1 files changed, 115 insertions, 7 deletions

diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index e95a5989602..c2effc91725 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -216,6 +216,104 @@ restart:	adr	r0, LC0
                 mov     r10, r6
 #endif
 
+                mov     r5, #0                  @ init dtb size to 0
+#ifdef CONFIG_ARM_APPENDED_DTB
+/*
+ *   r0  = delta
+ *   r2  = BSS start
+ *   r3  = BSS end
+ *   r4  = final kernel address
+ *   r5  = appended dtb size (still unknown)
+ *   r6  = _edata
+ *   r7  = architecture ID
+ *   r8  = atags/device tree pointer
+ *   r9  = size of decompressed image
+ *   r10 = end of this image, including  bss/stack/malloc space if non XIP
+ *   r11 = GOT start
+ *   r12 = GOT end
+ *   sp  = stack pointer
+ *
+ * if there are device trees (dtb) appended to zImage, advance r10 so that the
+ * dtb data will get relocated along with the kernel if necessary.
+ */
+
+                ldr     lr, [r6, #0]
+#ifndef __ARMEB__
+                ldr     r1, =0xedfe0dd0         @ sig is 0xd00dfeed big endian
+#else
+                ldr     r1, =0xd00dfeed
+#endif
+                cmp     lr, r1
+                bne     dtb_check_done          @ not found
+
+#ifdef CONFIG_ARM_ATAG_DTB_COMPAT
+                /*
+                 * 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.
+                */
+                add     sp, sp, #0x10000
+                stmfd   sp!, {r0-r3, ip, lr}
+                mov     r0, r8
+                mov     r1, r6
+                sub     r2, sp, r6
+                bl      atags_to_fdt
+
+                /*
+                 * If returned value is 1, there is no ATAG at the location
+                 * pointed by r8.  Try the typical 0x100 offset from start
+                 * of RAM and hope for the best.
+                 */
+                cmp     r0, #1
+                sub     r0, r4, #TEXT_OFFSET
+                add     r0, r0, #0x100
+                mov     r1, r6
+                sub     r2, sp, r6
+                blne    atags_to_fdt
+
+                ldmfd   sp!, {r0-r3, ip, lr}
+                sub     sp, sp, #0x10000
+#endif
+
+                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__
+                /* convert r5 (dtb size) 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
+
+                /* preserve 64-bit alignment */
+                add     r5, r5, #7
+                bic     r5, r5, #7
+
+                /* relocate some pointers past the appended dtb */
+                add     r6, r6, r5
+                add     r10, r10, r5
+                add     sp, sp, r5
+dtb_check_done:
+#endif
+
 /*
  * Check to see if we will overwrite ourselves.
  *   r4  = final kernel address
@@ -223,15 +321,14 @@ restart:	adr	r0, LC0
  *   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
 
 /*
@@ -285,14 +382,16 @@ wont_overwrite:
  *   r2  = BSS start
  *   r3  = BSS end
  *   r4  = kernel execution address
+ *   r5  = appended dtb size (0 if not present)
  *   r7  = architecture ID
  *   r8  = atags pointer
  *   r11 = GOT start
  *   r12 = GOT end
  *   sp  = stack pointer
  */
-                teq     r0, #0
+                orrs    r1, r0, r5
                 beq     not_relocated
+
                 add     r11, r11, r0
                 add     r12, r12, r0
 
@@ -307,12 +406,21 @@ wont_overwrite:
 
                 /*
                  * Relocate all entries in the GOT table.
+                 * Bump bss entries to _edata + dtb size
                  */
 1:              ldr     r1, [r11, #0]           @ relocate entries in the GOT
-                add     r1, r1, r0              @ table.  This fixes up the
-                str     r1, [r11], #4           @ C references.
+                add     r1, r1, r0              @ This fixes up C references
+                cmp     r1, r2                  @ if entry >= bss_start &&
+                cmphs   r3, r1                  @       bss_end > entry
+                addhi   r1, r1, r5              @    entry += dtb size
+                str     r1, [r11], #4           @ next entry
                 cmp     r11, r12
                 blo     1b
+
+                /* bump our bss pointers too */
+                add     r2, r2, r5
+                add     r3, r3, r5
+
 #else
 
                 /*