From: robherring2@gmail.com (Rob Herring)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: map ATAGs when not in first 1MB of RAM
Date: Thu, 27 Jan 2011 09:50:43 -0600 [thread overview]
Message-ID: <1296143443-9442-1-git-send-email-robherring2@gmail.com> (raw)
From: Rob Herring <rob.herring@calxeda.com>
If ATAGs or DTB pointer is not within first 1MB of RAM, then the boot params
will not be mapped early enough, so map the 1MB region that r2 points to. Only
map the first 1MB when r2 is 0.
Some assembly improvements from Nicolas Pitre.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
---
arch/arm/kernel/head.S | 19 ++++++++++++++++++-
1 files changed, 18 insertions(+), 1 deletions(-)
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 65d9489..9c688bf 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -205,15 +205,32 @@ __create_page_tables:
#endif
/*
- * Then map first 1MB of ram in case it contains our boot params.
+ * Then map first 1MB of ram if boot params address is not specified.
*/
+ cmp r2, #0
+ bne 1f
add r0, r4, #PAGE_OFFSET >> 18
orr r6, r7, #(PHYS_OFFSET & 0xff000000)
.if (PHYS_OFFSET & 0x00f00000)
orr r6, r6, #(PHYS_OFFSET & 0x00f00000)
.endif
str r6, [r0]
+ b 2f
+ /*
+ * Otherwise map the 1MB region r2 points to (atags or dtb)
+ */
+1: mov r0, r2, lsr #20
+ mov r0, r0, lsl #20
+ sub r3, r0, #(PHYS_OFFSET & 0xff000000)
+ .if (PHYS_OFFSET & 0x00f00000)
+ sub r3, r3, #(PHYS_OFFSET & 0x00f00000)
+ .endif
+ add r3, r3, #PAGE_OFFSET
+ add r3, r4, r3, lsr #18
+ orr r6, r7, r0
+ str r6, [r3]
+2:
#ifdef CONFIG_DEBUG_LL
#ifndef CONFIG_DEBUG_ICEDCC
/*
--
1.7.1
next reply other threads:[~2011-01-27 15:50 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-27 15:50 Rob Herring [this message]
2011-01-27 16:31 ` [PATCH] ARM: map ATAGs when not in first 1MB of RAM Russell King - ARM Linux
2011-01-27 17:41 ` Rob Herring
2011-01-27 17:46 ` Russell King - ARM Linux
2011-02-02 3:26 ` Grant Likely
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