Re: [PATCH v2] firmware_loader: Align .builtin_fw to 8
From: Nathan Chancellor <nathan@kernel.org>
Date: 2021-02-05 19:11:59
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On Mon, Dec 07, 2020 at 09:46:46PM -0800, Fangrui Song wrote:
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).
Fixes: 5658c76 ("firmware: allow firmware files to be built into kernel image")
Link: https://github.com/ClangBuiltLinux/linux/issues/1204
Reported-by: kernel test robot <redacted>
Signed-off-by: Fangrui Song <redacted>
Acked-by: Arnd Bergmann <arnd@arndb.de>Acked-by: Nathan Chancellor <nathan@kernel.org> Andrew, is there any way to get this picked up with the following tags for 5.11? Tested-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Nick Desaulniers <redacted> Tested-by: Nick Desaulniers <redacted> If not, please let me know and I can try to shuffle this along to Linus next week.
quoted hunk ↗ jump to hunk
--- Change in v2: * Use output section alignment instead of inappropriate ALIGN_FUNCTION() --- 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 b2b3d81b1535..b97c628ad91f 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 = .; \-- 2.29.2.576.ga3fc446d84-goog