ` David Laight
2017-09-25 19:41 ` Segher Boessenkool [this message]
2017-09-25 19:41 ` Segher Boessenkool
2017-10-02 19:29 ` Kees Cook
2017-10-02 19:29 ` Kees Cook
2017-10-02 20:08 ` Segher Boessenkool
2017-10-02 20:08 ` Segher Boessenkool
2017-10-02 20:27 ` Kees Cook
2017-10-02 20:27 ` Kees Cook
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