+ firmware_loader-align-builtin_fw-to-8.patch added to -mm tree

+ firmware_loader-align-builtin_fw-to-8.patch added to -mm tree

[akpm]

The patch titled
     Subject: firmware_loader: align .builtin_fw to 8
has been added to the -mm tree.  Its filename is
     firmware_loader-align-builtin_fw-to-8.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/firmware_loader-align-builtin_fw-to-8.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/firmware_loader-align-builtin_fw-to-8.patch

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------------------------------------------------------
From: Fangrui Song <maskray@google.com>
Subject: 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>
---

 include/asm-generic/vmlinux.lds.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/asm-generic/vmlinux.lds.h~firmware_loader-align-builtin_fw-to-8
+++ a/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 = .;					\
_

Patches currently in -mm which might be from maskray@google.com are

firmware_loader-align-builtin_fw-to-8.patch