usr/src/lib/libc/capabilities/sun4v/common/smt_pause.s

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
  24  */
  25
  26         .file   "smt_pause.s"
  27
  28 /*
  29  * void smt_pause(void)
  30  *
  31  * Do nothing efficiently.
  32  *
  33  */
  34
  35 #include <sys/asm_linkage.h>
  36 #include <sys/niagaraasi.h>
  37 #include <sys/asi.h>
  38 #include <sys/stack.h>
  39
  40 #if defined(NIAGARA_IMPL)
  41 #include <assym.h>
  42 #endif
  43
  44         ENTRY(smt_pause)
  45 #if defined(NIAGARA2_IMPL) || defined(VFALLS_IMPL) || defined(KT_IMPL)
  46         rd      %ccr, %g0
  47         rd      %ccr, %g0
  48         retl
  49         rd      %ccr, %g0
  50 #else   /* NIAGARA2_IMPL */
  51 #define BANKS   (4 * 64)        /* 4 cachelines, cover all banks */
  52         save %sp, -SA(MINFRAME+BANKS), %sp
  53
  54         ld      [%g7 + UL_LWPID], %i3   ! curthread->ul_lwpid
  55         add     %fp, STACK_BIAS-BANKS, %i0
  56         and     %i3, 0x3, %i2           ! save last 2 bits
  57         sllx    %i2, 0x6, %i1           ! pick a slot
  58         add     %i1, %i0, %o0
  59
  60         casx    [%o0], %g0, %g0
  61         casx    [%o0], %g0, %g0
  62         casx    [%o0], %g0, %g0
  63         ret
  64         restore
  65 #endif  /* NIAGARA2_IMPL */
  66         SET_SIZE(smt_pause)
  67