From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Boyd Subject: Re: [PATCH] ARM: avoid mis-detecting some V7 cores in the decompressor Date: Wed, 15 May 2013 12:38:12 -0700 Message-ID: <5193E424.9090605@codeaurora.org> References: <1368049671-22879-1-git-send-email-sboyd@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from wolverine02.qualcomm.com ([199.106.114.251]:14290 "EHLO wolverine02.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753212Ab3EOTiN (ORCPT ); Wed, 15 May 2013 15:38:13 -0400 In-Reply-To: <1368049671-22879-1-git-send-email-sboyd@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: Russell King Cc: Brian Swetland , linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org On 05/08/13 14:47, Stephen Boyd wrote: > From: Brian Swetland > > Currently v7 CPUs with an MIDR that has no bits set in the range > [16:12] will be detected as old ARM CPUs with no caches and so > the cache will never be turned on during decompression. ARM's > Cortex chips have an 0xC in the range [16:12] so they never match > this entry, but Qualcomm's Scorpion and Krait processors never > set these bits to anything besides 0 so they always match. > > Skip this entry if we've compiled in support for v7 CPUs. This > allows kernel decompression to happen nearly instantly instead of > taking over 20 seconds. > > Signed-off-by: Brian Swetland > [sboyd: Clarified and extended commit text] > Signed-off-by: Stephen Boyd > --- Ping? > arch/arm/boot/compressed/head.S | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S > index fe4d9c3..a236190 100644 > --- a/arch/arm/boot/compressed/head.S > +++ b/arch/arm/boot/compressed/head.S > @@ -805,6 +805,8 @@ call_cache_fn: adr r12, proc_types > .align 2 > .type proc_types,#object > proc_types: > +#if !defined(CONFIG_CPU_V7) > + /* This collides with some V7 IDs, preventing correct detection */ > .word 0x00000000 @ old ARM ID > .word 0x0000f000 > mov pc, lr > @@ -813,6 +815,7 @@ proc_types: > THUMB( nop ) > mov pc, lr > THUMB( nop ) > +#endif > > .word 0x41007000 @ ARM7/710 > .word 0xfff8fe00 -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation