From owner-svn-src-head@freebsd.org  Wed Mar 22 17:33:59 2017
Return-Path: <owner-svn-src-head@freebsd.org>
Delivered-To: svn-src-head@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id F4148D18A49;
 Wed, 22 Mar 2017 17:33:58 +0000 (UTC)
 (envelope-from markj@FreeBSD.org)
Received: from repo.freebsd.org (repo.freebsd.org
 [IPv6:2610:1c1:1:6068::e6a:0])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id B285B1E61;
 Wed, 22 Mar 2017 17:33:58 +0000 (UTC)
 (envelope-from markj@FreeBSD.org)
Received: from repo.freebsd.org ([127.0.1.37])
 by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id v2MHXvE2023872;
 Wed, 22 Mar 2017 17:33:57 GMT (envelope-from markj@FreeBSD.org)
Received: (from markj@localhost)
 by repo.freebsd.org (8.15.2/8.15.2/Submit) id v2MHXvUG023871;
 Wed, 22 Mar 2017 17:33:57 GMT (envelope-from markj@FreeBSD.org)
Message-Id: <201703221733.v2MHXvUG023871@repo.freebsd.org>
X-Authentication-Warning: repo.freebsd.org: markj set sender to
 markj@FreeBSD.org using -f
From: Mark Johnston <markj@FreeBSD.org>
Date: Wed, 22 Mar 2017 17:33:57 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: svn commit: r315719 - head/sys/compat/linuxkpi/common/include/asm
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-BeenThere: svn-src-head@freebsd.org
X-Mailman-Version: 2.1.23
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
 <svn-src-head.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head/>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 22 Mar 2017 17:33:59 -0000

Author: markj
Date: Wed Mar 22 17:33:57 2017
New Revision: 315719
URL: https://svnweb.freebsd.org/changeset/base/315719

Log:
  Extend cmpxchg() to support 8- and 16-bit values, and add xchg().
  
  These are needed to support updated revisions of the DRM code.
  
  Reviewed by:	hselasky (previous version)
  MFC after:	2 weeks

Modified:
  head/sys/compat/linuxkpi/common/include/asm/atomic.h

Modified: head/sys/compat/linuxkpi/common/include/asm/atomic.h
==============================================================================
--- head/sys/compat/linuxkpi/common/include/asm/atomic.h	Wed Mar 22 17:29:04 2017	(r315718)
+++ head/sys/compat/linuxkpi/common/include/asm/atomic.h	Wed Mar 22 17:33:57 2017	(r315719)
@@ -28,11 +28,13 @@
  *
  * $FreeBSD$
  */
-#ifndef	_ASM_ATOMIC_H_
+
+#ifndef _ASM_ATOMIC_H_
 #define	_ASM_ATOMIC_H_
 
 #include <sys/cdefs.h>
 #include <sys/types.h>
+
 #include <machine/atomic.h>
 
 #define	ATOMIC_INIT(x)	{ .counter = (x) }
@@ -158,31 +160,47 @@ atomic_cmpxchg(atomic_t *v, int old, int
 }
 
 #define	cmpxchg(ptr, old, new) ({				\
-	__typeof(*(ptr)) __ret = (old);				\
-	CTASSERT(sizeof(__ret) == 4 || sizeof(__ret) == 8);	\
-	for (;;) {						\
-		if (sizeof(__ret) == 4) {			\
-			if (atomic_cmpset_int((volatile int *)	\
-			    (ptr), (old), (new)))		\
-				break;				\
-			__ret = atomic_load_acq_int(		\
-			    (volatile int *)(ptr));		\
-			if (__ret != (old))			\
-				break;				\
-		} else {					\
-			if (atomic_cmpset_64(			\
-			    (volatile int64_t *)(ptr),		\
-			    (old), (new)))			\
-				break;				\
-			__ret = atomic_load_acq_64(		\
-			    (volatile int64_t *)(ptr));		\
-			if (__ret != (old))			\
-				break;				\
-		}						\
+	__typeof(*(ptr)) __ret;					\
+								\
+	CTASSERT(sizeof(__ret) == 1 || sizeof(__ret) == 2 ||	\
+	    sizeof(__ret) == 4 || sizeof(__ret) == 8);		\
+								\
+	__ret = (old);						\
+	switch (sizeof(__ret)) {				\
+	case 1:							\
+		while (!atomic_fcmpset_8((volatile int8_t *)(ptr), \
+		    (int8_t *)&__ret, (new)) && __ret == (old))	\
+			;					\
+		break;						\
+	case 2:							\
+		while (!atomic_fcmpset_16((volatile int16_t *)(ptr), \
+		    (int16_t *)&__ret, (new)) && __ret == (old)) \
+			;					\
+		break;						\
+	case 4:							\
+		while (!atomic_fcmpset_32((volatile int32_t *)(ptr), \
+		    (int32_t *)&__ret, (new)) && __ret == (old)) \
+			;					\
+		break;						\
+	case 8:							\
+		while (!atomic_fcmpset_64((volatile int64_t *)(ptr), \
+		    (int64_t *)&__ret, (new)) && __ret == (old)) \
+			;					\
+		break;						\
 	}							\
 	__ret;							\
 })
 
+#define	cmpxchg_relaxed	cmpxchg
+
+#define	xchg(ptr, v) ({						\
+	__typeof(*(ptr)) __ret;					\
+								\
+	__ret = *(ptr);						\
+	*(ptr) = v;						\
+	__ret;							\
+})
+
 #define	LINUX_ATOMIC_OP(op, c_op)				\
 static inline void atomic_##op(int i, atomic_t *v)		\
 {								\