lkml.org 
[lkml]   [2015]   [Apr]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
SubjectRe: [PATCH 7/7] modpost: handle relocations mismatch in __ex_table.
Date
Quentin Casasnovas <quentin.casasnovas@oracle.com> writes:
> On Tue, Apr 14, 2015 at 02:14:14PM +0200, Thierry Reding wrote:
>> On Tue, Mar 17, 2015 at 01:40:02PM +0100, Quentin Casasnovas wrote:
>> > If one of these addresses point to a non-executable section, something is
>> > seriously wrong since it either means the kernel will never fault from
>> > there or it will not be able to jump to there. As both cases are serious
>> > enough, we simply error out in these cases so the build fails and the
>> > developper has to fix the issue.
>> >
>> > Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
>> > ---
>> > scripts/mod/modpost.c | 141 ++++++++++++++++++++++++++++++++++++++++++++++++++
>> > 1 file changed, 141 insertions(+)
>>
>> This causes a bunch of mismatch warnings on 32-bit and 64-bit ARM
>> because there are two additional sections, .text.fixup and
>> .exception.text that store executable code. I've attached a patch
>> to fix those, but feel free to squash that into the original commit
>> if that's still possible.
>>
>
> Thanks Thierry!
>
> Your patch looks good to me, though I was wondering if we should just add
> .text.* in the TEXT_SECTIONS macro. Some architectures define
> -ffunction-sections (parisc, score, metag and frv) so there are tons of
> useless warnings on these.. It also means the current modpost sanity
> checks don't run for those so it might even uncover some real mismatch ;)

Yes, but this adds ".exception.text" so a .text.* wildcard won't quite
cover it.

I've applied his patch, then the following:

modpost: handle -ffunction-sections

52dc0595d540 introduced OTHER_TEXT_SECTIONS for identifying what
sections could validly have __ex_table entries. Unfortunately, it
wasn't tested with -ffunction-sections, which some architectures
use.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index cbd53e08769d..22dbc604cdb9 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -876,7 +876,7 @@ static void check_section(const char *modname, struct elf_info *elf,
#define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
".kprobes.text"
#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
- ".fixup", ".entry.text"
+ ".fixup", ".entry.text", ".exception.text", ".text.*"

#define INIT_SECTIONS ".init.*"
#define MEM_INIT_SECTIONS ".meminit.*"

\
 
 \ /
  Last update: 2015-04-15 06:01    [W:0.086 / U:0.196 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site