From: Ard Biesheuvel ard.biesheuvel@linaro.org

[ Upstream commit 60ce2858514ed9ccaf00dc7e9f4dc219537e9855 ]

Commit 06a4b6d009a1 ("ARM: 8677/1: boot/compressed: fix decompressor header layout for v7-M") fixed an issue in the layout of the header of the compressed kernel image that was caused by the assembler emitting narrow opcodes for 'mov r0, r0', and for this reason, the mnemonic was updated to use the W() macro, which will append the .w suffix (which forces a wide encoding) if required, i.e., when building the kernel in Thumb2 mode.

However, this failed to take into account that on Thumb2 kernels built for CPUs that are also ARM capable, the entry point is entered in ARM mode, and so the instructions emitted here will be ARM instructions that only exist in a wide encoding to begin with, which is why the assembler rejects the .w suffix here and aborts the build with the following message:

head.S: Assembler messages: head.S:132: Error: width suffixes are invalid in ARM mode -- `mov.w r0,r0'

So replace the W(mov) with separate ARM and Thumb2 instructions, where the latter will only be used for THUMB2_ONLY builds.

Fixes: 06a4b6d009a1 ("ARM: 8677/1: boot/compressed: fix decompressor ...") Reported-by: Arnd Bergmann arnd@arndb.de Acked-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org Signed-off-by: Russell King rmk+kernel@armlinux.org.uk Signed-off-by: Chris Brandt chris.brandt@renesas.com ---

For the 4.9.x tree, commit 7b5407843691 was applied, but that caused an issue for CONFIG_THUMB2 builds as you can see in the commit message above.

Therefore, this upstream fix (that came 2 weeks later) is also required in the 4.9.x tree to make it build again. --- arch/arm/boot/compressed/efi-header.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/compressed/efi-header.S b/arch/arm/boot/compressed/efi-header.S index 3f7d1b74c5e0..a17ca8d78656 100644 --- a/arch/arm/boot/compressed/efi-header.S +++ b/arch/arm/boot/compressed/efi-header.S @@ -17,7 +17,8 @@ @ there. .inst 'M' | ('Z' << 8) | (0x1310 << 16) @ tstne r0, #0x4d000 #else - W(mov) r0, r0 + AR_CLASS( mov r0, r0 ) + M_CLASS( nop.w ) #endif .endm