arch/arm/kvm/interrupts.S

   1 /*
   2  * Copyright (C) 2012 - Virtual Open Systems and Columbia University
   3  * Author: Christoffer Dall <c.dall@virtualopensystems.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  */
  18
  19 #include <linux/linkage.h>
  20
  21         .text
  22
  23 /********************************************************************
  24  *  Call function in Hyp mode
  25  *
  26  *
  27  * unsigned long kvm_call_hyp(void *hypfn, ...);
  28  *
  29  * This is not really a variadic function in the classic C-way and care must
  30  * be taken when calling this to ensure parameters are passed in registers
  31  * only, since the stack will change between the caller and the callee.
  32  *
  33  * Call the function with the first argument containing a pointer to the
  34  * function you wish to call in Hyp mode, and subsequent arguments will be
  35  * passed as r0, r1, and r2 (a maximum of 3 arguments in addition to the
  36  * function pointer can be passed).  The function being called must be mapped
  37  * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c).  Return values are
  38  * passed in r0 (strictly 32bit).
  39  *
  40  * The calling convention follows the standard AAPCS:
  41  *   r0 - r3: caller save
  42  *   r12:     caller save
  43  *   rest:    callee save
  44  */
  45 ENTRY(kvm_call_hyp)
  46         hvc     #0
  47         bx      lr
  48 ENDPROC(kvm_call_hyp)