X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=kern%2Fproc.c;h=b8431b50e1b277317716b3b9f7f9f20defdb673f;hb=HEAD;hp=a9e956243a2677267449f74241541f87f0e55862;hpb=f3ba158c1ebfcef6c85759056d0a3d5f421ea870;p=bertos.git diff --git a/kern/proc.c b/kern/proc.c deleted file mode 100644 index a9e95624..00000000 --- a/kern/proc.c +++ /dev/null @@ -1,416 +0,0 @@ -/** - * \file - * - * - * \brief Simple realtime multitasking scheduler. - * Context switching is only done cooperatively. - * - * \version $Id$ - * - * \author Bernardo Innocenti - * \author Stefano Fedrigo - */ - - -#include "proc_p.h" -#include "proc.h" -//#include "hw.h" -#include -#include -#include -#include -#include -#include -#include /* ARCH_EMUL */ -#include /* ABS() */ - -#include /* memset() */ - -/** - * CPU dependent context switching routines. - * - * \note This function *MUST* preserve also the status of the interrupts. - */ -EXTERN_C void asm_switch_context(cpustack_t **new_sp, cpustack_t **save_sp); -EXTERN_C int asm_switch_version(void); - -/* - * The scheduer tracks ready and waiting processes - * by enqueuing them in these lists. A pointer to the currently - * running process is stored in the CurrentProcess pointer. - * - * NOTE: these variables are protected by DI/EI locking - */ -REGISTER Process *CurrentProcess; -REGISTER List ProcReadyList; - - -#if CONFIG_KERN_PREEMPTIVE -/* - * The time sharing scheduler forces a task switch when - * the current process has consumed its quantum. - */ -uint16_t Quantum; -#endif - - -/* In Win32 we must emulate stack on the real process stack */ -#if (ARCH & ARCH_EMUL) -extern List StackFreeList; -#endif - -/** The main process (the one that executes main()). */ -struct Process MainProcess; - - -static void proc_init_struct(Process *proc) -{ - /* Avoid warning for unused argument. */ - (void)proc; - -#if CONFIG_KERN_SIGNALS - proc->sig_recv = 0; -#endif - -#if CONFIG_KERN_PREEMPTIVE - proc->forbid_cnt = 0; -#endif - -#if CONFIG_KERN_HEAP - proc->flags = 0; -#endif -} - -MOD_DEFINE(proc); - -void proc_init(void) -{ - LIST_INIT(&ProcReadyList); - -#if CONFIG_KERN_MONITOR - monitor_init(); -#endif - - /* We "promote" the current context into a real process. The only thing we have - * to do is create a PCB and make it current. We don't need to setup the stack - * pointer because it will be written the first time we switch to another process. - */ - proc_init_struct(&MainProcess); - CurrentProcess = &MainProcess; - - /* Make sure the assembly routine is up-to-date with us */ - ASSERT(asm_switch_version() == 1); - MOD_INIT(proc); -} - - -/** - * Create a new process, starting at the provided entry point. - * - * \return Process structure of new created process - * if successful, NULL otherwise. - */ -struct Process *proc_new_with_name(UNUSED(const char *, name), void (*entry)(void), iptr_t data, size_t stacksize, cpustack_t *stack_base) -{ - Process *proc; - size_t i; - size_t proc_size_words = ROUND2(sizeof(Process), sizeof(cpustack_t)) / sizeof(cpustack_t); -#if CONFIG_KERN_HEAP - bool free_stack = false; -#endif - -#if (ARCH & ARCH_EMUL) - /* Ignore stack provided by caller and use the large enough default instead. */ - stack_base = (cpustack_t *)LIST_HEAD(&StackFreeList); - REMOVE(LIST_HEAD(&StackFreeList)); - stacksize = CONFIG_PROC_DEFSTACKSIZE; -#elif CONFIG_KERN_HEAP - /* Did the caller provide a stack for us? */ - if (!stack_base) - { - /* Did the caller specify the desired stack size? */ - if (!stacksize) - stacksize = CONFIG_PROC_DEFSTACKSIZE + sizeof(Process); - - /* Allocate stack dinamically */ - if (!(stack_base = heap_alloc(stacksize))) - return NULL; - - free_stack = true; - } -#else - /* Stack must have been provided by the user */ - ASSERT(stack_base); - ASSERT(stacksize); -#endif - -#if CONFIG_KERN_MONITOR - /* Fill-in the stack with a special marker to help debugging */ - memset(stack_base, CONFIG_KERN_STACKFILLCODE, stacksize / sizeof(cpustack_t)); -#endif - - /* Initialize the process control block */ - if (CPU_STACK_GROWS_UPWARD) - { - proc = (Process*)stack_base; - proc->stack = stack_base + proc_size_words; - if (CPU_SP_ON_EMPTY_SLOT) - proc->stack++; - } - else - { - proc = (Process*)(stack_base + stacksize / sizeof(cpustack_t) - proc_size_words); - proc->stack = (cpustack_t*)proc; - if (CPU_SP_ON_EMPTY_SLOT) - proc->stack--; - } - - proc_init_struct(proc); - proc->user_data = data; - -#if CONFIG_KERN_HEAP - proc->stack_base = stack_base; - proc->stack_size = stack_size; - if (free_stack) - proc->flags |= PF_FREESTACK; -#endif - - /* Initialize process stack frame */ - CPU_PUSH_CALL_CONTEXT(proc->stack, proc_exit); - CPU_PUSH_CALL_CONTEXT(proc->stack, entry); - - /* Push a clean set of CPU registers for asm_switch_context() */ - for (i = 0; i < CPU_SAVED_REGS_CNT; i++) - CPU_PUSH_WORD(proc->stack, CPU_REG_INIT_VALUE(i)); - - /* Add to ready list */ - ATOMIC(SCHED_ENQUEUE(proc)); - -#if CONFIG_KERN_MONITOR - monitor_add(proc, name, stack_base, stacksize); -#endif - - return proc; -} - -/** Rename a process */ -void proc_rename(struct Process *proc, const char *name) -{ -#if CONFIG_KERN_MONITOR - monitor_rename(proc, name); -#else - (void)proc; (void)name; -#endif -} - - -/** - * System scheduler: pass CPU control to the next process in - * the ready queue. - * - * Saving and restoring the context on the stack is done - * by a CPU-dependent support routine which must usually be - * written in assembly. - */ -void proc_schedule(void) -{ - struct Process *old_process; - cpuflags_t flags; - - /* Remember old process to save its context later */ - old_process = CurrentProcess; - -#ifdef IRQ_RUNNING - /* Scheduling in interrupts is a nono. */ - ASSERT(!IRQ_RUNNING()); -#endif - - /* Poll on the ready queue for the first ready process */ - IRQ_SAVE_DISABLE(flags); - while (!(CurrentProcess = (struct Process *)list_remHead(&ProcReadyList))) - { - /* - * Make sure we physically reenable interrupts here, no matter what - * the current task status is. This is important because if we - * are idle-spinning, we must allow interrupts, otherwise no - * process will ever wake up. - * - * During idle-spinning, can occur an interrupt, it may be able to - * modify \p ProcReadyList. To ensure that compiler reload this - * variable every while cycle we call CPU_MEMORY_BARRIER. - * The memory barrier ensure that all variables used in this context - * are reloaded. - * \todo If there was a way to write sig_wait() so that it does not - * disable interrupts while waiting, there would not be any - * reason to do this. - */ - IRQ_ENABLE; - CPU_IDLE; - MEMORY_BARRIER; - IRQ_DISABLE; - } - IRQ_RESTORE(flags); - - /* - * Optimization: don't switch contexts when the active - * process has not changed. - */ - if (CurrentProcess != old_process) - { - cpustack_t *dummy; - -#if CONFIG_KERN_PREEMPTIVE - /* Reset quantum for this process */ - Quantum = CONFIG_KERN_QUANTUM; -#endif - - /* Save context of old process and switch to new process. If there is no - * old process, we save the old stack pointer into a dummy variable that - * we ignore. In fact, this happens only when the old process has just - * exited. - * TODO: Instead of physically clearing the process at exit time, a zombie - * list should be created. - */ - asm_switch_context(&CurrentProcess->stack, old_process ? &old_process->stack : &dummy); - } - - /* This RET resumes the execution on the new process */ -} - - -/** - * Terminate the current process - */ -void proc_exit(void) -{ -#if CONFIG_KERN_MONITOR - monitor_remove(CurrentProcess); -#endif - -#if CONFIG_KERN_HEAP - /* - * The following code is BROKEN. - * We are freeing our own stack before entering proc_schedule() - * BAJO: A correct fix would be to rearrange the scheduler with - * an additional parameter which frees the old stack/process - * after a context switch. - */ - if (CurrentProcess->flags & PF_FREESTACK) - heap_free(CurrentProcess->stack_base, CurrentProcess->stack_size); - heap_free(CurrentProcess); -#endif - -#if (ARCH & ARCH_EMUL) -#warning This is wrong - /* Reinsert process stack in free list */ - ADDHEAD(&StackFreeList, (Node *)(CurrentProcess->stack - - (CONFIG_PROC_DEFSTACKSIZE / sizeof(cpustack_t)))); - - /* - * NOTE: At this point the first two words of what used - * to be our stack contain a list node. From now on, we - * rely on the compiler not reading/writing the stack. - */ -#endif /* ARCH_EMUL */ - - CurrentProcess = NULL; - proc_schedule(); - /* not reached */ -} - - -/** - * Co-operative context switch - */ -void proc_switch(void) -{ - cpuflags_t flags; - - IRQ_SAVE_DISABLE(flags); - SCHED_ENQUEUE(CurrentProcess); - IRQ_RESTORE(flags); - - proc_schedule(); -} - - -/** - * Get the pointer to the current process - */ -struct Process *proc_current(void) -{ - return CurrentProcess; -} - -/** - * Get the pointer to the user data of the current process - */ -iptr_t proc_current_user_data(void) -{ - return CurrentProcess->user_data; -} - - -#if CONFIG_KERN_PREEMPTIVE - -/** - * Disable preemptive task switching. - * - * The scheduler maintains a per-process 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(). - * - * Calling functions that could sleep while task switching is disabled - * is dangerous, although supported. Preemptive task switching is - * resumed while the process is sleeping and disabled again as soon as - * it wakes up again. - * - * \sa proc_permit() - */ -void proc_forbid(void) -{ - /* No need to protect against interrupts here. */ - ++CurrentProcess->forbid_cnt; -} - -/** - * Re-enable preemptive task switching. - * - * \sa proc_forbid() - */ -void proc_permit(void) -{ - /* No need to protect against interrupts here. */ - --CurrentProcess->forbid_cnt; -} - -#endif /* CONFIG_KERN_PREEMPTIVE */