firmware_loader: align .builtin_fw to 8

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-maskray@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 <maskray@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Fangrui Song 2021-02-09 13:42:07 -08:00 committed by Linus Torvalds
parent 1cc4cdb521
commit 793f49a87a

View File

@ -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 = .; \