[PATCH RFC 00/22] proc: convert the arch and platform entries

[Christian Brauner <brauner@kernel.org>]

This converts the proc entries under arch/ and the ones of ACPI, the
platform drivers, via-pmu and PNP to what "proc: let procfs own the
data path" set up: procfs owns the seq_file, copies in writes, copies
out reads and copies ioctl arguments in and out, so the entries' code
only ever runs with the entry pinned and never touches userspace
memory.

One patch per subsystem and method, in the order seq_file, write, read,
ioctl. Most of them just stop copying in or out themselves, or switch
from kstrto*_from_user() to kstrto*() and from simple_read_from_buffer()
to memory_read_from_buffer(). Where a write that is larger than
anything the entry parses now fails with -EINVAL from procfs I've called
that out in the commit. The rtas flash files take their image in 4k
pieces and keep doing that with PROC_ENTRY_SHORT_WRITES, the rtas error
log is a stream and hands out a record before procfs copies it out, so
a reader that passes a bad buffer loses it. /proc/mtrr's ioctls are
table driven now, the native and the 32-bit commands share one table.

Build tested per commit on x86_64 and with W=1 on the touched objects on
alpha, arm, m68k, powerpc, sh, sparc, um, x86 and xtensa. The entries I
could get at in an x86 VM behave the same with and without the series.

This is on top of "proc: let procfs own the data path". The other three
conversion series don't depend on it and it doesn't depend on them.

Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
---
Christian Brauner (22):
      alpha: srm_env: let procfs copy in writes
      ARM: alignment: let procfs copy in writes
      ARM: atags: let procfs copy out reads of /proc/atags
      m68k/bootinfo: let procfs copy out reads of /proc/bootinfo
      powerpc/rtas: let procfs copy in writes
      powerpc/rtas: let procfs copy out reads
      powerpc/pseries: let procfs copy in writes
      powerpc/procfs: let procfs copy out reads of /proc/powerpc/systemcfg
      sh: alignment: let procfs copy in writes
      sparc: led: let procfs copy in writes
      um: let procfs copy in writes
      x86/mtrr: let procfs own the seq_file of /proc/mtrr
      x86/mtrr: let procfs copy in writes to /proc/mtrr
      x86/mtrr: let procfs copy the ioctl arguments of /proc/mtrr
      xtensa: simdisk: let procfs copy in writes
      xtensa: simdisk: let procfs copy out reads
      ACPI: proc: let procfs copy in writes to /proc/acpi/wakeup
      macintosh/via-pmu: let procfs copy in writes to the options file
      platform/x86: thinkpad_acpi: let procfs copy in writes
      platform/x86: toshiba_acpi: let procfs copy in writes
      PNP: pnpbios: let procfs copy in writes
      PNP: isapnp: let procfs copy out reads

 arch/alpha/kernel/srm_env.c                 | 12 +---
 arch/arm/kernel/atags_proc.c                |  6 +-
 arch/arm/mm/alignment.c                     |  7 +--
 arch/m68k/kernel/bootinfo_proc.c            |  6 +-
 arch/powerpc/kernel/proc_powerpc.c          |  6 +-
 arch/powerpc/kernel/rtas-proc.c             | 40 ++++++------
 arch/powerpc/kernel/rtas_flash.c            | 62 +++++++++----------
 arch/powerpc/kernel/rtasd.c                 | 19 ++----
 arch/powerpc/platforms/pseries/lpar.c       | 14 ++---
 arch/powerpc/platforms/pseries/lparcfg.c    |  7 +--
 arch/powerpc/platforms/pseries/reconfig.c   | 22 +++----
 arch/sh/mm/alignment.c                      |  7 +--
 arch/sparc/kernel/led.c                     | 13 +---
 arch/um/drivers/mconsole_kern.c             | 11 +---
 arch/um/kernel/exitcode.c                   | 14 ++---
 arch/x86/kernel/cpu/mtrr/if.c               | 95 ++++++++++++++++-------------
 arch/xtensa/platforms/iss/simdisk.c         | 32 ++++------
 drivers/acpi/proc.c                         |  7 +--
 drivers/macintosh/via-pmu.c                 |  7 +--
 drivers/platform/x86/lenovo/thinkpad_acpi.c | 14 +----
 drivers/platform/x86/toshiba_acpi.c         | 36 ++++-------
 drivers/pnp/isapnp/proc.c                   | 20 +++---
 drivers/pnp/pnpbios/proc.c                  |  9 +--
 23 files changed, 193 insertions(+), 273 deletions(-)
---
base-commit: 65ba8f34ec886ec72b2c07ddc8cf3d815c32869d
change-id: 20261101-work-procfs-arch-8d4ade48be31
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