X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=bertos%2Fkern%2Fproc.c;h=bce8ac3e8a7fcadfd4eaf4d7073c659bf0813ff6;hb=8cfe12e5b95974d75b98ec964fc7edaf37919f0e;hp=a9e956243a2677267449f74241541f87f0e55862;hpb=791e167e053bdd9250d34a9a5ccae6ccde4d6679;p=bertos.git diff --git a/bertos/kern/proc.c b/bertos/kern/proc.c index a9e95624..bce8ac3e 100644 --- a/bertos/kern/proc.c +++ b/bertos/kern/proc.c @@ -26,65 +26,57 @@ * 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 Bernardo Innocenti - * + * Copyright 2001, 2004 Develer S.r.l. (http://www.develer.com/) + * Copyright 1999, 2000, 2001, 2008 Bernie Innocenti * --> * * \brief Simple realtime multitasking scheduler. * Context switching is only done cooperatively. * * \version $Id$ - * - * \author Bernardo Innocenti + * \author Bernie Innocenti * \author Stefano Fedrigo */ - #include "proc_p.h" #include "proc.h" -//#include "hw.h" -#include + +#include "cfg/cfg_arch.h" /* ARCH_EMUL */ +#include "cfg/cfg_kern.h" +#include + #include #include #include -#include -#include -#include /* ARCH_EMUL */ -#include /* ABS() */ +#include -#include /* memset() */ +#include /* memset() */ -/** - * CPU dependent context switching routines. +#if CONFIG_KERN_PREEMPT +#include "preempt.h" +#endif + +/* + * The scheduer tracks ready processes by enqueuing them in the + * ready list. * - * \note This function *MUST* preserve also the status of the interrupts. + * \note Access to the list must occur while interrupts are disabled. */ -EXTERN_C void asm_switch_context(cpustack_t **new_sp, cpustack_t **save_sp); -EXTERN_C int asm_switch_version(void); +REGISTER List ProcReadyList; /* - * 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. + * Holds a pointer to the TCB of the currently running process. * - * NOTE: these variables are protected by DI/EI locking + * \note User applications should use proc_current() to retrieve this value. */ REGISTER Process *CurrentProcess; -REGISTER List ProcReadyList; - -#if CONFIG_KERN_PREEMPTIVE +#if (ARCH & ARCH_EMUL) /* - * The time sharing scheduler forces a task switch when - * the current process has consumed its quantum. + * In hosted environments, we must emulate the stack on the real process stack. + * + * Access to this list must be protected by PROC_ATOMIC(). */ -uint16_t Quantum; -#endif - - -/* In Win32 we must emulate stack on the real process stack */ -#if (ARCH & ARCH_EMUL) extern List StackFreeList; #endif @@ -116,19 +108,23 @@ 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 + /* + * 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); +#if CONFIG_KERN_MONITOR + monitor_init(); + monitor_add(CurrentProcess, "main"); +#endif + +#if CONFIG_KERN_PREEMPTIVE + preempt_init(); +#endif + MOD_INIT(proc); } @@ -139,56 +135,57 @@ void proc_init(void) * \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) +struct Process *proc_new_with_name(UNUSED(const char *, name), void (*entry)(void), iptr_t data, size_t stack_size, cpustack_t *stack_base) { Process *proc; size_t i; - size_t proc_size_words = ROUND2(sizeof(Process), sizeof(cpustack_t)) / sizeof(cpustack_t); + const size_t PROC_SIZE_WORDS = ROUND2(sizeof(Process), sizeof(cpustack_t)) / sizeof(cpustack_t); #if CONFIG_KERN_HEAP bool free_stack = false; #endif + TRACEMSG("name=%s", name); #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; + PROC_ATOMIC(stack_base = (cpustack_t *)list_remHead(&StackFreeList)); + + stack_size = 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); + if (!stack_size) + stack_size = CONFIG_PROC_DEFSTACKSIZE + sizeof(Process); /* Allocate stack dinamically */ - if (!(stack_base = heap_alloc(stacksize))) + if (!(stack_base = heap_alloc(stack_size))) return NULL; free_stack = true; } #else /* Stack must have been provided by the user */ - ASSERT(stack_base); - ASSERT(stacksize); + ASSERT_VALID_PTR(stack_base); + ASSERT(stack_size); #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)); + memset(stack_base, CONFIG_KERN_STACKFILLCODE, stack_size); #endif /* Initialize the process control block */ if (CPU_STACK_GROWS_UPWARD) { proc = (Process*)stack_base; - proc->stack = stack_base + proc_size_words; + 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 = (Process*)(stack_base + stack_size / sizeof(cpustack_t) - PROC_SIZE_WORDS); proc->stack = (cpustack_t*)proc; if (CPU_SP_ON_EMPTY_SLOT) proc->stack--; @@ -197,16 +194,18 @@ struct Process *proc_new_with_name(UNUSED(const char *, name), void (*entry)(voi proc_init_struct(proc); proc->user_data = data; -#if CONFIG_KERN_HEAP +#if CONFIG_KERN_HEAP | CONFIG_KERN_MONITOR | (ARCH & ARCH_EMUL) proc->stack_base = stack_base; proc->stack_size = stack_size; + #if CONFIG_KERN_HEAP if (free_stack) proc->flags |= PF_FREESTACK; + #endif #endif /* Initialize process stack frame */ - CPU_PUSH_CALL_CONTEXT(proc->stack, proc_exit); - CPU_PUSH_CALL_CONTEXT(proc->stack, entry); + CPU_PUSH_CALL_FRAME(proc->stack, proc_exit); + CPU_PUSH_CALL_FRAME(proc->stack, entry); /* Push a clean set of CPU registers for asm_switch_context() */ for (i = 0; i < CPU_SAVED_REGS_CNT; i++) @@ -214,9 +213,10 @@ struct Process *proc_new_with_name(UNUSED(const char *, name), void (*entry)(voi /* Add to ready list */ ATOMIC(SCHED_ENQUEUE(proc)); + ATOMIC(LIST_ASSERT_VALID(&ProcReadyList)); #if CONFIG_KERN_MONITOR - monitor_add(proc, name, stack_base, stacksize); + monitor_add(proc, name); #endif return proc; @@ -233,85 +233,13 @@ void proc_rename(struct Process *proc, const char *name) } -/** - * 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) { + TRACE; + #if CONFIG_KERN_MONITOR monitor_remove(CurrentProcess); #endif @@ -332,8 +260,8 @@ void proc_exit(void) #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)))); + PROC_ATOMIC(ADDHEAD(&StackFreeList, (Node *)(CurrentProcess->stack + - (CONFIG_PROC_DEFSTACKSIZE / sizeof(cpustack_t))))); /* * NOTE: At this point the first two words of what used @@ -348,21 +276,6 @@ void proc_exit(void) } -/** - * 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 */ @@ -378,39 +291,3 @@ 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 */