On Mon, Feb 21, 2011 at 06:03:16PM -0800, Linus Torvalds wrote:
On Mon, Feb 21, 2011 at 5:58 PM, Benjamin Herrenschmidt
<benh@xxxxxxxxxxxxxxxxxxx> wrote:
The only sane thing I can see is make sure that such structures that
we put into sections "arrays" like that are naturally aligned with
padding.
The sad part is, that assuming I read the gcc sources correctly (see
the earlier emails where David pointed to it), that alignment is:
- architecture-specific
- depends on the size of the structure
- seems to depend on the version of gcc itself.
The _one_ safe case is likely to be "structure size is a power of
two". And it does look like using a pointer is going to be safe, not
only because the gcc auto-alignment only triggers for things like
structs/unions/arrays, but because at least the x86 code only does it
if the structure was bigger than the alignment size itself.
So using pointer indirection is likely to be safe. It's still ugly and
annoying as heck, though.
Regardless the approach we'll take I think the following patch is also
needed (for cris architecture). I am not sure why __param section is
inly defined for one specific subarch but I they need __param they'll
need __modev as well.
Thanks,
Dmitry
From a567280f900c15891a55e7ea4e2919b38e1d1a01 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dtor@xxxxxxxxxx>
Date: Thu, 17 Feb 2011 13:12:26 -0800
Subject: [PATCH] cris: add missing __modver section
Commit e94965ed5beb23c6fabf7ed31f625e66d7ff28de added a new __modver
section to store module version information for drivers built into the
kernel, but missed the fact that cris does some additional steps to
set up sections.
Signed-off-by: Dmitry Torokhov <dtor@xxxxxxxxxx>
---
arch/cris/kernel/vmlinux.lds.S | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/arch/cris/kernel/vmlinux.lds.S b/arch/cris/kernel/vmlinux.lds.S
index 4422189..fae1b7b 100644
--- a/arch/cris/kernel/vmlinux.lds.S
+++ b/arch/cris/kernel/vmlinux.lds.S
@@ -73,6 +73,10 @@ SECTIONS
.init.data : { INIT_DATA }
.init.setup : { INIT_SETUP(16) }
#ifdef CONFIG_ETRAX_ARCH_V32
+ __start___modver = .;
+ __modver : { *(__modver) }
+ __stop___modver = .;
+
__start___param = .;
__param : { *(__param) }
__stop___param = .;
--
1.7.3.2
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