[v5,00/10] ARM: remove set_fs callers and implementation

Message

Arnd Bergmann July 26, 2021, 2:11 p.m. UTC

From: Arnd Bergmann <[e-mail]>

Hi Christoph, Russell,

This is the rebased version of my ARM set_fs patches on top of
v5.14-rc2. There were a couple of minor conflicts that I resolved,
but otherwise this is still identical to the version I tested earlier.

The one notable change this time is that I rename thread_info->syscall
to thread_info->abi_syscall, to clarify that this field now contains
both the ABI bits (0x900000 for OABI, 0x000000 for EABI) in kernels
that support both, and every access to this has to mask out the bits
it needs. As Russell mentioned before, having a 'syscall' field that
not just contains the syscall number is confusing and error-prone, so
I hope this change is good enough.

I have tested the oabi-compat changes using the LTP tests for the three
modified syscalls using an Armv7 kernel and a Debian 5 OABI user space.

I also tested the syscall_get_nr() in all combinations of OABI/EABI
kernel user space and fixed the bugs I found after Russell pointed out
those issues in the early versions.

Linus Walleij did additional testing of v4 on Footbridge with OABI
user space.

With this and the m68k changes getting merged, we are very close
to eliminating set_fs completely.

Russell, you can pull these from

 https://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground.git arm-setfs_v5

or I can add them to the ARM patch tracker if you prefer.

     Arnd

v4: https://lore.kernel.org/linux-arm-kernel/[e-mail]/
v3: https://lore.kernel.org/linux-arm-kernel/[e-mail]/
v2: https://lore.kernel.org/linux-arm-kernel/[e-mail]/
v1: https://lore.kernel.org/linux-arm-kernel/[e-mail]/

Arnd Bergmann (9):
  mm/maccess: fix unaligned copy_{from,to}_kernel_nofault
  ARM: traps: use get_kernel_nofault instead of set_fs()
  ARM: oabi-compat: add epoll_pwait handler
  ARM: syscall: always store thread_info->abi_syscall
  ARM: oabi-compat: rework epoll_wait/epoll_pwait emulation
  ARM: oabi-compat: rework sys_semtimedop emulation
  ARM: oabi-compat: rework fcntl64() emulation
  ARM: uaccess: add __{get,put}_kernel_nofault
  ARM: uaccess: remove set_fs() implementation
  ARM: oabi-compat: fix oabi epoll sparse warning

 arch/arm/Kconfig                   |   1 -
 arch/arm/include/asm/ptrace.h      |   1 -
 arch/arm/include/asm/syscall.h     |  16 ++-
 arch/arm/include/asm/thread_info.h |   6 +-
 arch/arm/include/asm/uaccess-asm.h |   6 -
 arch/arm/include/asm/uaccess.h     | 169 ++++++++++++-----------
 arch/arm/include/uapi/asm/unistd.h |   1 +
 arch/arm/kernel/asm-offsets.c      |   3 +-
 arch/arm/kernel/entry-common.S     |  20 +--
 arch/arm/kernel/process.c          |   7 +-
 arch/arm/kernel/ptrace.c           |  14 +-
 arch/arm/kernel/signal.c           |   8 --
 arch/arm/kernel/sys_oabi-compat.c  | 214 +++++++++++++++++------------
 arch/arm/kernel/traps.c            |  47 +++----
 arch/arm/lib/copy_from_user.S      |   3 +-
 arch/arm/lib/copy_to_user.S        |   3 +-
 arch/arm/tools/syscall.tbl         |   2 +-
 fs/eventpoll.c                     |   5 +-
 include/linux/eventpoll.h          |  18 +++
 include/linux/syscalls.h           |   3 +
 ipc/sem.c                          |  84 ++++++-----
 mm/maccess.c                       |  28 +++-
 22 files changed, 361 insertions(+), 298 deletions(-)

Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: Alexander Viro <[e-mail]>
Cc: Linus Walleij <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>

Comments

Christoph Hellwig Aug. 11, 2021, 6:39 a.m. UTC | #1

From my high-level perspective this looks great and I'd love to see it
merged:

Acked-by: Christoph Hellwig <[e-mail]>

Arnd Bergmann Aug. 11, 2021, 7:31 a.m. UTC | #2

On Wed, Aug 11, 2021 at 8:39 AM Christoph Hellwig <[e-mail]> wrote:
>
> From my high-level perspective this looks great and I'd love to see it
> merged:
>
> Acked-by: Christoph Hellwig <[e-mail]>

Thank you for taking another look, and for the reminder. I've now added the
series to Russell's patch tracker.

       Arnd