From: Fangrui Song <mask...@google.com>

[ Upstream commit 793f49a87aae24e5bcf92ad98d764153fc936570 ]

arm64 references the start address of .builtin_fw (__start_builtin_fw)
with a pair of R_AARCH64_ADR_PREL_PG_HI21/R_AARCH64_LDST64_ABS_LO12_NC
relocations.  The compiler is allowed to emit the
R_AARCH64_LDST64_ABS_LO12_NC relocation because struct builtin_fw in
include/linux/firmware.h is 8-byte aligned.

The R_AARCH64_LDST64_ABS_LO12_NC relocation requires the address to be a
multiple of 8, which may not be the case if .builtin_fw is empty.
Unconditionally align .builtin_fw to fix the linker error.  32-bit
architectures could use ALIGN(4) but that would add unnecessary
complexity, so just use ALIGN(8).

Link: https://lkml.kernel.org/r/20201208054646.2913063-1-mask...@google.com
Link: https://github.com/ClangBuiltLinux/linux/issues/1204
Fixes: 5658c76 ("firmware: allow firmware files to be built into kernel image")
Signed-off-by: Fangrui Song <mask...@google.com>
Reported-by: kernel test robot <l...@intel.com>
Acked-by: Arnd Bergmann <a...@arndb.de>
Reviewed-by: Nick Desaulniers <ndesaulni...@google.com>
Tested-by: Nick Desaulniers <ndesaulni...@google.com>
Tested-by: Douglas Anderson <diand...@chromium.org>
Acked-by: Nathan Chancellor <nat...@kernel.org>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 include/asm-generic/vmlinux.lds.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/asm-generic/vmlinux.lds.h 
b/include/asm-generic/vmlinux.lds.h
index b2b3d81b1535a..b97c628ad91ff 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -459,7 +459,7 @@
        }                                                               \
                                                                        \
        /* Built-in firmware blobs */                                   \
-       .builtin_fw        : AT(ADDR(.builtin_fw) - LOAD_OFFSET) {      \
+       .builtin_fw : AT(ADDR(.builtin_fw) - LOAD_OFFSET) ALIGN(8) {    \
                __start_builtin_fw = .;                                 \
                KEEP(*(.builtin_fw))                                    \
                __end_builtin_fw = .;                                   \
-- 
2.27.0



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