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alistair23-linux/arch/x86/lib/atomic64_32.c

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x86: Adjust asm constraints in atomic64 wrappers Eric pointed out overly restrictive constraints in atomic64_set(), but there are issues throughout the file. In the cited case, %ebx and %ecx are inputs only (don't get changed by either of the two low level implementations). This was also the case elsewhere. Further in many cases early-clobber indicators were missing. Finally, the previous implementation rolled a custom alternative instruction macro from scratch, rather than using alternative_call() (which was introduced with the commit that the description of the change in question actually refers to). Adjusting has the benefit of not hiding referenced symbols from the compiler, which however requires them to be declared not just in the exporting source file (which, as a desirable side effect, in turn allows that exporting file to become a real 5-line stub). This patch does not eliminate the overly restrictive memory clobbers, however: Doing so would occasionally make the compiler set up a second register for accessing the memory object (to satisfy the added "m" constraint), and it's not clear which of the two non-optimal alternatives is better. v2: Re-do the declaration and exporting of the internal symbols. Reported-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Link: http://lkml.kernel.org/r/4F19A2A5020000780006E0D9@nat28.tlf.novell.com Cc: Luca Barbieri <luca@luca-barbieri.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2012-01-20 09:21:41 -07:00
#define ATOMIC64_EXPORT EXPORT_SYMBOL
x86: atomic64: Export APIs to modules atomic64_t primitives are used by a handful of drivers, so export the APIs consistently. These were inlined before. Also mark atomic64_32.o a core object, so that the symbols are available even if not linked to core kernel pieces. Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> LKML-Reference: <tip-05118ab8859492ac9ddda0154cf90e37b0a4a0b0@git.kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-03 09:28:57 -06:00
x86: Adjust asm constraints in atomic64 wrappers Eric pointed out overly restrictive constraints in atomic64_set(), but there are issues throughout the file. In the cited case, %ebx and %ecx are inputs only (don't get changed by either of the two low level implementations). This was also the case elsewhere. Further in many cases early-clobber indicators were missing. Finally, the previous implementation rolled a custom alternative instruction macro from scratch, rather than using alternative_call() (which was introduced with the commit that the description of the change in question actually refers to). Adjusting has the benefit of not hiding referenced symbols from the compiler, which however requires them to be declared not just in the exporting source file (which, as a desirable side effect, in turn allows that exporting file to become a real 5-line stub). This patch does not eliminate the overly restrictive memory clobbers, however: Doing so would occasionally make the compiler set up a second register for accessing the memory object (to satisfy the added "m" constraint), and it's not clear which of the two non-optimal alternatives is better. v2: Re-do the declaration and exporting of the internal symbols. Reported-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Link: http://lkml.kernel.org/r/4F19A2A5020000780006E0D9@nat28.tlf.novell.com Cc: Luca Barbieri <luca@luca-barbieri.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2012-01-20 09:21:41 -07:00
#include <linux/export.h>
atomic: use <linux/atomic.h> This allows us to move duplicated code in <asm/atomic.h> (atomic_inc_not_zero() for now) to <linux/atomic.h> Signed-off-by: Arun Sharma <asharma@fb.com> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-26 17:09:06 -06:00
#include <linux/atomic.h>