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authorNicolas Pitre <nicolas.pitre@linaro.org>2015-01-27 16:10:42 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2015-01-29 15:23:01 +0000
commitc2607f74aad96d18316a6e709b40e0ffe9def148 (patch)
tree7ca8b21b5631d9fe31faa075544cfe1c26db5f3f
parentc2273a185354fe9420fb342b1ca09a6fed857fb3 (diff)
downloadlinux-c2607f74aad96d18316a6e709b40e0ffe9def148.tar.bz2
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: Pali Rohár <pali.rohar@gmail.com> Tested-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/boot/compressed/head.S39
1 files changed, 30 insertions, 9 deletions
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 68be9017593d..132c70e2d2f1 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -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 */