sys/arch/xen/x86/xen_intr.c

   1 /*      $NetBSD: xen_intr.c,v 1.8 2008/07/01 18:44:50 bouyer Exp $      */
   2
   3 /*-
   4  * Copyright (c) 1998, 2001 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Charles M. Hannum, and by Jason R. Thorpe.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __KERNEL_RCSID(0, "$NetBSD: xen_intr.c,v 1.8 2008/07/01 18:44:50 bouyer Exp $");
  34
  35 #include <sys/param.h>
  36
  37 #include <machine/cpu.h>
  38 #include <machine/intr.h>
  39
  40 /*
  41  * Add a mask to cpl, and return the old value of cpl.
  42  */
  43 int
  44 splraise(int nlevel)
  45 {
  46         int olevel;
  47         struct cpu_info *ci = curcpu();
  48
  49         olevel = ci->ci_ilevel;
  50         if (nlevel > olevel)
  51                 ci->ci_ilevel = nlevel;
  52         __insn_barrier();
  53         return (olevel);
  54 }
  55
  56 /*
  57  * Restore a value to cpl (unmasking interrupts).  If any unmasked
  58  * interrupts are pending, call Xspllower() to process them.
  59  */
  60 void
  61 spllower(int nlevel)
  62 {
  63         struct cpu_info *ci = curcpu();
  64         uint32_t imask;
  65         u_long psl;
  66
  67         if (ci->ci_ilevel <= nlevel)
  68                 return;
  69
  70         __insn_barrier();
  71
  72         imask = IUNMASK(ci, nlevel);
  73         psl = x86_read_psl();
  74         x86_disable_intr();
  75         if (ci->ci_ipending & imask) {
  76                 KASSERT(psl == 0);
  77                 Xspllower(nlevel);
  78                 /* Xspllower does enable_intr() */
  79         } else {
  80                 ci->ci_ilevel = nlevel;
  81                 x86_write_psl(psl);
  82         }
  83 }
  84
  85 void
  86 x86_disable_intr(void)
  87 {
  88         __cli();
  89 }
  90
  91 void
  92 x86_enable_intr(void)
  93 {
  94         __sti();
  95 }
  96
  97 u_long
  98 x86_read_psl(void)
  99 {
 100
 101         return (curcpu()->ci_vcpu->evtchn_upcall_mask);
 102 }
 103
 104 void
 105 x86_write_psl(u_long psl)
 106 {
 107         struct cpu_info *ci = curcpu();
 108
 109         ci->ci_vcpu->evtchn_upcall_mask = psl;
 110         xen_rmb();
 111         if (ci->ci_vcpu->evtchn_upcall_pending && psl == 0) {
 112                 hypervisor_force_callback();
 113         }
 114 }