path: root/arch/arm/kvm/interrupts.S

/*
 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/linkage.h>

	.text

/********************************************************************
 *  Call function in Hyp mode
 *
 *
 * unsigned long kvm_call_hyp(void *hypfn, ...);
 *
 * This is not really a variadic function in the classic C-way and care must
 * be taken when calling this to ensure parameters are passed in registers
 * only, since the stack will change between the caller and the callee.
 *
 * Call the function with the first argument containing a pointer to the
 * function you wish to call in Hyp mode, and subsequent arguments will be
 * passed as r0, r1, and r2 (a maximum of 3 arguments in addition to the
 * function pointer can be passed).  The function being called must be mapped
 * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c).  Return values are
 * passed in r0 (strictly 32bit).
 *
 * A function pointer with a value of 0xffffffff has a special meaning,
 * and is used to implement __hyp_get_vectors in the same way as in
 * arch/arm/kernel/hyp_stub.S.
 *
 * The calling convention follows the standard AAPCS:
 *   r0 - r3: caller save
 *   r12:     caller save
 *   rest:    callee save
 */
ENTRY(kvm_call_hyp)
	hvc	#0
	bx	lr
ENDPROC(kvm_call_hyp)