diff options
author | Tom Rini <trini@kernel.crashing.org> | 2006-09-27 11:28:20 +0900 |
---|---|---|
committer | Paul Mundt <lethal@linux-sh.org> | 2006-09-27 11:28:20 +0900 |
commit | e4e3b5ccd77226c9c4dbb0737106b868dfc182d9 (patch) | |
tree | 8401beac23ca03f79c52094ea10139658661769d /include/asm-sh/system.h | |
parent | 0c91c1a7012911e4b0180a1c1ae258e2b706f987 (diff) | |
download | linux-stable-e4e3b5ccd77226c9c4dbb0737106b868dfc182d9.tar.gz linux-stable-e4e3b5ccd77226c9c4dbb0737106b868dfc182d9.tar.bz2 linux-stable-e4e3b5ccd77226c9c4dbb0737106b868dfc182d9.zip |
sh: Add a simple cmpxchg().
We didn't have one of these before, a simple implementation
borrowed from MIPS as well as the __HAVE_ARCH_CMPXCHG bits.
Signed-off-by: Tom Rini <trini@kernel.crashing.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'include/asm-sh/system.h')
-rw-r--r-- | include/asm-sh/system.h | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/include/asm-sh/system.h b/include/asm-sh/system.h index ad35ad4958f4..e89728d405d8 100644 --- a/include/asm-sh/system.h +++ b/include/asm-sh/system.h @@ -6,6 +6,7 @@ * Copyright (C) 2002 Paul Mundt */ +#include <asm/types.h> /* * switch_to() should switch tasks to task nr n, first @@ -260,6 +261,45 @@ static __inline__ unsigned long __xchg(unsigned long x, volatile void * ptr, int return x; } +static inline unsigned long __cmpxchg_u32(volatile int * m, unsigned long old, + unsigned long new) +{ + __u32 retval; + unsigned long flags; + + local_irq_save(flags); + retval = *m; + if (retval == old) + *m = new; + local_irq_restore(flags); /* implies memory barrier */ + return retval; +} + +/* This function doesn't exist, so you'll get a linker error + * if something tries to do an invalid cmpxchg(). */ +extern void __cmpxchg_called_with_bad_pointer(void); + +#define __HAVE_ARCH_CMPXCHG 1 + +static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old, + unsigned long new, int size) +{ + switch (size) { + case 4: + return __cmpxchg_u32(ptr, old, new); + } + __cmpxchg_called_with_bad_pointer(); + return old; +} + +#define cmpxchg(ptr,o,n) \ + ({ \ + __typeof__(*(ptr)) _o_ = (o); \ + __typeof__(*(ptr)) _n_ = (n); \ + (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \ + (unsigned long)_n_, sizeof(*(ptr))); \ + }) + /* XXX * disable hlt during certain critical i/o operations */ |