From mboxrd@z Thu Jan 1 00:00:00 1970 From: sboyd@codeaurora.org (Stephen Boyd) Date: Thu, 23 May 2013 10:54:26 -0700 Subject: [PATCH] ARM: avoid mis-detecting some V7 cores in the decompressor In-Reply-To: <5193E424.9090605@codeaurora.org> References: <1368049671-22879-1-git-send-email-sboyd@codeaurora.org> <5193E424.9090605@codeaurora.org> Message-ID: <519E57D2.3050000@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 05/15/13 12:38, Stephen Boyd wrote: > 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? Russell, shall I add this to the patch tracker? > >> 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