[PATCH] powerpc/boot: Fix zImage TOC alignment

Recent toolchains force the TOC to be 256 byte aligned. We need to
enforce this alignment in the zImage linker script, otherwise pointers
to our TOC variables (__toc_start) could be incorrect. If the actual
start of the TOC and __toc_start don't have the same value we crash
early in the zImage wrapper.

Cc: stable@vger.kernel.org
Suggested-by: Alan Modra <redacted>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/boot/zImage.lds.S | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/boot/zImage.lds.S b/arch/powerpc/boot/zImage.lds.S
index 861e72109df2..f080abfc2f83 100644
--- a/arch/powerpc/boot/zImage.lds.S
+++ b/arch/powerpc/boot/zImage.lds.S

@@ -68,6 +68,7 @@ SECTIONS
   }
 
 #ifdef CONFIG_PPC64_BOOT_WRAPPER
+  . = ALIGN(256);
   .got :
   {
     __toc_start = .;

-- 
2.7.4

On Tue, 2017-03-07 at 23:40:21 UTC, Michael Ellerman wrote:

Recent toolchains force the TOC to be 256 byte aligned. We need to
enforce this alignment in the zImage linker script, otherwise pointers
to our TOC variables (__toc_start) could be incorrect. If the actual
start of the TOC and __toc_start don't have the same value we crash
early in the zImage wrapper.

Cc: stable@vger.kernel.org
Suggested-by: Alan Modra <redacted>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Applied to powerpc fixes.

https://git.kernel.org/powerpc/c/97ee351b50a49717543533cfb85b4b

cheers