svn commit: r306667 - head/sys/arm/include

Michal Meloun mmel at FreeBSD.org
Tue Oct 4 09:51:55 UTC 2016


Author: mmel
Date: Tue Oct  4 09:51:54 2016
New Revision: 306667
URL: https://svnweb.freebsd.org/changeset/base/306667

Log:
  ARM: Add atomic_swap_64(). It's need by linuxkpi and drm-next-4.7.
  
  MFC after: 2 weeks

Modified:
  head/sys/arm/include/atomic-v6.h

Modified: head/sys/arm/include/atomic-v6.h
==============================================================================
--- head/sys/arm/include/atomic-v6.h	Tue Oct  4 09:14:48 2016	(r306666)
+++ head/sys/arm/include/atomic-v6.h	Tue Oct  4 09:51:54 2016	(r306667)
@@ -660,6 +660,26 @@ atomic_swap_32(volatile uint32_t *p, uin
 	return (ret);
 }
 
+static __inline uint64_t
+atomic_swap_64(volatile uint64_t *p, uint64_t v)
+{
+	uint64_t ret;
+	uint32_t exflag;
+
+	__asm __volatile(
+	    "1: ldrexd	%Q[ret], %R[ret], [%[ptr]]		\n"
+	    "   strexd	%[exf], %Q[val], %R[val], [%[ptr]]	\n"
+	    "   teq	%[exf], #0				\n"
+	    "   it	ne					\n"
+	    "   bne	1b					\n"
+	    : [ret] "=&r" (ret),
+	      [exf] "=&r" (exflag)
+	    : [val] "r"   (v),
+	      [ptr] "r"   (p)
+	    : "cc", "memory");
+	return (ret);
+}
+
 #undef ATOMIC_ACQ_REL
 #undef ATOMIC_ACQ_REL_LONG
 


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