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powerpc: Use BUILD_BUG_ON_MSG() for unsupported {cmp}xchg sizes 

__xchg_called_with_bad_pointer() can't tell us which code uses {cmp}xchg
with an unsupported size, and no error is reported until the link stage.

To make such problems easier to debug, use BUILD_BUG_ON_MSG() instead.

Signed-off-by: pan xinhui <xinhui.pan@linux.vnet.ibm.com>
[mpe: Tweak change log wording & add relaxed/acquire]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

fixup
This commit is contained in:
pan xinhui 2016-02-23 19:05:01 +08:00 committed by Michael Ellerman
parent 289543a5c2
commit 10d8b1480e
1 changed files with 7 additions and 16 deletions
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23
arch/powerpc/include/asm/cmpxchg.h
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@ -5,6 +5,7 @@
#include <linux/compiler.h> #include <linux/compiler.h>
#include <asm/synch.h> #include <asm/synch.h>
#include <asm/asm-compat.h> #include <asm/asm-compat.h>
#include <linux/bug.h>
/* /*
* Atomic exchange * Atomic exchange
@ -83,12 +84,6 @@ __xchg_u64_relaxed(u64 *p, unsigned long val)
} }
#endif #endif
/*
* This function doesn't exist, so you'll get a linker error
* if something tries to do an invalid xchg().
*/
extern void __xchg_called_with_bad_pointer(void);
static __always_inline unsigned long static __always_inline unsigned long
__xchg_local(volatile void *ptr, unsigned long x, unsigned int size) __xchg_local(volatile void *ptr, unsigned long x, unsigned int size)
{ {
@ -100,7 +95,7 @@ __xchg_local(volatile void *ptr, unsigned long x, unsigned int size)
return __xchg_u64_local(ptr, x); return __xchg_u64_local(ptr, x);
#endif #endif
} }
__xchg_called_with_bad_pointer(); BUILD_BUG_ON_MSG(1, "Unsupported size for __xchg");
return x; return x;
} }
@ -115,7 +110,7 @@ __xchg_relaxed(void *ptr, unsigned long x, unsigned int size)
return __xchg_u64_relaxed(ptr, x); return __xchg_u64_relaxed(ptr, x);
#endif #endif
} }
__xchg_called_with_bad_pointer(); BUILD_BUG_ON_MSG(1, "Unsupported size for __xchg_local");
return x; return x;
} }
#define xchg_local(ptr,x) \ #define xchg_local(ptr,x) \
@ -316,10 +311,6 @@ __cmpxchg_u64_acquire(u64 *p, unsigned long old, unsigned long new)
} }
#endif #endif
/* 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);
static __always_inline unsigned long static __always_inline unsigned long
__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new,
unsigned int size) unsigned int size)
@ -332,7 +323,7 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new,
return __cmpxchg_u64(ptr, old, new); return __cmpxchg_u64(ptr, old, new);
#endif #endif
} }
__cmpxchg_called_with_bad_pointer(); BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg");
return old; return old;
} }
@ -348,7 +339,7 @@ __cmpxchg_local(volatile void *ptr, unsigned long old, unsigned long new,
return __cmpxchg_u64_local(ptr, old, new); return __cmpxchg_u64_local(ptr, old, new);
#endif #endif
} }
__cmpxchg_called_with_bad_pointer(); BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg_local");
return old; return old;
} }
@ -364,7 +355,7 @@ __cmpxchg_relaxed(void *ptr, unsigned long old, unsigned long new,
return __cmpxchg_u64_relaxed(ptr, old, new); return __cmpxchg_u64_relaxed(ptr, old, new);
#endif #endif
} }
__cmpxchg_called_with_bad_pointer(); BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg_relaxed");
return old; return old;
} }
@ -380,7 +371,7 @@ __cmpxchg_acquire(void *ptr, unsigned long old, unsigned long new,
return __cmpxchg_u64_acquire(ptr, old, new); return __cmpxchg_u64_acquire(ptr, old, new);
#endif #endif
} }
__cmpxchg_called_with_bad_pointer(); BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg_acquire");
return old; return old;
} }
#define cmpxchg(ptr, o, n) \ #define cmpxchg(ptr, o, n) \