[PATCH 0/7] xen/bitops: Reduce the mess, starting with ffs()

From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xenproject.org>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Jan Beulich" <JBeulich@suse.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>, "Wei Liu" <wl@xen.org>,
	"Stefano Stabellini" <sstabellini@kernel.org>,
	"Julien Grall" <julien@xen.org>,
	"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
	"Bertrand Marquis" <bertrand.marquis@arm.com>,
	"Michal Orzel" <michal.orzel@amd.com>,
	"Oleksii Kurochko" <oleksii.kurochko@gmail.com>,
	"Shawn Anastasio" <sanastasio@raptorengineering.com>,
	"consulting @ bugseng . com" <consulting@bugseng.com>,
	"Simone Ballarin" <simone.ballarin@bugseng.com>,
	"Federico Serafini" <federico.serafini@bugseng.com>,
	"Nicola Vetrini" <nicola.vetrini@bugseng.com>
Subject: [PATCH 0/7] xen/bitops: Reduce the mess, starting with ffs()
Date: Wed, 13 Mar 2024 17:27:09 +0000	[thread overview]
Message-ID: <20240313172716.2325427-1-andrew.cooper3@citrix.com> (raw)

bitops.h is a mess.  It has grown organtically over many years, and forces
unreasonable repsonsibilities out into the per-arch stubs.

Start cleaning it up with ffs() and friends.  Across the board, this adds:

 * Functioning bitops without arch-specific asm
 * An option for arches to provide more optimal code generation
 * Compile-time constant folding
 * Testing at both compile time and during init that the basic operations
   behave according to spec.

and the only reason this series isn't a net reduction in code alone is the
because of the testing infrastructure in patch 1.

This form is superior in many ways, including getting RISC-V support for free.

Testing:
  https://gitlab.com/xen-project/people/andyhhp/xen/-/pipelines/1212269924
  https://cirrus-ci.com/build/4939856296542208

Andrew Cooper (7):
  xen/bitops: Cleanup ahead of rearrangements
  xen/bitops: Implement ffs() in common logic
  xen/bitops: Implement ffsl() in common logic
  xen/bitops: Delete generic_ffs{,l}()
  xen/bitops: Implement ffs64() in common logic
  xen: Swap find_first_set_bit() for ffsl() - 1
  xen/bitops: Delete find_first_set_bit()

 xen/arch/arm/include/asm/bitops.h            | 16 +---
 xen/arch/ppc/include/asm/bitops.h            | 11 ---
 xen/arch/x86/guest/xen/xen.c                 |  4 +-
 xen/arch/x86/hvm/dom0_build.c                |  2 +-
 xen/arch/x86/hvm/hpet.c                      |  8 +-
 xen/arch/x86/include/asm/bitops.h            | 53 +++++------
 xen/arch/x86/include/asm/pt-contig-markers.h |  2 +-
 xen/arch/x86/mm.c                            |  2 +-
 xen/arch/x86/mm/p2m-pod.c                    |  4 +-
 xen/common/Makefile                          |  1 +
 xen/common/bitops.c                          | 70 ++++++++++++++
 xen/common/page_alloc.c                      |  2 +-
 xen/common/softirq.c                         |  2 +-
 xen/drivers/passthrough/amd/iommu_map.c      |  2 +-
 xen/drivers/passthrough/iommu.c              |  4 +-
 xen/drivers/passthrough/x86/iommu.c          |  4 +-
 xen/include/xen/bitops.h                     | 97 +++++++++-----------
 xen/include/xen/compiler.h                   |  3 +-
 18 files changed, 160 insertions(+), 127 deletions(-)
 create mode 100644 xen/common/bitops.c

base-commit: 03cf7ca23e0e876075954c558485b267b7d02406
-- 
2.30.2