Message ID | 56CC1C1C.6030405@linux.vnet.ibm.com (mailing list archive) |
---|---|
State | Superseded, archived |
Headers | show |
On Tue, Feb 23, 2016 at 04:45:16PM +0800, Pan Xinhui wrote: > From: pan xinhui <xinhui.pan@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.pan@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.feng@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 >
On Tue, 2016-02-23 at 17:15 +0800, Boqun Feng wrote: > On Tue, Feb 23, 2016 at 04:45:16PM +0800, Pan Xinhui wrote: > > From: pan xinhui <xinhui.pan@linux.vnet.ibm.com> > > > > 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 > > @@ -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. Yes I would prefer there was a message. Please send a v2. cheers
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(); 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; }