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-rw-r--r--arch/arm/boot/compressed/head.S122
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
/*