X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=bertos%2Fkern%2Fproc.h;h=842566b9db08cc3a77488b7092c866f9eff12b2e;hb=ae8a609173e4490fd03875f96e388038053b9288;hp=a668c18f4b0b1e3e7273d48b16033d87ee4d1a8f;hpb=4cc44c9888a0336b9d01121ec0b7ad95f4a76195;p=bertos.git diff --git a/bertos/kern/proc.h b/bertos/kern/proc.h index a668c18f..842566b9 100644 --- a/bertos/kern/proc.h +++ b/bertos/kern/proc.h @@ -26,53 +26,297 @@ * invalidate any other reasons why the executable file might be covered by * the GNU General Public License. * - * Copyright 2001,2004 Develer S.r.l. (http://www.develer.com/) - * Copyright 1999,2000,2001 Bernie Innocenti - * + * Copyright 2001, 2004 Develer S.r.l. (http://www.develer.com/) + * Copyright 1999, 2000, 2001, 2008 Bernie Innocenti * --> * - * \brief Process scheduler (public interface). + * \brief BeRTOS Kernel core (Process scheduler). * * \version $Id$ - * * \author Bernie Innocenti + * + * $WIZ$ module_name = "kernel" + * $WIZ$ module_configuration = "bertos/cfg/cfg_proc.h" + * $WIZ$ module_depends = "switch_ctx", "coop", "preempt" + * $WIZ$ module_supports = "not atmega103" */ + #ifndef KERN_PROC_H #define KERN_PROC_H -#include "cfg/cfg_kern.h" +#include "cfg/cfg_proc.h" +#include "cfg/cfg_signal.h" +#include "cfg/cfg_monitor.h" + +#include // Node, PriNode + #include -#include +#if CONFIG_KERN_PREEMPT + #include // ASSERT() + #include +#endif + +#include // cpu_stack_t +#include // CPU_SAVED_REGS_CNT + +/* + * WARNING: struct Process is considered private, so its definition can change any time + * without notice. DO NOT RELY on any field defined here, use only the interface + * functions below. + * + * You have been warned. + */ +typedef struct Process +{ +#if CONFIG_KERN_PRI + PriNode link; /**< Link Process into scheduler lists */ +#else + Node link; /**< Link Process into scheduler lists */ +#endif + cpu_stack_t *stack; /**< Per-process SP */ + iptr_t user_data; /**< Custom data passed to the process */ + +#if CONFIG_KERN_SIGNALS + sigmask_t sig_wait; /**< Signals the process is waiting for */ + sigmask_t sig_recv; /**< Received signals */ +#endif + +#if CONFIG_KERN_HEAP + uint16_t flags; /**< Flags */ +#endif + +#if CONFIG_KERN_HEAP | CONFIG_KERN_MONITOR + cpu_stack_t *stack_base; /**< Base of process stack */ + size_t stack_size; /**< Size of process stack */ +#endif -/* Fwd decl */ -struct Process; + /* The actual process entry point */ + void (*user_entry)(void); -/* Task scheduling services */ +#if CONFIG_KERN_MONITOR + struct ProcMonitor + { + Node link; + const char *name; + } monitor; +#endif + +} Process; + +/** + * Initialize the process subsystem (kernel). + * It must be called before using any process related function. + */ void proc_init(void); -struct Process *proc_new_with_name(const char* name, void (*entry)(void), iptr_t data, size_t stacksize, cpustack_t *stack); + +struct Process *proc_new_with_name(const char *name, void (*entry)(void), iptr_t data, size_t stacksize, cpu_stack_t *stack); #if !CONFIG_KERN_MONITOR + /** + * Create a new named process and schedules it for execution. + * + * When defining the stacksize take into account that you may want at least: + * \li save all the registers for each nested function call; + * \li have memory for the struct Process, which is positioned at the bottom + * of the stack; + * \li have some memory for temporary variables inside called functions. + * + * The value given by KERN_MINSTACKSIZE is rather safe to use in the first place. + * + * \param entry Function that the process will execute. + * \param data Pointer to user data. + * \param size Length of the stack. + * \param stack Pointer to the memory area to be used as a stack. + * + * \return Process structure of new created process + * if successful, NULL otherwise. + */ #define proc_new(entry,data,size,stack) proc_new_with_name(NULL,(entry),(data),(size),(stack)) #else #define proc_new(entry,data,size,stack) proc_new_with_name(#entry,(entry),(data),(size),(stack)) #endif +/** + * Terminate the execution of the current process. + */ void proc_exit(void); -void proc_switch(void); -void proc_test(void); -struct Process *proc_current(void); -iptr_t proc_current_user_data(void); -void proc_rename(struct Process *proc, const char* name); - -#if CONFIG_KERN_PREEMPTIVE - void proc_forbid(void); - void proc_permit(void); + +/** + * Public scheduling class methods. + */ +void proc_yield(void); +void proc_preempt(void); +int proc_needPreempt(void); + +/** + * Dummy function that defines unimplemented scheduler class methods. + */ +INLINE void __proc_noop(void) +{ +} + +#if CONFIG_KERN_PREEMPT + /** + * Preemptive scheduler public methods. + */ + #define preempt_yield proc_yield + #define preempt_needPreempt proc_needPreempt + #define preempt_preempt proc_preempt + /** + * Preemptive scheduler: private methods. + */ + #define preempt_switch proc_switch + #define preempt_init proc_schedInit +#else + /** + * Co-operative scheduler: public methods. + */ + #define coop_yield proc_yield + #define proc_needPreempt __proc_noop + #define proc_preempt __proc_noop + /** + * Co-operative scheduler: private methods. + */ + #define coop_switch proc_switch + #define proc_schedInit __proc_noop +#endif + +void proc_rename(struct Process *proc, const char *name); +const char *proc_name(struct Process *proc); +const char *proc_currentName(void); + +/** + * Return a pointer to the user data of the current process. + * + * To obtain user data, just call this function inside the process. Remember to cast + * the returned pointer to the correct type. + * \return Pointer to the user data of the current process. + */ +iptr_t proc_currentUserData(void); + +int proc_testSetup(void); +int proc_testRun(void); +int proc_testTearDown(void); + +/** + * Return the context structure of the currently running process. + * + * The details of the Process structure are private to the scheduler. + * The address returned by this function is an opaque pointer that can + * be passed as an argument to other process-related functions. + */ +INLINE struct Process *proc_current(void) +{ + extern struct Process *current_process; + return current_process; +} + +#if CONFIG_KERN_PRI + void proc_setPri(struct Process *proc, int pri); #else - INLINE void proc_forbid(void) { /* nop */ } - INLINE void proc_permit(void) { /* nop */ } + INLINE void proc_setPri(UNUSED_ARG(struct Process *,proc), UNUSED_ARG(int, pri)) + { + } #endif +#if CONFIG_KERN_PREEMPT + + /** + * Disable preemptive task switching. + * + * The scheduler maintains a global nesting counter. Task switching is + * effectively re-enabled only when the number of calls to proc_permit() + * matches the number of calls to proc_forbid(). + * + * \note Calling functions that could sleep while task switching is disabled + * is dangerous and unsupported. + * + * \note proc_permit() expands inline to 1-2 asm instructions, so it's a + * very efficient locking primitive in simple but performance-critical + * situations. In all other cases, semaphores offer a more flexible and + * fine-grained locking primitive. + * + * \sa proc_permit() + */ + INLINE void proc_forbid(void) + { + extern cpu_atomic_t preempt_count; + /* + * We don't need to protect the counter against other processes. + * The reason why is a bit subtle. + * + * If a process gets here, preempt_forbid_cnt can be either 0, + * or != 0. In the latter case, preemption is already disabled + * and no concurrency issues can occur. + * + * In the former case, we could be preempted just after reading the + * value 0 from memory, and a concurrent process might, in fact, + * bump the value of preempt_forbid_cnt under our nose! + * + * BUT: if this ever happens, then we won't get another chance to + * run until the other process calls proc_permit() to re-enable + * preemption. At this point, the value of preempt_forbid_cnt + * must be back to 0, and thus what we had originally read from + * memory happens to be valid. + * + * No matter how hard you think about it, and how complicated you + * make your scenario, the above holds true as long as + * "preempt_forbid_cnt != 0" means that no task switching is + * possible. + */ + ++preempt_count; + + /* + * Make sure preempt_count is flushed to memory so the preemption + * softirq will see the correct value from now on. + */ + MEMORY_BARRIER; + } + + /** + * Re-enable preemptive task switching. + * + * \sa proc_forbid() + */ + INLINE void proc_permit(void) + { + extern cpu_atomic_t preempt_count; + + /* + * This is to ensure any global state changed by the process gets + * flushed to memory before task switching is re-enabled. + */ + MEMORY_BARRIER; + /* No need to protect against interrupts here. */ + ASSERT(preempt_count > 0); + --preempt_count; + /* + * This ensures preempt_count is flushed to memory immediately so the + * preemption interrupt sees the correct value. + */ + MEMORY_BARRIER; + } + + /** + * \return true if preemptive task switching is allowed. + * \note This accessor is needed because preempt_count + * must be absoultely private. + */ + INLINE bool proc_preemptAllowed(void) + { + extern cpu_atomic_t preempt_count; + return (preempt_count == 0); + } +#else /* CONFIG_KERN_PREEMPT */ + #define proc_forbid() /* NOP */ + #define proc_permit() /* NOP */ + #define proc_preemptAllowed() (true) +#endif /* CONFIG_KERN_PREEMPT */ + +/** Deprecated, use the proc_preemptAllowed() macro. */ +#define proc_allowed() proc_preemptAllowed() + /** * Execute a block of \a CODE atomically with respect to task scheduling. */ @@ -83,4 +327,96 @@ void proc_rename(struct Process *proc, const char* name); proc_permit(); \ } while(0) +/** + * Default stack size for each thread, in bytes. + * + * The goal here is to allow a minimal task to save all of its + * registers twice, plus push a maximum of 32 variables on the + * stack. We add also struct Process size since we save it into the process' + * stack. + * + * The actual size computed by the default formula greatly depends on what + * options are active and on the architecture. + * + * Note that on most 16bit architectures, interrupts will also + * run on the stack of the currently running process. Nested + * interrupts will greatly increases the amount of stack space + * required per process. Use irqmanager to minimize stack + * usage. + */ + +#if (ARCH & ARCH_EMUL) + /* We need a large stack because system libraries are bloated */ + #define KERN_MINSTACKSIZE 65536 +#else + #if CONFIG_KERN_PREEMPT + /* + * A preemptible kernel needs a larger stack compared to the + * cooperative case. A task can be interrupted anytime in each + * node of the call graph, at any level of depth. This may + * result in a higher stack consumption, to call the ISR, save + * the current user context and to execute the kernel + * preemption routines implemented as ISR prologue and + * epilogue. All these calls are nested into the process stack. + * + * So, to reduce the risk of stack overflow/underflow problems + * add a x2 to the portion stack reserved to the user process. + */ + #define KERN_MINSTACKSIZE \ + (sizeof(Process) + CPU_SAVED_REGS_CNT * 2 * sizeof(cpu_stack_t) \ + + 32 * sizeof(int) * 2) + #else + #define KERN_MINSTACKSIZE \ + (sizeof(Process) + CPU_SAVED_REGS_CNT * 2 * sizeof(cpu_stack_t) \ + + 32 * sizeof(int)) + #endif /* CONFIG_KERN_PREEMPT */ + +#endif + +#ifndef CONFIG_KERN_MINSTACKSIZE + /* For backward compatibility */ + #define CONFIG_KERN_MINSTACKSIZE KERN_MINSTACKSIZE +#else + #warning FIXME: This macro is deprecated, use KERN_MINSTACKSIZE instead +#endif + +/** + * Utility macro to allocate a stack of size \a size. + * + * This macro define a static stack for one process and do + * check if given stack size is enough to run process. + * \note If you plan to use kprintf() and similar functions, you will need + * at least KERN_MINSTACKSIZE * 2 bytes. + * + * \param name Variable name for the stack. + * \param size Stack size in bytes. It must be at least KERN_MINSTACKSIZE. + */ +#define PROC_DEFINE_STACK(name, size) \ + cpu_stack_t name[((size) + sizeof(cpu_stack_t) - 1) / sizeof(cpu_stack_t)]; \ + STATIC_ASSERT((size) >= KERN_MINSTACKSIZE); + +/* Memory fill codes to help debugging */ +#if CONFIG_KERN_MONITOR + #include + #if (SIZEOF_CPUSTACK_T == 1) + /* 8bit cpu_stack_t */ + #define CONFIG_KERN_STACKFILLCODE 0xA5 + #define CONFIG_KERN_MEMFILLCODE 0xDB + #elif (SIZEOF_CPUSTACK_T == 2) + /* 16bit cpu_stack_t */ + #define CONFIG_KERN_STACKFILLCODE 0xA5A5 + #define CONFIG_KERN_MEMFILLCODE 0xDBDB + #elif (SIZEOF_CPUSTACK_T == 4) + /* 32bit cpu_stack_t */ + #define CONFIG_KERN_STACKFILLCODE 0xA5A5A5A5UL + #define CONFIG_KERN_MEMFILLCODE 0xDBDBDBDBUL + #elif (SIZEOF_CPUSTACK_T == 8) + /* 64bit cpu_stack_t */ + #define CONFIG_KERN_STACKFILLCODE 0xA5A5A5A5A5A5A5A5ULL + #define CONFIG_KERN_MEMFILLCODE 0xDBDBDBDBDBDBDBDBULL + #else + #error No cpu_stack_t size supported! + #endif +#endif + #endif /* KERN_PROC_H */