From: ben.dooks@codethink.co.uk (Ben Dooks)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: kdgb: use .inst for data to be assembled as intruction
Date: Thu, 25 Jul 2013 18:13:18 +0100 [thread overview]
Message-ID: <51F15CAE.7020008@codethink.co.uk> (raw)
In-Reply-To: <20130725171130.GE2546@localhost.localdomain>
On 25/07/13 18:11, Dave Martin wrote:
> On Thu, Jul 25, 2013 at 03:49:38PM +0100, Ben Dooks wrote:
>> The arch_kgdb_breakpoint() function uses an inline assembly directive
>> to assemble a specific instruction using .word. This means the linker
>> will not treat is as an instruction, and therefore incorrectly swap
>> the endian-ness if running BE8.
>>
>> Note, not tested, please comment if this is wrong.
>>
>> Signed-off-by: Ben Dooks<ben.dooks@codethink.co.uk>
>> ---
>> arch/arm/include/asm/kgdb.h | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/include/asm/kgdb.h b/arch/arm/include/asm/kgdb.h
>> index 48066ce..76227c8 100644
>> --- a/arch/arm/include/asm/kgdb.h
>> +++ b/arch/arm/include/asm/kgdb.h
>> @@ -41,7 +41,7 @@
>>
>> static inline void arch_kgdb_breakpoint(void)
>> {
>> - asm(".word 0xe7ffdeff");
>> + asm(".inst 0xe7ffdeff");
>
> Yikes, this isn't going to work in a Thumb kernel.
>
> We should make HAVE_ARCH_KGDB depend on !THUMB2_KERNEL until/unless that
> gets fixed... It looks like the incompatibilities may be more extensive
> than just this one instruction.
>
>
> For the ARM case, similarly to the other patches, please use the __inst
> macros from<asm/opcodes.h> instead of emitting the opcode explicitly.
See previous objections to that, plus they're marked for internal use
only!
--
Ben Dooks http://www.codethink.co.uk/
Senior Engineer Codethink - Providing Genius
next prev parent reply other threads:[~2013-07-25 17:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-25 14:49 kdgb fix Ben Dooks
2013-07-25 14:49 ` [PATCH] ARM: kdgb: use .inst for data to be assembled as intruction Ben Dooks
2013-07-25 16:02 ` Will Deacon
2013-07-25 17:11 ` Dave Martin
2013-07-25 17:13 ` Ben Dooks [this message]
2013-07-25 18:09 ` Dave Martin
2013-07-26 10:31 ` Ben Dooks
2013-07-26 14:59 ` Dave Martin
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