Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f3834b9e authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

x86: Generate cmpxchg build failures 



Rework the x86 cmpxchg() implementation to generate build failures
when used on improper types.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <1254771187.21044.22.camel@laptop>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 63312b6a

arch/x86/include/asm/cmpxchg_32.h

+86 −132
Original line number Diff line number Diff line
@@ -8,14 +8,50 @@ 
 *       you need to test for the feature in boot_cpu_data.

 */



#define xchg(ptr, v)							\

	((__typeof__(*(ptr)))__xchg((unsigned long)(v), (ptr), sizeof(*(ptr))))

extern void __xchg_wrong_size(void);



/*

 * Note: no "lock" prefix even on SMP: xchg always implies lock anyway

 * Note 2: xchg has side effect, so that attribute volatile is necessary,

 *	  but generally the primitive is invalid, *ptr is output argument. --ANK

 */



struct __xchg_dummy {

	unsigned long a[100];

};

#define __xg(x) ((struct __xchg_dummy *)(x))



#define __xchg(x, ptr, size)						\

({									\

	__typeof(*(ptr)) __x = (x);					\

	switch (size) {							\

	case 1:								\

		asm volatile("xchgb %b0,%1"				\

			     : "=q" (__x)				\

			     : "m" (*__xg(ptr)), "0" (__x)		\

			     : "memory");				\

		break;							\

	case 2:								\

		asm volatile("xchgw %w0,%1"				\

			     : "=r" (__x)				\

			     : "m" (*__xg(ptr)), "0" (__x)		\

			     : "memory");				\

		break;							\

	case 4:								\

		asm volatile("xchgl %0,%1"				\

			     : "=r" (__x)				\

			     : "m" (*__xg(ptr)), "0" (__x)		\

			     : "memory");				\

		break;							\

	default:							\

		__xchg_wrong_size();					\

	}								\

	__x;								\

})



#define xchg(ptr, v)							\

	__xchg((v), (ptr), sizeof(*ptr))



/*

 * The semantics of XCHGCMP8B are a bit strange, this is why

 * there is a loop and the loading of %%eax and %%edx has to
@@ -71,57 +107,63 @@ static inline void __set_64bit_var(unsigned long long *ptr, 
		       (unsigned int)((value) >> 32))			\

	 : __set_64bit(ptr, ll_low((value)), ll_high((value))))



/*

 * Note: no "lock" prefix even on SMP: xchg always implies lock anyway

 * Note 2: xchg has side effect, so that attribute volatile is necessary,

 *	  but generally the primitive is invalid, *ptr is output argument. --ANK

 */

static inline unsigned long __xchg(unsigned long x, volatile void *ptr,

				   int size)

{

	switch (size) {

	case 1:

		asm volatile("xchgb %b0,%1"

			     : "=q" (x)

			     : "m" (*__xg(ptr)), "0" (x)

			     : "memory");

		break;

	case 2:

		asm volatile("xchgw %w0,%1"

			     : "=r" (x)

			     : "m" (*__xg(ptr)), "0" (x)

			     : "memory");

		break;

	case 4:

		asm volatile("xchgl %0,%1"

			     : "=r" (x)

			     : "m" (*__xg(ptr)), "0" (x)

			     : "memory");

		break;

	}

	return x;

}

extern void __cmpxchg_wrong_size(void);



/*

 * Atomic compare and exchange.  Compare OLD with MEM, if identical,

 * store NEW in MEM.  Return the initial value in MEM.  Success is

 * indicated by comparing RETURN with OLD.

 */

#define __raw_cmpxchg(ptr, old, new, size, lock)			\

({									\

	__typeof__(*(ptr)) __ret;					\

	__typeof__(*(ptr)) __old = (old);				\

	__typeof__(*(ptr)) __new = (new);				\

	switch (size) {							\

	case 1:								\

		asm volatile(lock "cmpxchgb %b1,%2"			\

			     : "=a"(__ret)				\

			     : "q"(__new), "m"(*__xg(ptr)), "0"(__old)	\

			     : "memory");				\

		break;							\

	case 2:								\

		asm volatile(lock "cmpxchgw %w1,%2"			\

			     : "=a"(__ret)				\

			     : "r"(__new), "m"(*__xg(ptr)), "0"(__old)	\

			     : "memory");				\

		break;							\

	case 4:								\

		asm volatile(lock "cmpxchgl %1,%2"			\

			     : "=a"(__ret)				\

			     : "r"(__new), "m"(*__xg(ptr)), "0"(__old)	\

			     : "memory");				\

		break;							\

	default:							\

		__cmpxchg_wrong_size();					\

	}								\

	__ret;								\

})



#define __cmpxchg(ptr, old, new, size)					\

	__raw_cmpxchg((ptr), (old), (new), (size), LOCK_PREFIX)



#define __sync_cmpxchg(ptr, old, new, size)				\

	__raw_cmpxchg((ptr), (old), (new), (size), "lock; ")



#define __cmpxchg_local(ptr, old, new, size)				\

	__raw_cmpxchg((ptr), (old), (new), (size), "")



#ifdef CONFIG_X86_CMPXCHG

#define __HAVE_ARCH_CMPXCHG 1

#define cmpxchg(ptr, o, n)						\

	((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o),	\

				       (unsigned long)(n),		\

				       sizeof(*(ptr))))

#define sync_cmpxchg(ptr, o, n)						\

	((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o),	\

					    (unsigned long)(n),		\

					    sizeof(*(ptr))))

#define cmpxchg_local(ptr, o, n)					\

	((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o),	\

					     (unsigned long)(n),	\

					     sizeof(*(ptr))))



#define cmpxchg(ptr, old, new)						\

	__cmpxchg((ptr), (old), (new), sizeof(*ptr))



#define sync_cmpxchg(ptr, old, new)					\

	__sync_cmpxchg((ptr), (old), (new), sizeof(*ptr))



#define cmpxchg_local(ptr, old, new)					\

	__cmpxchg_local((ptr), (old), (new), sizeof(*ptr))

#endif



#ifdef CONFIG_X86_CMPXCHG64
@@ -133,94 +175,6 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, 
					       (unsigned long long)(n)))

#endif



static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,

				      unsigned long new, int size)

{

	unsigned long prev;

	switch (size) {

	case 1:

		asm volatile(LOCK_PREFIX "cmpxchgb %b1,%2"

			     : "=a"(prev)

			     : "q"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 2:

		asm volatile(LOCK_PREFIX "cmpxchgw %w1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 4:

		asm volatile(LOCK_PREFIX "cmpxchgl %1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	}

	return old;

}



/*

 * Always use locked operations when touching memory shared with a

 * hypervisor, since the system may be SMP even if the guest kernel

 * isn't.

 */

static inline unsigned long __sync_cmpxchg(volatile void *ptr,

					   unsigned long old,

					   unsigned long new, int size)

{

	unsigned long prev;

	switch (size) {

	case 1:

		asm volatile("lock; cmpxchgb %b1,%2"

			     : "=a"(prev)

			     : "q"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 2:

		asm volatile("lock; cmpxchgw %w1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 4:

		asm volatile("lock; cmpxchgl %1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	}

	return old;

}



static inline unsigned long __cmpxchg_local(volatile void *ptr,

					    unsigned long old,

					    unsigned long new, int size)

{

	unsigned long prev;

	switch (size) {

	case 1:

		asm volatile("cmpxchgb %b1,%2"

			     : "=a"(prev)

			     : "q"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 2:

		asm volatile("cmpxchgw %w1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 4:

		asm volatile("cmpxchgl %1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	}

	return old;

}



static inline unsigned long long __cmpxchg64(volatile void *ptr,

					     unsigned long long old,

					     unsigned long long new)

arch/x86/include/asm/cmpxchg_64.h

+91 −143
Original line number Diff line number Diff line
@@ -3,9 +3,6 @@ 


#include <asm/alternative.h> /* Provides LOCK_PREFIX */



#define xchg(ptr, v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v), \

						 (ptr), sizeof(*(ptr))))



#define __xg(x) ((volatile long *)(x))



static inline void set_64bit(volatile unsigned long *ptr, unsigned long val)
@@ -15,167 +12,118 @@ static inline void set_64bit(volatile unsigned long *ptr, unsigned long val) 


#define _set_64bit set_64bit



extern void __xchg_wrong_size(void);

extern void __cmpxchg_wrong_size(void);



/*

 * Note: no "lock" prefix even on SMP: xchg always implies lock anyway

 * Note 2: xchg has side effect, so that attribute volatile is necessary,

 *	  but generally the primitive is invalid, *ptr is output argument. --ANK

 */

static inline unsigned long __xchg(unsigned long x, volatile void *ptr,

				   int size)

{

	switch (size) {

	case 1:

		asm volatile("xchgb %b0,%1"

			     : "=q" (x)

			     : "m" (*__xg(ptr)), "0" (x)

			     : "memory");

		break;

	case 2:

		asm volatile("xchgw %w0,%1"

			     : "=r" (x)

			     : "m" (*__xg(ptr)), "0" (x)

			     : "memory");

		break;

	case 4:

		asm volatile("xchgl %k0,%1"

			     : "=r" (x)

			     : "m" (*__xg(ptr)), "0" (x)

			     : "memory");

		break;

	case 8:

		asm volatile("xchgq %0,%1"

			     : "=r" (x)

			     : "m" (*__xg(ptr)), "0" (x)

			     : "memory");

		break;

	}

	return x;

}

#define __xchg(x, ptr, size)						\

({									\

	__typeof(*(ptr)) __x = (x);					\

	switch (size) {							\

	case 1:								\

		asm volatile("xchgb %b0,%1"				\

			     : "=q" (__x)				\

			     : "m" (*__xg(ptr)), "0" (__x)		\

			     : "memory");				\

		break;							\

	case 2:								\

		asm volatile("xchgw %w0,%1"				\

			     : "=r" (__x)				\

			     : "m" (*__xg(ptr)), "0" (__x)		\

			     : "memory");				\

		break;							\

	case 4:								\

		asm volatile("xchgl %k0,%1"				\

			     : "=r" (__x)				\

			     : "m" (*__xg(ptr)), "0" (__x)		\

			     : "memory");				\

		break;							\

	case 8:								\

		asm volatile("xchgq %0,%1"				\

			     : "=r" (__x)				\

			     : "m" (*__xg(ptr)), "0" (__x)		\

			     : "memory");				\

		break;							\

	default:							\

		__xchg_wrong_size();					\

	}								\

	__x;								\

})



#define xchg(ptr, v)							\

	__xchg((v), (ptr), sizeof(*ptr))



#define __HAVE_ARCH_CMPXCHG 1



/*

 * Atomic compare and exchange.  Compare OLD with MEM, if identical,

 * store NEW in MEM.  Return the initial value in MEM.  Success is

 * indicated by comparing RETURN with OLD.

 */

#define __raw_cmpxchg(ptr, old, new, size, lock)			\

({									\

	__typeof__(*(ptr)) __ret;					\

	__typeof__(*(ptr)) __old = (old);				\

	__typeof__(*(ptr)) __new = (new);				\

	switch (size) {							\

	case 1:								\

		asm volatile(lock "cmpxchgb %b1,%2"			\

			     : "=a"(__ret)				\

			     : "q"(__new), "m"(*__xg(ptr)), "0"(__old)	\

			     : "memory");				\

		break;							\

	case 2:								\

		asm volatile(lock "cmpxchgw %w1,%2"			\

			     : "=a"(__ret)				\

			     : "r"(__new), "m"(*__xg(ptr)), "0"(__old)	\

			     : "memory");				\

		break;							\

	case 4:								\

		asm volatile(lock "cmpxchgl %k1,%2"			\

			     : "=a"(__ret)				\

			     : "r"(__new), "m"(*__xg(ptr)), "0"(__old)	\

			     : "memory");				\

		break;							\

	case 8:								\

		asm volatile(lock "cmpxchgq %1,%2"			\

			     : "=a"(__ret)				\

			     : "r"(__new), "m"(*__xg(ptr)), "0"(__old)	\

			     : "memory");				\

		break;							\

	default:							\

		__cmpxchg_wrong_size();					\

	}								\

	__ret;								\

})



#define __HAVE_ARCH_CMPXCHG 1

#define __cmpxchg(ptr, old, new, size)					\

	__raw_cmpxchg((ptr), (old), (new), (size), LOCK_PREFIX)



static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,

				      unsigned long new, int size)

{

	unsigned long prev;

	switch (size) {

	case 1:

		asm volatile(LOCK_PREFIX "cmpxchgb %b1,%2"

			     : "=a"(prev)

			     : "q"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 2:

		asm volatile(LOCK_PREFIX "cmpxchgw %w1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 4:

		asm volatile(LOCK_PREFIX "cmpxchgl %k1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 8:

		asm volatile(LOCK_PREFIX "cmpxchgq %1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	}

	return old;

}

#define __sync_cmpxchg(ptr, old, new, size)				\

	__raw_cmpxchg((ptr), (old), (new), (size), "lock; ")



/*

 * Always use locked operations when touching memory shared with a

 * hypervisor, since the system may be SMP even if the guest kernel

 * isn't.

 */

static inline unsigned long __sync_cmpxchg(volatile void *ptr,

					   unsigned long old,

					   unsigned long new, int size)

{

	unsigned long prev;

	switch (size) {

	case 1:

		asm volatile("lock; cmpxchgb %b1,%2"

			     : "=a"(prev)

			     : "q"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 2:

		asm volatile("lock; cmpxchgw %w1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 4:

		asm volatile("lock; cmpxchgl %1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	}

	return old;

}

#define __cmpxchg_local(ptr, old, new, size)				\

	__raw_cmpxchg((ptr), (old), (new), (size), "")



static inline unsigned long __cmpxchg_local(volatile void *ptr,

					    unsigned long old,

					    unsigned long new, int size)

{

	unsigned long prev;

	switch (size) {

	case 1:

		asm volatile("cmpxchgb %b1,%2"

			     : "=a"(prev)

			     : "q"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 2:

		asm volatile("cmpxchgw %w1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 4:

		asm volatile("cmpxchgl %k1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	case 8:

		asm volatile("cmpxchgq %1,%2"

			     : "=a"(prev)

			     : "r"(new), "m"(*__xg(ptr)), "0"(old)

			     : "memory");

		return prev;

	}

	return old;

}

#define cmpxchg(ptr, old, new)						\

	__cmpxchg((ptr), (old), (new), sizeof(*ptr))



#define sync_cmpxchg(ptr, old, new)					\

	__sync_cmpxchg((ptr), (old), (new), sizeof(*ptr))



#define cmpxchg_local(ptr, old, new)					\

	__cmpxchg_local((ptr), (old), (new), sizeof(*ptr))



#define cmpxchg(ptr, o, n)						\

	((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o),	\

				       (unsigned long)(n), sizeof(*(ptr))))

#define cmpxchg64(ptr, o, n)						\

({									\

	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\

	cmpxchg((ptr), (o), (n));					\

})

#define cmpxchg_local(ptr, o, n)					\

	((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o),	\

					     (unsigned long)(n),	\

					     sizeof(*(ptr))))

#define sync_cmpxchg(ptr, o, n)						\

	((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o),	\

					    (unsigned long)(n),		\

					    sizeof(*(ptr))))



#define cmpxchg64_local(ptr, o, n)					\

({									\

	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\