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Commit 10d8b148 authored by pan xinhui's avatar pan xinhui Committed by Michael Ellerman
Browse files

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

fixup
parent 289543a5

arch/powerpc/include/asm/cmpxchg.h

+7 −16
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
#include <linux/compiler.h>

#include <asm/synch.h>

#include <asm/asm-compat.h>

#include <linux/bug.h>



/*

 * Atomic exchange
@@ -83,12 +84,6 @@ __xchg_u64_relaxed(u64 *p, unsigned long val) 
}

#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

__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);

#endif

	}

	__xchg_called_with_bad_pointer();

	BUILD_BUG_ON_MSG(1, "Unsupported size for __xchg");

	return x;

}
@@ -115,7 +110,7 @@ __xchg_relaxed(void *ptr, unsigned long x, unsigned int size) 
		return __xchg_u64_relaxed(ptr, x);

#endif

	}

	__xchg_called_with_bad_pointer();

	BUILD_BUG_ON_MSG(1, "Unsupported size for __xchg_local");

	return x;

}

#define xchg_local(ptr,x)						     \
@@ -316,10 +311,6 @@ __cmpxchg_u64_acquire(u64 *p, unsigned long old, unsigned long new) 
}

#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

__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new,

	  unsigned int size)
@@ -332,7 +323,7 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, 
		return __cmpxchg_u64(ptr, old, new);

#endif

	}

	__cmpxchg_called_with_bad_pointer();

	BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg");

	return old;

}
@@ -348,7 +339,7 @@ __cmpxchg_local(volatile void *ptr, unsigned long old, unsigned long new, 
		return __cmpxchg_u64_local(ptr, old, new);

#endif

	}

	__cmpxchg_called_with_bad_pointer();

	BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg_local");

	return old;

}
@@ -364,7 +355,7 @@ __cmpxchg_relaxed(void *ptr, unsigned long old, unsigned long new, 
		return __cmpxchg_u64_relaxed(ptr, old, new);

#endif

	}

	__cmpxchg_called_with_bad_pointer();

	BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg_relaxed");

	return old;

}
@@ -380,7 +371,7 @@ __cmpxchg_acquire(void *ptr, unsigned long old, unsigned long new, 
		return __cmpxchg_u64_acquire(ptr, old, new);

#endif

	}

	__cmpxchg_called_with_bad_pointer();

	BUILD_BUG_ON_MSG(1, "Unsupported size for __cmpxchg_acquire");

	return old;

}

#define cmpxchg(ptr, o, n)						 \