linux/arch
Mikael Pettersson e4f2dfbb5e m68k: implement futex.h to support userspace robust futexes and PI mutexes
Linux/M68K currently doesn't support robust futexes or PI mutexes.
The problem is that the futex code needs to perform certain ops
(cmpxchg, set, add, or, andn, xor) atomically on user-space
addresses, and M68K's lack of a futex.h causes those operations
to be unsupported and disabled.

This patch adds that support, but only for uniprocessor machines,
which is adequate for M68K.  For UP it's enough to disable preemption
to ensure mutual exclusion (futexes don't need to care about other
hardware agents), and the mandatory pagefault_disable() does just that.

This patch is closely based on the one I co-wrote for UP ARM back
in August 2008.  The main change is that this patch uses the C
get_user/put_user accessors instead of inline assembly code with
exception table fixups.

For non-MMU machines the new futex.h simply redirects to the generic
futex.h, so there is no functional change for them.

Tested on aranym with the glibc-2.17 test suite: no regressions, and
a number of mutex/condvar test cases went from failing to succeeding
(tst-mutexpi{5,5a,6,9}, tst-cond2[45], tst-robust[1-9], tst-robustpi[1-8]).
Also tested with glibc-2.18 HEAD and a local glibc patch to enable PI
mutexes: no regressions.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Acked-by: Andreas Schwab <schwab@linux-m68k.org>
[geert: Added removal of ""generic-y += futex.h"]
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2013-05-21 21:29:13 +02:00
..
alpha Removal of GENERIC_GPIO for v3.10 2013-05-09 09:59:16 -07:00
arc Aliasing VIPT dcache support for ARC 2013-05-10 07:24:14 -07:00
arm Merge branch 'devm_no_resource_check' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2013-05-18 10:54:54 -07:00
arm64 arm64: debug: fix mdscr.ss check when enabling debug exceptions 2013-05-17 18:24:19 +01:00
avr32 Removal of GENERIC_GPIO for v3.10 2013-05-09 09:59:16 -07:00
blackfin blackfin updates for Linux 3.10 2013-05-10 07:21:16 -07:00
c6x dump_stack: unify debug information printed by show_regs() 2013-04-30 17:04:02 -07:00
cris - Lots of cleanups from Artem, including deletion of some obsolete drivers 2013-05-09 10:15:46 -07:00
frv Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-05-01 14:08:52 -07:00
h8300 We get rid of the general module prefix confusion with a binary config option, 2013-05-05 10:58:06 -07:00
hexagon Removal of GENERIC_GPIO for v3.10 2013-05-09 09:59:16 -07:00
ia64 Removal of GENERIC_GPIO for v3.10 2013-05-09 09:59:16 -07:00
m32r Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-05-01 14:08:52 -07:00
m68k m68k: implement futex.h to support userspace robust futexes and PI mutexes 2013-05-21 21:29:13 +02:00
metag Removal of GENERIC_GPIO for v3.10 2013-05-09 09:59:16 -07:00
microblaze Merge branch 'next' of git://git.monstr.eu/linux-2.6-microblaze 2013-05-10 07:19:52 -07:00
mips Merge branch 'devm_no_resource_check' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2013-05-18 10:54:54 -07:00
mn10300 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-05-01 14:08:52 -07:00
openrisc Removal of GENERIC_GPIO for v3.10 2013-05-09 09:59:16 -07:00
parisc parisc: make default cross compiler search more robust (v3) 2013-05-13 22:11:57 +02:00
powerpc Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2013-05-14 07:43:11 -07:00
s390 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2013-05-10 09:21:05 -07:00
score Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
sh Removal of GENERIC_GPIO for v3.10 2013-05-09 09:59:16 -07:00
sparc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2013-05-10 09:21:05 -07:00
tile Merge branch 'stable' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile 2013-05-09 14:34:58 -07:00
um Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-07 15:14:53 -07:00
unicore32 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2013-05-10 09:21:05 -07:00
x86 x86: Fix bit corruption at CPU resume time 2013-05-20 11:36:03 -07:00
xtensa Xtensa patchset for v3.10-rc1 2013-05-09 14:38:16 -07:00
.gitignore
Kconfig Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-05-15 14:04:00 -07:00