linux.git/Documentation/kbuild, branch v5.1

kbuild: force all architectures except um to include mandatory-y

2019-03-17T03:56:32+00:00

Currently, every arch/*/include/uapi/asm/Kbuild explicitly includes
the common Kbuild.asm file. Factor out the duplicated include directives
to scripts/Makefile.asm-generic so that no architecture would opt out
of the mandatory-y mechanism.

um is not forced to include mandatory-y since it is a very exceptional
case which does not support UAPI.

Signed-off-by: Masahiro Yamada

kbuild: remove cc-version macro

2019-03-04T13:34:59+00:00

There is no more direct user of this macro; it is only used by
cc-ifversion.

Calling this macro is not efficient since it invokes the compiler to
get the compiler version. CONFIG_GCC_VERSION is already calculated in
the Kconfig stage, so Makefile can reuse it.

Here is a note about the slight difference between cc-version and
CONFIG_GCC_VERSION:

When using Clang, cc-version is evaluated to '0402' because Clang
defines __GNUC__ and __GNUC__MINOR__, and looks like GCC 4.2 in the
version point of view. On the other hand, CONFIG_GCC_VERSION=0
when $(CC) is clang.

There are currently two users of cc-ifversion:
  arch/mips/loongson64/Platform
  arch/powerpc/Makefile

They are not affected by this change.

The format of cc-version is , while CONFIG_GCC_VERSION
. I adjusted cc-ifversion for the difference of
the number of digits.

Signed-off-by: Masahiro Yamada

kbuild: turn '/' into an alias of './'

2019-02-20T00:42:47+00:00

Commit 06300b21f4c7 ("kbuild: support building individual files for
external modules") introduced the '/' target. It works only for
external modules to build all .o files, but skip the modpost stage.

However, 'make /' looks a bit weird to me. 'make ./' is more sensible
if you want to build all objects under the current directory, and it
works as expected.

Let's change '/' into a phony target that is an alias of './', but
I may feel like deprecating it in the future.

Signed-off-by: Masahiro Yamada

kbuild: merge KBUILD_VMLINUX_{INIT,MAIN} into KBUILD_VMLINUX_OBJS

2019-01-28T00:11:17+00:00

The top Makefile does not need to export KBUILD_VMLINUX_INIT and
KBUILD_VMLINUX_MAIN separately.

Put every built-in.a into KBUILD_VMLINUX_OBJS. The order of
$(head-y), $(init-y), $(core-y), ... is still retained.

Signed-off-by: Masahiro Yamada

kbuild: remove top-level built-in.a

2019-01-28T00:11:17+00:00

The symbol table in the final archive is unneeded; the linker does not
require the symbol table after the --whole-archive option. Every object
file in the archive is included in the link anyway.

Pass thin archives from subdirectories directly to the linker, and
remove the final archiving step.

Fix up the document and comments as well.

Signed-off-by: Masahiro Yamada 
Acked-by: Nicholas Piggin

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

2019-01-06T00:46:51+00:00

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 
Signed-off-by: Masahiro Yamada 
Acked-by: Sam Ravnborg

kbuild: announce removal of SUBDIRS if used

2018-12-01T13:21:56+00:00

SUBDIRS has been kept as a backward compatibility since
commit ("[PATCH] kbuild: external module support") in 2002.

We do not need multiple ways to do the same thing, so I will remove
SUBDIRS after the Linux 5.3 release. I cleaned up in-tree code, and
updated the document so that nobody would try to use it.

Meanwhile, display the following warning if SUBDIRS is used.

Makefile:189: ================= WARNING ================
Makefile:190: 'SUBDIRS' will be removed after Linux 5.3
Makefile:191: Please use 'M=' or 'KBUILD_EXTMOD' instead
Makefile:192: ==========================================

Signed-off-by: Masahiro Yamada 
Acked-by: Boris Brezillon  # for scx200_docflash.c
Acked-by: Guenter Roeck  # for scx200_wdt.c

kbuild: remove unused cc-fullversion variable

2018-11-01T15:15:26+00:00

The last user of cc-fullversion was removed by commit f2910f0e6835
("powerpc: remove old GCC version checks").

Signed-off-by: Masahiro Yamada

Drop all 00-INDEX files from Documentation/

2018-09-09T21:08:58+00:00

This is a respin with a wider audience (all that get_maintainer returned)
and I know this spams a *lot* of people. Not sure what would be the correct
way, so my apologies for ruining your inbox.

The 00-INDEX files are supposed to give a summary of all files present
in a directory, but these files are horribly out of date and their
usefulness is brought into question. Often a simple "ls" would reveal
the same information as the filenames are generally quite descriptive as
a short introduction to what the file covers (it should not surprise
anyone what Documentation/sched/sched-design-CFS.txt covers)

A few years back it was mentioned that these files were no longer really
needed, and they have since then grown further out of date, so perhaps
it is time to just throw them out.

A short status yields the following _outdated_ 00-INDEX files, first
counter is files listed in 00-INDEX but missing in the directory, last
is files present but not listed in 00-INDEX.

List of outdated 00-INDEX:
Documentation: (4/10)
Documentation/sysctl: (0/1)
Documentation/timers: (1/0)
Documentation/blockdev: (3/1)
Documentation/w1/slaves: (0/1)
Documentation/locking: (0/1)
Documentation/devicetree: (0/5)
Documentation/power: (1/1)
Documentation/powerpc: (0/5)
Documentation/arm: (1/0)
Documentation/x86: (0/9)
Documentation/x86/x86_64: (1/1)
Documentation/scsi: (4/4)
Documentation/filesystems: (2/9)
Documentation/filesystems/nfs: (0/2)
Documentation/cgroup-v1: (0/2)
Documentation/kbuild: (0/4)
Documentation/spi: (1/0)
Documentation/virtual/kvm: (1/0)
Documentation/scheduler: (0/2)
Documentation/fb: (0/1)
Documentation/block: (0/1)
Documentation/networking: (6/37)
Documentation/vm: (1/3)

Then there are 364 subdirectories in Documentation/ with several files that
are missing 00-INDEX alltogether (and another 120 with a single file and no
00-INDEX).

I don't really have an opinion to whether or not we /should/ have 00-INDEX,
but the above 00-INDEX should either be removed or be kept up to date. If
we should keep the files, I can try to keep them updated, but I rather not
if we just want to delete them anyway.

As a starting point, remove all index-files and references to 00-INDEX and
see where the discussion is going.

Signed-off-by: Henrik Austad 
Acked-by: "Paul E. McKenney" 
Just-do-it-by: Steven Rostedt 
Reviewed-by: Jens Axboe 
Acked-by: Paul Moore 
Acked-by: Greg Kroah-Hartman 
Acked-by: Mark Brown 
Acked-by: Mike Rapoport 
Cc: [Almost everybody else]
Signed-off-by: Jonathan Corbet

kbuild: Fix LOADLIBES rename in Documentation/kbuild/makefiles.txt

2018-08-22T14:21:42+00:00

Fixes: 8377bd2b9ee1 ("kbuild: Rename HOST_LOADLIBES to KBUILD_HOSTLDLIBS")
Signed-off-by: Michal Suchanek 
Acked-by: Laura Abbott 
Signed-off-by: Masahiro Yamada