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ia64: remove generated/nr-irqs.h generation to fix build warning 

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 213060a4d6
("[IA64] pvops: paravirtualize NR_IRQS") to pre-calculate:

   NR_IRQS = max(IA64_NATIVE_NR_IRQS, XEN_NR_IRQS, FOO_NR_IRQS...)

Since commit d52eefb47d ("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@infradead.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
master
Masahiro Yamada 2020-08-29 14:15:24 +09:00
parent a5b7c61ee6
commit fa1e160b08
4 changed files with 3 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
arch/ia64/Makefile
View File

@ -86,9 +86,3 @@ 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

4
arch/ia64/include/asm/irq.h
View File

@ -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)

5
arch/ia64/kernel/Makefile
View File

@ -47,8 +47,3 @@ 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

22
arch/ia64/kernel/nr-irqs.c
View File

@ -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));
}