From: robherring2@gmail•com (Rob Herring)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 3/5] ARM: use generic unaligned.h
Date: Mon, 08 Oct 2012 21:27:31 -0500 [thread overview]
Message-ID: <50738B93.6090704@gmail.com> (raw)
In-Reply-To: <20121008232853.GA21822@S2101-09.ap.freescale.net>
On 10/08/2012 06:28 PM, Shawn Guo wrote:
> On Mon, Oct 08, 2012 at 03:34:57PM -0500, Rob Herring wrote:
>> On 10/08/2012 11:43 AM, Shawn Guo wrote:
>>> This patch has been merged into mainline as commit below.
>>>
>>> d25c881 ARM: 7493/1: use generic unaligned.h
>>>
>>> It introduces a regression for me. Check out the commit on mainline,
>>> build a v7 only kernel (imx5/6) with imx_v6_v7_defconfig, the kernel
>>> halts in decompressor. But v6/v7 kernel (imx3/5/6) works fine. The
>>> kernel built on the parent commit below works all fine.
>>
>> It actually fails in the decompressor or that's the last output you get?
>
> I think it fails in the decompressor, because what I see is
>
> Uncompressing Linux...
>
> not
>
> Uncompressing Linux... done, booting the kernel.
>
>> I compared the decompressor disassembly of both cases and get the same
>> number of ldrb/strb instructions, so I don't think it is directly
>> related to alignment.
>>
>> I tried the XY decompressor as that is one difference, but that works
>> fine for me on highbank.
>>
>> Does it work with an empty uncompress.h functions? That should be the
>> only difference in our decompressor code.
>
> No, empty putc() in uncompress.h does not help.
>
> New finding is that it only fails with LZO decompressor while the other
> 3 Gzip, LZMA and XZ all work good. We happen to have LZO as the default
> one in imx_v6_v7_defconfig.
I must have had an old config with XZ. LZO fails because of this:
lib/decompress_unlzo.c: version = get_unaligned_be16(parse);
lib/decompress_unlzo.c: if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
lib/decompress_unlzo.c: dst_len = get_unaligned_be32(in_buf);
lib/decompress_unlzo.c: src_len = get_unaligned_be32(in_buf);
This was what I was afraid of. The decompressor runs with the sysctrl
register A bit in whatever state the bootloader left it in. In the case
of u-boot it is set, and the maintainers are pretty set on not allowing
unaligned accesses if you've seen the recent discussion.
This should fix things.
Rob
8<---------------------------------------------------------------------
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index bc67cbf..1f87d22 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -654,6 +654,7 @@ __armv7_mmu_cache_on:
#endif
mrc p15, 0, r0, c1, c0, 0 @ read control reg
bic r0, r0, #1 << 28 @ clear SCTLR.TRE
+ bic r0, r0, #1 << 1 @ clear SCTLR.A
orr r0, r0, #0x5000 @ I-cache enable, RR cache replacement
orr r0, r0, #0x003c @ write buffer
#ifdef CONFIG_MMU
next prev parent reply other threads:[~2012-10-09 2:27 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-05 1:23 [PATCH v2 0/5] Use more asm-generic headers Rob Herring
2012-08-05 1:23 ` [PATCH v2 1/5] ARM: use generic version of identical asm headers Rob Herring
2012-08-05 1:23 ` [PATCH v2 2/5] ARM: add strstr declaration for decompressors Rob Herring
2012-08-05 1:23 ` [PATCH v2 3/5] ARM: use generic unaligned.h Rob Herring
2012-10-08 16:43 ` Shawn Guo
2012-10-08 20:34 ` Rob Herring
2012-10-08 23:28 ` Shawn Guo
2012-10-09 2:27 ` Rob Herring [this message]
2012-10-09 2:45 ` Shawn Guo
2012-10-09 4:01 ` Nicolas Pitre
2012-10-10 13:29 ` Rob Herring
2012-10-10 13:57 ` Nicolas Pitre
2012-10-11 12:43 ` [PATCH] ARM: decompressor: clear SCTLR.A bit for v7 cores Rob Herring
2012-10-11 13:09 ` Russell King - ARM Linux
2012-10-11 13:31 ` Rob Herring
2012-10-11 13:41 ` Russell King - ARM Linux
2012-10-11 15:44 ` Nicolas Pitre
2012-10-23 20:32 ` Gregory CLEMENT
2012-10-25 12:07 ` Russell King - ARM Linux
2012-10-11 13:59 ` Russell King - ARM Linux
2012-10-11 15:58 ` Nicolas Pitre
2012-10-25 9:34 ` Johannes Stezenbach
2012-10-25 12:41 ` Rob Herring
2012-10-25 13:30 ` Arnd Bergmann
2012-10-25 14:16 ` Johannes Stezenbach
2012-10-25 14:25 ` Rob Herring
2012-10-25 15:02 ` Nicolas Pitre
2012-10-25 15:08 ` Johannes Stezenbach
2012-11-05 10:48 ` Dave Martin
2012-11-05 11:13 ` Russell King - ARM Linux
2012-11-05 13:02 ` Dave Martin
2012-11-05 13:43 ` Johannes Stezenbach
2012-11-05 15:39 ` Russell King - ARM Linux
2012-11-05 16:13 ` Nicolas Pitre
2012-11-05 17:26 ` Dave Martin
2012-11-05 17:44 ` Rob Herring
2012-11-05 20:02 ` Nicolas Pitre
2012-11-05 17:46 ` Nicolas Pitre
2012-11-05 13:48 ` Rob Herring
2012-11-05 22:02 ` Michael Hope
2013-02-20 14:56 ` Johannes Stezenbach
2013-02-20 15:07 ` Johannes Stezenbach
2012-08-05 1:23 ` [PATCH v2 4/5] ARM: use generic termios.h Rob Herring
2012-08-05 1:24 ` [PATCH v2 5/5] ARM: convert asm/irqflags.h to use asm-generic/irqflags.h Rob Herring
2012-08-05 9:34 ` [PATCH v2 0/5] Use more asm-generic headers Thomas Petazzoni
2012-08-06 14:35 ` Arnd Bergmann
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