arch/ia64/xen/xenivt.S

   1 /*
   2  * arch/ia64/xen/ivt.S
   3  *
   4  * Copyright (C) 2005 Hewlett-Packard Co
   5  *      Dan Magenheimer <dan.magenheimer@hp.com>
   6  *
   7  * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
   8  *                    VA Linux Systems Japan K.K.
   9  *                    pv_ops.
  10  */
  11
  12 #include <asm/asmmacro.h>
  13 #include <asm/kregs.h>
  14 #include <asm/pgtable.h>
  15
  16 #include "../kernel/minstate.h"
  17
  18         .section .text,"ax"
  19 GLOBAL_ENTRY(xen_event_callback)
  20         mov r31=pr              // prepare to save predicates
  21         ;;
  22         SAVE_MIN_WITH_COVER     // uses r31; defines r2 and r3
  23         ;;
  24         movl r3=XSI_PSR_IC
  25         mov r14=1
  26         ;;
  27         st4 [r3]=r14
  28         ;;
  29         adds r3=8,r2            // set up second base pointer for SAVE_REST
  30         srlz.i                  // ensure everybody knows psr.ic is back on
  31         ;;
  32         SAVE_REST
  33         ;;
  34 1:
  35         alloc r14=ar.pfs,0,0,1,0 // must be first in an insn group
  36         add out0=16,sp          // pass pointer to pt_regs as first arg
  37         ;;
  38         br.call.sptk.many b0=xen_evtchn_do_upcall
  39         ;;
  40         movl r20=XSI_PSR_I_ADDR
  41         ;;
  42         ld8 r20=[r20]
  43         ;;
  44         adds r20=-1,r20         // vcpu_info->evtchn_upcall_pending
  45         ;;
  46         ld1 r20=[r20]
  47         ;;
  48         cmp.ne p6,p0=r20,r0     // if there are pending events,
  49         (p6) br.spnt.few 1b     // call evtchn_do_upcall again.
  50         br.sptk.many xen_leave_kernel   // we know ia64_leave_kernel is
  51                                         // paravirtualized as xen_leave_kernel
  52 END(xen_event_callback)