[PATCH v3 00/12] arch: Make virt_to_pfn into a static inline

Tue May 23 07:05:24 PDT 2023

This is an attempt to harden the typing on virt_to_pfn()
and pfn_to_virt().

Making virt_to_pfn() a static inline taking a strongly typed
(const void *) makes the contract of a passing a pointer of that
type to the function explicit and exposes any misuse of the
macro virt_to_pfn() acting polymorphic and accepting many types
such as (void *), (unitptr_t) or (unsigned long) as arguments
without warnings.

For symmetry, we do the same with pfn_to_virt().

The problem with this inconsistent typing was pointed out by
Russell King:
https://lore.kernel.org/linux-arm-kernel/YoJDKJXc0MJ2QZTb@shell.armlinux.org.uk/

And confirmed by Andrew Morton:
https://lore.kernel.org/linux-mm/20220701160004.2ffff4e5ab59a55499f4c736@linux-foundation.org/

So the recognition of the problem is widespread.

These platforms have been chosen as initial conversion targets:

- ARC
- ARM
- ARM64/Aarch64
- asm-generic (including for example x86)
- m68k

The idea is that if this goes in, it will block further misuse
of the function signatures due to the large compile coverage,
and then I can go in and fix the remaining platforms on a
one-by-one basis.

Some of the patches have been circulated before but were not
picked up by subsystem maintainers, so now the arch tree is
target for this series.

It has passed zeroday builds after a lot of iterations in my
personal tree, but there could be some randconfig outliers.

The To/Cc list would be too long if I include all the minor
patches maintainers, so I have trimmed it down to the mailing
lists since these people certainly have received the patches
before.

Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
Changes in v3:
- Fix up the Coldfire changes in accordance with Geert's feedback.
- Link to v2: https://lore.kernel.org/r/20230503-virt-to-pfn-v6-4-rc1-v2-0-0948d38bddab@linaro.org

Changes in v2:
- Fix some "void * x" into "void *x" in generic page accessors and
  in m68k.
- Collected a few ACKs
- All build tests appear to pass!
- Added Andrew Mortin to To: line to see what he thinks
- Link to v1: https://lore.kernel.org/r/20230503-virt-to-pfn-v6-4-rc1-v1-0-6c4698dcf9c8@linaro.org

---
Linus Walleij (12):
      fs/proc/kcore.c: Pass a pointer to virt_addr_valid()
      m68k: Pass a pointer to virt_to_pfn() virt_to_page()
      ARC: init: Pass a pointer to virt_to_pfn() in init
      riscv: mm: init: Pass a pointer to virt_to_page()
      cifs: Pass a pointer to virt_to_page()
      cifs: Pass a pointer to virt_to_page() in cifsglob
      netfs: Pass a pointer to virt_to_page()
      arm64: vdso: Pass (void *) to virt_to_page()
      asm-generic/page.h: Make pfn accessors static inlines
      ARM: mm: Make virt_to_pfn() a static inline
      arm64: memory: Make virt_to_pfn() a static inline
      m68k/mm: Make pfn accessors static inlines

 arch/arc/mm/init.c                   |  2 +-
 arch/arm/common/sharpsl_param.c      |  2 +-
 arch/arm/include/asm/delay.h         |  2 +-
 arch/arm/include/asm/io.h            |  2 +-
 arch/arm/include/asm/memory.h        | 17 ++++++++++++-----
 arch/arm/include/asm/page.h          |  4 ++--
 arch/arm/include/asm/pgtable.h       |  2 +-
 arch/arm/include/asm/proc-fns.h      |  2 --
 arch/arm/include/asm/sparsemem.h     |  2 +-
 arch/arm/include/asm/uaccess-asm.h   |  2 +-
 arch/arm/include/asm/uaccess.h       |  2 +-
 arch/arm/kernel/asm-offsets.c        |  2 +-
 arch/arm/kernel/entry-armv.S         |  2 +-
 arch/arm/kernel/entry-common.S       |  2 +-
 arch/arm/kernel/entry-v7m.S          |  2 +-
 arch/arm/kernel/head-nommu.S         |  3 +--
 arch/arm/kernel/head.S               |  2 +-
 arch/arm/kernel/hibernate.c          |  2 +-
 arch/arm/kernel/suspend.c            |  2 +-
 arch/arm/kernel/tcm.c                |  2 +-
 arch/arm/kernel/vmlinux-xip.lds.S    |  3 +--
 arch/arm/kernel/vmlinux.lds.S        |  3 +--
 arch/arm/mach-berlin/platsmp.c       |  2 +-
 arch/arm/mach-keystone/keystone.c    |  2 +-
 arch/arm/mach-omap2/sleep33xx.S      |  2 +-
 arch/arm/mach-omap2/sleep43xx.S      |  2 +-
 arch/arm/mach-omap2/sleep44xx.S      |  2 +-
 arch/arm/mach-pxa/gumstix.c          |  2 +-
 arch/arm/mach-rockchip/sleep.S       |  2 +-
 arch/arm/mach-sa1100/pm.c            |  2 +-
 arch/arm/mach-shmobile/headsmp-scu.S |  2 +-
 arch/arm/mach-shmobile/headsmp.S     |  2 +-
 arch/arm/mach-socfpga/headsmp.S      |  2 +-
 arch/arm/mach-spear/spear.h          |  2 +-
 arch/arm/mm/cache-fa.S               |  1 -
 arch/arm/mm/cache-v4wb.S             |  1 -
 arch/arm/mm/dma-mapping.c            |  2 +-
 arch/arm/mm/dump.c                   |  2 +-
 arch/arm/mm/init.c                   |  2 +-
 arch/arm/mm/kasan_init.c             |  1 -
 arch/arm/mm/mmu.c                    |  2 +-
 arch/arm/mm/physaddr.c               |  2 +-
 arch/arm/mm/pmsa-v8.c                |  2 +-
 arch/arm/mm/proc-v7.S                |  2 +-
 arch/arm/mm/proc-v7m.S               |  2 +-
 arch/arm/mm/pv-fixup-asm.S           |  2 +-
 arch/arm64/include/asm/memory.h      |  9 ++++++++-
 arch/arm64/kernel/vdso.c             |  2 +-
 arch/m68k/include/asm/mcf_pgtable.h  |  3 +--
 arch/m68k/include/asm/page_mm.h      | 11 +++++++++--
 arch/m68k/include/asm/page_no.h      | 11 +++++++++--
 arch/m68k/include/asm/sun3_pgtable.h |  4 ++--
 arch/m68k/mm/mcfmmu.c                |  3 ++-
 arch/m68k/mm/motorola.c              |  4 ++--
 arch/m68k/mm/sun3mmu.c               |  2 +-
 arch/m68k/sun3/dvma.c                |  2 +-
 arch/m68k/sun3x/dvma.c               |  2 +-
 arch/riscv/mm/init.c                 |  4 ++--
 drivers/memory/ti-emif-sram-pm.S     |  2 +-
 fs/cifs/cifsglob.h                   |  2 +-
 fs/cifs/smbdirect.c                  |  2 +-
 fs/netfs/iterator.c                  |  2 +-
 fs/proc/kcore.c                      |  2 +-
 include/asm-generic/page.h           | 12 ++++++++++--
 64 files changed, 108 insertions(+), 80 deletions(-)
---
base-commit: ac9a78681b921877518763ba0e89202254349d1b
change-id: 20230503-virt-to-pfn-v6-4-rc1-4f5739e8d60d

Best regards,
-- 
Linus Walleij <linus.walleij at linaro.org>