From: Sascha Hauer <s.hauer@pengutronix.de>
To: steve@scheftech.com
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH] Avoid SDRAM access crash
Date: Tue, 3 Jul 2012 09:36:05 +0200 [thread overview]
Message-ID: <20120703073605.GT2698@pengutronix.de> (raw)
In-Reply-To: <1341249753-5480-1-git-send-email-steve@scheftech.com>
Hi Steve,
On Mon, Jul 02, 2012 at 01:22:33PM -0400, steve@scheftech.com wrote:
> From: Steve Schefter <steve@scheftech.com>
>
> When remapping the SDRAM with the MMU enabled, we need to ensure
> that the translation tables are not still in cache before
> invalidating the TLB. Failure to do so will result in the following
> crash approximately 50% of the time:
>
> booting kernel from /dev/nand0.kernel.bb
> Image Name: Linux-3.3.0PD12.0.0
> OS: Linux
> Architecture: ARM
> Type: Kernel Image
> Compression: uncompressed
> Data Size: 3384824 Bytes = 3.2 MB
> Load Address: 80008000
> Entry Point: 80008000
> unable to handle paging request at address 0x80028000
> pc : [<8f01f280>] lr : [<8f005330>]
> sp : 8cfff9b0 ip : 0000003f fp : 00000000
> r10: 00001000 r9 : 00000000 r8 : 8d2a8f70
> r7 : 8f043818 r6 : 0033a5f8 r5 : 8f04381c r4 : 00001000
> r3 : 80028000 r2 : 00000fff r1 : 8d2a8f71 r0 : 80028000
> Flags: nzCv IRQs off FIQs off Mode SVC_32
> [<8f01f280>] (memcpy+0x18/0x20) from [<8f005330>] (uimage_sdram_flush+0x90/0xb8)
> [<8f005330>] (uimage_sdram_flush+0x90/0xb8) from [<8f0053a4>] (uncompress_copy+0x4c/0x74)
I wonder why this has never hit me. On what hardware did you see this?
Does the following patch solve your problem aswell?
8<----------------------------------------------------
ARM mmu: flush page tables in arm_mmu_remap_sdram()
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
arch/arm/cpu/mmu.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/arm/cpu/mmu.c b/arch/arm/cpu/mmu.c
index 55b07a4..607f357 100644
--- a/arch/arm/cpu/mmu.c
+++ b/arch/arm/cpu/mmu.c
@@ -147,7 +147,7 @@ static int arm_mmu_remap_sdram(struct memory_bank *bank)
if ((phys & (SZ_1M - 1)) || (bank->size & (SZ_1M - 1)))
return -EINVAL;
- ptes = memalign(0x400, num_ptes * sizeof(u32));
+ ptes = memalign(PAGE_SIZE, num_ptes * sizeof(u32));
debug("ptes: 0x%p ttb_start: 0x%08lx ttb_end: 0x%08lx\n",
ptes, ttb_start, ttb_end);
@@ -165,6 +165,9 @@ static int arm_mmu_remap_sdram(struct memory_bank *bank)
pte += 256;
}
+ dma_flush_range((unsigned long)ttb, (unsigned long)ttb + 0x4000);
+ dma_flush_range((unsigned long)ptes, num_ptes * sizeof(u32));
+
tlb_invalidate();
return 0;
--
1.7.10
--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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next prev parent reply other threads:[~2012-07-03 7:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-02 17:22 steve
2012-07-03 7:36 ` Sascha Hauer [this message]
2012-07-03 11:22 ` Steve Schefter
2012-07-04 6:51 ` Sascha Hauer
2012-07-04 11:18 ` Steve Schefter
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