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Revision 340b3a5b35c0919e1535b355a9eafe1f81c4cae3 authored by Linus Torvalds on 28 February 2016, 00:58:32 UTC, committed by Linus Torvalds on 28 February 2016, 00:58:32 UTC 
Merge tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
 
Pull ARM SoC fixes from Olof Johansson:
 "We didn't have a batch last week, so this one is slightly larger.

  None of them are scary though, a handful of fixes for small DT pieces,
  replacing properties with newer conventions.

  Highlights:
   - N900 fix for setting system revision
   - onenand init fix to avoid filesystem corruption
   - Clock fix for audio on Beaglebone-x15
   - Fixes on shmobile to deal with CONFIG_DEBUG_RODATA (default y in 4.6)

  + misc smaller stuff"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  MAINTAINERS: Extend info, add wiki and ml for meson arch
  MAINTAINERS: alpine: add a new maintainer and update the entry
  ARM: at91/dt: fix typo in sama5d2 pinmux descriptions
  ARM: OMAP2+: Fix onenand initialization to avoid filesystem corruption
  Revert "regulator: tps65217: remove tps65217.dtsi file"
  ARM: shmobile: Remove shmobile_boot_arg
  ARM: shmobile: Move shmobile_smp_{mpidr, fn, arg}[] from .text to .bss
  ARM: shmobile: r8a7779: Remove remainings of removed SCU boot setup code
  ARM: shmobile: Move shmobile_scu_base from .text to .bss
  ARM: OMAP2+: Fix omap_device for module reload on PM runtime forbid
  ARM: OMAP2+: Improve omap_device error for driver writers
  ARM: DTS: am57xx-beagle-x15: Select SYS_CLK2 for audio clocks
  ARM: dts: am335x/am57xx: replace gpio-key,wakeup with wakeup-source property
  ARM: OMAP2+: Set system_rev from ATAGS for n900
  ARM: dts: orion5x: fix the missing mtd flash on linkstation lswtgl
  ARM: dts: kirkwood: use unique machine name for ds112
  ARM: dts: imx6: remove bogus interrupt-parent from CAAM node
2 parent s 691429e + d877a21
Raw File
highuid.txt 
Notes on the change from 16-bit UIDs to 32-bit UIDs:

- kernel code MUST take into account __kernel_uid_t and __kernel_uid32_t
  when communicating between user and kernel space in an ioctl or data
  structure.

- kernel code should use uid_t and gid_t in kernel-private structures and
  code.

What's left to be done for 32-bit UIDs on all Linux architectures:

- Disk quotas have an interesting limitation that is not related to the
  maximum UID/GID. They are limited by the maximum file size on the
  underlying filesystem, because quota records are written at offsets
  corresponding to the UID in question.
  Further investigation is needed to see if the quota system can cope
  properly with huge UIDs. If it can deal with 64-bit file offsets on all 
  architectures, this should not be a problem.

- Decide whether or not to keep backwards compatibility with the system
  accounting file, or if we should break it as the comments suggest
  (currently, the old 16-bit UID and GID are still written to disk, and
  part of the former pad space is used to store separate 32-bit UID and
  GID)

- Need to validate that OS emulation calls the 16-bit UID
  compatibility syscalls, if the OS being emulated used 16-bit UIDs, or
  uses the 32-bit UID system calls properly otherwise.

  This affects at least:
	iBCS on Intel

	sparc32 emulation on sparc64
	(need to support whatever new 32-bit UID system calls are added to
	sparc32)

- Validate that all filesystems behave properly.

  At present, 32-bit UIDs _should_ work for:
	ext2
	ufs
	isofs
	nfs
	coda
	udf

  Ioctl() fixups have been made for:
	ncpfs
	smbfs

  Filesystems with simple fixups to prevent 16-bit UID wraparound:
	minix
	sysv
	qnx4

  Other filesystems have not been checked yet.

- The ncpfs and smpfs filesystems cannot presently use 32-bit UIDs in
  all ioctl()s. Some new ioctl()s have been added with 32-bit UIDs, but
  more are needed. (as well as new user<->kernel data structures)

- The ELF core dump format only supports 16-bit UIDs on arm, i386, m68k,
  sh, and sparc32. Fixing this is probably not that important, but would
  require adding a new ELF section.

- The ioctl()s used to control the in-kernel NFS server only support
  16-bit UIDs on arm, i386, m68k, sh, and sparc32.

- make sure that the UID mapping feature of AX25 networking works properly
  (it should be safe because it's always used a 32-bit integer to
  communicate between user and kernel)


Chris Wing
wingc@umich.edu

last updated: January 11, 2000
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