This patch set allows for building the Linux kernel for arm64 in macOS with
LLVM.

Patches are based on previous Nick's work and suggestions [1][2][3] to
enable build system in macOS hosts.

Since macOS does not provide some of the headers available in the GNU
C Library (glibc), the patches include a copy of these headers from
glibc-2.40, with minor modifications detailed in the commit message.

To set up the environment:

* Provide build dependencies (installed via Homebrew):

	coreutils, findutils, gnu-sed, gnu-tar, grep, llvm, make and pkg-config.

* A case sensitive volume for building:

	diskutil apfs addVolume /dev/disk<N> "Case-sensitive APFS" linux

* And include in your PATH all GNU tools required by the Linux kernel as
well as LLVM:

	PATH="/opt/homebrew/opt/coreutils/libexec/gnubin:$PATH"
	PATH="/opt/homebrew/opt/findutils/libexec/gnubin:$PATH"
	PATH="/opt/homebrew/opt/gnu-sed/libexec/gnubin:$PATH"
	PATH="/opt/homebrew/opt/gnu-tar/libexec/gnubin:$PATH"
	PATH="/opt/homebrew/opt/grep/libexec/gnubin:$PATH"
	PATH="/opt/homebrew/opt/make/libexec/gnubin:$PATH"
	PATH="/opt/homebrew/opt/llvm/bin:$PATH"

* Start the build using LLVM:

	make LLVM=1 allyesconfig
	make LLVM=1 -j$(nproc)

I believe other architectures could also be supported if we can move
forward this initiative. Additionally, we could incorporate Rust
support. I understand that Finn Behrens has some patches [4][5] based on
Nick's previous work.

[1]: WIP: build Linux on MacOS
https://github.com/ClangBuiltLinux/linux/commit/f06333e29addbc3d714adb340355f471c1dfe95a

[2] Subject: [PATCH] scripts: subarch.include: fix SUBARCH on MacOS hosts
https://lore.kernel.org/all/20221113233812.36784-1-nick.desaulniers@gmail.com/

[3] Subject: Any interest in building the Linux kernel from a MacOS host?
https://lore.kernel.org/all/CAH7mPvj64Scp6_Nbaj8KOfkoV5f7_N5L=Tv5Z9zGyn5SS+gsUw@mail.gmail.com/

[4] https://github.com/kloenk/linux/commits/rust-project_macos-dylib/

[5] https://kloenk.eu/posts/build-linux-on-m1-macos/

To: Masahiro Yamada <masahiroy@kernel.org>
To: Nathan Chancellor <nathan@kernel.org>
To: Nicolas Schier <nicolas@fjasle.eu>
To: Lucas De Marchi <lucas.demarchi@intel.com>
To: Thomas Hellström <thomas.hellstrom@linux.intel.com>
To: Rodrigo Vivi <rodrigo.vivi@intel.com>
To: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
To: Maxime Ripard <mripard@kernel.org>
To: Thomas Zimmermann <tzimmermann@suse.de>
To: David Airlie <airlied@gmail.com>
To: Daniel Vetter <daniel@ffwll.ch>
To: William Hubbs <w.d.hubbs@gmail.com>
To: Chris Brannon <chris@the-brannons.com>
To: Kirk Reiser <kirk@reisers.ca>
To: Samuel Thibault <samuel.thibault@ens-lyon.org>
To: Paul Moore <paul@paul-moore.com>
To: Stephen Smalley <stephen.smalley.work@gmail.com>
To: Ondrej Mosnacek <omosnace@redhat.com>
To: Catalin Marinas <catalin.marinas@arm.com>
To: Will Deacon <will@kernel.org>
To: Marc Zyngier <maz@kernel.org>
To: Oliver Upton <oliver.upton@linux.dev>
To: James Morse <james.morse@arm.com>
To: Suzuki K Poulose <suzuki.poulose@arm.com>
To: Zenghui Yu <yuzenghui@huawei.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Jiri Slaby <jirislaby@kernel.org>
To: Nick Desaulniers <ndesaulniers@google.com>
To: Bill Wendling <morbo@google.com>
To: Justin Stitt <justinstitt@google.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-kbuild@vger.kernel.org
Cc: intel-xe@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Cc: speakup@linux-speakup.org
Cc: selinux@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: kvmarm@lists.linux.dev
Cc: linux-serial@vger.kernel.org
Cc: llvm@lists.linux.dev
Cc: Finn Behrens <me@kloenk.dev>
Cc: Daniel Gomez (Samsung) <d+samsung@kruces.com>
Cc: gost.dev@samsung.com

Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
---
Daniel Gomez (11):
      kbuild: add header_install dependency to scripts
      file2alias: fix uuid_t definitions for macos
      drm/xe: xe_gen_wa_oob: fix program_invocation_short_name for macos
      accessiblity/speakup: genmap and makemapdata require linux/version.h
      selinux/genheaders: include bitsperlong and posix_types headers
      selinux/mdp: include bitsperlong and posix_types headers
      include: add elf.h support
      include: add endian.h support
      scripts/mod: add byteswap support
      tty/vt: conmakehash requires linux/limits.h
      scripts/kallsyms: add compatibility support for macos

Nick Desaulniers (1):
      scripts: subarch.include: fix SUBARCH on MacOS hosts

 Makefile                               |    2 +-
 arch/arm64/kernel/pi/Makefile          |    1 +
 arch/arm64/kernel/vdso32/Makefile      |    1 +
 arch/arm64/kvm/hyp/nvhe/Makefile       |    2 +-
 drivers/accessibility/speakup/Makefile |    2 +
 drivers/gpu/drm/xe/xe_gen_wa_oob.c     |    8 +-
 drivers/tty/vt/Makefile                |    1 +
 include/byteswap/byteswap.h            |   35 +
 include/elf/elf.h                      | 4491 ++++++++++++++++++++++++++++++++
 include/endian/bits/uintn-identity.h   |   48 +
 include/endian/endian.h                |   63 +
 scripts/Makefile                       |    3 +-
 scripts/kallsyms.c                     |    4 +
 scripts/mod/Makefile                   |    6 +
 scripts/mod/file2alias.c               |    3 +
 scripts/selinux/genheaders/Makefile    |    3 +-
 scripts/selinux/mdp/Makefile           |    3 +-
 scripts/subarch.include                |    3 +-
 18 files changed, 4672 insertions(+), 7 deletions(-)
---
base-commit: 1e391b34f6aa043c7afa40a2103163a0ef06d179
change-id: 20240807-macos-build-support-9ca0d77adb17

Best regards,
-- 
Daniel Gomez <da.gomez@samsung.com>

On Wed, Aug 07, 2024 at 01:09:14AM +0200, Daniel Gomez via B4 Relay wrote:
> This patch set allows for building the Linux kernel for arm64 in macOS with
> LLVM.

Is this a requirement somewhere that this must work?  It seems like an
odd request, what workflows require cross-operating-system builds like
this?

thanks,

greg k-h

On Wed, Aug 07, 2024 at 01:01:08PM GMT, Greg Kroah-Hartman wrote:
> On Wed, Aug 07, 2024 at 01:09:14AM +0200, Daniel Gomez via B4 Relay wrote:
> > This patch set allows for building the Linux kernel for arm64 in macOS with
> > LLVM.
> 
> Is this a requirement somewhere that this must work?  It seems like an
> odd request, what workflows require cross-operating-system builds like
> this?

This isn't a requirement, but it would, for example, support workflows for QEMU
users and developers on macOS. They could build/compile the kernel natively and
use it to launch QEMU instances, simplifying their process.

> 
> thanks,
> 
> greg k-h

On Wed, Aug 07, 2024 at 01:56:38PM +0000, Daniel Gomez wrote:
> On Wed, Aug 07, 2024 at 01:01:08PM GMT, Greg Kroah-Hartman wrote:
> > On Wed, Aug 07, 2024 at 01:09:14AM +0200, Daniel Gomez via B4 Relay wrote:
> > > This patch set allows for building the Linux kernel for arm64 in macOS with
> > > LLVM.
> > 
> > Is this a requirement somewhere that this must work?  It seems like an
> > odd request, what workflows require cross-operating-system builds like
> > this?
> 
> This isn't a requirement, but it would, for example, support workflows for QEMU
> users and developers on macOS. They could build/compile the kernel natively and
> use it to launch QEMU instances, simplifying their process.

But that's not a real workload of anyone?  How often does this ever come
up?  Who is going to maintain this cross-build functionality over time?

thanks,

greg k-h

On Wed, Aug 07, 2024 at 04:19:42PM +0200, Greg Kroah-Hartman wrote:
> On Wed, Aug 07, 2024 at 01:56:38PM +0000, Daniel Gomez wrote:
> > On Wed, Aug 07, 2024 at 01:01:08PM GMT, Greg Kroah-Hartman wrote:
> > > On Wed, Aug 07, 2024 at 01:09:14AM +0200, Daniel Gomez via B4 Relay wrote:
> > > > This patch set allows for building the Linux kernel for arm64 in macOS with
> > > > LLVM.
> > > 
> > > Is this a requirement somewhere that this must work?  It seems like an
> > > odd request, what workflows require cross-operating-system builds like
> > > this?
> > 
> > This isn't a requirement, but it would, for example, support workflows for QEMU
> > users and developers on macOS. They could build/compile the kernel natively and
> > use it to launch QEMU instances, simplifying their process.
> 
> But that's not a real workload of anyone?  How often does this ever come
> up?  Who is going to maintain this cross-build functionality over time?

The delta is becoming very small thanks to the latest patches from Masahiro.
Earlier this week (next-20240820) [1] I rebased the work with all the feedback
and the patch series has been reduced to 7.

For the maintenance part, I suggest keeping a CI to build and boot the lastest
linux-next tag available. I can set this up here [2] and take the responsability
for maintaining that. But I would be convenient to add documentation for it in
the LLVM section and mark this as 'experimental'. If that's okay, I will prepare
a v2 with this.

[1] https://github.com/SamsungDS/linux/commits/b4/macos-build-support/
[2] https://github.com/SamsungDS/linux

> 
> thanks,
> 
> greg k-h

On Sat, Aug 24, 2024 at 12:37:36AM +0200, Daniel Gomez wrote:
> On Wed, Aug 07, 2024 at 04:19:42PM +0200, Greg Kroah-Hartman wrote:
> > On Wed, Aug 07, 2024 at 01:56:38PM +0000, Daniel Gomez wrote:
> > > On Wed, Aug 07, 2024 at 01:01:08PM GMT, Greg Kroah-Hartman wrote:
> > > > On Wed, Aug 07, 2024 at 01:09:14AM +0200, Daniel Gomez via B4 Relay wrote:
> > > > > This patch set allows for building the Linux kernel for arm64 in macOS with
> > > > > LLVM.
> > > > 
> > > > Is this a requirement somewhere that this must work?  It seems like an
> > > > odd request, what workflows require cross-operating-system builds like
> > > > this?
> > > 
> > > This isn't a requirement, but it would, for example, support workflows for QEMU
> > > users and developers on macOS. They could build/compile the kernel natively and
> > > use it to launch QEMU instances, simplifying their process.
> > 
> > But that's not a real workload of anyone?  How often does this ever come
> > up?  Who is going to maintain this cross-build functionality over time?
> 
> The delta is becoming very small thanks to the latest patches from Masahiro.
> Earlier this week (next-20240820) [1] I rebased the work with all the feedback
> and the patch series has been reduced to 7.
> 
> For the maintenance part, I suggest keeping a CI to build and boot the lastest
> linux-next tag available. I can set this up here [2] and take the responsability
> for maintaining that. But I would be convenient to add documentation for it in
> the LLVM section and mark this as 'experimental'. If that's okay, I will prepare
> a v2 with this.

Let's see what v2 looks like and go from there.

thanks,

greg k-h

On Thu, Aug 8, 2024 at 2:20 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Wed, Aug 07, 2024 at 01:56:38PM +0000, Daniel Gomez wrote:
> > On Wed, Aug 07, 2024 at 01:01:08PM GMT, Greg Kroah-Hartman wrote:
> > > On Wed, Aug 07, 2024 at 01:09:14AM +0200, Daniel Gomez via B4 Relay wrote:
> > > > This patch set allows for building the Linux kernel for arm64 in macOS with
> > > > LLVM.
> > >
> > > Is this a requirement somewhere that this must work?  It seems like an
> > > odd request, what workflows require cross-operating-system builds like
> > > this?
> >
> > This isn't a requirement, but it would, for example, support workflows for QEMU
> > users and developers on macOS. They could build/compile the kernel natively and
> > use it to launch QEMU instances, simplifying their process.
>
> But that's not a real workload of anyone?  How often does this ever come
> up?  Who is going to maintain this cross-build functionality over time?

it is a real workload of me,  i was running qemu-system-aarch64 on x86
and it was
pretty slow. so got a M3 pro to accelerate my development. frequently changing
kernel's source code, i am using qemu-system-aarch64 to do quick verification.

>
> thanks,
>
> greg k-h
>

Thanks
Barry

On Aug 17 13:11, Barry Song wrote:
> On Thu, Aug 8, 2024 at 2:20 AM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > On Wed, Aug 07, 2024 at 01:56:38PM +0000, Daniel Gomez wrote:
> > > On Wed, Aug 07, 2024 at 01:01:08PM GMT, Greg Kroah-Hartman wrote:
> > > > On Wed, Aug 07, 2024 at 01:09:14AM +0200, Daniel Gomez via B4 Relay wrote:
> > > > > This patch set allows for building the Linux kernel for arm64 in macOS with
> > > > > LLVM.
> > > >
> > > > Is this a requirement somewhere that this must work?  It seems like an
> > > > odd request, what workflows require cross-operating-system builds like
> > > > this?
> > >
> > > This isn't a requirement, but it would, for example, support workflows for QEMU
> > > users and developers on macOS. They could build/compile the kernel natively and
> > > use it to launch QEMU instances, simplifying their process.
> >
> > But that's not a real workload of anyone?  How often does this ever come
> > up?  Who is going to maintain this cross-build functionality over time?
> 
> it is a real workload of me,  i was running qemu-system-aarch64 on x86
> and it was
> pretty slow. so got a M3 pro to accelerate my development. frequently changing
> kernel's source code, i am using qemu-system-aarch64 to do quick verification.
> 

Allow me to chime in as well. Working with qemu-system-aarch64 on an Mx
are a daily thing for me as well. Working with custom built kernels have
been a pain, and this really helps.