openocd: avoid checking for non NULL pointer to free it

[openocd.git] / src / rtos / chibios.c

/***************************************************************************
 *   Copyright (C) 2012 by Matthias Blaicher                               *
 *   Matthias Blaicher - matthias@blaicher.com                             *
 *                                                                         *
 *   Copyright (C) 2011 by Broadcom Corporation                            *
 *   Evan Hunter - ehunter@broadcom.com                                    *
 *                                                                         *
 *   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/>. *
 ***************************************************************************/

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

#include <helper/time_support.h>
#include <jtag/jtag.h>
#include "target/target.h"
#include "target/target_type.h"
#include "target/armv7m.h"
#include "target/cortex_m.h"
#include "rtos.h"
#include "helper/log.h"
#include "helper/types.h"
#include "rtos_chibios_stackings.h"

/**
 * @brief   ChibiOS/RT memory signature record.
 *
 * @details Definition copied from os/kernel/include/chregistry.h of ChibiOS/RT.
 */
struct chibios_chdebug {
        char      ch_identifier[4];       /**< @brief Always set to "main".       */
        uint8_t   ch_zero;                /**< @brief Must be zero.               */
        uint8_t   ch_size;                /**< @brief Size of this structure.     */
        uint16_t  ch_version;             /**< @brief Encoded ChibiOS/RT version. */
        uint8_t   ch_ptrsize;             /**< @brief Size of a pointer.          */
        uint8_t   ch_timesize;            /**< @brief Size of a @p systime_t.     */
        uint8_t   ch_threadsize;          /**< @brief Size of a @p Thread struct. */
        uint8_t   cf_off_prio;            /**< @brief Offset of @p p_prio field.  */
        uint8_t   cf_off_ctx;             /**< @brief Offset of @p p_ctx field.   */
        uint8_t   cf_off_newer;           /**< @brief Offset of @p p_newer field. */
        uint8_t   cf_off_older;           /**< @brief Offset of @p p_older field. */
        uint8_t   cf_off_name;            /**< @brief Offset of @p p_name field.  */
        uint8_t   cf_off_stklimit;        /**< @brief Offset of @p p_stklimit
                                                                                                field.                        */
        uint8_t   cf_off_state;           /**< @brief Offset of @p p_state field. */
        uint8_t   cf_off_flags;           /**< @brief Offset of @p p_flags field. */
        uint8_t   cf_off_refs;            /**< @brief Offset of @p p_refs field.  */
        uint8_t   cf_off_preempt;         /**< @brief Offset of @p p_preempt
                                                                                                field.                        */
        uint8_t   cf_off_time;            /**< @brief Offset of @p p_time field.  */
};

#define GET_CH_KERNEL_MAJOR(codedVersion) ((codedVersion >> 11) & 0x1f)
#define GET_CH_KERNEL_MINOR(codedVersion) ((codedVersion >> 6) & 0x1f)
#define GET_CH_KERNEL_PATCH(codedVersion) ((codedVersion >> 0) & 0x3f)

/**
 * @brief ChibiOS thread states.
 */
static const char * const chibios_thread_states[] = { "READY", "CURRENT",
"WTSTART", "SUSPENDED", "QUEUED", "WTSEM", "WTMTX", "WTCOND", "SLEEPING",
"WTEXIT", "WTOREVT", "WTANDEVT", "SNDMSGQ", "SNDMSG", "WTMSG", "FINAL"
};

#define CHIBIOS_NUM_STATES (sizeof(chibios_thread_states)/sizeof(char *))

/* Maximum ChibiOS thread name. There is no real limit set by ChibiOS but 64
 * chars ought to be enough.
 */
#define CHIBIOS_THREAD_NAME_STR_SIZE (64)

struct chibios_params {
        const char *target_name;

        struct chibios_chdebug *signature;
        const struct rtos_register_stacking *stacking_info;
};

static struct chibios_params chibios_params_list[] = {
        {
        "cortex_m",                                                     /* target_name */
        0,
        NULL,                                                                   /* stacking_info */
        },
        {
        "hla_target",                                                   /* target_name */
        0,
        NULL,                                                                   /* stacking_info */
        }
};
#define CHIBIOS_NUM_PARAMS ((int)(sizeof(chibios_params_list)/sizeof(struct chibios_params)))

static bool chibios_detect_rtos(struct target *target);
static int chibios_create(struct target *target);
static int chibios_update_threads(struct rtos *rtos);
static int chibios_get_thread_reg_list(struct rtos *rtos, int64_t thread_id,
                struct rtos_reg **reg_list, int *num_regs);
static int chibios_get_symbol_list_to_lookup(symbol_table_elem_t *symbol_list[]);

struct rtos_type chibios_rtos = {
        .name = "chibios",

        .detect_rtos = chibios_detect_rtos,
        .create = chibios_create,
        .update_threads = chibios_update_threads,
        .get_thread_reg_list = chibios_get_thread_reg_list,
        .get_symbol_list_to_lookup = chibios_get_symbol_list_to_lookup,
};


/* In ChibiOS/RT 3.0 the rlist structure has become part of a system
 * data structure ch. We declare both symbols as optional and later
 * use whatever is available.
 */

enum chibios_symbol_values {
        CHIBIOS_VAL_RLIST = 0,
        CHIBIOS_VAL_CH = 1,
        CHIBIOS_VAL_CH_DEBUG = 2
};

static symbol_table_elem_t chibios_symbol_list[] = {
        { "rlist", 0, true},            /* Thread ready list */
        { "ch", 0, true},                       /* System data structure */
        { "ch_debug", 0, false},        /* Memory Signature containing offsets of fields in rlist */
        { NULL, 0, false}
};

/* Offset of the rlist structure within the system data structure (ch) */
#define CH_RLIST_OFFSET 0x00

static int chibios_update_memory_signature(struct rtos *rtos)
{
        int retval;
        struct chibios_params *param;
        struct chibios_chdebug *signature;

        param = (struct chibios_params *) rtos->rtos_specific_params;

        /* Free existing memory description.*/
        free(param->signature);
        param->signature = NULL;

        signature = malloc(sizeof(*signature));
        if (!signature) {
                LOG_ERROR("Could not allocate space for ChibiOS/RT memory signature");
                return -1;
        }

        retval = target_read_buffer(rtos->target,
                                                                rtos->symbols[CHIBIOS_VAL_CH_DEBUG].address,
                                                                sizeof(*signature),
                                                                (uint8_t *) signature);
        if (retval != ERROR_OK) {
                LOG_ERROR("Could not read ChibiOS/RT memory signature from target");
                goto errfree;
        }

        if (strncmp(signature->ch_identifier, "main", 4) != 0) {
                LOG_ERROR("Memory signature identifier does not contain magic bytes.");
                goto errfree;
        }

        if (signature->ch_size < sizeof(*signature)) {
                LOG_ERROR("ChibiOS/RT memory signature claims to be smaller "
                                "than expected");
                goto errfree;
        }

        if (signature->ch_size > sizeof(*signature)) {
                LOG_WARNING("ChibiOS/RT memory signature claims to be bigger than"
                                        " expected. Assuming compatibility...");
        }

        /* Convert endianness of version field */
        const uint8_t *versionTarget = (const uint8_t *)
                                                                                &signature->ch_version;
        signature->ch_version = rtos->target->endianness == TARGET_LITTLE_ENDIAN ?
                        le_to_h_u32(versionTarget) : be_to_h_u32(versionTarget);

        const uint16_t ch_version = signature->ch_version;
        LOG_INFO("Successfully loaded memory map of ChibiOS/RT target "
                        "running version %i.%i.%i", GET_CH_KERNEL_MAJOR(ch_version),
                        GET_CH_KERNEL_MINOR(ch_version), GET_CH_KERNEL_PATCH(ch_version));

        /* Currently, we have the inherent assumption that all address pointers
         * are 32 bit wide. */
        if (signature->ch_ptrsize != sizeof(uint32_t)) {
                LOG_ERROR("ChibiOS/RT target memory signature claims an address "
                                  "width unequal to 32 bits!");
                free(signature);
                return -1;
        }

        param->signature = signature;
        return 0;

errfree:
        /* Error reading the ChibiOS memory structure */
        free(signature);
        param->signature = 0;
        return -1;
}


static int chibios_update_stacking(struct rtos *rtos)
{
        /* Sometimes the stacking can not be determined only by looking at the
         * target name but only a runtime.
         *
         * For example, this is the case for Cortex-M4 targets and ChibiOS which
         * only stack the FPU registers if it is enabled during ChibiOS build.
         *
         * Terminating which stacking is used is target depending.
         *
         * Assumptions:
         *  - Once ChibiOS is actually initialized, the stacking is fixed.
         *  - During startup code, the FPU might not be initialized and the
         *    detection might fail.
         *  - Since no threads are running during startup, the problem is solved
         *    by delaying stacking detection until there are more threads
         *    available than the current execution. In which case
         *    chibios_get_thread_reg_list is called.
         */
        int retval;

        if (!rtos->rtos_specific_params)
                return -1;

        struct chibios_params *param;
        param = (struct chibios_params *) rtos->rtos_specific_params;

        /* Check for armv7m with *enabled* FPU, i.e. a Cortex-M4  */
        struct armv7m_common *armv7m_target = target_to_armv7m(rtos->target);
        if (is_armv7m(armv7m_target)) {
                if (armv7m_target->fp_feature != FP_NONE) {
                        /* Found ARM v7m target which includes a FPU */
                        uint32_t cpacr;

                        retval = target_read_u32(rtos->target, FPU_CPACR, &cpacr);
                        if (retval != ERROR_OK) {
                                LOG_ERROR("Could not read CPACR register to check FPU state");
                                return -1;
                        }

                        /* Check if CP10 and CP11 are set to full access.
                         * In ChibiOS this is done in ResetHandler() in crt0.c */
                        if (cpacr & 0x00F00000) {
                                LOG_DEBUG("Enabled FPU detected.");
                                param->stacking_info = &rtos_chibios_arm_v7m_stacking_w_fpu;
                                return 0;
                        }
                }

                /* Found ARM v7m target with no or disabled FPU */
                param->stacking_info = &rtos_chibios_arm_v7m_stacking;
                return 0;
        }

        return -1;
}

static int chibios_update_threads(struct rtos *rtos)
{
        int retval;
        const struct chibios_params *param;
        int tasks_found = 0;
        int rtos_valid = -1;

        if (!rtos->rtos_specific_params)
                return -1;

        if (!rtos->symbols) {
                LOG_ERROR("No symbols for ChibiOS");
                return -3;
        }

        param = (const struct chibios_params *) rtos->rtos_specific_params;
        /* Update the memory signature saved in the target memory */
        if (!param->signature) {
                retval = chibios_update_memory_signature(rtos);
                if (retval != ERROR_OK) {
                        LOG_ERROR("Reading the memory signature of ChibiOS/RT failed");
                        return retval;
                }
        }

        /* wipe out previous thread details if any */
        rtos_free_threadlist(rtos);

        /* ChibiOS does not save the current thread count. We have to first
         * parse the double linked thread list to check for errors and the number of
         * threads. */
        const uint32_t rlist = rtos->symbols[CHIBIOS_VAL_RLIST].address ?
                rtos->symbols[CHIBIOS_VAL_RLIST].address :
                rtos->symbols[CHIBIOS_VAL_CH].address + CH_RLIST_OFFSET /* ChibiOS3 */;
        const struct chibios_chdebug *signature = param->signature;
        uint32_t current;
        uint32_t previous;
        uint32_t older;

        current = rlist;
        previous = rlist;
        while (1) {
                retval = target_read_u32(rtos->target,
                                                                 current + signature->cf_off_newer, &current);
                if (retval != ERROR_OK) {
                        LOG_ERROR("Could not read next ChibiOS thread");
                        return retval;
                }
                /* Could be NULL if the kernel is not initialized yet or if the
                 * registry is corrupted. */
                if (current == 0) {
                        LOG_ERROR("ChibiOS registry integrity check failed, NULL pointer");

                        rtos_valid = 0;
                        break;
                }
                /* Fetch previous thread in the list as a integrity check. */
                retval = target_read_u32(rtos->target,
                                                                 current + signature->cf_off_older, &older);
                if ((retval != ERROR_OK) || (older == 0) || (older != previous)) {
                        LOG_ERROR("ChibiOS registry integrity check failed, "
                                                "double linked list violation");
                        rtos_valid = 0;
                        break;
                }
                /* Check for full iteration of the linked list. */
                if (current == rlist)
                        break;
                tasks_found++;
                previous = current;
        }
        if (!rtos_valid) {
                /* No RTOS, there is always at least the current execution, though */
                LOG_INFO("Only showing current execution because of a broken "
                                "ChibiOS thread registry.");

                const char tmp_thread_name[] = "Current Execution";
                const char tmp_thread_extra_info[] = "No RTOS thread";

                rtos->thread_details = malloc(
                                sizeof(struct thread_detail));
                rtos->thread_details->threadid = 1;
                rtos->thread_details->exists = true;

                rtos->thread_details->extra_info_str = malloc(
                                sizeof(tmp_thread_extra_info));
                strcpy(rtos->thread_details->extra_info_str, tmp_thread_extra_info);

                rtos->thread_details->thread_name_str = malloc(
                                sizeof(tmp_thread_name));
                strcpy(rtos->thread_details->thread_name_str, tmp_thread_name);

                rtos->current_thread = 1;
                rtos->thread_count = 1;
                return ERROR_OK;
        }

        /* create space for new thread details */
        rtos->thread_details = malloc(
                        sizeof(struct thread_detail) * tasks_found);
        if (!rtos->thread_details) {
                LOG_ERROR("Could not allocate space for thread details");
                return -1;
        }

        rtos->thread_count = tasks_found;
        /* Loop through linked list. */
        struct thread_detail *curr_thrd_details = rtos->thread_details;
        while (curr_thrd_details < rtos->thread_details + tasks_found) {
                uint32_t name_ptr = 0;
                char tmp_str[CHIBIOS_THREAD_NAME_STR_SIZE];

                retval = target_read_u32(rtos->target,
                                                                 current + signature->cf_off_newer, &current);
                if (retval != ERROR_OK) {
                        LOG_ERROR("Could not read next ChibiOS thread");
                        return -6;
                }

                /* Check for full iteration of the linked list. */
                if (current == rlist)
                        break;

                /* Save the thread pointer */
                curr_thrd_details->threadid = current;

                /* read the name pointer */
                retval = target_read_u32(rtos->target,
                                                                 current + signature->cf_off_name, &name_ptr);
                if (retval != ERROR_OK) {
                        LOG_ERROR("Could not read ChibiOS thread name pointer from target");
                        return retval;
                }

                /* Read the thread name */
                retval = target_read_buffer(rtos->target, name_ptr,
                                                                        CHIBIOS_THREAD_NAME_STR_SIZE,
                                                                        (uint8_t *)&tmp_str);
                if (retval != ERROR_OK) {
                        LOG_ERROR("Error reading thread name from ChibiOS target");
                        return retval;
                }
                tmp_str[CHIBIOS_THREAD_NAME_STR_SIZE - 1] = '\x00';

                if (tmp_str[0] == '\x00')
                        strcpy(tmp_str, "No Name");

                curr_thrd_details->thread_name_str = malloc(
                                strlen(tmp_str) + 1);
                strcpy(curr_thrd_details->thread_name_str, tmp_str);

                /* State info */
                uint8_t thread_state;
                const char *state_desc;

                retval = target_read_u8(rtos->target,
                                                                current + signature->cf_off_state, &thread_state);
                if (retval != ERROR_OK) {
                        LOG_ERROR("Error reading thread state from ChibiOS target");
                        return retval;
                }


                if (thread_state < CHIBIOS_NUM_STATES)
                        state_desc = chibios_thread_states[thread_state];
                else
                        state_desc = "Unknown";

                curr_thrd_details->extra_info_str = malloc(strlen(
                                        state_desc)+8);
                sprintf(curr_thrd_details->extra_info_str, "State: %s", state_desc);

                curr_thrd_details->exists = true;

                curr_thrd_details++;
        }

        uint32_t current_thrd;
        /* NOTE: By design, cf_off_name equals readylist_current_offset */
        retval = target_read_u32(rtos->target,
                                                         rlist + signature->cf_off_name,
                                                         &current_thrd);
        if (retval != ERROR_OK) {
                LOG_ERROR("Could not read current Thread from ChibiOS target");
                return retval;
        }
        rtos->current_thread = current_thrd;

        return 0;
}

static int chibios_get_thread_reg_list(struct rtos *rtos, int64_t thread_id,
                struct rtos_reg **reg_list, int *num_regs)
{
        int retval;
        const struct chibios_params *param;
        uint32_t stack_ptr = 0;

        if ((rtos == NULL) || (thread_id == 0) ||
                        (rtos->rtos_specific_params == NULL))
                return -1;

        param = (const struct chibios_params *) rtos->rtos_specific_params;

        if (!param->signature)
                return -1;

        /* Update stacking if it can only be determined from runtime information */
        if ((param->stacking_info == 0) &&
                (chibios_update_stacking(rtos) != ERROR_OK)) {
                LOG_ERROR("Failed to determine exact stacking for the target type %s", rtos->target->type->name);
                return -1;
        }

        /* Read the stack pointer */
        retval = target_read_u32(rtos->target,
                                                         thread_id + param->signature->cf_off_ctx, &stack_ptr);
        if (retval != ERROR_OK) {
                LOG_ERROR("Error reading stack frame from ChibiOS thread");
                return retval;
        }

        return rtos_generic_stack_read(rtos->target, param->stacking_info, stack_ptr, reg_list, num_regs);
}

static int chibios_get_symbol_list_to_lookup(symbol_table_elem_t *symbol_list[])
{
        *symbol_list = malloc(sizeof(chibios_symbol_list));

        if (*symbol_list == NULL)
                return ERROR_FAIL;

        memcpy(*symbol_list, chibios_symbol_list, sizeof(chibios_symbol_list));
        return 0;
}

static bool chibios_detect_rtos(struct target *target)
{
        if ((target->rtos->symbols != NULL) &&
                        ((target->rtos->symbols[CHIBIOS_VAL_RLIST].address != 0) ||
                         (target->rtos->symbols[CHIBIOS_VAL_CH].address != 0))) {

                if (target->rtos->symbols[CHIBIOS_VAL_CH_DEBUG].address == 0) {
                        LOG_INFO("It looks like the target may be running ChibiOS "
                                        "without ch_debug.");
                        return false;
                }

                /* looks like ChibiOS with memory map enabled.*/
                return true;
        }

        return false;
}

static int chibios_create(struct target *target)
{
        int i = 0;
        while ((i < CHIBIOS_NUM_PARAMS) &&
                        (0 != strcmp(chibios_params_list[i].target_name, target->type->name))) {
                i++;
        }
        if (i >= CHIBIOS_NUM_PARAMS) {
                LOG_WARNING("Could not find target \"%s\" in ChibiOS compatibility "
                                "list", target->type->name);
                return -1;
        }

        target->rtos->rtos_specific_params = (void *) &chibios_params_list[i];
        return 0;
}