From: Paul Mackerras paulus@ozlabs.org
[ Upstream commit 5564597d51c8ff5b88d95c76255e18b13b760879 ]
Commit 6975a783d7b4 ("powerpc/boot: Allow building the zImage wrapper as a relocatable ET_DYN", 2011-04-12) changed the procedure descriptor at the start of crt0.S to have a hard-coded start address of 0x500000 rather than a reference to _zimage_start, presumably because having a reference to a symbol introduced a relocation which is awkward to handle in a position-independent executable. Unfortunately, what is at 0x500000 in the COFF image is not the first instruction, but the procedure descriptor itself, that is, a word containing 0x500000, which is not a valid instruction. Hence, booting a COFF zImage results in a "DEFAULT CATCH!, code=FFF00700" message from Open Firmware.
This fixes the problem by (a) putting the procedure descriptor in the data section and (b) adding a branch to _zimage_start as the first instruction in the program.
Fixes: 6975a783d7b4 ("powerpc/boot: Allow building the zImage wrapper as a relocatable ET_DYN") Signed-off-by: Paul Mackerras paulus@ozlabs.org Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/boot/crt0.S | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/boot/crt0.S b/arch/powerpc/boot/crt0.S index 32dfe6d083f3..9b9d17437373 100644 --- a/arch/powerpc/boot/crt0.S +++ b/arch/powerpc/boot/crt0.S @@ -15,7 +15,7 @@ RELA = 7 RELACOUNT = 0x6ffffff9
- .text + .data /* A procedure descriptor used when booting this as a COFF file. * When making COFF, this comes first in the link and we're * linked at 0x500000. @@ -23,6 +23,8 @@ RELACOUNT = 0x6ffffff9 .globl _zimage_start_opd _zimage_start_opd: .long 0x500000, 0, 0, 0 + .text + b _zimage_start
#ifdef __powerpc64__ .balign 8