usr/src/uts/sun4/os/mp_call.c

   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  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 /*
  27  * Facilities for cross-processor subroutine calls using "mailbox" interrupts.
  28  */
  29
  30 #include <sys/types.h>
  31 #include <sys/thread.h>
  32 #include <sys/cpuvar.h>
  33 #include <sys/x_call.h>
  34 #include <sys/systm.h>
  35 #include <sys/machsystm.h>
  36 #include <sys/intr.h>
  37 #include <sys/xc_impl.h>
  38
  39 /*
  40  * Interrupt another CPU.
  41  *      This is useful to make the other CPU go through a trap so that
  42  *      it recognizes an address space trap (AST) for preempting a thread.
  43  *
  44  *      It is possible to be preempted here and be resumed on the CPU
  45  *      being poked, so it isn't an error to poke the current CPU.
  46  *      We could check this and still get preempted after the check, so
  47  *      we don't bother.
  48  */
  49 void
  50 poke_cpu(int cpun)
  51 {
  52         uint32_t *ptr = (uint32_t *)&cpu[cpun]->cpu_m.poke_cpu_outstanding;
  53
  54         /*
  55          * If panicstr is set or a poke_cpu is already pending,
  56          * no need to send another one. Use atomic swap to protect
  57          * against multiple CPUs sending redundant pokes.
  58          */
  59         if (panicstr || *ptr == B_TRUE ||
  60             atomic_swap_32(ptr, B_TRUE) == B_TRUE)
  61                 return;
  62
  63         xt_one(cpun, setsoftint_tl1, poke_cpu_inum, 0);
  64 }
  65
  66 extern int xc_spl_enter[];
  67
  68 /*
  69  * Call a function on a target CPU
  70  */
  71 void
  72 cpu_call(cpu_t *cp, cpu_call_func_t func, uintptr_t arg1, uintptr_t arg2)
  73 {
  74         if (panicstr)
  75                 return;
  76
  77         /*
  78          * Prevent CPU from going offline
  79          */
  80         kpreempt_disable();
  81
  82         /*
  83          * If we are on the target CPU, call the function directly, but raise
  84          * the PIL to XC_PIL.
  85          * This guarantees that functions called via cpu_call() can not ever
  86          * interrupt each other.
  87          */
  88         if (CPU != cp) {
  89                 xc_one(cp->cpu_id, (xcfunc_t *)func, (uint64_t)arg1,
  90                     (uint64_t)arg2);
  91         } else {
  92                 int lcx;
  93                 int opl;
  94
  95                 XC_SPL_ENTER(lcx, opl);
  96                 func(arg1, arg2);
  97                 XC_SPL_EXIT(lcx, opl);
  98         }
  99
 100         kpreempt_enable();
 101 }