On Tue, Feb 23, 2016 at 04:45:16PM +0800, Pan Xinhui wrote:
> From: pan xinhui <xinhui....@linux.vnet.ibm.com>
>
> __xchg_called_with_bad_pointer() can't tell us what codes use {cmp}xchg
> in incorrect way. And no error will be reported until the link stage.
> To fix such kinds of issues in a easy way, we use BUILD_BUG() here.
>
> Signed-off-by: pan xinhui <xinhui....@linux.vnet.ibm.com>
> ---
> arch/powerpc/include/asm/cmpxchg.h | 19 +++++--------------
> 1 file changed, 5 insertions(+), 14 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/cmpxchg.h
> b/arch/powerpc/include/asm/cmpxchg.h
> index d1a8d93..20c0a30 100644
> --- a/arch/powerpc/include/asm/cmpxchg.h
> +++ b/arch/powerpc/include/asm/cmpxchg.h
> @@ -5,6 +5,7 @@
> #include <linux/compiler.h>
> #include <asm/synch.h>
> #include <asm/asm-compat.h>
> +#include <linux/bug.h>
>
> /*
> * Atomic exchange
> @@ -92,12 +93,6 @@ __xchg_u64_local(volatile void *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(volatile void *ptr, unsigned long x, unsigned int size)
> {
> @@ -109,7 +104,7 @@ __xchg(volatile void *ptr, unsigned long x, unsigned int
> size)
> return __xchg_u64(ptr, x);
> #endif
> }
> - __xchg_called_with_bad_pointer();
> + BUILD_BUG();Maybe we can use BUILD_BUG_ON_MSG(1, "Unsupported size for xchg"), which could provide more information. With or without this verbosity: Acked-by: Boqun Feng <boqun.f...@gmail.com> Regards, Boqun > return x; > } > > @@ -124,7 +119,7 @@ __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(); > return x; > } > #define xchg(ptr,x) \ > @@ -235,10 +230,6 @@ __cmpxchg_u64_local(volatile unsigned long *p, unsigned > long old, > } > #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) > @@ -251,7 +242,7 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned > long new, > return __cmpxchg_u64(ptr, old, new); > #endif > } > - __cmpxchg_called_with_bad_pointer(); > + BUILD_BUG(); > return old; > } > > @@ -267,7 +258,7 @@ __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(); > return old; > } > > -- > 2.5.0 >
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