Thread (11 messages) 11 messages, 5 authors, 2021-02-05

Re: [PATCH v2] firmware_loader: Align .builtin_fw to 8

From: Doug Anderson <dianders@chromium.org>
Date: 2021-01-22 19:35:24
Also in: lkml

Hi,

On Tue, Jan 5, 2021 at 11:20 AM Nick Desaulniers
[off-list ref] wrote:
On Tue, Jan 5, 2021 at 9:45 AM Doug Anderson [off-list ref] wrote:
quoted
Hi,

On Mon, Dec 7, 2020 at 9:49 PM Fangrui Song [off-list ref] wrote:
quoted
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>

---
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(-)
Tested-by: Douglas Anderson <dianders@chromium.org>

For whatever reason this is hitting developers on Chrome OS a whole
lot suddenly.  Any chance it could be landed?  Which tree should it go
through?
Andrew,
Would you mind picking up this patch for us, please?
https://lore.kernel.org/lkml/20201208054646.2913063-1-maskray@google.com/ (local)
I just synced today and I'm still hitting this error when building
mainline.  Perhaps Andrew is busy and someone else can pick it up?
It'd be nice to get this into v5.11

-Doug
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