N900 v3.19-rc5 arm atags_to_fdt.c is broken

* Pali Roh?r [off-list ref] [150126 08:26]:

On Monday 26 January 2015 17:14:55 Tony Lindgren wrote:

quoted

* Pali Roh?r [off-list ref] [150123 14:39]:

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On Friday 23 January 2015 22:39:55 Pali Roh?r wrote:

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Hello,

when I boot zImage with appended DT n900 in qemu
fdt_open_into() function called from file
arch/arm/boot/compressed/atags_to_fdt.c (in function
atags_to_fdt) always returns -FDT_ERR_NOSPACE.

It means that all ATAGS (including cmdline arguments)
passed by bootloader are ignored.

On real n900 device I see that booted DT version also
ignore cmdline arguments from bootloader. I cannot debug
decompress code on real device, but I think it is same
problem as in qemu.

Looks like this quick patch is fixing above problem:

diff --git a/arch/arm/boot/compressed/head.S

b/arch/arm/boot/compressed/head.S index 68be901..4a7d75b
100644

--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S

@@ -268,7 +268,7 @@ restart:	adr	r0, LC0

 		 * area.  No GOT fixup has occurred yet, but none of 

the

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 		 * code we're about to call uses any global variable.
 		
 		*/

-		add	sp, sp, #0x10000
+		add	sp, sp, #0x20000

 		stmfd	sp!, {r0-r3, ip, lr}
 		mov	r0, r8
 		mov	r1, r6

@@ -289,7 +289,7 @@ restart:	adr	r0, LC0

 		bleq	atags_to_fdt
 		
 		ldmfd	sp!, {r0-r3, ip, lr}

-		sub	sp, sp, #0x10000
+		sub	sp, sp, #0x20000

 #endif
 
 		mov	r8, r6			@ use the appended device tree

Nico, got any ideas about this one? This seems like a
regression somewhere..

Regards,

Tony

$ du -b arch/arm/boot/dts/omap3-n900.dtb 
70212   arch/arm/boot/dts/omap3-n900.dtb

$ echo $((0x10000))
65536

I would say, problem is because omap3-n900 binary DT is too large

OK if that's the case, then your patch makes sense to me. It also
seems we can have the temporary stack be larger than the initial
stack just for atags_to_fdt.

Regards,

Tony