Similar to:
2ca052a x86: Use correct byte-sized register constraint in __xchg_op()
... the __add() macro also needs to use a "q" constraint in the
byte-sized case, lest we try to generate an illegal register.
Link: http://lkml.kernel.org/r/4F7A3315.501@goop.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Leigh Scott <leigh123linux@googlemail.com>
Cc: Thomas Reitmayr <treitmayr@devbase.at>
Cc: <stable@vger.kernel.org> v3.3
x86-64 can access the low half of any register, but i386 can only do
it with a subset of registers. 'r' causes compilation failures on i386,
but 'q' expresses the constraint properly.
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/4F7A3315.501@goop.org
Reported-by: Leigh Scott <leigh123linux@googlemail.com>
Tested-by: Thomas Reitmayr <treitmayr@devbase.at>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: <stable@vger.kernel.org> v3.3
Quite oddly, all of the arguments passed through from the top
level macros to the second level which didn't need parentheses
had them, while the only expression (involving a parameter)
needing them didn't.
Very recently I got bitten by the lack thereof when using
something like "array + index" for the first operand, with
"array" being an array more narrow than int.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/4F2183A9020000780006F3E6@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Just like the per-CPU ones they had several
problems/shortcomings:
Only the first memory operand was mentioned in the asm()
operands, and the 2x64-bit version didn't have a memory clobber
while the 2x32-bit one did. The former allowed the compiler to
not recognize the need to re-load the data in case it had it
cached in some register, while the latter was overly
destructive.
The types of the local copies of the old and new values were
incorrect (the types of the pointed-to variables should be used
here, to make sure the respective old/new variable types are
compatible).
The __dummy/__junk variables were pointless, given that local
copies of the inputs already existed (and can hence be used for
discarded outputs).
The 32-bit variant of cmpxchg_double_local() referenced
cmpxchg16b_local().
At once also:
- change the return value type to what it really is: 'bool'
- unify 32- and 64-bit variants
- abstract out the common part of the 'normal' and 'local' variants
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/4F01F12A020000780006A19B@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
They both have a basic "put new value in location, return old value"
pattern, so they can use the same macro easily.
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Use __compiletime_error() to produce a compile-time error rather than
link-time, where available.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Add a common xadd implementation.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Everything that's actually common between 32 and 64-bit is moved into
cmpxchg.h.
xchg/cmpxchg will fail with a link error if they're passed an
unsupported size (which includes 64-bit args on 32-bit systems).
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
