linux-kernel - Re: Lots of unexpected non-allocatable section warnings

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Message-ID: <20090504094928.GA6157@uranus.ravnborg.org>
Date:	Mon, 4 May 2009 11:49:28 +0200
From:	Sam Ravnborg <sam@...nborg.org>
To:	Manuel Lauss <mano@...rinelk.homelinux.net>
Cc:	Anders Kaseorg <andersk@....edu>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux-MIPS <linux-mips@...ux-mips.org>
Subject: Re: Lots of unexpected non-allocatable section warnings

On Mon, May 04, 2009 at 10:28:16AM +0200, Manuel Lauss wrote:
> Hi Sam,
> 
> On Sun, May 03, 2009 at 10:29:39PM +0200, Sam Ravnborg wrote:
> > This is due to the SUSE specific section as you expected.
> > We ignore sections named ".comment" but not ".comment" sections
> > with something appended to the name.
> 
> 
> On a related note, I see tons of the following warnings cross-building for
> MIPS:
> 
> WARNING: init/mounts.o (.mdebug.abi32): unexpected non-allocatable section.
> Did you forget to use "ax"/"aw" in a .S file?                              
> Note that for example <linux/init.h> contains                              
> section definitions for use in .S files.                                   
> 
> WARNING: init/mounts.o (.pdr): unexpected non-allocatable section.
> Did you forget to use "ax"/"aw" in a .S file?                     
> Note that for example <linux/init.h> contains                     
> section definitions for use in .S files. 
> 
> 
> I added ".pdr" and ".mdebug*" to the whitelist;  the resulting kernels still
> work.  (gcc-4.3.3, binutils-2.19.1)

Hi Manuel - thanks for reporting!

Is your mips target little or big endian?
If it is a big-endian target (which I expect) then the right fix
is the patch posted by Anders.

In other words - what happens if you back out your change
and apply the appended patch.

	Sam

>From 23938116e57f8597f3cead5e1f79a51ebbbe3dd6 Mon Sep 17 00:00:00 2001
From: Anders Kaseorg <andersk@....EDU>
Date: Sun, 3 May 2009 22:02:55 +0200
Subject: [PATCH 1/2] kbuild, modpost: fix unexpected non-allocatable section when cross compiling

The missing TO_NATIVE(sechdrs[i].sh_flags) was causing many
unexpected non-allocatable section warnings when cross-compiling
for an architecture with a different endianness.

Fix endianness of all the fields in the ELF header and
section headers, not just some of them so we are not
hit by this anohter time.

Signed-off-by: Anders Kaseorg <andersk@....edu>
Reported-by: Sean MacLennan <smaclennan@...atech.com>
Signed-off-by: Sam Ravnborg <sam@...nborg.org>
---
 scripts/mod/modpost.c |   35 +++++++++++++++++++++++------------
 1 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 936b6f8..a5c17db 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -384,11 +384,19 @@ static int parse_elf(struct elf_info *info, const char *filename)
 		return 0;
 	}
 	/* Fix endianness in ELF header */
-	hdr->e_shoff    = TO_NATIVE(hdr->e_shoff);
-	hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
-	hdr->e_shnum    = TO_NATIVE(hdr->e_shnum);
-	hdr->e_machine  = TO_NATIVE(hdr->e_machine);
-	hdr->e_type     = TO_NATIVE(hdr->e_type);
+	hdr->e_type      = TO_NATIVE(hdr->e_type);
+	hdr->e_machine   = TO_NATIVE(hdr->e_machine);
+	hdr->e_version   = TO_NATIVE(hdr->e_version);
+	hdr->e_entry     = TO_NATIVE(hdr->e_entry);
+	hdr->e_phoff     = TO_NATIVE(hdr->e_phoff);
+	hdr->e_shoff     = TO_NATIVE(hdr->e_shoff);
+	hdr->e_flags     = TO_NATIVE(hdr->e_flags);
+	hdr->e_ehsize    = TO_NATIVE(hdr->e_ehsize);
+	hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
+	hdr->e_phnum     = TO_NATIVE(hdr->e_phnum);
+	hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
+	hdr->e_shnum     = TO_NATIVE(hdr->e_shnum);
+	hdr->e_shstrndx  = TO_NATIVE(hdr->e_shstrndx);
 	sechdrs = (void *)hdr + hdr->e_shoff;
 	info->sechdrs = sechdrs;
 
@@ -402,13 +410,16 @@ static int parse_elf(struct elf_info *info, const char *filename)
 
 	/* Fix endianness in section headers */
 	for (i = 0; i < hdr->e_shnum; i++) {
-		sechdrs[i].sh_type   = TO_NATIVE(sechdrs[i].sh_type);
-		sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
-		sechdrs[i].sh_size   = TO_NATIVE(sechdrs[i].sh_size);
-		sechdrs[i].sh_link   = TO_NATIVE(sechdrs[i].sh_link);
-		sechdrs[i].sh_name   = TO_NATIVE(sechdrs[i].sh_name);
-		sechdrs[i].sh_info   = TO_NATIVE(sechdrs[i].sh_info);
-		sechdrs[i].sh_addr   = TO_NATIVE(sechdrs[i].sh_addr);
+		sechdrs[i].sh_name      = TO_NATIVE(sechdrs[i].sh_name);
+		sechdrs[i].sh_type      = TO_NATIVE(sechdrs[i].sh_type);
+		sechdrs[i].sh_flags     = TO_NATIVE(sechdrs[i].sh_flags);
+		sechdrs[i].sh_addr      = TO_NATIVE(sechdrs[i].sh_addr);
+		sechdrs[i].sh_offset    = TO_NATIVE(sechdrs[i].sh_offset);
+		sechdrs[i].sh_size      = TO_NATIVE(sechdrs[i].sh_size);
+		sechdrs[i].sh_link      = TO_NATIVE(sechdrs[i].sh_link);
+		sechdrs[i].sh_info      = TO_NATIVE(sechdrs[i].sh_info);
+		sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
+		sechdrs[i].sh_entsize   = TO_NATIVE(sechdrs[i].sh_entsize);
 	}
 	/* Find symbol table. */
 	for (i = 1; i < hdr->e_shnum; i++) {
-- 
1.6.3.rc3.40.g75b44

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