mbox series

[RFC,0/12] Unify asm/unaligned.h around struct helper

Message ID 20210507220813.365382-1-arnd@kernel.org (mailing list archive)
Headers show
Series Unify asm/unaligned.h around struct helper | expand

Message

Arnd Bergmann May 7, 2021, 10:07 p.m. UTC 
From: Arnd Bergmann <arnd@arndb.de>

The get_unaligned()/put_unaligned() helpers are traditionally architecture
specific, with the two main variants being the "access-ok.h" version
that assumes unaligned pointer accesses always work on a particular
architecture, and the "le-struct.h" version that casts the data to a
byte aligned type before dereferencing, for architectures that cannot
always do unaligned accesses in hardware.

Based on the discussion linked below, it appears that the access-ok
version is not realiable on any architecture, but the struct version
probably has no downsides. This series changes the code to use the
same implementation on all architectures, addressing the few exceptions
separately.

I've pushed the patches to the asm-generic git tree for testing.

	Arnd

Link: https://lore.kernel.org/lkml/75d07691-1e4f-741f-9852-38c0b4f520bc@synopsys.com/
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100363
Link: git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git unaligned-rework

Arnd Bergmann (12):
  asm-generic: use asm-generic/unaligned.h for most architectures
  openrisc: always use unaligned-struct header
  sh: remove unaligned access for sh4a
  m68k: select CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  powerpc: use linux/unaligned/le_struct.h on LE power7
  asm-generic: unaligned: remove byteshift helpers
  asm-generic: unaligned always use struct helpers
  partitions: msdos: fix one-byte get_unaligned()
  apparmor: use get_unaligned() only for multi-byte words
  mwifiex: re-fix for unaligned accesses
  netpoll: avoid put_unaligned() on single character
  asm-generic: simplify asm/unaligned.h

 arch/alpha/include/asm/unaligned.h          |  12 --
 arch/arm/include/asm/unaligned.h            |  27 ---
 arch/ia64/include/asm/unaligned.h           |  12 --
 arch/m68k/Kconfig                           |   1 +
 arch/m68k/include/asm/unaligned.h           |  26 ---
 arch/microblaze/include/asm/unaligned.h     |  27 ---
 arch/mips/crypto/crc32-mips.c               |   2 +-
 arch/openrisc/include/asm/unaligned.h       |  47 -----
 arch/parisc/include/asm/unaligned.h         |   6 +-
 arch/powerpc/include/asm/unaligned.h        |  22 ---
 arch/sh/include/asm/unaligned-sh4a.h        | 199 --------------------
 arch/sh/include/asm/unaligned.h             |  13 --
 arch/sparc/include/asm/unaligned.h          |  11 --
 arch/x86/include/asm/unaligned.h            |  15 --
 arch/xtensa/include/asm/unaligned.h         |  29 ---
 block/partitions/ldm.h                      |   2 +-
 block/partitions/msdos.c                    |   2 +-
 drivers/net/wireless/marvell/mwifiex/pcie.c |  10 +-
 include/asm-generic/unaligned.h             | 149 ++++++++++++---
 include/linux/unaligned/access_ok.h         |  68 -------
 include/linux/unaligned/be_byteshift.h      |  71 -------
 include/linux/unaligned/be_memmove.h        |  37 ----
 include/linux/unaligned/be_struct.h         |  37 ----
 include/linux/unaligned/generic.h           | 115 -----------
 include/linux/unaligned/le_byteshift.h      |  71 -------
 include/linux/unaligned/le_memmove.h        |  37 ----
 include/linux/unaligned/le_struct.h         |  37 ----
 include/linux/unaligned/memmove.h           |  46 -----
 net/core/netpoll.c                          |   4 +-
 security/apparmor/policy_unpack.c           |   2 +-
 30 files changed, 137 insertions(+), 1000 deletions(-)
 delete mode 100644 arch/alpha/include/asm/unaligned.h
 delete mode 100644 arch/arm/include/asm/unaligned.h
 delete mode 100644 arch/ia64/include/asm/unaligned.h
 delete mode 100644 arch/m68k/include/asm/unaligned.h
 delete mode 100644 arch/microblaze/include/asm/unaligned.h
 delete mode 100644 arch/openrisc/include/asm/unaligned.h
 delete mode 100644 arch/powerpc/include/asm/unaligned.h
 delete mode 100644 arch/sh/include/asm/unaligned-sh4a.h
 delete mode 100644 arch/sh/include/asm/unaligned.h
 delete mode 100644 arch/sparc/include/asm/unaligned.h
 delete mode 100644 arch/x86/include/asm/unaligned.h
 delete mode 100644 arch/xtensa/include/asm/unaligned.h
 delete mode 100644 include/linux/unaligned/access_ok.h
 delete mode 100644 include/linux/unaligned/be_byteshift.h
 delete mode 100644 include/linux/unaligned/be_memmove.h
 delete mode 100644 include/linux/unaligned/be_struct.h
 delete mode 100644 include/linux/unaligned/generic.h
 delete mode 100644 include/linux/unaligned/le_byteshift.h
 delete mode 100644 include/linux/unaligned/le_memmove.h
 delete mode 100644 include/linux/unaligned/le_struct.h
 delete mode 100644 include/linux/unaligned/memmove.h

Cc: Amitkumar Karwar <amitkarwar@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ganapathi Bhat <ganapathi017@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: James Morris <jmorris@namei.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: "Richard Russon (FlatCap)" <ldm@flatcap.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Sharvari Harisangam <sharvari.harisangam@nxp.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
Cc: Xinming Hu <huxinming820@gmail.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-crypto@vger.kernel.org
Cc: openrisc@lists.librecores.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linux-ntfs-dev@lists.sourceforge.net
Cc: linux-block@vger.kernel.org
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-security-module@vger.kernel.org

Comments

Arnd Bergmann May 7, 2021, 10:07 p.m. UTC | #1 
From: Arnd Bergmann <arnd@arndb.de>

The get_unaligned()/put_unaligned() helpers are traditionally architecture
specific, with the two main variants being the "access-ok.h" version
that assumes unaligned pointer accesses always work on a particular
architecture, and the "le-struct.h" version that casts the data to a
byte aligned type before dereferencing, for architectures that cannot
always do unaligned accesses in hardware.

Based on the discussion linked below, it appears that the access-ok
version is not realiable on any architecture, but the struct version
probably has no downsides. This series changes the code to use the
same implementation on all architectures, addressing the few exceptions
separately.

I've pushed the patches to the asm-generic git tree for testing.

	Arnd

Link: https://lore.kernel.org/lkml/75d07691-1e4f-741f-9852-38c0b4f520bc@synopsys.com/
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100363
Link: git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git unaligned-rework

Arnd Bergmann (12):
  asm-generic: use asm-generic/unaligned.h for most architectures
  openrisc: always use unaligned-struct header
  sh: remove unaligned access for sh4a
  m68k: select CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  powerpc: use linux/unaligned/le_struct.h on LE power7
  asm-generic: unaligned: remove byteshift helpers
  asm-generic: unaligned always use struct helpers
  partitions: msdos: fix one-byte get_unaligned()
  apparmor: use get_unaligned() only for multi-byte words
  mwifiex: re-fix for unaligned accesses
  netpoll: avoid put_unaligned() on single character
  asm-generic: simplify asm/unaligned.h

 arch/alpha/include/asm/unaligned.h          |  12 --
 arch/arm/include/asm/unaligned.h            |  27 ---
 arch/ia64/include/asm/unaligned.h           |  12 --
 arch/m68k/Kconfig                           |   1 +
 arch/m68k/include/asm/unaligned.h           |  26 ---
 arch/microblaze/include/asm/unaligned.h     |  27 ---
 arch/mips/crypto/crc32-mips.c               |   2 +-
 arch/openrisc/include/asm/unaligned.h       |  47 -----
 arch/parisc/include/asm/unaligned.h         |   6 +-
 arch/powerpc/include/asm/unaligned.h        |  22 ---
 arch/sh/include/asm/unaligned-sh4a.h        | 199 --------------------
 arch/sh/include/asm/unaligned.h             |  13 --
 arch/sparc/include/asm/unaligned.h          |  11 --
 arch/x86/include/asm/unaligned.h            |  15 --
 arch/xtensa/include/asm/unaligned.h         |  29 ---
 block/partitions/ldm.h                      |   2 +-
 block/partitions/msdos.c                    |   2 +-
 drivers/net/wireless/marvell/mwifiex/pcie.c |  10 +-
 include/asm-generic/unaligned.h             | 149 ++++++++++++---
 include/linux/unaligned/access_ok.h         |  68 -------
 include/linux/unaligned/be_byteshift.h      |  71 -------
 include/linux/unaligned/be_memmove.h        |  37 ----
 include/linux/unaligned/be_struct.h         |  37 ----
 include/linux/unaligned/generic.h           | 115 -----------
 include/linux/unaligned/le_byteshift.h      |  71 -------
 include/linux/unaligned/le_memmove.h        |  37 ----
 include/linux/unaligned/le_struct.h         |  37 ----
 include/linux/unaligned/memmove.h           |  46 -----
 net/core/netpoll.c                          |   4 +-
 security/apparmor/policy_unpack.c           |   2 +-
 30 files changed, 137 insertions(+), 1000 deletions(-)
 delete mode 100644 arch/alpha/include/asm/unaligned.h
 delete mode 100644 arch/arm/include/asm/unaligned.h
 delete mode 100644 arch/ia64/include/asm/unaligned.h
 delete mode 100644 arch/m68k/include/asm/unaligned.h
 delete mode 100644 arch/microblaze/include/asm/unaligned.h
 delete mode 100644 arch/openrisc/include/asm/unaligned.h
 delete mode 100644 arch/powerpc/include/asm/unaligned.h
 delete mode 100644 arch/sh/include/asm/unaligned-sh4a.h
 delete mode 100644 arch/sh/include/asm/unaligned.h
 delete mode 100644 arch/sparc/include/asm/unaligned.h
 delete mode 100644 arch/x86/include/asm/unaligned.h
 delete mode 100644 arch/xtensa/include/asm/unaligned.h
 delete mode 100644 include/linux/unaligned/access_ok.h
 delete mode 100644 include/linux/unaligned/be_byteshift.h
 delete mode 100644 include/linux/unaligned/be_memmove.h
 delete mode 100644 include/linux/unaligned/be_struct.h
 delete mode 100644 include/linux/unaligned/generic.h
 delete mode 100644 include/linux/unaligned/le_byteshift.h
 delete mode 100644 include/linux/unaligned/le_memmove.h
 delete mode 100644 include/linux/unaligned/le_struct.h
 delete mode 100644 include/linux/unaligned/memmove.h

Cc: Amitkumar Karwar <amitkarwar@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ganapathi Bhat <ganapathi017@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: James Morris <jmorris@namei.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: "Richard Russon (FlatCap)" <ldm@flatcap.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Sharvari Harisangam <sharvari.harisangam@nxp.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
Cc: Xinming Hu <huxinming820@gmail.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-crypto@vger.kernel.org
Cc: openrisc@lists.librecores.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linux-ntfs-dev@lists.sourceforge.net
Cc: linux-block@vger.kernel.org
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-security-module@vger.kernel.org