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xen_intr.c revision 1.2.22.3 
      1 /*	$NetBSD: xen_intr.c,v 1.2.22.3 2009/01/17 13:28:39 mjf 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 1.2.22.3 2009/01/17 13:28:39 mjf 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 }
    115