From: Fangrui Song <maskray@google.com>
To: Arnd Bergmann <arnd@arndb.de>, linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
Nathan Chancellor <natechancellor@gmail.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Fangrui Song <maskray@google.com>,
kernel test robot <lkp@intel.com>
Subject: [PATCH v2] firmware_loader: Align .builtin_fw to 8
Date: Mon, 7 Dec 2020 21:46:46 -0800 [thread overview]
Message-ID: <20201208054646.2913063-1-maskray@google.com> (raw)
In-Reply-To: <20201203202737.7c4wrifqafszyd5y@google.com>
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 <lkp@intel.com>
Signed-off-by: Fangrui Song <maskray@google.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
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
next prev parent reply other threads:[~2020-12-08 5:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-03 17:05 [PATCH] firmware_loader: Align .builtin_fw to 8 Fangrui Song
2020-12-03 18:00 ` Arnd Bergmann
2020-12-03 19:04 ` Nick Desaulniers
2020-12-03 20:27 ` Fangrui Song
2020-12-08 5:46 ` Fangrui Song [this message]
2020-12-08 17:59 ` [PATCH v2] " Nick Desaulniers
2021-01-05 17:44 ` Doug Anderson
2021-01-05 19:20 ` Nick Desaulniers
2021-01-22 19:04 ` Doug Anderson
2021-02-05 17:19 ` Doug Anderson
2021-02-05 19:08 ` Nathan Chancellor
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