From: sboyd@codeaurora.org (Stephen Boyd)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/3] ARM: Work around faulty ISAR0 register in some Krait CPUs
Date: Mon, 18 Mar 2013 10:03:49 -0700 [thread overview]
Message-ID: <514748F5.70504@codeaurora.org> (raw)
In-Reply-To: <20130317142854.GC19071@mudshark.cambridge.arm.com>
On 03/17/13 07:28, Will Deacon wrote:
> On Wed, Mar 13, 2013 at 01:32:01AM +0000, Stephen Boyd wrote:
>> Some early versions of the Krait CPU design incorrectly indicate
>> that they only support the UDIV and SDIV instructions in Thumb
>> mode when they actually support them in ARM and Thumb mode. It
>> seems that these CPUs follow the DDI0406B ARM ARM which has two
>> possible values for the divide instructions field, instead of the
>> DDI0406C document which has three possible values.
>>
>> Work around this problem by checking the MIDR against Krait CPUs
>> with this faulty ISAR0 register and force the detection code
>> to indicate support in both modes.
>>
>> Cc: Will Deacon <will.deacon@arm.com>
>> Cc: Stepan Moskovchenko <stepanm@codeaurora.org>
>> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
>> ---
>> arch/arm/kernel/setup.c | 8 ++++++++
>> 1 file changed, 8 insertions(+)
> After all this, you might as well just pass the relevant HWCAPs for your
> krait entry in proc-v7.S rather than have an exception in the CPU-agnostic
> code.
Ok. Care to ack the previous patch I sent then?
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation
next prev parent reply other threads:[~2013-03-18 17:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-13 1:31 [PATCH 0/3] Detect UDIV/SDIV support from ISAR0 Stephen Boyd
2013-03-13 1:31 ` [PATCH 1/3] ARM: Clear IDIVT hwcap if CONFIG_ARM_THUMB=n Stephen Boyd
2013-03-17 14:29 ` Will Deacon
2013-03-13 1:32 ` [PATCH 2/3] ARM: Detect support for SDIV/UDIV from ISAR0 register Stephen Boyd
2013-03-17 14:36 ` Will Deacon
2013-03-18 17:13 ` Stephen Boyd
2013-03-13 1:32 ` [PATCH 3/3] ARM: Work around faulty ISAR0 register in some Krait CPUs Stephen Boyd
2013-03-17 14:28 ` Will Deacon
2013-03-18 17:03 ` Stephen Boyd [this message]
2013-03-18 18:19 ` Will Deacon
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