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  1. Mar 17, 2019
  3. Mar 06, 2019
  5. Mar 04, 2019
    • Linus Torvalds's avatar
      get rid of legacy 'get_ds()' function · 736706be
      Linus Torvalds authored 
      
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: default avatarJann Horn <jannh@google.com>
Inspired-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      736706be
  7. Feb 28, 2019
  9. Feb 22, 2019
  11. Feb 13, 2019
  13. Jan 25, 2019
  15. Jan 22, 2019
    • Logan Gunthorpe's avatar
      iomap: introduce io{read|write}64_{lo_hi|hi_lo} · 79bf0cbd
      Logan Gunthorpe authored 
      
In order to provide non-atomic functions for io{read|write}64 that will
use readq and writeq when appropriate. We define a number of variants
of these functions in the generic iomap that will do non-atomic
operations on pio but atomic operations on mmio.

These functions are only defined if readq and writeq are defined. If
they are not, then the wrappers that always use non-atomic operations
from include/linux/io-64-nonatomic*.h will be used.

Signed-off-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Suresh Warrier <warrier@linux.vnet.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      79bf0cbd
  17. Jan 04, 2019
    • Matthew Wilcox's avatar
      fls: change parameter to unsigned int · 3fc2579e
      Matthew Wilcox authored 
      When testing in userspace, UBSAN pointed out that shifting into the sign
bit is undefined behaviour.  It doesn't really make sense to ask for the
highest set bit of a negative value, so just turn the argument type into
an unsigned int.

Some architectures (eg ppc) already had it declared as an unsigned int,
so I don't expect too many problems.

Link: http://lkml.kernel.org/r/20181105221117.31828-1-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox <willy@infradead.org>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3fc2579e
    • Linus Torvalds's avatar
      Remove 'type' argument from access_ok() function · 96d4f267
      Linus Torvalds authored 
      
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: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      96d4f267
  19. Dec 28, 2018
  21. Dec 19, 2018
  23. Dec 14, 2018
  25. Dec 13, 2018
  27. Dec 05, 2018
  29. Dec 01, 2018
    • Masahiro Yamada's avatar
      kbuild: simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS · bbda5ec6
      Masahiro Yamada authored 
      
My main motivation of this commit is to clean up scripts/Kbuild.include
and scripts/Makefile.build.

Currently, CONFIG_TRIM_UNUSED_KSYMS works with a tricky gimmick;
possibly exported symbols are detected by letting $(CPP) replace
EXPORT_SYMBOL* with a special string '=== __KSYM_*===', which is
post-processed by sed, and passed to fixdep. The extra preprocessing
is costly, and hacking cmd_and_fixdep is ugly.

I came up with a new way to find exported symbols; insert a dummy
symbol __ksym_marker_* to each potentially exported symbol. Those
dummy symbols are picked up by $(NM), post-processed by sed, then
appended to .*.cmd files. I collected the post-process part to a
new shell script scripts/gen_ksymdeps.sh for readability. The dummy
symbols are put into the .discard.* section so that the linker
script rips them off the final vmlinux or modules.

A nice side-effect is building with CONFIG_TRIM_UNUSED_KSYMS will
be much faster.

Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: default avatarNicolas Pitre <nico@linaro.org>
      bbda5ec6
  31. Nov 02, 2018
  33. Nov 01, 2018
    • Mark Rutland's avatar
      locking/atomics: Switch to generated instrumentation · aa525d06
      Mark Rutland authored 
      
As a step towards ensuring the atomic* APIs are consistent, let's switch
to wrappers generated by gen-atomic-instrumented.h, using the same table
used to generate the fallbacks and atomic-long wrappers.

These are checked in rather than generated with Kbuild, since:

* This allows inspection of the atomics with git grep and ctags on a
  pristine tree, which Linus strongly prefers being able to do.

* The fallbacks are not affected by machine details or configuration
  options, so it is not necessary to regenerate them to take these into
  account.

* These are included by files required *very* early in the build process
  (e.g. for generating bounds.h), and we'd rather not complicate the
  top-level Kbuild file with dependencies.

Generating the atomic headers means that the instrumented wrappers will
remain in sync with the rest of the atomic APIs, and we gain all the
ordering variants of each atomic without having to manually expanded
them all.

The KASAN checks are automatically generated based on the function
parameters defined in atomics.tbl. Note that try_cmpxchg() now correctly
treats 'old' as a parameter that may be written to, and not only read as
the hand-written instrumentation assumed.

Other than the change to try_cmpxchg(), existing code should not be
affected by this patch. The patch introduces instrumentation for all
optional atomics (and ordering variants), along with the ifdeffery this
requires, enabling other architectures to make use of the instrumented
atomics.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: catalin.marinas@arm.com
Cc: linuxdrivers@attotech.com
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Link: http://lkml.kernel.org/r/20180904104830.2975-5-mark.rutland@arm.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      aa525d06
    • Mark Rutland's avatar
      locking/atomics: Switch to generated atomic-long · b5d47ef9
      Mark Rutland authored 
      
As a step towards ensuring the atomic* APIs are consistent, let's switch
to wrappers generated by gen-atomic-long.h, using the same table that
gen-atomic-fallbacks.h uses to fill in gaps in the atomic_* and
atomic64_* APIs.

These are checked in rather than generated with Kbuild, since:

* This allows inspection of the atomics with git grep and ctags on a
  pristine tree, which Linus strongly prefers being able to do.

* The fallbacks are not affected by machine details or configuration
  options, so it is not necessary to regenerate them to take these into
  account.

* These are included by files required *very* early in the build process
  (e.g. for generating bounds.h), and we'd rather not complicate the
  top-level Kbuild file with dependencies.

Other than *_INIT() and *_cond_read_acquire(), all API functions are
implemented as static inline C functions, ensuring consistent type
promotion and/or truncation without requiring explicit casts to be
applied to parameters or return values.

Since we typedef atomic_long_t to either atomic_t or atomic64_t, we know
these types are equivalent, and don't require explicit casts between
them. However, as the try_cmpxchg*() functions take a pointer for the
'old' parameter, which may be an int or s64, an explicit cast is
generated for this.

There should be no functional change as a result of this patch (i.e.
existing code should not be affected). However, this introduces a number
of functions into the atomic_long_* API, bringing it into line with the
atomic_* and atomic64_* APIs.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: catalin.marinas@arm.com
Cc: linuxdrivers@attotech.com
Cc: dvyukov@google.com
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: aryabinin@virtuozzo.com
Cc: glider@google.com
Link: http://lkml.kernel.org/r/20180904104830.2975-4-mark.rutland@arm.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      b5d47ef9
  35. Oct 31, 2018
  37. Oct 26, 2018