Szabolcs Nagy ran into a kernel build failure with a custom gcc
toochain that sets -mfpu=auto -mfloat-abi=hard:
/tmp/ccmNdcdf.s:1898: Error: selected processor does not support `cpsid i' in ARM mode
The problem is that $(call cc-option, -march=armv7-a) fails before the
kernel overrides the gcc options to also pass -msoft-float.
Move the option to the beginning the Makefile, before we call
cc-option for the first time.
Reported-by: Szabolcs Nagy <[email protected]>
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87302
Signed-off-by: Arnd Bergmann <[email protected]>
---
arch/arm/Makefile | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 7d5cd0f85461..e428ea6eb0fa 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -16,6 +16,8 @@ LDFLAGS_vmlinux += --be8
KBUILD_LDFLAGS_MODULE += --be8
endif
+KBUILD_CFLAGS += -msoft-float
+
ifeq ($(CONFIG_ARM_MODULE_PLTS),y)
KBUILD_LDS_MODULE += $(srctree)/arch/arm/kernel/module.lds
endif
@@ -135,7 +137,7 @@ AFLAGS_ISA :=$(CFLAGS_ISA)
endif
# Need -Uarm for gcc < 3.x
-KBUILD_CFLAGS +=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -msoft-float -Uarm
+KBUILD_CFLAGS +=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -Uarm
KBUILD_AFLAGS +=$(CFLAGS_ABI) $(AFLAGS_ISA) $(arch-y) $(tune-y) -include asm/unified.h -msoft-float
CHECKFLAGS += -D__arm__
--
2.26.2
On Tue, May 19, 2020 at 3:09 PM Arnd Bergmann <[email protected]> wrote:
>
> Szabolcs Nagy ran into a kernel build failure with a custom gcc
> toochain that sets -mfpu=auto -mfloat-abi=hard:
>
> /tmp/ccmNdcdf.s:1898: Error: selected processor does not support `cpsid i' in ARM mode
>
> The problem is that $(call cc-option, -march=armv7-a) fails before the
> kernel overrides the gcc options to also pass -msoft-float.
The call to `$(call cc-option, -march=armv7-a)
>
> Move the option to the beginning the Makefile, before we call
beginning of the
> cc-option for the first time.
>
> Reported-by: Szabolcs Nagy <[email protected]>
> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87302
> Signed-off-by: Arnd Bergmann <[email protected]>
Moving this looks harmless enough, though it's not clear to me how the
failure you're describing would occur. I don't see calls to as-instr
in arch/arm/Makefile. Which object is being built before -msoft-float
is being set?
> ---
> arch/arm/Makefile | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/Makefile b/arch/arm/Makefile
> index 7d5cd0f85461..e428ea6eb0fa 100644
> --- a/arch/arm/Makefile
> +++ b/arch/arm/Makefile
> @@ -16,6 +16,8 @@ LDFLAGS_vmlinux += --be8
> KBUILD_LDFLAGS_MODULE += --be8
> endif
>
> +KBUILD_CFLAGS += -msoft-float
> +
> ifeq ($(CONFIG_ARM_MODULE_PLTS),y)
> KBUILD_LDS_MODULE += $(srctree)/arch/arm/kernel/module.lds
> endif
> @@ -135,7 +137,7 @@ AFLAGS_ISA :=$(CFLAGS_ISA)
> endif
>
> # Need -Uarm for gcc < 3.x
> -KBUILD_CFLAGS +=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -msoft-float -Uarm
> +KBUILD_CFLAGS +=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -Uarm
> KBUILD_AFLAGS +=$(CFLAGS_ABI) $(AFLAGS_ISA) $(arch-y) $(tune-y) -include asm/unified.h -msoft-float
>
> CHECKFLAGS += -D__arm__
> --
> 2.26.2
>
--
Thanks,
~Nick Desaulniers
sorry, hit tab/enter too soon...
On Tue, May 19, 2020 at 5:37 PM Nick Desaulniers
<[email protected]> wrote:
>
> On Tue, May 19, 2020 at 3:09 PM Arnd Bergmann <[email protected]> wrote:
> >
> > Szabolcs Nagy ran into a kernel build failure with a custom gcc
> > toochain that sets -mfpu=auto -mfloat-abi=hard:
> >
> > /tmp/ccmNdcdf.s:1898: Error: selected processor does not support `cpsid i' in ARM mode
> >
> > The problem is that $(call cc-option, -march=armv7-a) fails before the
> > kernel overrides the gcc options to also pass -msoft-float.
>
> The call to `$(call cc-option, -march=armv7-a) is th
The call to `$(call cc-option, -march=armv7-a) is the one that fails or...?
>
> >
> > Move the option to the beginning the Makefile, before we call
>
> beginning of the
>
> > cc-option for the first time.
> >
> > Reported-by: Szabolcs Nagy <[email protected]>
> > Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87302
> > Signed-off-by: Arnd Bergmann <[email protected]>
>
> Moving this looks harmless enough, though it's not clear to me how the
> failure you're describing would occur. I don't see calls to as-instr
> in arch/arm/Makefile. Which object is being built before -msoft-float
> is being set?
... ^
>
> > ---
> > arch/arm/Makefile | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/arm/Makefile b/arch/arm/Makefile
> > index 7d5cd0f85461..e428ea6eb0fa 100644
> > --- a/arch/arm/Makefile
> > +++ b/arch/arm/Makefile
> > @@ -16,6 +16,8 @@ LDFLAGS_vmlinux += --be8
> > KBUILD_LDFLAGS_MODULE += --be8
> > endif
> >
> > +KBUILD_CFLAGS += -msoft-float
> > +
> > ifeq ($(CONFIG_ARM_MODULE_PLTS),y)
> > KBUILD_LDS_MODULE += $(srctree)/arch/arm/kernel/module.lds
> > endif
> > @@ -135,7 +137,7 @@ AFLAGS_ISA :=$(CFLAGS_ISA)
> > endif
> >
> > # Need -Uarm for gcc < 3.x
> > -KBUILD_CFLAGS +=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -msoft-float -Uarm
> > +KBUILD_CFLAGS +=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -Uarm
> > KBUILD_AFLAGS +=$(CFLAGS_ABI) $(AFLAGS_ISA) $(arch-y) $(tune-y) -include asm/unified.h -msoft-float
> >
> > CHECKFLAGS += -D__arm__
> > --
> > 2.26.2
> >
--
Thanks,
~Nick Desaulniers
The 05/19/2020 17:38, Nick Desaulniers wrote:
> sorry, hit tab/enter too soon...
>
> On Tue, May 19, 2020 at 5:37 PM Nick Desaulniers
> <[email protected]> wrote:
> >
> > On Tue, May 19, 2020 at 3:09 PM Arnd Bergmann <[email protected]> wrote:
> > >
> > > Szabolcs Nagy ran into a kernel build failure with a custom gcc
> > > toochain that sets -mfpu=auto -mfloat-abi=hard:
> > >
> > > /tmp/ccmNdcdf.s:1898: Error: selected processor does not support `cpsid i' in ARM mode
> > >
> > > The problem is that $(call cc-option, -march=armv7-a) fails before the
> > > kernel overrides the gcc options to also pass -msoft-float.
> >
> > The call to `$(call cc-option, -march=armv7-a) is th
>
> The call to `$(call cc-option, -march=armv7-a) is the one that fails or...?
the flag -march=armv7-a is invalid if the float abi
is hard and no fpu is specified (since gcc-8).
either an fpu should be specified or -march=armv7-a+fp
(my toolchain was configured with the latter and it does
not work if the kernel overrides it with -march=armv7-a)
because of this cc-option failure the kernel goes on to
pass nonsense flags everywhere (-march=armv5t) and some
compilation eventually fails with an asm error.
> > >
> > > Move the option to the beginning the Makefile, before we call
> >
> > beginning of the
> >
> > > cc-option for the first time.
> > >
> > > Reported-by: Szabolcs Nagy <[email protected]>
> > > Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87302
> > > Signed-off-by: Arnd Bergmann <[email protected]>
> >
> > Moving this looks harmless enough, though it's not clear to me how the
> > failure you're describing would occur. I don't see calls to as-instr
> > in arch/arm/Makefile. Which object is being built before -msoft-float
> > is being set?
>
> ... ^
>
> >
> > > ---
> > > arch/arm/Makefile | 4 +++-
> > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/arch/arm/Makefile b/arch/arm/Makefile
> > > index 7d5cd0f85461..e428ea6eb0fa 100644
> > > --- a/arch/arm/Makefile
> > > +++ b/arch/arm/Makefile
> > > @@ -16,6 +16,8 @@ LDFLAGS_vmlinux += --be8
> > > KBUILD_LDFLAGS_MODULE += --be8
> > > endif
> > >
> > > +KBUILD_CFLAGS += -msoft-float
> > > +
> > > ifeq ($(CONFIG_ARM_MODULE_PLTS),y)
> > > KBUILD_LDS_MODULE += $(srctree)/arch/arm/kernel/module.lds
> > > endif
> > > @@ -135,7 +137,7 @@ AFLAGS_ISA :=$(CFLAGS_ISA)
> > > endif
> > >
> > > # Need -Uarm for gcc < 3.x
> > > -KBUILD_CFLAGS +=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -msoft-float -Uarm
> > > +KBUILD_CFLAGS +=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -Uarm
> > > KBUILD_AFLAGS +=$(CFLAGS_ABI) $(AFLAGS_ISA) $(arch-y) $(tune-y) -include asm/unified.h -msoft-float
> > >
> > > CHECKFLAGS += -D__arm__
> > > --
> > > 2.26.2
> > >
>
> --
> Thanks,
> ~Nick Desaulniers
--
On Wed, May 20, 2020 at 1:36 AM Szabolcs Nagy <[email protected]> wrote:
>
> The 05/19/2020 17:38, Nick Desaulniers wrote:
> > sorry, hit tab/enter too soon...
> >
> > On Tue, May 19, 2020 at 5:37 PM Nick Desaulniers
> > <[email protected]> wrote:
> > >
> > > On Tue, May 19, 2020 at 3:09 PM Arnd Bergmann <[email protected]> wrote:
> > > >
> > > > Szabolcs Nagy ran into a kernel build failure with a custom gcc
> > > > toochain that sets -mfpu=auto -mfloat-abi=hard:
> > > >
> > > > /tmp/ccmNdcdf.s:1898: Error: selected processor does not support `cpsid i' in ARM mode
> > > >
> > > > The problem is that $(call cc-option, -march=armv7-a) fails before the
> > > > kernel overrides the gcc options to also pass -msoft-float.
> > >
> > > The call to `$(call cc-option, -march=armv7-a) is th
> >
> > The call to `$(call cc-option, -march=armv7-a) is the one that fails or...?
>
> the flag -march=armv7-a is invalid if the float abi
> is hard and no fpu is specified (since gcc-8).
>
> either an fpu should be specified or -march=armv7-a+fp
> (my toolchain was configured with the latter and it does
> not work if the kernel overrides it with -march=armv7-a)
>
> because of this cc-option failure the kernel goes on to
> pass nonsense flags everywhere (-march=armv5t) and some
> compilation eventually fails with an asm error.
Cool, thanks for the additional info. Arnd, if you wanted to include
more of that snippet the commit message when submitting, I wouldn't
complain. :)
Reviewed-by: Nick Desaulniers <[email protected]>
>
> > > >
> > > > Move the option to the beginning the Makefile, before we call
> > >
> > > beginning of the
> > >
> > > > cc-option for the first time.
> > > >
> > > > Reported-by: Szabolcs Nagy <[email protected]>
> > > > Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87302
> > > > Signed-off-by: Arnd Bergmann <[email protected]>
> > >
> > > Moving this looks harmless enough, though it's not clear to me how the
> > > failure you're describing would occur. I don't see calls to as-instr
> > > in arch/arm/Makefile. Which object is being built before -msoft-float
> > > is being set?
> >
> > ... ^
> >
> > >
> > > > ---
> > > > arch/arm/Makefile | 4 +++-
> > > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/arch/arm/Makefile b/arch/arm/Makefile
> > > > index 7d5cd0f85461..e428ea6eb0fa 100644
> > > > --- a/arch/arm/Makefile
> > > > +++ b/arch/arm/Makefile
> > > > @@ -16,6 +16,8 @@ LDFLAGS_vmlinux += --be8
> > > > KBUILD_LDFLAGS_MODULE += --be8
> > > > endif
> > > >
> > > > +KBUILD_CFLAGS += -msoft-float
> > > > +
> > > > ifeq ($(CONFIG_ARM_MODULE_PLTS),y)
> > > > KBUILD_LDS_MODULE += $(srctree)/arch/arm/kernel/module.lds
> > > > endif
> > > > @@ -135,7 +137,7 @@ AFLAGS_ISA :=$(CFLAGS_ISA)
> > > > endif
> > > >
> > > > # Need -Uarm for gcc < 3.x
> > > > -KBUILD_CFLAGS +=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -msoft-float -Uarm
> > > > +KBUILD_CFLAGS +=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -Uarm
> > > > KBUILD_AFLAGS +=$(CFLAGS_ABI) $(AFLAGS_ISA) $(arch-y) $(tune-y) -include asm/unified.h -msoft-float
> > > >
> > > > CHECKFLAGS += -D__arm__
> > > > --
> > > > 2.26.2
> > > >
> >
> > --
> > Thanks,
> > ~Nick Desaulniers
>
> --
--
Thanks,
~Nick Desaulniers