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Diffstat (limited to 'arch/arm/boot/compressed/head.S')
-rw-r--r--arch/arm/boot/compressed/head.S36
1 files changed, 33 insertions, 3 deletions
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index d4837c2d0359..262b5b6e45d1 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -279,10 +279,40 @@ not_angel:
* are already placing their zImage in (eg) the top 64MB
* of this range.
*/
- mov r4, pc
- and r4, r4, #0xf8000000
+ mov r0, pc
+ and r0, r0, #0xf8000000
+#ifdef CONFIG_USE_OF
+ adr r1, LC1
+#ifdef CONFIG_ARM_APPENDED_DTB
+ /*
+ * Look for an appended DTB. If found, we cannot use it to
+ * validate the calculated start of physical memory, as its
+ * memory nodes may need to be augmented by ATAGS stored at
+ * an offset from the same start of physical memory.
+ */
+ ldr r2, [r1, #4] @ get &_edata
+ add r2, r2, r1 @ relocate it
+ ldr r2, [r2] @ get DTB signature
+ ldr r3, =OF_DT_MAGIC
+ cmp r2, r3 @ do we have a DTB there?
+ beq 1f @ if yes, skip validation
+#endif /* CONFIG_ARM_APPENDED_DTB */
+
+ /*
+ * Make sure we have some stack before calling C code.
+ * No GOT fixup has occurred yet, but none of the code we're
+ * about to call uses any global variables.
+ */
+ ldr sp, [r1] @ get stack location
+ add sp, sp, r1 @ apply relocation
+
+ /* Validate calculated start against passed DTB */
+ mov r1, r8
+ bl fdt_check_mem_start
+1:
+#endif /* CONFIG_USE_OF */
/* Determine final kernel image address. */
- add r4, r4, #TEXT_OFFSET
+ add r4, r0, #TEXT_OFFSET
#else
ldr r4, =zreladdr
#endif