RT-Thread
目录
1 线程管理
1.1 线程对象
struct rt_thread
{
struct rt_object parent; /** object结构实现 */
rt_list_t tlist; /**< the thread list */
/* stack point and entry */
void *sp; /**< stack point */
void *entry; /**< entry */
void *parameter; /**< parameter */
void *stack_addr; /**< stack address */
rt_uint32_t stack_size; /**< stack size */
/* error code */
rt_err_t error; /**< error code */
rt_uint8_t stat; /**< thread status */
#ifdef RT_USING_SMP
rt_uint8_t bind_cpu; /**< thread is bind to cpu */
rt_uint8_t oncpu; /**< process on cpu */
rt_uint16_t scheduler_lock_nest; /**< scheduler lock count */
rt_uint16_t cpus_lock_nest; /**< cpus lock count */
rt_uint16_t critical_lock_nest; /**< critical lock count */
#endif /*RT_USING_SMP*/
/* priority */
rt_uint8_t current_priority; /**< current priority */
rt_uint8_t init_priority; /**< initialized priority */
#if RT_THREAD_PRIORITY_MAX > 32
rt_uint8_t number;
rt_uint8_t high_mask;
#endif /* RT_THREAD_PRIORITY_MAX > 32 */
rt_uint32_t number_mask; /**< priority number mask */
#ifdef RT_USING_MUTEX
/* object for IPC */
rt_list_t taken_object_list;
rt_object_t pending_object;
#endif
#ifdef RT_USING_EVENT
/* thread event */
rt_uint32_t event_set;
rt_uint8_t event_info;
#endif /* RT_USING_EVENT */
#ifdef RT_USING_SIGNALS
rt_sigset_t sig_pending; /**< the pending signals */
rt_sigset_t sig_mask; /**< the mask bits of signal */
#ifndef RT_USING_SMP
void *sig_ret; /**< the return stack pointer from signal */
#endif /* RT_USING_SMP */
rt_sighandler_t *sig_vectors; /**< vectors of signal handler */
void *si_list; /**< the signal infor list */
#endif /* RT_USING_SIGNALS */
#ifdef RT_USING_SMART
void *msg_ret; /**< the return msg */
#endif
rt_ubase_t init_tick; /**< thread's initialized tick */
rt_ubase_t remaining_tick; /**< remaining tick */
#ifdef RT_USING_CPU_USAGE
rt_uint64_t duration_tick; /**< cpu usage tick */
#endif /* RT_USING_CPU_USAGE */
#ifdef RT_USING_PTHREADS
void *pthread_data; /**< the handle of pthread data, adapt 32/64bit */
#endif /* RT_USING_PTHREADS */
struct rt_timer thread_timer; /**< built-in thread timer */
void (*cleanup)(struct rt_thread *tid); /**< cleanup function when thread exit */
/* light weight process if present */
#ifdef RT_USING_SMART
void *lwp;
/* for user create */
void *user_entry;
void *user_stack;
rt_uint32_t user_stack_size;
rt_uint32_t *kernel_sp; /**< kernel stack point */
rt_list_t sibling; /**< next thread of same process */
lwp_sigset_t signal;
lwp_sigset_t signal_mask;
int signal_mask_bak;
rt_uint32_t signal_in_process;
#ifndef ARCH_MM_MMU
lwp_sighandler_t signal_handler[32];
#endif
struct rt_user_context user_ctx;
struct rt_wakeup wakeup; /**< wakeup data */
int exit_request;
#if defined(ARCH_MM_MMU)
int step_exec;
int debug_attach_req;
int debug_ret_user;
int debug_suspend;
struct rt_hw_exp_stack *regs;
void * thread_idr; /** lwp thread indicator */
int *clear_child_tid;
#endif
int tid;
#endif
rt_ubase_t user_data; /**< private user data beyond this thread */
};
typedef struct rt_thread *rt_thread_t;1.2 创建任务
rt_thread_t rt_thread_create(const char *name,
void (*entry)(void *parameter),
void *parameter,
rt_uint32_t stack_size,
rt_uint8_t priority,
rt_uint32_t tick);graph LR rt_thread_create --> rt_object_allocate rt_thread_create --> _thread_init _thread_init --> 填充成员数据
1.3 启动任务
rt_err_t rt_thread_startup(rt_thread_t thread);graph LR rt_thread_startup --> rt_thread_resume rt_thread_resume --> rt_hw_interrupt_disable rt_thread_resume --> rt_list_remove rt_thread_resume --> rt_timer_stop rt_thread_resume --> rt_hw_interrupt_enable rt_thread_resume --> rt_schedule_insert_thread rt_schedule_insert_thread --> rt_list_insert_before rt_schedule_insert_thread --> rt_list_insert_after
经过上面的代码分析，创建任务与启动的操作时将任务管理结构体链接进入rt_thread_priority_table
rt_list_t rt_thread_priority_table[RT_THREAD_PRIORITY_MAX];
rt_uint32_t rt_thread_ready_priority_group;1.4 删除任务
rt_err_t rt_thread_delete(rt_thread_t thread);与创建任务相反的操作,删除任务的流程大致如下
graph LR rt_thread_delete --> rt_schedule_remove_thread
1.5 任务调度
任务调度实现实时操作系统的核心
void rt_schedule(void);graph LR rt_schedule --> _scheduler_get_highest_priority_thread rt_schedule --> rt_hw_context_switch
调度是如何发生的呢？
调度器rt_schedule的调用路线
ARM64调度 scheduler_mp.c
(gdb) bt
#0 rt_schedule () at /home/mengdemao/work/rt-thread/src/scheduler_mp.c:820
#1 0x00000000400e28c8 in rt_scheduler_ipi_handler (vector=0, param=0x0)
at /home/mengdemao/work/rt-thread/src/scheduler_mp.c:515
#2 0x00000000400958b0 in _rt_hw_trap_irq (
irq_context=0x40156d70 <rt_system_stack+7360>)
at /home/mengdemao/work/rt-thread/libcpu/aarch64/common/trap.c:264
#3 0x00000000400958f0 in rt_hw_trap_irq (
regs=0x40156d80 <rt_system_stack+7376>)
at /home/mengdemao/work/rt-thread/libcpu/aarch64/common/trap.c:286
#4 0x0000000040096b2c in vector_irq ()
at /home/mengdemao/work/rt-thread/libcpu/aarch64/common/vector_gcc.S:114ARM32调度器实现 scheduler_up.c
#0 rt_schedule () at /home/mengdemao/work/rt-thread/src/scheduler_up.c:206
#1 0x6009be04 in rt_exit_critical ()
at /home/mengdemao/work/rt-thread/src/scheduler_up.c:542
#2 0x6009bd18 in rt_exit_critical_safe (critical_level=0)
at /home/mengdemao/work/rt-thread/src/scheduler_up.c:491
#3 0x6008fe0c in rt_spin_unlock_irqrestore (lock=0x600e6190 <_htimer_lock>,
level=-1610612334) at /home/mengdemao/work/rt-thread/src/cpu_up.c:84
#4 0x6009dba8 in _timer_check (timer_list=0x600e6188 <_timer_list>,
lock=0x600e6190 <_htimer_lock>)
at /home/mengdemao/work/rt-thread/src/timer.c:527
#5 0x6009e1c0 in rt_timer_check ()
at /home/mengdemao/work/rt-thread/src/timer.c:771
#6 0x6008f9d0 in rt_tick_increase ()
at /home/mengdemao/work/rt-thread/src/clock.c:147
#7 0x6006cdf4 in rt_hw_timer_isr (vector=35, param=0x0)
at drivers/drv_timer.c:68
#8 0x600690dc in rt_hw_trap_irq ()
at /home/mengdemao/work/rt-thread/libcpu/arm/cortex-a/trap.c:363
#9 0x6009f4ac in vector_irq ()
at /home/mengdemao/work/rt-thread/libcpu/arm/cortex-a/start_gcc.S:3852 线程间同步与通信
3 IPC对象
struct rt_ipc_object
{
struct rt_object parent; /**< inherit from rt_object */
rt_list_t suspend_thread; /**< threads pended on this resource */
};graph TD rt_semaphore --> rt_ipc_object rt_mutex --> rt_ipc_object rt_event --> rt_ipc_object rt_mailbox --> rt_ipc_object rt_messagequeue --> rt_ipc_object
4 信号量
struct rt_semaphore
{
struct rt_ipc_object parent; /**< inherit from ipc_object */
rt_uint16_t value; /**< value of semaphore. */
rt_uint16_t reserved; /**< reserved field */
};
typedef struct rt_semaphore *rt_sem_t;
// sem初始化
rt_err_t rt_sem_init(rt_sem_t sem,
const char *name,
rt_uint32_t value,
rt_uint8_t flag);5 互斥量
struct rt_mutex
{
struct rt_ipc_object parent; /**< inherit from ipc_object */
rt_uint8_t ceiling_priority; /**< the priority ceiling of mutexe */
rt_uint8_t priority; /**< the maximal priority for pending thread */
rt_uint8_t hold; /**< numbers of thread hold the mutex */
rt_uint8_t reserved; /**< reserved field */
struct rt_thread *owner; /**< current owner of mutex */
rt_list_t taken_list; /**< the object list taken by thread */
};
typedef struct rt_mutex *rt_mutex_t;6 事件集
#define RT_EVENT_FLAG_AND 0x01 /**< logic and */
#define RT_EVENT_FLAG_OR 0x02 /**< logic or */
#define RT_EVENT_FLAG_CLEAR 0x04 /**< clear flag */
struct rt_event
{
struct rt_ipc_object parent; /**< inherit from ipc_object */
rt_uint32_t set; /**< event set */
};
typedef struct rt_event *rt_event_t;7 邮箱
struct rt_mailbox
{
struct rt_ipc_object parent; /**< inherit from ipc_object */
rt_ubase_t *msg_pool; /**< start address of message buffer */
rt_uint16_t size; /**< size of message pool */
rt_uint16_t entry; /**< index of messages in msg_pool */
rt_uint16_t in_offset; /**< input offset of the message buffer */
rt_uint16_t out_offset; /**< output offset of the message buffer */
rt_list_t suspend_sender_thread; /**< sender thread suspended on this mailbox */
};
typedef struct rt_mailbox *rt_mailbox_t;8 消息队列
struct rt_messagequeue
{
struct rt_ipc_object parent; /**< inherit from ipc_object */
void *msg_pool; /**< start address of message queue */
rt_uint16_t msg_size; /**< message size of each message */
rt_uint16_t max_msgs; /**< max number of messages */
rt_uint16_t entry; /**< index of messages in the queue */
void *msg_queue_head; /**< list head */
void *msg_queue_tail; /**< list tail */
void *msg_queue_free; /**< pointer indicated the free node of queue */
rt_list_t suspend_sender_thread; /**< sender thread suspended on this message queue */
};
typedef struct rt_messagequeue *rt_mq_t;9 信号
typedef unsigned long rt_sigset_t;
typedef siginfo_t rt_siginfo_t;
typedef void (*rt_sighandler_t)(int signo);
#define RT_SIG_MAX 3210 内存管理
rt_weak void rt_system_heap_init(void *begin_addr, void *end_addr)
{
rt_ubase_t begin_align = RT_ALIGN((rt_ubase_t)begin_addr, RT_ALIGN_SIZE);
rt_ubase_t end_align = RT_ALIGN_DOWN((rt_ubase_t)end_addr, RT_ALIGN_SIZE);
RT_ASSERT(end_align > begin_align);
/* Initialize system memory heap */
_MEM_INIT("heap", begin_addr, end_align - begin_align);
/* Initialize multi thread contention lock */
_heap_lock_init();
}
rt_weak void *rt_malloc(rt_size_t size)
{
rt_base_t level;
void *ptr;
/* Enter critical zone */
level = _heap_lock();
/* allocate memory block from system heap */
ptr = _MEM_MALLOC(size);
/* Exit critical zone */
_heap_unlock(level);
/* call 'rt_malloc' hook */
RT_OBJECT_HOOK_CALL(rt_malloc_hook, (ptr, size));
return ptr;
}
rt_weak void *rt_realloc(void *ptr, rt_size_t newsize)
{
rt_base_t level;
void *nptr;
/* Enter critical zone */
level = _heap_lock();
/* Change the size of previously allocated memory block */
nptr = _MEM_REALLOC(ptr, newsize);
/* Exit critical zone */
_heap_unlock(level);
return nptr;
}
rt_weak void rt_free(void *ptr)
{
rt_base_t level;
/* call 'rt_free' hook */
RT_OBJECT_HOOK_CALL(rt_free_hook, (ptr));
/* NULL check */
if (ptr == RT_NULL) return;
/* Enter critical zone */
level = _heap_lock();
_MEM_FREE(ptr);
/* Exit critical zone */
_heap_unlock(level);
}进入不同的分配算法实现
- 小内存分配算法
#define _MEM_INIT(_name, _start, _size) \
system_heap = rt_smem_init(_name, _start, _size)
#define _MEM_MALLOC(_size) \
rt_smem_alloc(system_heap, _size)
#define _MEM_REALLOC(_ptr, _newsize)\
rt_smem_realloc(system_heap, _ptr, _newsize)
#define _MEM_FREE(_ptr) \
rt_smem_free(_ptr)
#define _MEM_INFO(_total, _used, _max) \
_smem_info(_total, _used, _max)- slab分配算法
#define _MEM_INIT(_name, _start, _size) \
rt_memheap_init(&system_heap, _name, _start, _size)
#define _MEM_MALLOC(_size) \
_memheap_alloc(&system_heap, _size)
#define _MEM_REALLOC(_ptr, _newsize) \
_memheap_realloc(&system_heap, _ptr, _newsize)
#define _MEM_FREE(_ptr) \
_memheap_free(_ptr)
#define _MEM_INFO(_total, _used, _max) \
rt_memheap_info(&system_heap, _total, _used, _max)- 内存池分配算法
#define _MEM_INIT(_name, _start, _size) \
system_heap = rt_slab_init(_name, _start, _size)
#define _MEM_MALLOC(_size) \
rt_slab_alloc(system_heap, _size)
#define _MEM_REALLOC(_ptr, _newsize) \
rt_slab_realloc(system_heap, _ptr, _newsize)
#define _MEM_FREE(_ptr) \
rt_slab_free(system_heap, _ptr)
#define _MEM_INFO _slab_info11 时钟管理
11.1 tick自增函数
void rt_tick_increase(void)
{
struct rt_thread *thread;
rt_base_t level;
RT_OBJECT_HOOK_CALL(rt_tick_hook, ());
/* 关闭全局中断 */
level = rt_hw_interrupt_disable();
/* 增加全局的ticks */
#ifdef RT_USING_SMP
rt_cpu_self()->tick ++;
#else
++ rt_tick;
#endif /* RT_USING_SMP */
/* 检查当前thread的时间片 */
thread = rt_thread_self();
/* 时间片已经使用结束 */
-- thread->remaining_tick;
if (thread->remaining_tick == 0)
{
/* 重载剩余的时间 */
thread->remaining_tick = thread->init_tick;
/* 设置线程的状态为yield */
thread->stat |= RT_THREAD_STAT_YIELD;
/* 开启中断 */
rt_hw_interrupt_enable(level);
/* 执行调度器 */
rt_schedule();
}
else
{
/* 时间片没有使用完，直接全局中断 */
rt_hw_interrupt_enable(level);
}
/* check timer */
rt_timer_check();
}11.2 获取tick
直接获取滴答函数的计数
#ifdef RT_USING_SMP
#define rt_tick rt_cpu_index(0)->tick
#else
static volatile rt_tick_t rt_tick = 0;
#endif /* RT_USING_SMP */
rt_tick_t rt_tick_get(void)
{
/* return the global tick */
return rt_tick;
}11.3 定时器实现
struct rt_timer
{
struct rt_object parent; /**< inherit from rt_object */
rt_list_t row[RT_TIMER_SKIP_LIST_LEVEL];
void (*timeout_func)(void *parameter); /**< timeout function */
void *parameter; /**< timeout function's parameter */
rt_tick_t init_tick; /**< timer timeout tick */
rt_tick_t timeout_tick; /**< timeout tick */
};
typedef struct rt_timer *rt_timer_t;
**开启定时器**
> rt_timer_start
## 内核移植
[内核移植](https://www.rt-thread.org/document/site/#/rt-thread-version/rt-thread-standard/programming-manual/porting/porting?id=%e5%86%85%e6%a0%b8%e7%a7%bb%e6%a4%8d)
| **Functions and Variables** | **Description** |
| ------------------------------------------------------------ | ------------------------------------------------------------ |
| rt_base_t rt_hw_interrupt_disable(void); | disable global interrupt |
| void rt_hw_interrupt_enable(rt_base_t level); | enable global interrupt |
| rt_uint8_t \*rt_hw_stack_init(void \*tentry, void \*parameter, rt_uint8_t \*stack_addr, void \*texit); | The initialization of the thread stack, the kernel will call this function during thread creation and thread initialization. |
| void rt_hw_context_switch_to(rt_uint32 to); | Context switch without source thread, which is called when the scheduler starts the first thread, and is called in the signal. |
| void rt_hw_context_switch(rt_uint32 from, rt_uint32 to); | Switch from *from* thread to *to* thread, used for switch between threads. |
| void rt_hw_context_switch_interrupt(rt_uint32 from, rt_uint32 to); | Switch from *from* thread to *to* thread, used for switch in interrupt. |
| rt_uint32_t rt_thread_switch_interrupt_flag; | A flag indicating that a switch is needed in the interrupt. |
| rt_uint32_t rt_interrupt_from_thread, rt_interrupt_to_thread; | Used to save *from* and *to* threads when the thread is context switching. |
## 调试指令
+ 配置vscode arm调试指令
+ 配置vscode aarch64调试指令
```json
{
"version": "0.2.0",
"configurations": [
{
"name": "rt-thread-aarch64",
"type": "cppdbg",
"request": "launch",
"program": "${workspaceRoot}/bsp/qemu-virt64-aarch64/rtthread.elf",
"args": [],
"stopAtEntry": true,
"cwd": "${workspaceRoot}",
"environment": [],
"externalConsole": true,
"MIMode": "gdb",
"logging": {
"moduleLoad": false,
"engineLogging": false,
"trace": false
},
"setupCommands": [
{
"description": "Enable pretty-printing for gdb",
"text": "-enable-pretty-printing",
"ignoreFailures": true
},
{
"description": "set architecture aarch64",
"text": "set architecture aarch64",
"ignoreFailures": true
}
],
"miDebuggerPath":"gdb-multiarch",
"miDebuggerServerAddress":"localhost:1234"
},
{
"name": "rt-thread-arm",
"type": "cppdbg",
"request": "launch",
"program": "${workspaceRoot}/bsp/qemu-vexpress-a9/rtthread.elf",
"args": [],
"stopAtEntry": true,
"cwd": "${workspaceRoot}",
"environment": [],
"externalConsole": true,
"MIMode": "gdb",
"logging": {
"moduleLoad": false,
"engineLogging": false,
"trace": false
},
"setupCommands": [
{
"description": "Enable pretty-printing for gdb",
"text": "-enable-pretty-printing",
"ignoreFailures": true
},
{
"description": "set architecture arm",
"text": "set architecture arm",
"ignoreFailures": true
}
],
"miDebuggerPath":"gdb-multiarch",
"miDebuggerServerAddress":"localhost:1234"
}
]
}