Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 91998731 authored by Masahiro Yamada's avatar Masahiro Yamada
Browse files

kbuild: generate asm-generic wrappers if mandatory headers are missing 

Some time ago, Sam pointed out a certain degree of overwrap between
generic-y and mandatory-y. (https://lkml.org/lkml/2017/7/10/121

)

I tweaked the meaning of mandatory-y a little bit; now it defines the
minimum set of ASM headers that all architectures must have.

If arch does not have specific implementation of a mandatory header,
Kbuild will let it fallback to the asm-generic one by automatically
generating a wrapper. This will allow to drop lots of redundant
generic-y defines.

Previously, "mandatory" was used in the context of UAPI, but I guess
this can be extended to kernel space ASM headers.

Suggested-by: default avatarSam Ravnborg <sam@ravnborg.org>
Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: default avatarSam Ravnborg <sam@ravnborg.org>
parent d4ce5458

Documentation/kbuild/makefiles.txt

+6 −3
Original line number Diff line number Diff line
@@ -1296,9 +1296,12 @@ See subsequent chapter for the syntax of the Kbuild file. 


--- 7.4 mandatory-y



	mandatory-y is essentially used by include/uapi/asm-generic/Kbuild.asm

	to define the minimum set of headers that must be exported in

	include/asm.

	mandatory-y is essentially used by include/(uapi/)asm-generic/Kbuild.asm

	to define the minimum set of ASM headers that all architectures must have.



	This works like optional generic-y. If a mandatory header is missing

	in arch/$(ARCH)/include/(uapi/)/asm, Kbuild will automatically generate

	a wrapper of the asm-generic one.



	The convention is to list one subdir per line and

	preferably in alphabetic order.

scripts/Makefile.asm-generic

+4 −0
Original line number Diff line number Diff line
@@ -14,6 +14,10 @@ src := $(subst /generated,,$(obj)) 


include scripts/Kbuild.include



# If arch does not implement mandatory headers, fallback to asm-generic ones.

mandatory-y := $(filter-out $(generated-y), $(mandatory-y))

generic-y   += $(foreach f, $(mandatory-y), $(if $(wildcard $(srctree)/$(src)/$(f)),,$(f)))



generic-y   := $(addprefix $(obj)/, $(generic-y))

generated-y := $(addprefix $(obj)/, $(generated-y))

scripts/Makefile.headersinst

+0 −7
Original line number Diff line number Diff line
@@ -56,13 +56,6 @@ check-file := $(installdir)/.check 
all-files     := $(header-files) $(genhdr-files)

output-files  := $(addprefix $(installdir)/, $(all-files))



ifneq ($(mandatory-y),)

missing       := $(filter-out $(all-files),$(mandatory-y))

ifneq ($(missing),)

$(error Some mandatory headers ($(missing)) are missing in $(obj))

endif

endif



# Work out what needs to be removed

oldheaders    := $(patsubst $(installdir)/%,%,$(wildcard $(installdir)/*.h))

unwanted      := $(filter-out $(all-files),$(oldheaders))