$(call ld-option, --fix-cortex-a53-843419) in arch/arm64/Makefile is
evaluated every time even for Make targets that do not need the linker,
such as "make ARCH=arm64 install".
Recently, the Kbuild tree queued up a patch to avoid needless
compiler/linker flag evaluation. I beleive it is a good improvement
itself, but causing a false-positive warning for arm64 installation
in linux-next. (Thanks to Nathan for the report)
Kconfig can test the linker capability just once, and store it in the
.config file. The build and installation steps that follow do not need
to test the liniker over again.
Reported-by: Nathan Chancellor <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>
---
I was not sure what the preferred CONFIG option name is.
Please suggest a one if you have a better idea.
arch/arm64/Kconfig | 3 +++
arch/arm64/Makefile | 2 +-
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 5656e7aacd69..4a33428de8ac 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -521,6 +521,9 @@ config ARM64_ERRATUM_843419
If unsure, say Y.
+config ARM64_LD_HAS_FIX_ERRATUM_843419
+ def_bool $(ld-option,--fix-cortex-a53-843419)
+
config ARM64_ERRATUM_1024718
bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
default y
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 5b84aec31ed3..7ef44478560d 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -21,7 +21,7 @@ LDFLAGS_vmlinux += -shared -Bsymbolic -z notext \
endif
ifeq ($(CONFIG_ARM64_ERRATUM_843419),y)
- ifeq ($(call ld-option, --fix-cortex-a53-843419),)
+ ifneq ($(CONFIG_ARM64_LD_HAS_FIX_ERRATUM_843419),y)
$(warning ld does not support --fix-cortex-a53-843419; kernel may be susceptible to erratum)
else
LDFLAGS_vmlinux += --fix-cortex-a53-843419
--
2.27.0
Hi Masahiro,
On Wed, Mar 24, 2021 at 04:11:28PM +0900, Masahiro Yamada wrote:
> $(call ld-option, --fix-cortex-a53-843419) in arch/arm64/Makefile is
> evaluated every time even for Make targets that do not need the linker,
> such as "make ARCH=arm64 install".
>
> Recently, the Kbuild tree queued up a patch to avoid needless
> compiler/linker flag evaluation. I beleive it is a good improvement
> itself, but causing a false-positive warning for arm64 installation
> in linux-next. (Thanks to Nathan for the report)
>
> Kconfig can test the linker capability just once, and store it in the
> .config file. The build and installation steps that follow do not need
> to test the liniker over again.
>
> Reported-by: Nathan Chancellor <[email protected]>
> Signed-off-by: Masahiro Yamada <[email protected]>
> ---
>
> I was not sure what the preferred CONFIG option name is.
> Please suggest a one if you have a better idea.
>
>
> arch/arm64/Kconfig | 3 +++
> arch/arm64/Makefile | 2 +-
> 2 files changed, 4 insertions(+), 1 deletion(-)
Would you like this patch to go in via the arm64 tree or you will queue
it via the kbuild tree?
Thanks.
--
Catalin
On Fri, Mar 26, 2021 at 11:36 PM Catalin Marinas
<[email protected]> wrote:
>
> Hi Masahiro,
>
> On Wed, Mar 24, 2021 at 04:11:28PM +0900, Masahiro Yamada wrote:
> > $(call ld-option, --fix-cortex-a53-843419) in arch/arm64/Makefile is
> > evaluated every time even for Make targets that do not need the linker,
> > such as "make ARCH=arm64 install".
> >
> > Recently, the Kbuild tree queued up a patch to avoid needless
> > compiler/linker flag evaluation. I beleive it is a good improvement
> > itself, but causing a false-positive warning for arm64 installation
> > in linux-next. (Thanks to Nathan for the report)
> >
> > Kconfig can test the linker capability just once, and store it in the
> > .config file. The build and installation steps that follow do not need
> > to test the liniker over again.
> >
> > Reported-by: Nathan Chancellor <[email protected]>
> > Signed-off-by: Masahiro Yamada <[email protected]>
> > ---
> >
> > I was not sure what the preferred CONFIG option name is.
> > Please suggest a one if you have a better idea.
> >
> >
> > arch/arm64/Kconfig | 3 +++
> > arch/arm64/Makefile | 2 +-
> > 2 files changed, 4 insertions(+), 1 deletion(-)
>
> Would you like this patch to go in via the arm64 tree or you will queue
> it via the kbuild tree?
I applied this to linux-kbuild with Will's Ack.
Thanks.
--
Best Regards
Masahiro Yamada
On Sun, Mar 28, 2021 at 03:59:29PM +0900, Masahiro Yamada wrote:
> On Fri, Mar 26, 2021 at 11:36 PM Catalin Marinas
> <[email protected]> wrote:
> > On Wed, Mar 24, 2021 at 04:11:28PM +0900, Masahiro Yamada wrote:
> > > $(call ld-option, --fix-cortex-a53-843419) in arch/arm64/Makefile is
> > > evaluated every time even for Make targets that do not need the linker,
> > > such as "make ARCH=arm64 install".
> > >
> > > Recently, the Kbuild tree queued up a patch to avoid needless
> > > compiler/linker flag evaluation. I beleive it is a good improvement
> > > itself, but causing a false-positive warning for arm64 installation
> > > in linux-next. (Thanks to Nathan for the report)
> > >
> > > Kconfig can test the linker capability just once, and store it in the
> > > .config file. The build and installation steps that follow do not need
> > > to test the liniker over again.
> > >
> > > Reported-by: Nathan Chancellor <[email protected]>
> > > Signed-off-by: Masahiro Yamada <[email protected]>
> > > ---
> > >
> > > I was not sure what the preferred CONFIG option name is.
> > > Please suggest a one if you have a better idea.
> > >
> > >
> > > arch/arm64/Kconfig | 3 +++
> > > arch/arm64/Makefile | 2 +-
> > > 2 files changed, 4 insertions(+), 1 deletion(-)
> >
> > Would you like this patch to go in via the arm64 tree or you will queue
> > it via the kbuild tree?
>
> I applied this to linux-kbuild with Will's Ack.
Great, I'll cross it off my list. Thanks.
--
Catalin