From b8af6b78be197b6a24bf372442dcb6e044d729b3 Mon Sep 17 00:00:00 2001
From: mjg <mjg@FreeBSD.org>
Date: Thu, 16 Mar 2017 06:00:27 +0000
Subject: MFC r311169,r311898,r312925,r312973,r312975,r313007,r313040,r313080, 
    r313254,r313341

amd64: add atomic_fcmpset

==

sparc64: add atomic_fcmpset

==

Implement atomic_fcmpset_* for arm and arm64.

==

Add atomic_fcmpset_*() inlines for powerpc

Summary:
atomic_fcmpset_*() is analogous to atomic_cmpset(), but saves off the read value
from the target memory location into the 'old' pointer in the case of failure.

==

i386: add atomic_fcmpset

==

Don't retry a lost reservation in atomic_fcmpset()

The desired behavior of atomic_fcmpset_() is to always exit on error.  Instead
of retrying on lost reservation, leave the retry to the caller, and return

==

Add atomic_fcmpset_*() inlines for MIPS

atomic_fcmpset_*() is analogous to atomic_cmpset(), but saves off the
read value from the target memory location into the 'old' pointer.

==

i386: fixup fcmpset

An incorrect output specifier was used which worked with clang by accident,
but breaks with the in-tree gcc version.

While here plug a whitespace nit.

==

Implement atomic_fcmpset_*() for RISC-V.

==

Use 64bit store instruction in atomic_fcmpset_64.
---
 sys/powerpc/include/atomic.h | 123 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)

(limited to 'sys/powerpc')

diff --git a/sys/powerpc/include/atomic.h b/sys/powerpc/include/atomic.h
index c4db5ff..cd9fa0d 100644
--- a/sys/powerpc/include/atomic.h
+++ b/sys/powerpc/include/atomic.h
@@ -674,6 +674,129 @@ atomic_cmpset_rel_long(volatile u_long *p, u_long cmpval, u_long newval)
 #define	atomic_cmpset_rel_ptr	atomic_cmpset_rel_int
 #endif
 
+/*
+ * Atomically compare the value stored at *p with *cmpval and if the
+ * two values are equal, update the value of *p with newval. Returns
+ * zero if the compare failed and sets *cmpval to the read value from *p,
+ * nonzero otherwise.
+ */
+static __inline int
+atomic_fcmpset_int(volatile u_int *p, u_int *cmpval, u_int newval)
+{
+	int	ret;
+
+#ifdef __GNUCLIKE_ASM
+	__asm __volatile (
+		"lwarx %0, 0, %3\n\t"	/* load old value */
+		"cmplw %4, %0\n\t"		/* compare */
+		"bne 1f\n\t"			/* exit if not equal */
+		"stwcx. %5, 0, %3\n\t"      	/* attempt to store */
+		"bne- 1f\n\t"			/* exit if failed */
+		"li %0, 1\n\t"			/* success - retval = 1 */
+		"b 2f\n\t"			/* we've succeeded */
+		"1:\n\t"
+		"stwcx. %0, 0, %3\n\t"       	/* clear reservation (74xx) */
+		"stwx %0, 0, %7\n\t"
+		"li %0, 0\n\t"			/* failure - retval = 0 */
+		"2:\n\t"
+		: "=&r" (ret), "=m" (*p), "=m" (*cmpval)
+		: "r" (p), "r" (*cmpval), "r" (newval), "m" (*p), "r"(cmpval)
+		: "cr0", "memory");
+#endif
+
+	return (ret);
+}
+static __inline int
+atomic_fcmpset_long(volatile u_long *p, u_long *cmpval, u_long newval)
+{
+	int ret;
+
+#ifdef __GNUCLIKE_ASM
+	__asm __volatile (
+	    #ifdef __powerpc64__
+		"ldarx %0, 0, %3\n\t"	/* load old value */
+		"cmpld %4, %0\n\t"		/* compare */
+		"bne 1f\n\t"			/* exit if not equal */
+		"stdcx. %5, 0, %3\n\t"		/* attempt to store */
+	    #else
+		"lwarx %0, 0, %3\n\t"	/* load old value */
+		"cmplw %4, %0\n\t"		/* compare */
+		"bne 1f\n\t"			/* exit if not equal */
+		"stwcx. %5, 0, %3\n\t"		/* attempt to store */
+	    #endif
+		"bne- 1f\n\t"			/* exit if failed */
+		"li %0, 1\n\t"			/* success - retval = 1 */
+		"b 2f\n\t"			/* we've succeeded */
+		"1:\n\t"
+	    #ifdef __powerpc64__
+		"stdcx. %0, 0, %3\n\t"		/* clear reservation (74xx) */
+		"stdx %0, 0, %7\n\t"
+	    #else
+		"stwcx. %0, 0, %3\n\t"		/* clear reservation (74xx) */
+		"stwx %0, 0, %7\n\t"
+	    #endif
+		"li %0, 0\n\t"			/* failure - retval = 0 */
+		"2:\n\t"
+		: "=&r" (ret), "=m" (*p), "=m" (*cmpval)
+		: "r" (p), "r" (*cmpval), "r" (newval), "m" (*p), "r"(cmpval)
+		: "cr0", "memory");
+#endif
+
+	return (ret);
+}
+
+static __inline int
+atomic_fcmpset_acq_int(volatile u_int *p, u_int *cmpval, u_int newval)
+{
+	int retval;
+
+	retval = atomic_fcmpset_int(p, cmpval, newval);
+	__ATOMIC_ACQ();
+	return (retval);
+}
+
+static __inline int
+atomic_fcmpset_rel_int(volatile u_int *p, u_int *cmpval, u_int newval)
+{
+	__ATOMIC_REL();
+	return (atomic_fcmpset_int(p, cmpval, newval));
+}
+
+static __inline int
+atomic_fcmpset_acq_long(volatile u_long *p, u_long *cmpval, u_long newval)
+{
+	u_long retval;
+
+	retval = atomic_fcmpset_long(p, cmpval, newval);
+	__ATOMIC_ACQ();
+	return (retval);
+}
+
+static __inline int
+atomic_fcmpset_rel_long(volatile u_long *p, u_long *cmpval, u_long newval)
+{
+	__ATOMIC_REL();
+	return (atomic_fcmpset_long(p, cmpval, newval));
+}
+
+#define	atomic_fcmpset_32	atomic_fcmpset_int
+#define	atomic_fcmpset_acq_32	atomic_fcmpset_acq_int
+#define	atomic_fcmpset_rel_32	atomic_fcmpset_rel_int
+
+#ifdef __powerpc64__
+#define	atomic_fcmpset_64	atomic_fcmpset_long
+#define	atomic_fcmpset_acq_64	atomic_fcmpset_acq_long
+#define	atomic_fcmpset_rel_64	atomic_fcmpset_rel_long
+
+#define	atomic_fcmpset_ptr	atomic_fcmpset_long
+#define	atomic_fcmpset_acq_ptr	atomic_fcmpset_acq_long
+#define	atomic_fcmpset_rel_ptr	atomic_fcmpset_rel_long
+#else
+#define	atomic_fcmpset_ptr	atomic_fcmpset_int
+#define	atomic_fcmpset_acq_ptr	atomic_fcmpset_acq_int
+#define	atomic_fcmpset_rel_ptr	atomic_fcmpset_rel_int
+#endif
+
 static __inline u_int
 atomic_fetchadd_int(volatile u_int *p, u_int v)
 {
-- 
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