2 files changed, 18 insertions, 4 deletions

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 0c74a6fab952..4867647b9796 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -104,6 +104,9 @@ endif
 ccflags-y := -fpic -fno-builtin
 asflags-y := -Wa,-march=all
 
+# Supply kernel BSS size to the decompressor via a linker symbol.
+KBSS_SZ = $(shell size $(obj)/../../../../vmlinux | awk 'END{print $$3}')
+LDFLAGS_vmlinux = --defsym _kernel_bss_size=$(KBSS_SZ)
 # Supply ZRELADDR to the decompressor via a linker symbol.
 ifneq ($(CONFIG_AUTO_ZRELADDR),y)
 LDFLAGS_vmlinux += --defsym zreladdr=$(ZRELADDR)
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 3ce5738ddb98..ba5c552f8c69 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -248,6 +248,18 @@ restart:	adr	r0, LC0
 
                 mov     r8, r6                  @ use the appended device tree
 
+                /*
+                 * Make sure that the DTB doesn't end up in the final
+                 * kernel's .bss area. To do so, we adjust the decompressed
+                 * kernel size to compensate if that .bss size is larger
+                 * than the relocated code.
+                 */
+                ldr     r5, =_kernel_bss_size
+                adr     r1, wont_overwrite
+                sub     r1, r6, r1
+                subs    r1, r5, r1
+                addhi   r9, r9, r1
+
                 /* Get the dtb's size */
                 ldr     r5, [r6, #4]
 #ifndef __ARMEB__
@@ -276,15 +288,14 @@ dtb_check_done:
  *   r10 = end of this image, including  bss/stack/malloc space if non XIP
  * We basically want:
  *   r4 - 16k page directory >= r10 -> OK
- *   r4 + image length <= current position (pc) -> OK
+ *   r4 + image length <= address of wont_overwrite -> OK
  */
                 add     r10, r10, #16384
                 cmp     r4, r10
                 bhs     wont_overwrite
                 add     r10, r4, r9
-   ARM(         cmp     r10, pc         )
- THUMB(         mov     lr, pc          )
- THUMB(         cmp     r10, lr         )
+                adr     r9, wont_overwrite
+                cmp     r10, r9
                 bls     wont_overwrite
 
 /*