Re: [PATCH 3/3] ia64: remove generated/nr-irqs.h generation to fix build warning

[Masahiro Yamada]

On Sat, Aug 29, 2020 at 2:15 PM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
>
> Randy reports the following warning when building ARCH=ia64 with
> CONFIG_IA64_PALINFO=m:
>
> ../scripts/Makefile.build:68: 'arch/ia64/kernel/palinfo.ko' will not be built even though obj-m is specified.
> ../scripts/Makefile.build:69: You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.
>
> This message is actually false-positive, and you can get palinfo.ko
> correctly built. It is emitted in the archprepare stage, where Kbuild
> descends into arch/ia64/kernel to generate include/generated/nr-irqs.h
> instead of any kind of kernel objects.
>
> arch/ia64/kernel/nr-irqs.c was introduced by commit 213060a4d699
> ("[IA64] pvops: paravirtualize NR_IRQS") to pre-calculate:
>
>    NR_IRQS = max(IA64_NATIVE_NR_IRQS, XEN_NR_IRQS, FOO_NR_IRQS...)
>
> Since commit d52eefb47d4e ("ia64/xen: Remove Xen support for ia64"), this
> union contains just one field, making NR_IRQS and IA64_NATIVE_NR_IRQS
> always match.
>
> So, the following hard-coding now works:
>
>   #define NR_IRQS                IA64_NATIVE_NR_IRQS
>
> If you need to re-introduce NR_IRQS = max(...) gimmick in the future,
> please try to implement it in asm-offsets.c instead of a separate file.
> It will be possible because the header inclusion has been consolidated
> to make asm-offsets.c independent of <asm/irqs.h>.
>
> Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>


This build issue is still remaining.

I will send this series in the next MW
via my kbuild tree.





> ---
>
>  arch/ia64/Makefile          |  6 ------
>  arch/ia64/include/asm/irq.h |  4 +++-
>  arch/ia64/kernel/Makefile   |  5 -----
>  arch/ia64/kernel/nr-irqs.c  | 22 ----------------------
>  4 files changed, 3 insertions(+), 34 deletions(-)
>  delete mode 100644 arch/ia64/kernel/nr-irqs.c
>
> diff --git a/arch/ia64/Makefile b/arch/ia64/Makefile
> index 2876a7df1b0a..3d54d411fcc4 100644
> --- a/arch/ia64/Makefile
> +++ b/arch/ia64/Makefile
> @@ -87,9 +87,3 @@ define archhelp
>    echo '  install      - Install compressed kernel image'
>    echo '* unwcheck     - Check vmlinux for invalid unwind info'
>  endef
> -
> -archprepare: make_nr_irqs_h
> -PHONY += make_nr_irqs_h
> -
> -make_nr_irqs_h:
> -       $(Q)$(MAKE) $(build)=arch/ia64/kernel include/generated/nr-irqs.h
> diff --git a/arch/ia64/include/asm/irq.h b/arch/ia64/include/asm/irq.h
> index 5acf52e90872..0eccf33dfe8b 100644
> --- a/arch/ia64/include/asm/irq.h
> +++ b/arch/ia64/include/asm/irq.h
> @@ -14,7 +14,9 @@
>
>  #include <linux/types.h>
>  #include <linux/cpumask.h>
> -#include <generated/nr-irqs.h>
> +#include <asm/native/irq.h>
> +
> +#define NR_IRQS                IA64_NATIVE_NR_IRQS
>
>  static __inline__ int
>  irq_canonicalize (int irq)
> diff --git a/arch/ia64/kernel/Makefile b/arch/ia64/kernel/Makefile
> index 1a8df6669eee..7c9354ee4b3e 100644
> --- a/arch/ia64/kernel/Makefile
> +++ b/arch/ia64/kernel/Makefile
> @@ -48,8 +48,3 @@ CFLAGS_traps.o  += -mfixed-range=f2-f5,f16-f31
>
>  # The gate DSO image is built using a special linker script.
>  include $(src)/Makefile.gate
> -
> -include/generated/nr-irqs.h: arch/$(SRCARCH)/kernel/nr-irqs.s FORCE
> -       $(call filechk,offsets,__ASM_NR_IRQS_H__)
> -
> -targets += nr-irqs.s
> diff --git a/arch/ia64/kernel/nr-irqs.c b/arch/ia64/kernel/nr-irqs.c
> deleted file mode 100644
> index f2633b22d3be..000000000000
> --- a/arch/ia64/kernel/nr-irqs.c
> +++ /dev/null
> @@ -1,22 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/*
> - * calculate
> - * NR_IRQS = max(IA64_NATIVE_NR_IRQS, XEN_NR_IRQS, FOO_NR_IRQS...)
> - * depending on config.
> - * This must be calculated before processing asm-offset.c.
> - */
> -
> -#define ASM_OFFSETS_C 1
> -
> -#include <linux/kbuild.h>
> -#include <linux/threads.h>
> -#include <asm/native/irq.h>
> -
> -void foo(void)
> -{
> -       union paravirt_nr_irqs_max {
> -               char ia64_native_nr_irqs[IA64_NATIVE_NR_IRQS];
> -       };
> -
> -       DEFINE(NR_IRQS, sizeof (union paravirt_nr_irqs_max));
> -}
> --
> 2.25.1
>


-- 
Best Regards
Masahiro Yamada