linux-toradex.git/arch/arm/include/asm/uaccess.h, branch v5.11

uaccess: remove segment_eq

2020-08-12T17:57:58+00:00

segment_eq is only used to implement uaccess_kernel.  Just open code
uaccess_kernel in the arch uaccess headers and remove one layer of
indirection.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Acked-by: Linus Torvalds 
Acked-by: Greentime Hu 
Acked-by: Geert Uytterhoeven 
Cc: Nick Hu 
Cc: Vincent Chen 
Cc: Paul Walmsley 
Cc: Palmer Dabbelt 
Link: http://lkml.kernel.org/r/20200710135706.537715-5-hch@lst.de
Signed-off-by: Linus Torvalds

ARM: uaccess: add further explanation of __range_ok()

2020-07-22T08:50:55+00:00

Detail the success return condition, and that we rely on KERNEL_DS
being zero for this to operate correctly.

Signed-off-by: Russell King

ARM: 8908/1: add __always_inline to functions called from __get_user_check()

2019-10-10T21:23:19+00:00

KernelCI reports that bcm2835_defconfig is no longer booting since
commit ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING
forcibly") (https://lkml.org/lkml/2019/9/26/825).

I also received a regression report from Nicolas Saenz Julienne
(https://lkml.org/lkml/2019/9/27/263).

This problem has cropped up on bcm2835_defconfig because it enables
CONFIG_CC_OPTIMIZE_FOR_SIZE. The compiler tends to prefer not inlining
functions with -Os. I was able to reproduce it with other boards and
defconfig files by manually enabling CONFIG_CC_OPTIMIZE_FOR_SIZE.

The __get_user_check() specifically uses r0, r1, r2 registers.
So, uaccess_save_and_enable() and uaccess_restore() must be inlined.
Otherwise, those register assignments would be entirely dropped,
according to my analysis of the disassembly.

Prior to commit 9012d011660e ("compiler: allow all arches to enable
CONFIG_OPTIMIZE_INLINING"), the 'inline' marker was always enough for
inlining functions, except on x86.

Since that commit, all architectures can enable CONFIG_OPTIMIZE_INLINING.
So, __always_inline is now the only guaranteed way of forcible inlining.

I added __always_inline to 4 functions in the call-graph from the
__get_user_check() macro.

Fixes: 9012d011660e ("compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING")
Reported-by: "kernelci.org bot" 
Reported-by: Nicolas Saenz Julienne 
Signed-off-by: Masahiro Yamada 
Tested-by: Nicolas Saenz Julienne 
Signed-off-by: Russell King

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Enrico Weigelt 
Reviewed-by: Kate Stewart 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman

ARM: 8852/1: uaccess: use unified assembler language syntax

2019-04-23T16:20:52+00:00

Convert the conditional infix to a postfix to make sure this inline
assembly is unified syntax. Since gcc assumes non-unified syntax
when emitting ARM instructions, make sure to define the syntax as
unified.

This allows to use LLVM's integrated assembler.

Additionally, for GCC ".syntax unified" for inline assembly.
When compiling non-Thumb2 GCC always emits a ".syntax divided"
at the beginning of the inline assembly which makes the
assembler fail. Since GCC 5 there is the -masm-syntax-unified
GCC option which make GCC assume unified syntax asm and hence
emits ".syntax unified" even in ARM mode. However, the option
is broken since GCC version 6 (see GCC PR88648 [1]). Work
around by adding ".syntax unified" as part of the inline
assembly.

[0] https://gcc.gnu.org/onlinedocs/gcc/ARM-Options.html#index-masm-syntax-unified
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88648

Signed-off-by: Stefan Agner 
Signed-off-by: Russell King

Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

2019-03-15T21:37:46+00:00

Pull ARM updates from Russell King:

 - An improvement from Ard Biesheuvel, who noted that the identity map
   setup was taking a long time due to flush_cache_louis().

 - Update a comment about dma_ops from Wolfram Sang.

 - Remove use of "-p" with ld, where this flag has been a no-op since
   2004.

 - Remove the printing of the virtual memory layout, which is no longer
   useful since we hide pointers.

 - Correct SCU help text.

 - Remove legacy TWD registration method.

 - Add pgprot_device() implementation for mapping PCI sysfs resource
   files.

 - Initialise PFN limits earlier for kmemleak.

 - Fix argument count to match macro definition (affects clang builds)

 - Use unified assembler language almost everywhere for clang, and other
   clang improvements (from Stefan Agner, Nathan Chancellor).

 - Support security extension for noMMU and other noMMU cleanups (from
   Vladimir Murzin).

 - Remove unnecessary SMP bringup code (which was incorrectly copy'n'
   pasted from the ARM platform implementations) and remove it from the
   arch code to discourge further copys of it appearing.

 - Add Cortex A9 erratum preventing kexec working on some SoCs.

 - AMBA bus identification updates from Mike Leach.

 - More use of raw spinlocks to avoid -RT kernel issues (from Yang Shi
   and Sebastian Andrzej Siewior).

 - MCPM hyp/svc mode mismatch fixes from Marek Szyprowski.

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (32 commits)
  ARM: 8849/1: NOMMU: Fix encodings for PMSAv8's PRBAR4/PRLAR4
  ARM: 8848/1: virt: Align GIC version check with arm64 counterpart
  ARM: 8847/1: pm: fix HYP/SVC mode mismatch when MCPM is used
  ARM: 8845/1: use unified assembler in c files
  ARM: 8844/1: use unified assembler in assembly files
  ARM: 8843/1: use unified assembler in headers
  ARM: 8841/1: use unified assembler in macros
  ARM: 8840/1: use a raw_spinlock_t in unwind
  ARM: 8839/1: kprobe: make patch_lock a raw_spinlock_t
  ARM: 8837/1: coresight: etmv4: Update ID register table to add UCI support
  ARM: 8836/1: drivers: amba: Update component matching to use the CoreSight UCI values.
  ARM: 8838/1: drivers: amba: Updates to component identification for driver matching.
  ARM: 8833/1: Ensure that NEON code always compiles with Clang
  ARM: avoid Cortex-A9 livelock on tight dmb loops
  ARM: smp: remove arch-provided "pen_release"
  ARM: actions: remove boot_lock and pen_release
  ARM: oxnas: remove CPU hotplug implementation
  ARM: qcom: remove unnecessary boot_lock
  ARM: 8832/1: NOMMU: Limit visibility for CONFIG_FLASH_{MEM_BASE,SIZE}
  ARM: 8831/1: NOMMU: pmsa-v8: remove unneeded semicolon
  ...

get rid of legacy 'get_ds()' function

2019-03-04T18:50:14+00:00

Every in-kernel use of this function defined it to KERNEL_DS (either as
an actual define, or as an inline function).  It's an entirely
historical artifact, and long long long ago used to actually read the
segment selector valueof '%ds' on x86.

Which in the kernel is always KERNEL_DS.

Inspired by a patch from Jann Horn that just did this for a very small
subset of users (the ones in fs/), along with Al who suggested a script.
I then just took it to the logical extreme and removed all the remaining
gunk.

Roughly scripted with

   git grep -l '(get_ds())' -- :^tools/ | xargs sed -i 's/(get_ds())/(KERNEL_DS)/'
   git grep -lw 'get_ds' -- :^tools/ | xargs sed -i '/^#define get_ds()/d'

plus manual fixups to remove a few unusual usage patterns, the couple of
inline function cases and to fix up a comment that had become stale.

The 'get_ds()' function remains in an x86 kvm selftest, since in user
space it actually does something relevant.

Inspired-by: Jann Horn 
Inspired-by: Al Viro 
Signed-off-by: Linus Torvalds

ARM: 8828/1: uaccess: use unified assembler language syntax

2019-02-01T21:44:14+00:00

Convert the conditional infix to a postfix to make sure this inline
assembly is unified syntax. Since gcc assumes non-unified syntax
when emitting ARM instructions, make sure to define the syntax as
unified.

This allows to use LLVM's integrated assembler.

Signed-off-by: Stefan Agner 
Signed-off-by: Russell King

Merge tag 'for-4.21' of git://git.armlinux.org.uk/~rmk/linux-arm

2019-01-05T19:23:17+00:00

Pull ARM updates from Russell King:
 "Included in this update:

   - Florian Fainelli noticed that userspace segfaults caused by the
     lack of kernel-userspace helpers was hard to diagnose; we now issue
     a warning when userspace tries to use the helpers but the kernel
     has them disabled.

   - Ben Dooks wants compatibility for the old ATAG serial number with
     DT systems.

   - Some cleanup of assembly by Nicolas Pitre.

   - User accessors optimisation from Vincent Whitchurch.

   - More robust kdump on SMP systems from Yufen Wang.

   - Sebastian Andrzej Siewior noticed problems with the SMP "boot_lock"
     on RT kernels, and so we convert the Versatile series of platforms
     to use a raw spinlock instead, consolidating the Versatile
     implementation. We entirely remove the boot_lock on OMAP systems,
     where it's unnecessary. Further patches for other systems will be
     submitted for the following merge window.

   - Start switching old StrongARM-11x0 systems to use gpiolib rather
     than their private GPIO implementation - mostly PCMCIA bits.

   - ARM Kconfig cleanups.

   - Cleanup a mostly harmless mistake in the recent Spectre patch in
     4.20 (which had the effect that data that can be placed into the
     init sections was incorrectly always placed in the rodata section)"

* tag 'for-4.21' of git://git.armlinux.org.uk/~rmk/linux-arm: (25 commits)
  ARM: omap2: remove unnecessary boot_lock
  ARM: versatile: rename and comment SMP implementation
  ARM: versatile: convert boot_lock to raw
  ARM: vexpress/realview: consolidate immitation CPU hotplug
  ARM: fix the cockup in the previous patch
  ARM: sa1100/cerf: switch to using gpio_led_register_device()
  ARM: sa1100/assabet: switch to using gpio leds
  ARM: sa1100/assabet: add gpio keys support for right-hand two buttons
  ARM: sa1111: remove legacy GPIO interfaces
  pcmcia: sa1100*: remove redundant bvd1/bvd2 setting
  ARM: pxa/lubbock: switch PCMCIA to MAX1600 library
  ARM: pxa/mainstone: switch PCMCIA to MAX1600 library and gpiod APIs
  ARM: sa1100/neponset: switch PCMCIA to MAX1600 library and gpiod APIs
  ARM: sa1100/jornada720: switch PCMCIA to gpiod APIs
  pcmcia: add MAX1600 library
  ARM: sa1100: explicitly register sa11x0-pcmcia devices
  ARM: 8813/1: Make aligned 2-byte getuser()/putuser() atomic on ARMv6+
  ARM: 8812/1: Optimise copy_{from/to}_user for !CPU_USE_DOMAINS
  ARM: 8811/1: always list both ldrd/strd registers explicitly
  ARM: 8808/1: kexec:offline panic_smp_self_stop CPU
  ...

Remove 'type' argument from access_ok() function

2019-01-04T02:57:57+00:00

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csky still had the old "verify_area()" name as an alias.

 - the iter_iov code had magical hardcoded knowledge of the actual
   values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
   really used it)

 - microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something.  Any missed conversion should be trivially fixable, though.

Signed-off-by: Linus Torvalds