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: Sam Ravnborg <sam@xxxxxxxxxxxx> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> Acked-by: Sam Ravnborg <sam@xxxxxxxxxxxx> --- Changes in v2: - Filter-out $(generiated-y) from $(mandatory-y) because ARCH may generate mandatory headers by other means Documentation/kbuild/makefiles.txt | 9 ++++++--- scripts/Makefile.asm-generic | 4 ++++ scripts/Makefile.headersinst | 7 ------- 3 files changed, 10 insertions(+), 10 deletions(-) diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 8da26c6..bf28c47 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -1296,9 +1296,12 @@ See subsequent chapter for the syntax of the Kbuild file. --- 7.4 mandatory-y - mandatory-y is essentially used by include/uapi/asm-generic/Kbuild.asm - to define the minimum set of headers that must be exported in - include/asm. + mandatory-y is essentially used by include/(uapi/)asm-generic/Kbuild.asm + to define the minimum set of ASM headers that all architectures must have. + + This works like optional generic-y. If a mandatory header is missing + in arch/$(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. diff --git a/scripts/Makefile.asm-generic b/scripts/Makefile.asm-generic index 760323e..a62d282 100644 --- a/scripts/Makefile.asm-generic +++ b/scripts/Makefile.asm-generic @@ -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)) diff --git a/scripts/Makefile.headersinst b/scripts/Makefile.headersinst index 45927fc..3d1ebaa 100644 --- a/scripts/Makefile.headersinst +++ b/scripts/Makefile.headersinst @@ -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)) -- 2.7.4
