source: mainline/kernel/arch/arm32/include/security_ext.h@ a640bc1

/*
 * Copyright (c) 2013 Jan Vesely
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup arm32
 * @{
 */
/** @file
 *  @brief Security Extensions Routines
 */

#ifndef KERN_arm32_SECURITY_EXT_H_
#define KERN_arm32_SECURITY_EXT_H_

#include <arch/cp15.h>
#include <arch/regutils.h>

/** Test whether the current cpu supports security extensions.
 * return true if security extensions are supported, false otherwise.
 * @note The Processor Feature Register 1 that provides this information
 * is available only on armv7+. This function returns false on all\
 * older archs.
 */
static inline bool sec_ext_is_implemented()
{
#ifdef PROCESSOR_armv7_a
        const uint32_t idpfr = ID_PFR1_read() & ID_PFR1_SEC_EXT_MASK;
        return idpfr == ID_PFR1_SEC_EXT || idpfr == ID_PFR1_SEC_EXT_RFR;
#endif
        return false;
}

/** Test whether we are running in monitor mode.
 * return true, if the current mode is Monitor mode, false otherwise.
 * @note this is safe to call even on machines that do not implement monitor
 * mode.
 */
static inline bool sec_ext_is_monitor_mode()
{
        return (current_status_reg_read() & MODE_MASK) == MONITOR_MODE;
}

/** Test whether we are running in a secure state.
 * return true if the current state is secure, false otherwise.
 *
 * @note: This functions will cause undef isntruction trap if we
 * are not running in the secure state.
 *
 * @note: u-boot enables non-secure access to cp 10/11, as well as some other
 * features and switches to non-secure state during boot.
 * Look for 'secureworld_exit' in arch/arm/cpu/armv7/omap3/board.c.
 */
static inline bool sec_ext_is_secure()
{
        return sec_ext_is_implemented()
            && (sec_ext_is_monitor_mode() || !(SCR_read() & SCR_NS_FLAG));
}

#endif
/** @}
 */