target/armv7m: rework Cortex-M register handling part 2

[openocd.git] / src / target / armv7m.c

/***************************************************************************
 *   Copyright (C) 2005 by Dominic Rath                                    *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   Copyright (C) 2006 by Magnus Lundin                                   *
 *   lundin@mlu.mine.nu                                                    *
 *                                                                         *
 *   Copyright (C) 2008 by Spencer Oliver                                  *
 *   spen@spen-soft.co.uk                                                  *
 *                                                                         *
 *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
 *   oyvind.harboe@zylin.com                                               *
 *                                                                         *
 *   Copyright (C) 2018 by Liviu Ionescu                                   *
 *   <ilg@livius.net>                                                      *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   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, see <http://www.gnu.org/licenses/>. *
 *                                                                         *
 *   ARMv7-M Architecture, Application Level Reference Manual              *
 *              ARM DDI 0405C (September 2008)                             *
 *                                                                         *
 ***************************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "breakpoints.h"
#include "armv7m.h"
#include "algorithm.h"
#include "register.h"
#include "semihosting_common.h"

#if 0
#define _DEBUG_INSTRUCTION_EXECUTION_
#endif

static const char * const armv7m_exception_strings[] = {
        "", "Reset", "NMI", "HardFault",
        "MemManage", "BusFault", "UsageFault", "SecureFault",
        "RESERVED", "RESERVED", "RESERVED", "SVCall",
        "DebugMonitor", "RESERVED", "PendSV", "SysTick"
};

/* PSP is used in some thread modes */
const int armv7m_psp_reg_map[ARMV7M_NUM_CORE_REGS] = {
        ARMV7M_R0, ARMV7M_R1, ARMV7M_R2, ARMV7M_R3,
        ARMV7M_R4, ARMV7M_R5, ARMV7M_R6, ARMV7M_R7,
        ARMV7M_R8, ARMV7M_R9, ARMV7M_R10, ARMV7M_R11,
        ARMV7M_R12, ARMV7M_PSP, ARMV7M_R14, ARMV7M_PC,
        ARMV7M_xPSR,
};

/* MSP is used in handler and some thread modes */
const int armv7m_msp_reg_map[ARMV7M_NUM_CORE_REGS] = {
        ARMV7M_R0, ARMV7M_R1, ARMV7M_R2, ARMV7M_R3,
        ARMV7M_R4, ARMV7M_R5, ARMV7M_R6, ARMV7M_R7,
        ARMV7M_R8, ARMV7M_R9, ARMV7M_R10, ARMV7M_R11,
        ARMV7M_R12, ARMV7M_MSP, ARMV7M_R14, ARMV7M_PC,
        ARMV7M_xPSR,
};

/*
 * These registers are not memory-mapped.  The ARMv7-M profile includes
 * memory mapped registers too, such as for the NVIC (interrupt controller)
 * and SysTick (timer) modules; those can mostly be treated as peripherals.
 *
 * The ARMv6-M profile is almost identical in this respect, except that it
 * doesn't include basepri or faultmask registers.
 */
static const struct {
        unsigned id;
        const char *name;
        unsigned bits;
        enum reg_type type;
        const char *group;
        const char *feature;
} armv7m_regs[] = {
        { ARMV7M_R0, "r0", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R1, "r1", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R2, "r2", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R3, "r3", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R4, "r4", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R5, "r5", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R6, "r6", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R7, "r7", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R8, "r8", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R9, "r9", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R10, "r10", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R11, "r11", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R12, "r12", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R13, "sp", 32, REG_TYPE_DATA_PTR, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_R14, "lr", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_PC, "pc", 32, REG_TYPE_CODE_PTR, "general", "org.gnu.gdb.arm.m-profile" },
        { ARMV7M_xPSR, "xPSR", 32, REG_TYPE_INT, "general", "org.gnu.gdb.arm.m-profile" },

        { ARMV7M_MSP, "msp", 32, REG_TYPE_DATA_PTR, "system", "org.gnu.gdb.arm.m-system" },
        { ARMV7M_PSP, "psp", 32, REG_TYPE_DATA_PTR, "system", "org.gnu.gdb.arm.m-system" },

        { ARMV7M_PRIMASK, "primask", 1, REG_TYPE_INT8, "system", "org.gnu.gdb.arm.m-system" },
        { ARMV7M_BASEPRI, "basepri", 8, REG_TYPE_INT8, "system", "org.gnu.gdb.arm.m-system" },
        { ARMV7M_FAULTMASK, "faultmask", 1, REG_TYPE_INT8, "system", "org.gnu.gdb.arm.m-system" },
        { ARMV7M_CONTROL, "control", 3, REG_TYPE_INT8, "system", "org.gnu.gdb.arm.m-system" },

        { ARMV7M_D0, "d0", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D1, "d1", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D2, "d2", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D3, "d3", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D4, "d4", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D5, "d5", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D6, "d6", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D7, "d7", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D8, "d8", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D9, "d9", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D10, "d10", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D11, "d11", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D12, "d12", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D13, "d13", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D14, "d14", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },
        { ARMV7M_D15, "d15", 64, REG_TYPE_IEEE_DOUBLE, "float", "org.gnu.gdb.arm.vfp" },

        { ARMV7M_FPSCR, "fpscr", 32, REG_TYPE_INT, "float", "org.gnu.gdb.arm.vfp" },
};

#define ARMV7M_NUM_REGS ARRAY_SIZE(armv7m_regs)

/**
 * Restores target context using the cache of core registers set up
 * by armv7m_build_reg_cache(), calling optional core-specific hooks.
 */
int armv7m_restore_context(struct target *target)
{
        int i;
        struct armv7m_common *armv7m = target_to_armv7m(target);
        struct reg_cache *cache = armv7m->arm.core_cache;

        LOG_DEBUG(" ");

        if (armv7m->pre_restore_context)
                armv7m->pre_restore_context(target);

        for (i = cache->num_regs - 1; i >= 0; i--) {
                if (cache->reg_list[i].dirty) {
                        armv7m->arm.write_core_reg(target, &cache->reg_list[i], i,
                                                   ARM_MODE_ANY, cache->reg_list[i].value);
                }
        }

        return ERROR_OK;
}

/* Core state functions */

/**
 * Maps ISR number (from xPSR) to name.
 * Note that while names and meanings for the first sixteen are standardized
 * (with zero not a true exception), external interrupts are only numbered.
 * They are assigned by vendors, which generally assign different numbers to
 * peripherals (such as UART0 or a USB peripheral controller).
 */
const char *armv7m_exception_string(int number)
{
        static char enamebuf[32];

        if ((number < 0) | (number > 511))
                return "Invalid exception";
        if (number < 16)
                return armv7m_exception_strings[number];
        sprintf(enamebuf, "External Interrupt(%i)", number - 16);
        return enamebuf;
}

static int armv7m_get_core_reg(struct reg *reg)
{
        int retval;
        struct arm_reg *armv7m_reg = reg->arch_info;
        struct target *target = armv7m_reg->target;
        struct arm *arm = target_to_arm(target);

        if (target->state != TARGET_HALTED)
                return ERROR_TARGET_NOT_HALTED;

        retval = arm->read_core_reg(target, reg, reg->number, arm->core_mode);

        return retval;
}

static int armv7m_set_core_reg(struct reg *reg, uint8_t *buf)
{
        struct arm_reg *armv7m_reg = reg->arch_info;
        struct target *target = armv7m_reg->target;

        if (target->state != TARGET_HALTED)
                return ERROR_TARGET_NOT_HALTED;

        buf_cpy(buf, reg->value, reg->size);
        reg->dirty = true;
        reg->valid = true;

        return ERROR_OK;
}

static uint32_t armv7m_map_id_to_regsel(unsigned int arm_reg_id)
{
        switch (arm_reg_id) {
        case ARMV7M_R0 ... ARMV7M_R14:
        case ARMV7M_PC:
        case ARMV7M_xPSR:
        case ARMV7M_MSP:
        case ARMV7M_PSP:
                /* NOTE:  we "know" here that the register identifiers
                 * match the Cortex-M DCRSR.REGSEL selectors values
                 * for R0..R14, PC, xPSR, MSP, and PSP.
                 */
                return arm_reg_id;

        case ARMV7M_FPSCR:
                return ARMV7M_REGSEL_FPSCR;

        case ARMV7M_D0 ... ARMV7M_D15:
                return ARMV7M_REGSEL_S0 + 2 * (arm_reg_id - ARMV7M_D0);

        /* TODO: remove. This is temporary hack until packing/unpacking
         * of special regs is moved to armv7m.c */
        case ARMV7M_PRIMASK:
        case ARMV7M_BASEPRI:
        case ARMV7M_FAULTMASK:
        case ARMV7M_CONTROL:
                return arm_reg_id;

        default:
                LOG_ERROR("Bad register ID %u", arm_reg_id);
                return arm_reg_id;
        }
}

static int armv7m_read_core_reg(struct target *target, struct reg *r,
        int num, enum arm_mode mode)
{
        uint32_t reg_value;
        int retval;
        struct arm_reg *armv7m_core_reg;
        struct armv7m_common *armv7m = target_to_armv7m(target);

        assert(num < (int)armv7m->arm.core_cache->num_regs);
        assert(num == (int)r->number);

        armv7m_core_reg = armv7m->arm.core_cache->reg_list[num].arch_info;

        uint32_t regsel = armv7m_map_id_to_regsel(armv7m_core_reg->num);

        if ((armv7m_core_reg->num >= ARMV7M_D0) && (armv7m_core_reg->num <= ARMV7M_D15)) {
                /* map D0..D15 to S0..S31 */
                retval = armv7m->load_core_reg_u32(target, regsel, &reg_value);
                if (retval != ERROR_OK)
                        return retval;
                buf_set_u32(armv7m->arm.core_cache->reg_list[num].value,
                            0, 32, reg_value);
                retval = armv7m->load_core_reg_u32(target, regsel + 1, &reg_value);
                if (retval != ERROR_OK)
                        return retval;
                buf_set_u32(armv7m->arm.core_cache->reg_list[num].value + 4,
                            0, 32, reg_value);
        } else {
                retval = armv7m->load_core_reg_u32(target,
                                                   regsel, &reg_value);
                if (retval != ERROR_OK)
                        return retval;
                buf_set_u32(armv7m->arm.core_cache->reg_list[num].value, 0, 32, reg_value);
        }

        armv7m->arm.core_cache->reg_list[num].valid = true;
        armv7m->arm.core_cache->reg_list[num].dirty = false;

        return retval;
}

static int armv7m_write_core_reg(struct target *target, struct reg *r,
        int num, enum arm_mode mode, uint8_t *value)
{
        int retval;
        struct arm_reg *armv7m_core_reg;
        struct armv7m_common *armv7m = target_to_armv7m(target);

        assert(num < (int)armv7m->arm.core_cache->num_regs);
        assert(num == (int)r->number);

        armv7m_core_reg = armv7m->arm.core_cache->reg_list[num].arch_info;

        uint32_t regsel = armv7m_map_id_to_regsel(armv7m_core_reg->num);

        if ((armv7m_core_reg->num >= ARMV7M_D0) && (armv7m_core_reg->num <= ARMV7M_D15)) {
                /* map D0..D15 to S0..S31 */
                uint32_t t = buf_get_u32(value, 0, 32);
                retval = armv7m->store_core_reg_u32(target, regsel, t);
                if (retval != ERROR_OK)
                        goto out_error;

                t = buf_get_u32(value + 4, 0, 32);
                retval = armv7m->store_core_reg_u32(target, regsel + 1, t);
                if (retval != ERROR_OK)
                        goto out_error;
        } else {
                uint32_t t = buf_get_u32(value, 0, 32);

                LOG_DEBUG("write core reg %i value 0x%" PRIx32 "", num, t);
                retval = armv7m->store_core_reg_u32(target, regsel, t);
                if (retval != ERROR_OK)
                        goto out_error;
        }

        armv7m->arm.core_cache->reg_list[num].valid = true;
        armv7m->arm.core_cache->reg_list[num].dirty = false;

        return ERROR_OK;

out_error:
        LOG_ERROR("Error setting register");
        armv7m->arm.core_cache->reg_list[num].dirty = armv7m->arm.core_cache->reg_list[num].valid;
        return ERROR_JTAG_DEVICE_ERROR;
}

/**
 * Returns generic ARM userspace registers to GDB.
 */
int armv7m_get_gdb_reg_list(struct target *target, struct reg **reg_list[],
                int *reg_list_size, enum target_register_class reg_class)
{
        struct armv7m_common *armv7m = target_to_armv7m(target);
        int i, size;

        if (reg_class == REG_CLASS_ALL)
                size = armv7m->arm.core_cache->num_regs;
        else
                size = ARMV7M_NUM_CORE_REGS;

        *reg_list = malloc(sizeof(struct reg *) * size);
        if (*reg_list == NULL)
                return ERROR_FAIL;

        for (i = 0; i < size; i++)
                (*reg_list)[i] = &armv7m->arm.core_cache->reg_list[i];

        *reg_list_size = size;

        return ERROR_OK;
}

/** Runs a Thumb algorithm in the target. */
int armv7m_run_algorithm(struct target *target,
        int num_mem_params, struct mem_param *mem_params,
        int num_reg_params, struct reg_param *reg_params,
        target_addr_t entry_point, target_addr_t exit_point,
        int timeout_ms, void *arch_info)
{
        int retval;

        retval = armv7m_start_algorithm(target,
                        num_mem_params, mem_params,
                        num_reg_params, reg_params,
                        entry_point, exit_point,
                        arch_info);

        if (retval == ERROR_OK)
                retval = armv7m_wait_algorithm(target,
                                num_mem_params, mem_params,
                                num_reg_params, reg_params,
                                exit_point, timeout_ms,
                                arch_info);

        return retval;
}

/** Starts a Thumb algorithm in the target. */
int armv7m_start_algorithm(struct target *target,
        int num_mem_params, struct mem_param *mem_params,
        int num_reg_params, struct reg_param *reg_params,
        target_addr_t entry_point, target_addr_t exit_point,
        void *arch_info)
{
        struct armv7m_common *armv7m = target_to_armv7m(target);
        struct armv7m_algorithm *armv7m_algorithm_info = arch_info;
        enum arm_mode core_mode = armv7m->arm.core_mode;
        int retval = ERROR_OK;

        /* NOTE: armv7m_run_algorithm requires that each algorithm uses a software breakpoint
         * at the exit point */

        if (armv7m_algorithm_info->common_magic != ARMV7M_COMMON_MAGIC) {
                LOG_ERROR("current target isn't an ARMV7M target");
                return ERROR_TARGET_INVALID;
        }

        if (target->state != TARGET_HALTED) {
                LOG_WARNING("target not halted");
                return ERROR_TARGET_NOT_HALTED;
        }

        /* refresh core register cache
         * Not needed if core register cache is always consistent with target process state */
        for (unsigned i = 0; i < armv7m->arm.core_cache->num_regs; i++) {

                armv7m_algorithm_info->context[i] = buf_get_u32(
                                armv7m->arm.core_cache->reg_list[i].value,
                                0,
                                32);
        }

        for (int i = 0; i < num_mem_params; i++) {
                if (mem_params[i].direction == PARAM_IN)
                        continue;
                retval = target_write_buffer(target, mem_params[i].address,
                                mem_params[i].size,
                                mem_params[i].value);
                if (retval != ERROR_OK)
                        return retval;
        }

        for (int i = 0; i < num_reg_params; i++) {
                if (reg_params[i].direction == PARAM_IN)
                        continue;

                struct reg *reg =
                        register_get_by_name(armv7m->arm.core_cache, reg_params[i].reg_name, 0);
/*              uint32_t regvalue; */

                if (!reg) {
                        LOG_ERROR("BUG: register '%s' not found", reg_params[i].reg_name);
                        return ERROR_COMMAND_SYNTAX_ERROR;
                }

                if (reg->size != reg_params[i].size) {
                        LOG_ERROR("BUG: register '%s' size doesn't match reg_params[i].size",
                                reg_params[i].reg_name);
                        return ERROR_COMMAND_SYNTAX_ERROR;
                }

/*              regvalue = buf_get_u32(reg_params[i].value, 0, 32); */
                armv7m_set_core_reg(reg, reg_params[i].value);
        }

        {
                /*
                 * Ensure xPSR.T is set to avoid trying to run things in arm
                 * (non-thumb) mode, which armv7m does not support.
                 *
                 * We do this by setting the entirety of xPSR, which should
                 * remove all the unknowns about xPSR state.
                 *
                 * Because xPSR.T is populated on reset from the vector table,
                 * it might be 0 if the vector table has "bad" data in it.
                 */
                struct reg *reg = &armv7m->arm.core_cache->reg_list[ARMV7M_xPSR];
                buf_set_u32(reg->value, 0, 32, 0x01000000);
                reg->valid = true;
                reg->dirty = true;
        }

        if (armv7m_algorithm_info->core_mode != ARM_MODE_ANY &&
                        armv7m_algorithm_info->core_mode != core_mode) {

                /* we cannot set ARM_MODE_HANDLER, so use ARM_MODE_THREAD instead */
                if (armv7m_algorithm_info->core_mode == ARM_MODE_HANDLER) {
                        armv7m_algorithm_info->core_mode = ARM_MODE_THREAD;
                        LOG_INFO("ARM_MODE_HANDLER not currently supported, using ARM_MODE_THREAD instead");
                }

                LOG_DEBUG("setting core_mode: 0x%2.2x", armv7m_algorithm_info->core_mode);
                buf_set_u32(armv7m->arm.core_cache->reg_list[ARMV7M_CONTROL].value,
                        0, 1, armv7m_algorithm_info->core_mode);
                armv7m->arm.core_cache->reg_list[ARMV7M_CONTROL].dirty = true;
                armv7m->arm.core_cache->reg_list[ARMV7M_CONTROL].valid = true;
        }

        /* save previous core mode */
        armv7m_algorithm_info->core_mode = core_mode;

        retval = target_resume(target, 0, entry_point, 1, 1);

        return retval;
}

/** Waits for an algorithm in the target. */
int armv7m_wait_algorithm(struct target *target,
        int num_mem_params, struct mem_param *mem_params,
        int num_reg_params, struct reg_param *reg_params,
        target_addr_t exit_point, int timeout_ms,
        void *arch_info)
{
        struct armv7m_common *armv7m = target_to_armv7m(target);
        struct armv7m_algorithm *armv7m_algorithm_info = arch_info;
        int retval = ERROR_OK;

        /* NOTE: armv7m_run_algorithm requires that each algorithm uses a software breakpoint
         * at the exit point */

        if (armv7m_algorithm_info->common_magic != ARMV7M_COMMON_MAGIC) {
                LOG_ERROR("current target isn't an ARMV7M target");
                return ERROR_TARGET_INVALID;
        }

        retval = target_wait_state(target, TARGET_HALTED, timeout_ms);
        /* If the target fails to halt due to the breakpoint, force a halt */
        if (retval != ERROR_OK || target->state != TARGET_HALTED) {
                retval = target_halt(target);
                if (retval != ERROR_OK)
                        return retval;
                retval = target_wait_state(target, TARGET_HALTED, 500);
                if (retval != ERROR_OK)
                        return retval;
                return ERROR_TARGET_TIMEOUT;
        }

        if (exit_point) {
                /* PC value has been cached in cortex_m_debug_entry() */
                uint32_t pc = buf_get_u32(armv7m->arm.pc->value, 0, 32);
                if (pc != exit_point) {
                        LOG_DEBUG("failed algorithm halted at 0x%" PRIx32 ", expected 0x%" TARGET_PRIxADDR,
                                          pc, exit_point);
                        return ERROR_TARGET_ALGO_EXIT;
                }
        }

        /* Read memory values to mem_params[] */
        for (int i = 0; i < num_mem_params; i++) {
                if (mem_params[i].direction != PARAM_OUT) {
                        retval = target_read_buffer(target, mem_params[i].address,
                                        mem_params[i].size,
                                        mem_params[i].value);
                        if (retval != ERROR_OK)
                                return retval;
                }
        }

        /* Copy core register values to reg_params[] */
        for (int i = 0; i < num_reg_params; i++) {
                if (reg_params[i].direction != PARAM_OUT) {
                        struct reg *reg = register_get_by_name(armv7m->arm.core_cache,
                                        reg_params[i].reg_name,
                                        0);

                        if (!reg) {
                                LOG_ERROR("BUG: register '%s' not found", reg_params[i].reg_name);
                                return ERROR_COMMAND_SYNTAX_ERROR;
                        }

                        if (reg->size != reg_params[i].size) {
                                LOG_ERROR(
                                        "BUG: register '%s' size doesn't match reg_params[i].size",
                                        reg_params[i].reg_name);
                                return ERROR_COMMAND_SYNTAX_ERROR;
                        }

                        buf_set_u32(reg_params[i].value, 0, 32, buf_get_u32(reg->value, 0, 32));
                }
        }

        for (int i = armv7m->arm.core_cache->num_regs - 1; i >= 0; i--) {
                uint32_t regvalue;
                regvalue = buf_get_u32(armv7m->arm.core_cache->reg_list[i].value, 0, 32);
                if (regvalue != armv7m_algorithm_info->context[i]) {
                        LOG_DEBUG("restoring register %s with value 0x%8.8" PRIx32,
                                        armv7m->arm.core_cache->reg_list[i].name,
                                armv7m_algorithm_info->context[i]);
                        buf_set_u32(armv7m->arm.core_cache->reg_list[i].value,
                                0, 32, armv7m_algorithm_info->context[i]);
                        armv7m->arm.core_cache->reg_list[i].valid = true;
                        armv7m->arm.core_cache->reg_list[i].dirty = true;
                }
        }

        /* restore previous core mode */
        if (armv7m_algorithm_info->core_mode != armv7m->arm.core_mode) {
                LOG_DEBUG("restoring core_mode: 0x%2.2x", armv7m_algorithm_info->core_mode);
                buf_set_u32(armv7m->arm.core_cache->reg_list[ARMV7M_CONTROL].value,
                        0, 1, armv7m_algorithm_info->core_mode);
                armv7m->arm.core_cache->reg_list[ARMV7M_CONTROL].dirty = true;
                armv7m->arm.core_cache->reg_list[ARMV7M_CONTROL].valid = true;
        }

        armv7m->arm.core_mode = armv7m_algorithm_info->core_mode;

        return retval;
}

/** Logs summary of ARMv7-M state for a halted target. */
int armv7m_arch_state(struct target *target)
{
        struct armv7m_common *armv7m = target_to_armv7m(target);
        struct arm *arm = &armv7m->arm;
        uint32_t ctrl, sp;

        /* avoid filling log waiting for fileio reply */
        if (target->semihosting && target->semihosting->hit_fileio)
                return ERROR_OK;

        ctrl = buf_get_u32(arm->core_cache->reg_list[ARMV7M_CONTROL].value, 0, 32);
        sp = buf_get_u32(arm->core_cache->reg_list[ARMV7M_R13].value, 0, 32);

        LOG_USER("target halted due to %s, current mode: %s %s\n"
                "xPSR: %#8.8" PRIx32 " pc: %#8.8" PRIx32 " %csp: %#8.8" PRIx32 "%s%s",
                debug_reason_name(target),
                arm_mode_name(arm->core_mode),
                armv7m_exception_string(armv7m->exception_number),
                buf_get_u32(arm->cpsr->value, 0, 32),
                buf_get_u32(arm->pc->value, 0, 32),
                (ctrl & 0x02) ? 'p' : 'm',
                sp,
                (target->semihosting && target->semihosting->is_active) ? ", semihosting" : "",
                (target->semihosting && target->semihosting->is_fileio) ? " fileio" : "");

        return ERROR_OK;
}

static const struct reg_arch_type armv7m_reg_type = {
        .get = armv7m_get_core_reg,
        .set = armv7m_set_core_reg,
};

/** Builds cache of architecturally defined registers.  */
struct reg_cache *armv7m_build_reg_cache(struct target *target)
{
        struct armv7m_common *armv7m = target_to_armv7m(target);
        struct arm *arm = &armv7m->arm;
        int num_regs = ARMV7M_NUM_REGS;
        struct reg_cache **cache_p = register_get_last_cache_p(&target->reg_cache);
        struct reg_cache *cache = malloc(sizeof(struct reg_cache));
        struct reg *reg_list = calloc(num_regs, sizeof(struct reg));
        struct arm_reg *arch_info = calloc(num_regs, sizeof(struct arm_reg));
        struct reg_feature *feature;
        int i;

        /* Build the process context cache */
        cache->name = "arm v7m registers";
        cache->next = NULL;
        cache->reg_list = reg_list;
        cache->num_regs = num_regs;
        (*cache_p) = cache;

        for (i = 0; i < num_regs; i++) {
                arch_info[i].num = armv7m_regs[i].id;
                arch_info[i].target = target;
                arch_info[i].arm = arm;

                reg_list[i].name = armv7m_regs[i].name;
                reg_list[i].size = armv7m_regs[i].bits;
                size_t storage_size = DIV_ROUND_UP(armv7m_regs[i].bits, 8);
                if (storage_size < 4)
                        storage_size = 4;
                reg_list[i].value = calloc(1, storage_size);
                reg_list[i].dirty = false;
                reg_list[i].valid = false;
                reg_list[i].type = &armv7m_reg_type;
                reg_list[i].arch_info = &arch_info[i];

                reg_list[i].group = armv7m_regs[i].group;
                reg_list[i].number = i;
                reg_list[i].exist = true;
                reg_list[i].caller_save = true; /* gdb defaults to true */

                feature = calloc(1, sizeof(struct reg_feature));
                if (feature) {
                        feature->name = armv7m_regs[i].feature;
                        reg_list[i].feature = feature;
                } else
                        LOG_ERROR("unable to allocate feature list");

                reg_list[i].reg_data_type = calloc(1, sizeof(struct reg_data_type));
                if (reg_list[i].reg_data_type)
                        reg_list[i].reg_data_type->type = armv7m_regs[i].type;
                else
                        LOG_ERROR("unable to allocate reg type list");
        }

        arm->cpsr = reg_list + ARMV7M_xPSR;
        arm->pc = reg_list + ARMV7M_PC;
        arm->core_cache = cache;

        return cache;
}

void armv7m_free_reg_cache(struct target *target)
{
        struct armv7m_common *armv7m = target_to_armv7m(target);
        struct arm *arm = &armv7m->arm;
        struct reg_cache *cache;
        struct reg *reg;
        unsigned int i;

        cache = arm->core_cache;

        if (!cache)
                return;

        for (i = 0; i < cache->num_regs; i++) {
                reg = &cache->reg_list[i];

                free(reg->feature);
                free(reg->reg_data_type);
                free(reg->value);
        }

        free(cache->reg_list[0].arch_info);
        free(cache->reg_list);
        free(cache);

        arm->core_cache = NULL;
}

static int armv7m_setup_semihosting(struct target *target, int enable)
{
        /* nothing todo for armv7m */
        return ERROR_OK;
}

/** Sets up target as a generic ARMv7-M core */
int armv7m_init_arch_info(struct target *target, struct armv7m_common *armv7m)
{
        struct arm *arm = &armv7m->arm;

        armv7m->common_magic = ARMV7M_COMMON_MAGIC;
        armv7m->fp_feature = FP_NONE;
        armv7m->trace_config.trace_bus_id = 1;
        /* Enable stimulus port #0 by default */
        armv7m->trace_config.itm_ter[0] = 1;

        arm->core_type = ARM_CORE_TYPE_M_PROFILE;
        arm->arch_info = armv7m;
        arm->setup_semihosting = armv7m_setup_semihosting;

        arm->read_core_reg = armv7m_read_core_reg;
        arm->write_core_reg = armv7m_write_core_reg;

        return arm_init_arch_info(target, arm);
}

/** Generates a CRC32 checksum of a memory region. */
int armv7m_checksum_memory(struct target *target,
        target_addr_t address, uint32_t count, uint32_t *checksum)
{
        struct working_area *crc_algorithm;
        struct armv7m_algorithm armv7m_info;
        struct reg_param reg_params[2];
        int retval;

        static const uint8_t cortex_m_crc_code[] = {
#include "../../contrib/loaders/checksum/armv7m_crc.inc"
        };

        retval = target_alloc_working_area(target, sizeof(cortex_m_crc_code), &crc_algorithm);
        if (retval != ERROR_OK)
                return retval;

        retval = target_write_buffer(target, crc_algorithm->address,
                        sizeof(cortex_m_crc_code), (uint8_t *)cortex_m_crc_code);
        if (retval != ERROR_OK)
                goto cleanup;

        armv7m_info.common_magic = ARMV7M_COMMON_MAGIC;
        armv7m_info.core_mode = ARM_MODE_THREAD;

        init_reg_param(&reg_params[0], "r0", 32, PARAM_IN_OUT);
        init_reg_param(&reg_params[1], "r1", 32, PARAM_OUT);

        buf_set_u32(reg_params[0].value, 0, 32, address);
        buf_set_u32(reg_params[1].value, 0, 32, count);

        int timeout = 20000 * (1 + (count / (1024 * 1024)));

        retval = target_run_algorithm(target, 0, NULL, 2, reg_params, crc_algorithm->address,
                        crc_algorithm->address + (sizeof(cortex_m_crc_code) - 6),
                        timeout, &armv7m_info);

        if (retval == ERROR_OK)
                *checksum = buf_get_u32(reg_params[0].value, 0, 32);
        else
                LOG_ERROR("error executing cortex_m crc algorithm");

        destroy_reg_param(&reg_params[0]);
        destroy_reg_param(&reg_params[1]);

cleanup:
        target_free_working_area(target, crc_algorithm);

        return retval;
}

/** Checks an array of memory regions whether they are erased. */
int armv7m_blank_check_memory(struct target *target,
        struct target_memory_check_block *blocks, int num_blocks, uint8_t erased_value)
{
        struct working_area *erase_check_algorithm;
        struct working_area *erase_check_params;
        struct reg_param reg_params[2];
        struct armv7m_algorithm armv7m_info;
        int retval;

        static bool timed_out;

        static const uint8_t erase_check_code[] = {
#include "../../contrib/loaders/erase_check/armv7m_erase_check.inc"
        };

        const uint32_t code_size = sizeof(erase_check_code);

        /* make sure we have a working area */
        if (target_alloc_working_area(target, code_size,
                &erase_check_algorithm) != ERROR_OK)
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;

        retval = target_write_buffer(target, erase_check_algorithm->address,
                        code_size, erase_check_code);
        if (retval != ERROR_OK)
                goto cleanup1;

        /* prepare blocks array for algo */
        struct algo_block {
                union {
                        uint32_t size;
                        uint32_t result;
                };
                uint32_t address;
        };

        uint32_t avail = target_get_working_area_avail(target);
        int blocks_to_check = avail / sizeof(struct algo_block) - 1;
        if (num_blocks < blocks_to_check)
                blocks_to_check = num_blocks;

        struct algo_block *params = malloc((blocks_to_check+1)*sizeof(struct algo_block));
        if (params == NULL) {
                retval = ERROR_FAIL;
                goto cleanup1;
        }

        int i;
        uint32_t total_size = 0;
        for (i = 0; i < blocks_to_check; i++) {
                total_size += blocks[i].size;
                target_buffer_set_u32(target, (uint8_t *)&(params[i].size),
                                                blocks[i].size / sizeof(uint32_t));
                target_buffer_set_u32(target, (uint8_t *)&(params[i].address),
                                                blocks[i].address);
        }
        target_buffer_set_u32(target, (uint8_t *)&(params[blocks_to_check].size), 0);

        uint32_t param_size = (blocks_to_check + 1) * sizeof(struct algo_block);
        if (target_alloc_working_area(target, param_size,
                        &erase_check_params) != ERROR_OK) {
                retval = ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
                goto cleanup2;
        }

        retval = target_write_buffer(target, erase_check_params->address,
                                param_size, (uint8_t *)params);
        if (retval != ERROR_OK)
                goto cleanup3;

        uint32_t erased_word = erased_value | (erased_value << 8)
                               | (erased_value << 16) | (erased_value << 24);

        LOG_DEBUG("Starting erase check of %d blocks, parameters@"
                 TARGET_ADDR_FMT, blocks_to_check, erase_check_params->address);

        armv7m_info.common_magic = ARMV7M_COMMON_MAGIC;
        armv7m_info.core_mode = ARM_MODE_THREAD;

        init_reg_param(&reg_params[0], "r0", 32, PARAM_OUT);
        buf_set_u32(reg_params[0].value, 0, 32, erase_check_params->address);

        init_reg_param(&reg_params[1], "r1", 32, PARAM_OUT);
        buf_set_u32(reg_params[1].value, 0, 32, erased_word);

        /* assume CPU clk at least 1 MHz */
        int timeout = (timed_out ? 30000 : 2000) + total_size * 3 / 1000;

        retval = target_run_algorithm(target,
                                0, NULL,
                                ARRAY_SIZE(reg_params), reg_params,
                                erase_check_algorithm->address,
                                erase_check_algorithm->address + (code_size - 2),
                                timeout,
                                &armv7m_info);

        timed_out = retval == ERROR_TARGET_TIMEOUT;
        if (retval != ERROR_OK && !timed_out)
                goto cleanup4;

        retval = target_read_buffer(target, erase_check_params->address,
                                param_size, (uint8_t *)params);
        if (retval != ERROR_OK)
                goto cleanup4;

        for (i = 0; i < blocks_to_check; i++) {
                uint32_t result = target_buffer_get_u32(target,
                                        (uint8_t *)&(params[i].result));
                if (result != 0 && result != 1)
                        break;

                blocks[i].result = result;
        }
        if (i && timed_out)
                LOG_INFO("Slow CPU clock: %d blocks checked, %d remain. Continuing...", i, num_blocks-i);

        retval = i;             /* return number of blocks really checked */

cleanup4:
        destroy_reg_param(&reg_params[0]);
        destroy_reg_param(&reg_params[1]);

cleanup3:
        target_free_working_area(target, erase_check_params);
cleanup2:
        free(params);
cleanup1:
        target_free_working_area(target, erase_check_algorithm);

        return retval;
}

int armv7m_maybe_skip_bkpt_inst(struct target *target, bool *inst_found)
{
        struct armv7m_common *armv7m = target_to_armv7m(target);
        struct reg *r = armv7m->arm.pc;
        bool result = false;


        /* if we halted last time due to a bkpt instruction
         * then we have to manually step over it, otherwise
         * the core will break again */

        if (target->debug_reason == DBG_REASON_BREAKPOINT) {
                uint16_t op;
                uint32_t pc = buf_get_u32(r->value, 0, 32);

                pc &= ~1;
                if (target_read_u16(target, pc, &op) == ERROR_OK) {
                        if ((op & 0xFF00) == 0xBE00) {
                                pc = buf_get_u32(r->value, 0, 32) + 2;
                                buf_set_u32(r->value, 0, 32, pc);
                                r->dirty = true;
                                r->valid = true;
                                result = true;
                                LOG_DEBUG("Skipping over BKPT instruction");
                        }
                }
        }

        if (inst_found)
                *inst_found = result;

        return ERROR_OK;
}

const struct command_registration armv7m_command_handlers[] = {
        {
                .chain = arm_command_handlers,
        },
        COMMAND_REGISTRATION_DONE
};