From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Boyd Subject: [PATCH] ARM: avoid mis-detecting some V7 cores in the decompressor Date: Wed, 8 May 2013 14:47:51 -0700 Message-ID: <1368049671-22879-1-git-send-email-sboyd@codeaurora.org> Return-path: Received: from wolverine02.qualcomm.com ([199.106.114.251]:41836 "EHLO wolverine02.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755885Ab3EHVr6 (ORCPT ); Wed, 8 May 2013 17:47:58 -0400 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 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 --- 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 -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation