x86: add user_atomic_cmpxchg_inatomic at uaccess.h

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This patch adds user_atomic_cmpxchg_inatomic() to use CMPXCHG
instruction against a user space address.

This generalizes the already existing futex_atomic_cmpxchg_inatomic()
so it can be used in other contexts.  This will be used in the
upcoming support for Intel MPX (Memory Protection Extensions.)

[ hpa: replaced #ifdef inside a macro with IS_ENABLED() ]

Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>
Link: http://lkml.kernel.org/r/1387002303-6620-1-git-send-email-qiaowei.ren@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>

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Qiaowei Ren 2013-12-14 14:25:02 +08:00 • committed by H. Peter Anvin

parent e7d820a5e5

commit f09174c501

1 changed files with 92 additions and 0 deletions

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arch/x86/include/asm/uaccess.h

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