[PATCH 07/10] powerpc: Update linker scripts to ensure appended device tree is aligned

[Tom Rini]

With commit 0535e46d55d7 ("scripts/dtc: Update to upstream version
v1.7.2-35-g52f07dcca47c") it is now a fatal error to U-Boot if our
device tree is not 8-byte aligned. In commit f613a6e15ef7 ("ARM: OMAP2+:
Pad SPL binary to 8-byte alignment before DTB") Beleswar Padhi explains
that we must have ALIGN(x) statements inside of a section to ensure that
padding is included and not simply that the linker address counter is
incremented. To that end, this patch:
- Aligns the final section before _end by 8-bytes by adding '. =
  ALIGN(8);' or changing an existing ALIGN(4) statement.
- Ensure that we do have alignment by adding an ASSERT so that when not
  aligned we fail to link (and explain why).

Signed-off-by: Tom Rini <trini at konsulko.com>
---
Cc: "Marek Behún" <kabel at kernel.org>
Cc: Christophe Leroy <christophe.leroy at csgroup.eu>
Cc: Ilias Apalodimas <ilias.apalodimas at linaro.org>
Cc: Marek Vasut <marek.vasut+renesas at mailbox.org>
Cc: Mario Six <mario.six at gdsys.cc>
Cc: Richard Henderson <richard.henderson at linaro.org>
---
 arch/powerpc/cpu/mpc83xx/u-boot.lds | 3 +++
 arch/powerpc/cpu/mpc85xx/u-boot.lds | 4 +++-
 board/cssi/cmpc885/u-boot.lds       | 3 +++
 board/cssi/mcr3000/u-boot.lds       | 3 +++
 4 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/cpu/mpc83xx/u-boot.lds b/arch/powerpc/cpu/mpc83xx/u-boot.lds
index 1a1e537b2a76..5becc4d236ef 100644
--- a/arch/powerpc/cpu/mpc83xx/u-boot.lds
+++ b/arch/powerpc/cpu/mpc83xx/u-boot.lds
@@ -56,6 +56,7 @@ SECTIONS
    * _end - This is end of u-boot.bin image.
    * dtb will be appended here to make u-boot-dtb.bin
    */
+  . = ALIGN(8);
   _end = .;
 
   . = ALIGN(4096);
@@ -77,3 +78,5 @@ SECTIONS
   PROVIDE (end = .);
 }
 ENTRY(_start)
+
+ASSERT(_end % 8 == 0, "_end must be 8-byte aligned for device tree");
diff --git a/arch/powerpc/cpu/mpc85xx/u-boot.lds b/arch/powerpc/cpu/mpc85xx/u-boot.lds
index 3af0dfdf336b..3c9959bef097 100644
--- a/arch/powerpc/cpu/mpc85xx/u-boot.lds
+++ b/arch/powerpc/cpu/mpc85xx/u-boot.lds
@@ -78,7 +78,7 @@ SECTIONS
   __init_begin = .;
   .text.init : { *(.text.init) }
   .data.init : { *(.data.init) }
-  . = ALIGN(4);
+  . = ALIGN(8);
   __init_end = .;
   _end = .;
 
@@ -119,3 +119,5 @@ SECTIONS
   __bss_end = . ;
   PROVIDE (end = .);
 }
+
+ASSERT(_end % 8 == 0, "_end must be 8-byte aligned for device tree");
diff --git a/board/cssi/cmpc885/u-boot.lds b/board/cssi/cmpc885/u-boot.lds
index 167606357e00..da9cff64d465 100644
--- a/board/cssi/cmpc885/u-boot.lds
+++ b/board/cssi/cmpc885/u-boot.lds
@@ -72,6 +72,7 @@ SECTIONS
 	 * _end - This is end of u-boot.bin image.
 	 * dtb will be appended here to make u-boot-dtb.bin
 	 */
+	. = ALIGN(8);
 	_end = .;
 
 	. = ALIGN(4096);
@@ -93,3 +94,5 @@ SECTIONS
 	PROVIDE (end = .);
 }
 ENTRY(_start)
+
+ASSERT(_end % 8 == 0, "_end must be 8-byte aligned for device tree");
diff --git a/board/cssi/mcr3000/u-boot.lds b/board/cssi/mcr3000/u-boot.lds
index 66afdebc0f77..1fd98726b2a8 100644
--- a/board/cssi/mcr3000/u-boot.lds
+++ b/board/cssi/mcr3000/u-boot.lds
@@ -72,6 +72,7 @@ SECTIONS
 	 * _end - This is end of u-boot.bin image.
 	 * dtb will be appended here to make u-boot-dtb.bin
 	 */
+	. = ALIGN(8);
 	_end = .;
 
 	. = ALIGN(4096);
@@ -93,3 +94,5 @@ SECTIONS
 	PROVIDE (end = .);
 }
 ENTRY(_start)
+
+ASSERT(_end % 8 == 0, "_end must be 8-byte aligned for device tree");
-- 
2.43.0