Revert "ARM: Add PI/robust mutexes support for SMP kernels"

This reverts commit c4bb07ec0084e26323047bcbe446d59ac352e07f.
A nicer version was posted by Will Deacon, which will replace it.

1 files changed, 7 insertions, 122 deletions

diff --git a/arch/arm/include/asm/futex.h b/arch/arm/include/asm/futex.h
index 2491b18f2e3..b33fe7065b3 100644
--- a/arch/arm/include/asm/futex.h
+++ b/arch/arm/include/asm/futex.h
@@ -3,133 +3,18 @@
 
 #ifdef __KERNEL__
 
+#ifdef CONFIG_SMP
+
+#include <asm-generic/futex.h>
+
+#else /* !SMP, we can work around lack of atomic ops by disabling preemption */
+
 #include <linux/futex.h>
 #include <linux/preempt.h>
 #include <linux/uaccess.h>
 #include <asm/errno.h>
 #include <asm/domain.h>
 
-#ifndef CONFIG_CPU_USE_DOMAINS
-
-#define __futex_atomic_op(insn, res, ret, oldval, uaddr, oparg)	\
-	__asm__ __volatile__(					\
-	"1:	ldrex	%2, [%3]\n"				\
-	"	" insn "\n"					\
-	"2:	strex	%0, %1, [%3]\n"				\
-	"	teq	%0, #0\n"				\
-	"	bne 1b\n"					\
-	"	mov	%1, #0\n"				\
-	"3:\n"							\
-	"	.pushsection __ex_table,\"a\"\n"		\
-	"	.align	3\n"					\
-	"	.long	1b, 4f, 2b, 4f\n"			\
-	"	.popsection\n"					\
-	"	.pushsection .fixup,\"ax\"\n"			\
-	"4:	mov	%1, %5\n"				\
-	"	b	3b\n"					\
-	"	.popsection"					\
-	: "=&r" (res), "=&r" (ret), "=&r" (oldval)		\
-	: "r" (uaddr), "r" (oparg), "Ir" (-EFAULT)		\
-	: "cc", "memory")
-
-static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
-{
-	int op = (encoded_op >> 28) & 7;
-	int cmp = (encoded_op >> 24) & 15;
-	int oparg = (encoded_op << 8) >> 20;
-	int cmparg = (encoded_op << 20) >> 20;
-	int oldval = 0, ret;
-	unsigned long res;
-
-	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
-		oparg = 1 << oparg;
-
-	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
-		return -EFAULT;
-
-	pagefault_disable();	/* implies preempt_disable() */
-
-	switch (op) {
-	case FUTEX_OP_SET:
-		__futex_atomic_op("mov	%1, %4", res, ret, oldval, uaddr, oparg);
-		break;
-	case FUTEX_OP_ADD:
-		__futex_atomic_op("add	%1, %2, %4", res, ret, oldval, uaddr, oparg);
-		break;
-	case FUTEX_OP_OR:
-		__futex_atomic_op("orr	%1, %2, %4", res, ret, oldval, uaddr, oparg);
-		break;
-	case FUTEX_OP_ANDN:
-		__futex_atomic_op("and	%1, %2, %4", res, ret, oldval, uaddr, ~oparg);
-		break;
-	case FUTEX_OP_XOR:
-		__futex_atomic_op("eor	%1, %2, %4", res, ret, oldval, uaddr, oparg);
-		break;
-	default:
-		ret = -ENOSYS;
-	}
-
-	pagefault_enable();	/* subsumes preempt_enable() */
-
-	if (!ret) {
-		switch (cmp) {
-		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
-		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
-		case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
-		case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
-		case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
-		case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
-		default: ret = -ENOSYS;
-		}
-	}
-	return ret;
-}
-
-static inline int
-futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
-{
-	unsigned long ret;
-	unsigned long res;
-
-	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
-		return -EFAULT;
-
-	smp_mb();
-
-	do {
-		asm volatile("@futex_atomic_cmpxchg_inatomic\n"
-		"1:	ldrex	%1, [%2]\n"
-		"	mov	%0, #0\n"
-		"	teq	%1, %3\n"
-		"	it      eq @ explicit IT needed for the 2b label\n"
-		"2:	strexeq %0, %4, [%2]\n"
-		"3:\n"
-		"	.pushsection __ex_table,\"a\"\n"
-		"	.align	3\n"
-		"	.long	1b, 4f, 2b, 4f\n"
-		"	.popsection\n"
-		"	.pushsection .fixup,\"ax\"\n"
-		"4:	mov	%0, #0\n"
-		"	mov	%1, %5\n"
-		"	b	3b\n"
-		"	.popsection"
-			: "=&r" (res), "=&r" (ret)
-			: "r" (uaddr), "Ir" (oldval), "r" (newval),
-			  "Ir" (-EFAULT)
-			: "memory", "cc");
-	} while (res);
-
-	smp_mb();
-
-	return ret;
-}
-
-#elif defined(CONFIG_SMP) 
-
-#include <asm-generic/futex.h>
-
-#else /* we can work around lack of atomic ops by disabling preemption */
-
 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)	\
 	__asm__ __volatile__(					\
 	"1:	" T(ldr) "	%1, [%2]\n"			\
@@ -235,7 +120,7 @@ futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
 	return val;
 }
 
-#endif
+#endif /* !SMP */
 
 #endif /* __KERNEL__ */
 #endif /* _ASM_ARM_FUTEX_H */