chibios.c

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// SPDX-License-Identifier: GPL-2.0-or-later
 
/***************************************************************************
 *   Copyright (C) 2012 by Matthias Blaicher                               *
 *   Matthias Blaicher - matthias@blaicher.com                             *
 *                                                                         *
 *   Copyright (C) 2011 by Broadcom Corporation                            *
 *   Evan Hunter - ehunter@broadcom.com                                    *
 ***************************************************************************/
 
#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"
 
struct chibios_chdebug {
    char      ch_identifier[4];       
    uint8_t   ch_zero;                
    uint8_t   ch_size;                
    uint16_t  ch_version;             
    uint8_t   ch_ptrsize;             
    uint8_t   ch_timesize;            
    uint8_t   ch_threadsize;          
    uint8_t   cf_off_prio;            
    uint8_t   cf_off_ctx;             
    uint8_t   cf_off_newer;           
    uint8_t   cf_off_older;           
    uint8_t   cf_off_name;            
    uint8_t   cf_off_stklimit;        
    uint8_t   cf_off_state;           
    uint8_t   cf_off_flags;           
    uint8_t   cf_off_refs;            
    uint8_t   cf_off_preempt;         
    uint8_t   cf_off_time;            
};
 
#define GET_CH_KERNEL_MAJOR(coded_version) ((coded_version >> 11) & 0x1f)
#define GET_CH_KERNEL_MINOR(coded_version) ((coded_version >> 6) & 0x1f)
#define GET_CH_KERNEL_PATCH(coded_version) ((coded_version >> 0) & 0x3f)
 
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 ARRAY_SIZE(chibios_thread_states)
 
/* 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 */
    }
};
 
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(struct symbol_table_elem *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 struct symbol_table_elem 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) || (thread_id == 0) ||
            (!rtos->rtos_specific_params))
        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(struct symbol_table_elem *symbol_list[])
{
    *symbol_list = malloc(sizeof(chibios_symbol_list));
 
    if (!*symbol_list)
        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) &&
            ((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)
{
    for (unsigned int i = 0; i < ARRAY_SIZE(chibios_params_list); i++)
        if (strcmp(chibios_params_list[i].target_name, target->type->name) == 0) {
            target->rtos->rtos_specific_params = (void *)&chibios_params_list[i];
            return 0;
        }
 
    LOG_WARNING("Could not find target \"%s\" in ChibiOS compatibility "
                "list", target->type->name);
    return -1;
}