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/*

 * Copyright (c) 2007 Petr Stepan

 * 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 Exception handlers and exception initialization routines.

 */

#include <arch/exception.h>

#include <arch/memstr.h>

#include <arch/regutils.h>

#include <interrupt.h>

#include <arch/mm/page_fault.h>

#include <arch/barrier.h>

#include <arch/machine.h>

#include <print.h>

#include <syscall/syscall.h>

/** Offset used in calculation of exception handler's relative address.

 *

 * @see install_handler()

 */

#define PREFETCH_OFFSET      0x8

/** LDR instruction's code */

#define LDR_OPCODE           0xe59ff000

/** Number of exception vectors. */

#define EXC_VECTORS          8

/** Size of memory block occupied by exception vectors. */

#define EXC_VECTORS_SIZE     (EXC_VECTORS * 4)

/** Updates specified exception vector to jump to given handler.

 *

 *  Addresses of handlers are stored in memory following exception vectors.

 */

static void install_handler(unsigned handler_addr, unsigned *vector)

{

    /* relative address (related to exc. vector) of the word

     * where handler's address is stored

    */

    volatile uint32_t handler_address_ptr = EXC_VECTORS_SIZE -

        PREFETCH_OFFSET;

    /* make it LDR instruction and store at exception vector */

    *vector = handler_address_ptr | LDR_OPCODE;

    smc_coherence(*vector);

    /* store handler's address */

    *(vector + EXC_VECTORS) = handler_addr;

}

/** Software Interrupt handler.

 *

 * Dispatches the syscall.

 */

static void swi_exception(int exc_no, istate_t *istate)

{

    istate->r0 = syscall_handler(istate->r0, istate->r1, istate->r2,

        istate->r3, istate->r4, istate->r5, istate->r6);

}

/** Fills exception vectors with appropriate exception handlers. */

void install_exception_handlers(void)

{

    install_handler((unsigned) reset_exception_entry,

        (unsigned *) EXC_RESET_VEC);

    install_handler((unsigned) undef_instr_exception_entry,

        (unsigned *) EXC_UNDEF_INSTR_VEC);

    install_handler((unsigned) swi_exception_entry,

        (unsigned *) EXC_SWI_VEC);

    install_handler((unsigned) prefetch_abort_exception_entry,

        (unsigned *) EXC_PREFETCH_ABORT_VEC);

    install_handler((unsigned) data_abort_exception_entry,

        (unsigned *) EXC_DATA_ABORT_VEC);

    install_handler((unsigned) irq_exception_entry,

        (unsigned *) EXC_IRQ_VEC);

    install_handler((unsigned) fiq_exception_entry,

        (unsigned *) EXC_FIQ_VEC);

}

#ifdef HIGH_EXCEPTION_VECTORS

/** Activates use of high exception vectors addresses. */

static void high_vectors(void)

{

    uint32_t control_reg;

    asm volatile (

        "mrc p15, 0, %[control_reg], c1, c1"

        : [control_reg] "=r" (control_reg)

    );

    /* switch on the high vectors bit */

    control_reg |= CP15_R1_HIGH_VECTORS_BIT;

    asm volatile (

        "mcr p15, 0, %[control_reg], c1, c1"

        :: [control_reg] "r" (control_reg)

    );

}

#endif

/** Interrupt Exception handler.

 *

 * Determines the sources of interrupt and calls their handlers.

 */

static void irq_exception(int exc_no, istate_t *istate)

{

    machine_irq_exception(exc_no, istate);

}

/** Initializes exception handling.

 *

 * Installs low-level exception handlers and then registers

 * exceptions and their handlers to kernel exception dispatcher.

 */

void exception_init(void)

{

#ifdef HIGH_EXCEPTION_VECTORS

    high_vectors();

#endif

    install_exception_handlers();

    exc_register(EXC_IRQ, "interrupt", (iroutine) irq_exception);

    exc_register(EXC_PREFETCH_ABORT, "prefetch abort",

        (iroutine) prefetch_abort);

    exc_register(EXC_DATA_ABORT, "data abort", (iroutine) data_abort);

    exc_register(EXC_SWI, "software interrupt", (iroutine) swi_exception);

}

/** Prints #istate_t structure content.

 *

 * @param istate Structure to be printed.

 */

void print_istate(istate_t *istate)

{

    printf("istate dump:\n");

    printf(" r0: %x    r1: %x    r2: %x    r3: %x\n",

        istate->r0, istate->r1, istate->r2, istate->r3);

    printf(" r4: %x    r5: %x    r6: %x    r7: %x\n",

        istate->r4, istate->r5, istate->r6, istate->r7);

    printf(" r8: %x    r8: %x   r10: %x   r11: %x\n",

        istate->r8, istate->r9, istate->r10, istate->r11);

    printf(" r12: %x    sp: %x    lr: %x  spsr: %x\n",

        istate->r12, istate->sp, istate->lr, istate->spsr);

    printf(" pc: %x\n", istate->pc);

}

/** @}

 */