* [PATCH] [v2] arm64: fix unreachable code issue with cmpxchg
@ 2019-09-10 11:56 Arnd Bergmann
2019-09-17 20:34 ` Nathan Chancellor
0 siblings, 1 reply; 4+ messages in thread
From: Arnd Bergmann @ 2019-09-10 11:56 UTC (permalink / raw)
To: Catalin Marinas, Will Deacon
Cc: Mark Rutland, Arnd Bergmann, Peter Zijlstra (Intel),
Nick Desaulniers, linux-kernel, clang-built-linux, Andrew Murray,
Nathan Chancellor, Thomas Gleixner, linux-arm-kernel
On arm64 build with clang, sometimes the __cmpxchg_mb is not inlined
when CONFIG_OPTIMIZE_INLINING is set.
Clang then fails a compile-time assertion, because it cannot tell at
compile time what the size of the argument is:
mm/memcontrol.o: In function `__cmpxchg_mb':
memcontrol.c:(.text+0x1a4c): undefined reference to `__compiletime_assert_175'
memcontrol.c:(.text+0x1a4c): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `__compiletime_assert_175'
Mark all of the cmpxchg() style functions as __always_inline to
ensure that the compiler can see the result.
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/648
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>
Tested-by: Andrew Murray <andrew.murray@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v2: skip unneeded changes, as suggested by Andrew Murray
---
arch/arm64/include/asm/cmpxchg.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/cmpxchg.h b/arch/arm64/include/asm/cmpxchg.h
index a1398f2f9994..f9bef42c1411 100644
--- a/arch/arm64/include/asm/cmpxchg.h
+++ b/arch/arm64/include/asm/cmpxchg.h
@@ -62,7 +62,7 @@ __XCHG_CASE( , , mb_, 64, dmb ish, nop, , a, l, "memory")
#undef __XCHG_CASE
#define __XCHG_GEN(sfx) \
-static inline unsigned long __xchg##sfx(unsigned long x, \
+static __always_inline unsigned long __xchg##sfx(unsigned long x, \
volatile void *ptr, \
int size) \
{ \
@@ -148,7 +148,7 @@ __CMPXCHG_DBL(_mb)
#undef __CMPXCHG_DBL
#define __CMPXCHG_GEN(sfx) \
-static inline unsigned long __cmpxchg##sfx(volatile void *ptr, \
+static __always_inline unsigned long __cmpxchg##sfx(volatile void *ptr, \
unsigned long old, \
unsigned long new, \
int size) \
@@ -255,7 +255,7 @@ __CMPWAIT_CASE( , , 64);
#undef __CMPWAIT_CASE
#define __CMPWAIT_GEN(sfx) \
-static inline void __cmpwait##sfx(volatile void *ptr, \
+static __always_inline void __cmpwait##sfx(volatile void *ptr, \
unsigned long val, \
int size) \
{ \
--
2.20.0
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] [v2] arm64: fix unreachable code issue with cmpxchg
2019-09-10 11:56 [PATCH] [v2] arm64: fix unreachable code issue with cmpxchg Arnd Bergmann
@ 2019-09-17 20:34 ` Nathan Chancellor
2019-09-18 9:02 ` Will Deacon
0 siblings, 1 reply; 4+ messages in thread
From: Nathan Chancellor @ 2019-09-17 20:34 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Mark Rutland, Peter Zijlstra (Intel),
Catalin Marinas, Nick Desaulniers, linux-kernel,
clang-built-linux, Andrew Murray, Thomas Gleixner, Will Deacon,
linux-arm-kernel
On Tue, Sep 10, 2019 at 01:56:22PM +0200, Arnd Bergmann wrote:
> On arm64 build with clang, sometimes the __cmpxchg_mb is not inlined
> when CONFIG_OPTIMIZE_INLINING is set.
> Clang then fails a compile-time assertion, because it cannot tell at
> compile time what the size of the argument is:
>
> mm/memcontrol.o: In function `__cmpxchg_mb':
> memcontrol.c:(.text+0x1a4c): undefined reference to `__compiletime_assert_175'
> memcontrol.c:(.text+0x1a4c): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `__compiletime_assert_175'
>
> Mark all of the cmpxchg() style functions as __always_inline to
> ensure that the compiler can see the result.
>
> Acked-by: Nick Desaulniers <ndesaulniers@google.com>
> Reported-by: Nathan Chancellor <natechancellor@gmail.com>
> Link: https://github.com/ClangBuiltLinux/linux/issues/648
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> Reviewed-by: Andrew Murray <andrew.murray@arm.com>
> Tested-by: Andrew Murray <andrew.murray@arm.com>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> v2: skip unneeded changes, as suggested by Andrew Murray
> ---
> arch/arm64/include/asm/cmpxchg.h | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/include/asm/cmpxchg.h b/arch/arm64/include/asm/cmpxchg.h
> index a1398f2f9994..f9bef42c1411 100644
> --- a/arch/arm64/include/asm/cmpxchg.h
> +++ b/arch/arm64/include/asm/cmpxchg.h
> @@ -62,7 +62,7 @@ __XCHG_CASE( , , mb_, 64, dmb ish, nop, , a, l, "memory")
> #undef __XCHG_CASE
>
> #define __XCHG_GEN(sfx) \
> -static inline unsigned long __xchg##sfx(unsigned long x, \
> +static __always_inline unsigned long __xchg##sfx(unsigned long x, \
> volatile void *ptr, \
> int size) \
> { \
> @@ -148,7 +148,7 @@ __CMPXCHG_DBL(_mb)
> #undef __CMPXCHG_DBL
>
> #define __CMPXCHG_GEN(sfx) \
> -static inline unsigned long __cmpxchg##sfx(volatile void *ptr, \
> +static __always_inline unsigned long __cmpxchg##sfx(volatile void *ptr, \
> unsigned long old, \
> unsigned long new, \
> int size) \
> @@ -255,7 +255,7 @@ __CMPWAIT_CASE( , , 64);
> #undef __CMPWAIT_CASE
>
> #define __CMPWAIT_GEN(sfx) \
> -static inline void __cmpwait##sfx(volatile void *ptr, \
> +static __always_inline void __cmpwait##sfx(volatile void *ptr, \
> unsigned long val, \
> int size) \
> { \
> --
> 2.20.0
>
Looks like the arm64 pull request happened without this patch so clang
all{mod,yes}config builds are broken. Did the maintainers have any
further comments on it or could this make it in with the next one?
Cheers,
Nathan
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] [v2] arm64: fix unreachable code issue with cmpxchg
2019-09-17 20:34 ` Nathan Chancellor
@ 2019-09-18 9:02 ` Will Deacon
2019-09-18 16:02 ` Nathan Chancellor
0 siblings, 1 reply; 4+ messages in thread
From: Will Deacon @ 2019-09-18 9:02 UTC (permalink / raw)
To: Nathan Chancellor
Cc: Mark Rutland, Arnd Bergmann, Peter Zijlstra (Intel),
Catalin Marinas, Nick Desaulniers, linux-kernel,
clang-built-linux, Andrew Murray, Thomas Gleixner,
linux-arm-kernel
On Tue, Sep 17, 2019 at 01:34:25PM -0700, Nathan Chancellor wrote:
> On Tue, Sep 10, 2019 at 01:56:22PM +0200, Arnd Bergmann wrote:
> > On arm64 build with clang, sometimes the __cmpxchg_mb is not inlined
> > when CONFIG_OPTIMIZE_INLINING is set.
> > Clang then fails a compile-time assertion, because it cannot tell at
> > compile time what the size of the argument is:
> >
> > mm/memcontrol.o: In function `__cmpxchg_mb':
> > memcontrol.c:(.text+0x1a4c): undefined reference to `__compiletime_assert_175'
> > memcontrol.c:(.text+0x1a4c): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `__compiletime_assert_175'
> >
> > Mark all of the cmpxchg() style functions as __always_inline to
> > ensure that the compiler can see the result.
> >
> > Acked-by: Nick Desaulniers <ndesaulniers@google.com>
> > Reported-by: Nathan Chancellor <natechancellor@gmail.com>
> > Link: https://github.com/ClangBuiltLinux/linux/issues/648
> > Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> > Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> > Reviewed-by: Andrew Murray <andrew.murray@arm.com>
> > Tested-by: Andrew Murray <andrew.murray@arm.com>
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > v2: skip unneeded changes, as suggested by Andrew Murray
> > ---
> > arch/arm64/include/asm/cmpxchg.h | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/cmpxchg.h b/arch/arm64/include/asm/cmpxchg.h
> > index a1398f2f9994..f9bef42c1411 100644
> > --- a/arch/arm64/include/asm/cmpxchg.h
> > +++ b/arch/arm64/include/asm/cmpxchg.h
> > @@ -62,7 +62,7 @@ __XCHG_CASE( , , mb_, 64, dmb ish, nop, , a, l, "memory")
> > #undef __XCHG_CASE
> >
> > #define __XCHG_GEN(sfx) \
> > -static inline unsigned long __xchg##sfx(unsigned long x, \
> > +static __always_inline unsigned long __xchg##sfx(unsigned long x, \
> > volatile void *ptr, \
> > int size) \
> > { \
> > @@ -148,7 +148,7 @@ __CMPXCHG_DBL(_mb)
> > #undef __CMPXCHG_DBL
> >
> > #define __CMPXCHG_GEN(sfx) \
> > -static inline unsigned long __cmpxchg##sfx(volatile void *ptr, \
> > +static __always_inline unsigned long __cmpxchg##sfx(volatile void *ptr, \
> > unsigned long old, \
> > unsigned long new, \
> > int size) \
> > @@ -255,7 +255,7 @@ __CMPWAIT_CASE( , , 64);
> > #undef __CMPWAIT_CASE
> >
> > #define __CMPWAIT_GEN(sfx) \
> > -static inline void __cmpwait##sfx(volatile void *ptr, \
> > +static __always_inline void __cmpwait##sfx(volatile void *ptr, \
> > unsigned long val, \
> > int size) \
> > { \
> > --
> > 2.20.0
> >
>
> Looks like the arm64 pull request happened without this patch so clang
> all{mod,yes}config builds are broken. Did the maintainers have any
> further comments on it or could this make it in with the next one?
Fear not! I plan to send this with some other fixes we've got for -rc1.
I just to get my CI scripts going again (new machine), but that shouldn't
take long.
Will
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] [v2] arm64: fix unreachable code issue with cmpxchg
2019-09-18 9:02 ` Will Deacon
@ 2019-09-18 16:02 ` Nathan Chancellor
0 siblings, 0 replies; 4+ messages in thread
From: Nathan Chancellor @ 2019-09-18 16:02 UTC (permalink / raw)
To: Will Deacon
Cc: Mark Rutland, Arnd Bergmann, Peter Zijlstra (Intel),
Catalin Marinas, Nick Desaulniers, linux-kernel,
clang-built-linux, Andrew Murray, Thomas Gleixner,
linux-arm-kernel
On Wed, Sep 18, 2019 at 10:02:41AM +0100, Will Deacon wrote:
> On Tue, Sep 17, 2019 at 01:34:25PM -0700, Nathan Chancellor wrote:
> > On Tue, Sep 10, 2019 at 01:56:22PM +0200, Arnd Bergmann wrote:
> > > On arm64 build with clang, sometimes the __cmpxchg_mb is not inlined
> > > when CONFIG_OPTIMIZE_INLINING is set.
> > > Clang then fails a compile-time assertion, because it cannot tell at
> > > compile time what the size of the argument is:
> > >
> > > mm/memcontrol.o: In function `__cmpxchg_mb':
> > > memcontrol.c:(.text+0x1a4c): undefined reference to `__compiletime_assert_175'
> > > memcontrol.c:(.text+0x1a4c): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `__compiletime_assert_175'
> > >
> > > Mark all of the cmpxchg() style functions as __always_inline to
> > > ensure that the compiler can see the result.
> > >
> > > Acked-by: Nick Desaulniers <ndesaulniers@google.com>
> > > Reported-by: Nathan Chancellor <natechancellor@gmail.com>
> > > Link: https://github.com/ClangBuiltLinux/linux/issues/648
> > > Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> > > Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> > > Reviewed-by: Andrew Murray <andrew.murray@arm.com>
> > > Tested-by: Andrew Murray <andrew.murray@arm.com>
> > > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > > ---
> > > v2: skip unneeded changes, as suggested by Andrew Murray
> > > ---
> > > arch/arm64/include/asm/cmpxchg.h | 6 +++---
> > > 1 file changed, 3 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/arch/arm64/include/asm/cmpxchg.h b/arch/arm64/include/asm/cmpxchg.h
> > > index a1398f2f9994..f9bef42c1411 100644
> > > --- a/arch/arm64/include/asm/cmpxchg.h
> > > +++ b/arch/arm64/include/asm/cmpxchg.h
> > > @@ -62,7 +62,7 @@ __XCHG_CASE( , , mb_, 64, dmb ish, nop, , a, l, "memory")
> > > #undef __XCHG_CASE
> > >
> > > #define __XCHG_GEN(sfx) \
> > > -static inline unsigned long __xchg##sfx(unsigned long x, \
> > > +static __always_inline unsigned long __xchg##sfx(unsigned long x, \
> > > volatile void *ptr, \
> > > int size) \
> > > { \
> > > @@ -148,7 +148,7 @@ __CMPXCHG_DBL(_mb)
> > > #undef __CMPXCHG_DBL
> > >
> > > #define __CMPXCHG_GEN(sfx) \
> > > -static inline unsigned long __cmpxchg##sfx(volatile void *ptr, \
> > > +static __always_inline unsigned long __cmpxchg##sfx(volatile void *ptr, \
> > > unsigned long old, \
> > > unsigned long new, \
> > > int size) \
> > > @@ -255,7 +255,7 @@ __CMPWAIT_CASE( , , 64);
> > > #undef __CMPWAIT_CASE
> > >
> > > #define __CMPWAIT_GEN(sfx) \
> > > -static inline void __cmpwait##sfx(volatile void *ptr, \
> > > +static __always_inline void __cmpwait##sfx(volatile void *ptr, \
> > > unsigned long val, \
> > > int size) \
> > > { \
> > > --
> > > 2.20.0
> > >
> >
> > Looks like the arm64 pull request happened without this patch so clang
> > all{mod,yes}config builds are broken. Did the maintainers have any
> > further comments on it or could this make it in with the next one?
>
> Fear not! I plan to send this with some other fixes we've got for -rc1.
> I just to get my CI scripts going again (new machine), but that shouldn't
> take long.
>
> Will
Great, thank you!
Cheers,
Nathan
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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2019-09-10 11:56 [PATCH] [v2] arm64: fix unreachable code issue with cmpxchg Arnd Bergmann
2019-09-17 20:34 ` Nathan Chancellor
2019-09-18 9:02 ` Will Deacon
2019-09-18 16:02 ` Nathan Chancellor
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