linux/arch/s390
Huang Ying df013ffb81 Add Kconfig option ARCH_HAVE_NMI_SAFE_CMPXCHG
cmpxchg() is widely used by lockless code, including NMI-safe lockless
code.  But on some architectures, the cmpxchg() implementation is not
NMI-safe, on these architectures the lockless code may need a
spin_trylock_irqsave() based implementation.

This patch adds a Kconfig option: ARCH_HAVE_NMI_SAFE_CMPXCHG, so that
NMI-safe lockless code can depend on it or provide different
implementation according to it.

On many architectures, cmpxchg is only NMI-safe for several specific
operand sizes. So, ARCH_HAVE_NMI_SAFE_CMPXCHG define in this patch
only guarantees cmpxchg is NMI-safe for sizeof(unsigned long).

Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Richard Henderson <rth@twiddle.net>
CC: Mikael Starvik <starvik@axis.com>
Acked-by: David Howells <dhowells@redhat.com>
CC: Yoshinori Sato <ysato@users.sourceforge.jp>
CC: Tony Luck <tony.luck@intel.com>
CC: Hirokazu Takata <takata@linux-m32r.org>
CC: Geert Uytterhoeven <geert@linux-m68k.org>
CC: Michal Simek <monstr@monstr.eu>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
CC: Kyle McMartin <kyle@mcmartin.ca>
CC: Martin Schwidefsky <schwidefsky@de.ibm.com>
CC: Chen Liqin <liqin.chen@sunplusct.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Ingo Molnar <mingo@redhat.com>
CC: Chris Zankel <chris@zankel.net>
Signed-off-by: Len Brown <len.brown@intel.com>
2011-08-03 11:12:37 -04:00
..
appldata [S390] mm: add ZONE_DMA to 31-bit config again 2011-05-26 09:48:25 +02:00
boot Merge branch 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 2011-03-20 18:14:55 -07:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2011-05-20 17:24:14 -07:00
hypfs treewide: remove extra semicolons 2011-04-10 17:01:05 +02:00
include/asm [S390] fix kvm defines for 31 bit compile 2011-06-06 14:14:56 +02:00
kernel [S390] allow setting of upper 32 bit in smp_ctl_set_bit 2011-06-22 16:24:20 +02:00
kvm [S390] kvm-s390: fix stfle facilities numbers >=64 2011-06-06 14:14:56 +02:00
lib [S390] delay: implement ndelay 2011-05-26 09:48:25 +02:00
math-emu s390: change to new flag variable 2011-03-17 14:02:57 +01:00
mm [S390] use generic RCU page-table freeing code 2011-06-06 14:14:56 +02:00
oprofile [S390] hwsampler: Set a sane default sampling rate 2011-06-22 16:24:20 +02:00
defconfig [S390] Update default configuration 2011-01-12 09:55:24 +01:00
Kbuild [S390] standardize Kbuild rules 2010-10-25 16:10:14 +02:00
Kconfig Add Kconfig option ARCH_HAVE_NMI_SAFE_CMPXCHG 2011-08-03 11:12:37 -04:00
Kconfig.debug [S390] Write protect module text and RO data 2011-03-15 17:08:23 +01:00
Makefile [S390] remove redundant stack check option 2011-03-15 17:08:22 +01:00