From owner-svn-src-all@FreeBSD.ORG Sat Feb 20 16:13:44 2010 Return-Path: <owner-svn-src-all@FreeBSD.ORG> Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 44F791065676; Sat, 20 Feb 2010 16:13:44 +0000 (UTC) (envelope-from nwhitehorn@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id 330108FC17; Sat, 20 Feb 2010 16:13:44 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id o1KGDipB053067; Sat, 20 Feb 2010 16:13:44 GMT (envelope-from nwhitehorn@svn.freebsd.org) Received: (from nwhitehorn@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id o1KGDiiK053065; Sat, 20 Feb 2010 16:13:44 GMT (envelope-from nwhitehorn@svn.freebsd.org) Message-Id: <201002201613.o1KGDiiK053065@svn.freebsd.org> From: Nathan Whitehorn <nwhitehorn@FreeBSD.org> Date: Sat, 20 Feb 2010 16:13:44 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r204126 - head/sys/powerpc/booke X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" <svn-src-all.freebsd.org> List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-all>, <mailto:svn-src-all-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/svn-src-all> List-Post: <mailto:svn-src-all@freebsd.org> List-Help: <mailto:svn-src-all-request@freebsd.org?subject=help> List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-all>, <mailto:svn-src-all-request@freebsd.org?subject=subscribe> X-List-Received-Date: Sat, 20 Feb 2010 16:13:44 -0000 Author: nwhitehorn Date: Sat Feb 20 16:13:43 2010 New Revision: 204126 URL: http://svn.freebsd.org/changeset/base/204126 Log: Merge r198724 to Book-E. casuword() non-atomically read the current value of its argument before atomically replacing it, which could occasionally return the wrong value on an SMP system. This resulted in user mutex operations hanging when using threaded applications. Modified: head/sys/powerpc/booke/copyinout.c Modified: head/sys/powerpc/booke/copyinout.c ============================================================================== --- head/sys/powerpc/booke/copyinout.c Sat Feb 20 16:12:37 2010 (r204125) +++ head/sys/powerpc/booke/copyinout.c Sat Feb 20 16:13:43 2010 (r204126) @@ -295,8 +295,19 @@ casuword(volatile u_long *addr, u_long o return (EFAULT); } - val = *addr; - (void) atomic_cmpset_32((volatile uint32_t *)addr, old, new); + __asm __volatile ( + "1:\tlwarx %0, 0, %2\n\t" /* load old value */ + "cmplw %3, %0\n\t" /* compare */ + "bne 2f\n\t" /* exit if not equal */ + "stwcx. %4, 0, %2\n\t" /* attempt to store */ + "bne- 1b\n\t" /* spin if failed */ + "b 3f\n\t" /* we've succeeded */ + "2:\n\t" + "stwcx. %0, 0, %2\n\t" /* clear reservation (74xx) */ + "3:\n\t" + : "=&r" (val), "=m" (*addr) + : "r" (addr), "r" (old), "r" (new), "m" (*addr) + : "cc", "memory"); td->td_pcb->pcb_onfault = NULL;