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Commit c2607f74 authored by Nicolas Pitre's avatar Nicolas Pitre Committed by Russell King
Browse files

ARM: 8294/1: ATAG_DTB_COMPAT: remove the DT workspace's hardcoded 64KB size 



There is currently a hardcoded limit of 64KB for the DTB to live in and
be extended with ATAG info.  Some DTBs have outgrown that limit:

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

Furthermore, the actual size passed to atags_to_fdt() included the stack
size which is obviously wrong.

The initial DTB size is known, so use it to size the allocated workspace
with a 50% growth assumption and relocate the temporary stack above that.
This is also clamped to 32KB min / 1MB max for robustness against bad
DTB data.

Reported-by: default avatarPali Rohár <pali.rohar@gmail.com>
Tested-by: default avatarPavel Machek <pavel@ucw.cz>
Signed-off-by: default avatarNicolas Pitre <nico@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent c2273a18

arch/arm/boot/compressed/head.S

+30 −9
Original line number Diff line number Diff line
@@ -263,16 +263,37 @@ restart: adr r0, LC0 
		 * OK... Let's do some funky business here.

		 * If we do have a DTB appended to zImage, and we do have

		 * an ATAG list around, we want the later to be translated

		 * and folded into the former here.  To be on the safe side,

		 * let's temporarily move  the stack away into the malloc

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

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

		 * and folded into the former here. No GOT fixup has occurred

		 * yet, but none of the code we're about to call uses any

		 * global variable.

		*/

		add	sp, sp, #0x10000



		/* Get the initial DTB size */

		ldr	r5, [r6, #4]

#ifndef __ARMEB__

		/* convert to little endian */

		eor	r1, r5, r5, ror #16

		bic	r1, r1, #0x00ff0000

		mov	r5, r5, ror #8

		eor	r5, r5, r1, lsr #8

#endif

		/* 50% DTB growth should be good enough */

		add	r5, r5, r5, lsr #1

		/* preserve 64-bit alignment */

		add	r5, r5, #7

		bic	r5, r5, #7

		/* clamp to 32KB min and 1MB max */

		cmp	r5, #(1 << 15)

		movlo	r5, #(1 << 15)

		cmp	r5, #(1 << 20)

		movhi	r5, #(1 << 20)

		/* temporarily relocate the stack past the DTB work space */

		add	sp, sp, r5



		stmfd	sp!, {r0-r3, ip, lr}

		mov	r0, r8

		mov	r1, r6

		sub	r2, sp, r6

		mov	r2, r5

		bl	atags_to_fdt



		/*
@@ -285,11 +306,11 @@ restart: adr r0, LC0 
		bic	r0, r0, #1

		add	r0, r0, #0x100

		mov	r1, r6

		sub	r2, sp, r6

		mov	r2, r5

		bleq	atags_to_fdt



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

		sub	sp, sp, #0x10000

		sub	sp, sp, r5

#endif



		mov	r8, r6			@ use the appended device tree
@@ -306,7 +327,7 @@ restart: adr r0, LC0 
		subs	r1, r5, r1

		addhi	r9, r9, r1



		/* Get the dtb's size */

		/* Get the current DTB size */

		ldr	r5, [r6, #4]

#ifndef __ARMEB__

		/* convert r5 (dtb size) to little endian */