From: jon.medhurst@linaro.org (Jon Medhurst (Tixy))
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/3] ARM: iwmmxt: Port problematic iwmmxt support code to v7/Thumb-2
Date: Fri, 09 Sep 2011 10:55:02 +0100 [thread overview]
Message-ID: <1315562102.7961.5.camel@linaro1> (raw)
In-Reply-To: <CAMPhdO9USGfrpgR0fXUL6024qWGLqsS72vzaO6AH1oo-TW1RtA@mail.gmail.com>
On Thu, 2011-09-08 at 11:49 -0700, Eric Miao wrote:
> So the problem is really when compiling this file with existing toolchain,
> it's downgrading to v5 compatible mode, and the instruction below
>
> sub pc, lr, r1, lsr #32
>
> wouldn't be encoded when building a THUMB2 kernel. Considering the
> r1, lsr #32 is actually to create an explicit data dependency of the previous
> co-processor instruction, would it be one option to rewrite this as something
> like:
>
> mov r1, r1
> mov pc, lr
That doesn't include a data dependency of PC on R1, so it's possible for
MOV PC, LR and subsequent instructions to be executed before MOV R1, R1
has completed. We would want...
add lr, lr, r1, lsr #32
mov pc, lr
--
Tixy
next prev parent reply other threads:[~2011-09-09 9:55 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-08 16:04 [PATCH v2 0/3] ARM: iwmmxt/pj4 fixes for v7/Thumb-2 Dave Martin
2011-09-08 16:04 ` [PATCH v2 1/3] ARM: iwmmxt: Fix Makefile rules for building iwmmxt for Thumb-2 Dave Martin
2011-09-08 16:45 ` Arnd Bergmann
2011-09-08 17:14 ` Dave Martin
2011-09-08 17:09 ` Nicolas Pitre
2011-09-08 16:04 ` [PATCH v2 2/3] ARM: iwmmxt: Port problematic iwmmxt support code to v7/Thumb-2 Dave Martin
2011-09-08 16:45 ` Arnd Bergmann
2011-09-08 17:03 ` Eric Miao
2011-09-08 17:13 ` Jon Medhurst (Tixy)
2011-09-08 17:15 ` Eric Miao
2011-09-08 17:33 ` Nicolas Pitre
2011-09-08 17:20 ` Dave Martin
2011-09-08 17:32 ` Nicolas Pitre
2011-09-08 18:49 ` Eric Miao
2011-09-08 19:30 ` Nicolas Pitre
2011-09-09 9:55 ` Jon Medhurst (Tixy) [this message]
2011-09-09 13:21 ` Nicolas Pitre
2011-09-09 14:05 ` Jon Medhurst (Tixy)
2011-09-09 16:41 ` Dave Martin
2011-09-09 17:51 ` Nicolas Pitre
2011-09-12 14:37 ` Dave Martin
2011-09-12 14:43 ` Russell King - ARM Linux
2011-09-12 14:55 ` Nicolas Pitre
2011-09-12 16:22 ` Dave Martin
2011-09-08 16:04 ` [PATCH v2 3/3] ARM: pxa/pj4: Port problematic pj4 " Dave Martin
2011-09-08 16:44 ` Arnd Bergmann
2011-09-08 17:06 ` Eric Miao
2011-09-08 17:23 ` Dave Martin
2011-09-08 17:06 ` Nicolas Pitre
2011-09-08 17:06 ` Eric Miao
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