1 files changed, 208 insertions, 0 deletions
diff --git a/arch/sparc/include/asm/cmpxchg_64.h b/arch/sparc/include/asm/cmpxchg_64.h
new file mode 100644
index 000000000..3de25262c
--- /dev/null
+++ b/arch/sparc/include/asm/cmpxchg_64.h
@@ -0,0 +1,208 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* 64-bit atomic xchg() and cmpxchg() definitions.
+ *
+ * Copyright (C) 1996, 1997, 2000 David S. Miller (davem@redhat.com)
+ */
+
+#ifndef __ARCH_SPARC64_CMPXCHG__
+#define __ARCH_SPARC64_CMPXCHG__
+
+static inline unsigned long
+__cmpxchg_u32(volatile int *m, int old, int new)
+{
+	__asm__ __volatile__("cas [%2], %3, %0"
+			     : "=&r" (new)
+			     : "0" (new), "r" (m), "r" (old)
+			     : "memory");
+
+	return new;
+}
+
+static inline unsigned long xchg32(__volatile__ unsigned int *m, unsigned int val)
+{
+	unsigned long tmp1, tmp2;
+
+	__asm__ __volatile__(
+"	mov		%0, %1\n"
+"1:	lduw		[%4], %2\n"
+"	cas		[%4], %2, %0\n"
+"	cmp		%2, %0\n"
+"	bne,a,pn	%%icc, 1b\n"
+"	 mov		%1, %0\n"
+	: "=&r" (val), "=&r" (tmp1), "=&r" (tmp2)
+	: "0" (val), "r" (m)
+	: "cc", "memory");
+	return val;
+}
+
+static inline unsigned long xchg64(__volatile__ unsigned long *m, unsigned long val)
+{
+	unsigned long tmp1, tmp2;
+
+	__asm__ __volatile__(
+"	mov		%0, %1\n"
+"1:	ldx		[%4], %2\n"
+"	casx		[%4], %2, %0\n"
+"	cmp		%2, %0\n"
+"	bne,a,pn	%%xcc, 1b\n"
+"	 mov		%1, %0\n"
+	: "=&r" (val), "=&r" (tmp1), "=&r" (tmp2)
+	: "0" (val), "r" (m)
+	: "cc", "memory");
+	return val;
+}
+
+#define arch_xchg(ptr,x)							\
+({	__typeof__(*(ptr)) __ret;					\
+	__ret = (__typeof__(*(ptr)))					\
+		__arch_xchg((unsigned long)(x), (ptr), sizeof(*(ptr)));	\
+	__ret;								\
+})
+
+void __xchg_called_with_bad_pointer(void);
+
+/*
+ * Use 4 byte cas instruction to achieve 2 byte xchg. Main logic
+ * here is to get the bit shift of the byte we are interested in.
+ * The XOR is handy for reversing the bits for big-endian byte order.
+ */
+static inline unsigned long
+xchg16(__volatile__ unsigned short *m, unsigned short val)
+{
+	unsigned long maddr = (unsigned long)m;
+	int bit_shift = (((unsigned long)m & 2) ^ 2) << 3;
+	unsigned int mask = 0xffff << bit_shift;
+	unsigned int *ptr = (unsigned int  *) (maddr & ~2);
+	unsigned int old32, new32, load32;
+
+	/* Read the old value */
+	load32 = *ptr;
+
+	do {
+		old32 = load32;
+		new32 = (load32 & (~mask)) | val << bit_shift;
+		load32 = __cmpxchg_u32(ptr, old32, new32);
+	} while (load32 != old32);
+
+	return (load32 & mask) >> bit_shift;
+}
+
+static __always_inline unsigned long
+__arch_xchg(unsigned long x, __volatile__ void * ptr, int size)
+{
+	switch (size) {
+	case 2:
+		return xchg16(ptr, x);
+	case 4:
+		return xchg32(ptr, x);
+	case 8:
+		return xchg64(ptr, x);
+	}
+	__xchg_called_with_bad_pointer();
+	return x;
+}
+
+/*
+ * 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.
+ */
+
+#include <asm-generic/cmpxchg-local.h>
+
+
+static inline unsigned long
+__cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)
+{
+	__asm__ __volatile__("casx [%2], %3, %0"
+			     : "=&r" (new)
+			     : "0" (new), "r" (m), "r" (old)
+			     : "memory");
+
+	return new;
+}
+
+/*
+ * Use 4 byte cas instruction to achieve 1 byte cmpxchg. Main logic
+ * here is to get the bit shift of the byte we are interested in.
+ * The XOR is handy for reversing the bits for big-endian byte order
+ */
+static inline unsigned long
+__cmpxchg_u8(volatile unsigned char *m, unsigned char old, unsigned char new)
+{
+	unsigned long maddr = (unsigned long)m;
+	int bit_shift = (((unsigned long)m & 3) ^ 3) << 3;
+	unsigned int mask = 0xff << bit_shift;
+	unsigned int *ptr = (unsigned int *) (maddr & ~3);
+	unsigned int old32, new32, load;
+	unsigned int load32 = *ptr;
+
+	do {
+		new32 = (load32 & ~mask) | (new << bit_shift);
+		old32 = (load32 & ~mask) | (old << bit_shift);
+		load32 = __cmpxchg_u32(ptr, old32, new32);
+		if (load32 == old32)
+			return old;
+		load = (load32 & mask) >> bit_shift;
+	} while (load == old);
+
+	return load;
+}
+
+/* This function doesn't exist, so you'll get a linker error
+   if something tries to do an invalid cmpxchg().  */
+void __cmpxchg_called_with_bad_pointer(void);
+
+static inline unsigned long
+__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
+{
+	switch (size) {
+		case 1:
+			return __cmpxchg_u8(ptr, old, new);
+		case 4:
+			return __cmpxchg_u32(ptr, old, new);
+		case 8:
+			return __cmpxchg_u64(ptr, old, new);
+	}
+	__cmpxchg_called_with_bad_pointer();
+	return old;
+}
+
+#define arch_cmpxchg(ptr,o,n)						 \
+  ({									 \
+     __typeof__(*(ptr)) _o_ = (o);					 \
+     __typeof__(*(ptr)) _n_ = (n);					 \
+     (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,		 \
+				    (unsigned long)_n_, sizeof(*(ptr))); \
+  })
+
+/*
+ * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
+ * them available.
+ */
+
+static inline unsigned long __cmpxchg_local(volatile void *ptr,
+				      unsigned long old,
+				      unsigned long new, int size)
+{
+	switch (size) {
+	case 4:
+	case 8:	return __cmpxchg(ptr, old, new, size);
+	default:
+		return __generic_cmpxchg_local(ptr, old, new, size);
+	}
+
+	return old;
+}
+
+#define arch_cmpxchg_local(ptr, o, n)				  	\
+	((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o),	\
+			(unsigned long)(n), sizeof(*(ptr))))
+#define arch_cmpxchg64_local(ptr, o, n)					\
+  ({									\
+	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
+	arch_cmpxchg_local((ptr), (o), (n));					\
+  })
+#define arch_cmpxchg64(ptr, o, n)	arch_cmpxchg64_local((ptr), (o), (n))
+
+#endif /* __ARCH_SPARC64_CMPXCHG__ */