X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=kern%2Fproc.c;h=a9e956243a2677267449f74241541f87f0e55862;hb=4ac43159891e8090defc821852e2753d7508bf5f;hp=3971df00bb54907424748e89878b691151851de0;hpb=99ebec567d8485806f6ebe23b8c8a1b825d0cf4d;p=bertos.git diff --git a/kern/proc.c b/kern/proc.c old mode 100755 new mode 100644 index 3971df00..a9e95624 --- a/kern/proc.c +++ b/kern/proc.c @@ -1,9 +1,34 @@ -/*! +/** * \file * * * \brief Simple realtime multitasking scheduler. @@ -15,43 +40,28 @@ * \author Stefano Fedrigo */ -/* - * $Log$ - * Revision 1.6 2004/07/30 14:24:16 rasky - * Task switching con salvataggio perfetto stato di interrupt (SR) - * Kernel monitor per dump informazioni su stack dei processi - * - * Revision 1.5 2004/07/14 14:18:09 rasky - * Merge da SC: Rimosso timer dentro il task, che è uno spreco di memoria per troppi task - * - * Revision 1.4 2004/07/13 19:21:28 aleph - * Avoid warning for unused arg when compiled without some CONFIG_KERN_xx options - * - * Revision 1.3 2004/06/06 18:37:57 bernie - * Rename event macros to look like regular functions. - * - * Revision 1.2 2004/06/03 11:27:09 bernie - * Add dual-license information. - * - * Revision 1.1 2004/05/23 17:27:00 bernie - * Import kern/ subdirectory. - * - */ -#include "cpu.h" #include "proc_p.h" #include "proc.h" -#include "event.h" -#include "hw.h" -#include +//#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. +/** + * CPU dependent context switching routines. + * + * \note This function *MUST* preserve also the status of the interrupts. */ -extern void asm_switch_context(cpustack_t **new_sp, cpustack_t **save_sp); -extern int asm_switch_version(void); +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 @@ -78,97 +88,33 @@ uint16_t Quantum; extern List StackFreeList; #endif -/* The main process (the one that executes main()) */ +/** The main process (the one that executes main()). */ struct Process MainProcess; -#if CONFIG_KERN_MONITOR -List MonitorProcs; - -static void monitor_init(void) -{ - INITLIST(&MonitorProcs); -} - -static void monitor_add(Process* proc, cpustack_t* stack_base, size_t stack_size) -{ - proc->monitor.stack_base = stack_base; - proc->monitor.stack_size = stack_size; - - ADDTAIL(&MonitorProcs, &proc->monitor.link); -} - -static void monitor_remove(Process* proc) +static void proc_init_struct(Process *proc) { - REMOVE(&proc->monitor.link); -} - -#define MONITOR_NODE_TO_PROCESS(node) \ - (struct Process*)((char*)(node) - offsetof(struct Process, monitor.link)) - -size_t monitor_check_stack(cpustack_t* stack_base, size_t stack_size) -{ - cpustack_t* beg; - cpustack_t* cur; - cpustack_t* end; - size_t sp_free; - - beg = stack_base; - end = stack_base + stack_size / sizeof(cpustack_t) - 1; - - if (CPU_STACK_GROWS_UPWARD) - { - cur = beg; - beg = end; - end = cur; - } - - cur = beg; - while (cur != end) - { - if (*cur != CONFIG_KERN_STACKFILLCODE) - break; - - if (CPU_STACK_GROWS_UPWARD) - cur--; - else - cur++; - } - - sp_free = ABS(cur - beg) * sizeof(cpustack_t); - return sp_free; -} - -void monitor_debug_stacks(void) -{ - struct Process* p; - - for (p = MONITOR_NODE_TO_PROCESS(MonitorProcs.head); - p->monitor.link.succ; - p = MONITOR_NODE_TO_PROCESS(p->monitor.link.succ)) - { - size_t free = monitor_check_stack(p->monitor.stack_base, p->monitor.stack_size); - kprintf("TCB: %x sp_base: %x sp_size: %x sp_free: %x\n", (uint16_t)p, (uint16_t)p->monitor.stack_base, (uint16_t)p->monitor.stack_size, (uint16_t)free); - } -} - -#endif + /* Avoid warning for unused argument. */ + (void)proc; - -static void proc_init_struct(Process* 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) { - INITLIST(&ProcReadyList); + LIST_INIT(&ProcReadyList); #if CONFIG_KERN_MONITOR monitor_init(); @@ -183,19 +129,19 @@ void proc_init(void) /* 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. */ -Process *proc_new(void (*entry)(void), 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 stacksize, cpustack_t *stack_base) { Process *proc; - cpuflags_t flags; size_t i; size_t proc_size_words = ROUND2(sizeof(Process), sizeof(cpustack_t)) / sizeof(cpustack_t); #if CONFIG_KERN_HEAP @@ -203,19 +149,17 @@ Process *proc_new(void (*entry)(void), size_t stacksize, cpustack_t *stack_base) #endif #if (ARCH & ARCH_EMUL) - /* Ignore stack provided by caller - * and use the large enough default instead - */ - stack_base = (cpustack_t *)StackFreeList.head; - REMOVE((Node *)stack_base); - stacksize = DEF_STACKSIZE; + /* 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_KERN_DEFSTACKSIZE + sizeof(Process); + stacksize = CONFIG_PROC_DEFSTACKSIZE + sizeof(Process); /* Allocate stack dinamically */ if (!(stack_base = heap_alloc(stacksize))) @@ -251,6 +195,7 @@ Process *proc_new(void (*entry)(void), size_t stacksize, cpustack_t *stack_base) } proc_init_struct(proc); + proc->user_data = data; #if CONFIG_KERN_HEAP proc->stack_base = stack_base; @@ -268,19 +213,27 @@ Process *proc_new(void (*entry)(void), size_t stacksize, cpustack_t *stack_base) CPU_PUSH_WORD(proc->stack, CPU_REG_INIT_VALUE(i)); /* Add to ready list */ - DISABLE_IRQSAVE(flags); - SCHED_ENQUEUE(proc); - ENABLE_IRQRESTORE(flags); + ATOMIC(SCHED_ENQUEUE(proc)); #if CONFIG_KERN_MONITOR - monitor_add(proc, stack_base, stacksize); + 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. * @@ -290,19 +243,20 @@ Process *proc_new(void (*entry)(void), size_t stacksize, cpustack_t *stack_base) */ void proc_schedule(void) { - /* This function must not have any "auto" variables, otherwise - * the compiler might put them on the stack of the process - * being switched out. - */ - static Process *old_process; - static cpuflags_t flags; + 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 */ - DISABLE_IRQSAVE(flags); - while (!(CurrentProcess = (struct Process*)REMHEAD(&ProcReadyList))) + IRQ_SAVE_DISABLE(flags); + while (!(CurrentProcess = (struct Process *)list_remHead(&ProcReadyList))) { /* * Make sure we physically reenable interrupts here, no matter what @@ -310,22 +264,29 @@ void proc_schedule(void) * are idle-spinning, we must allow interrupts, otherwise no * process will ever wake up. * - * \todo If there was a way to code sig_wait so that it does not + * 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. */ - ENABLE_INTS; - SCHEDULER_IDLE; - DISABLE_INTS; + IRQ_ENABLE; + CPU_IDLE; + MEMORY_BARRIER; + IRQ_DISABLE; } - ENABLE_IRQRESTORE(flags); + IRQ_RESTORE(flags); - /* Optimization: don't switch contexts when the active + /* + * Optimization: don't switch contexts when the active * process has not changed. */ if (CurrentProcess != old_process) { - static cpustack_t* dummy; + cpustack_t *dummy; #if CONFIG_KERN_PREEMPTIVE /* Reset quantum for this process */ @@ -346,13 +307,18 @@ void proc_schedule(void) } -/*! +/** * 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. + /* + * 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 @@ -364,44 +330,40 @@ void proc_exit(void) #endif #if (ARCH & ARCH_EMUL) -#error This is wrong +#warning This is wrong /* Reinsert process stack in free list */ ADDHEAD(&StackFreeList, (Node *)(CurrentProcess->stack - - (DEF_STACKSIZE / sizeof(cpustack_t)))); + - (CONFIG_PROC_DEFSTACKSIZE / sizeof(cpustack_t)))); - /* NOTE: At this point the first two words of what used + /* + * 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 */ -#if CONFIG_KERN_MONITOR - monitor_remove(CurrentProcess); -#endif - CurrentProcess = NULL; proc_schedule(); /* not reached */ } -/*! +/** * Co-operative context switch */ void proc_switch(void) { - /* Just like proc_schedule, this function must not have auto variables. */ - static cpuflags_t flags; + cpuflags_t flags; - DISABLE_IRQSAVE(flags); + IRQ_SAVE_DISABLE(flags); SCHED_ENQUEUE(CurrentProcess); - ENABLE_IRQRESTORE(flags); + IRQ_RESTORE(flags); proc_schedule(); } -/*! +/** * Get the pointer to the current process */ struct Process *proc_current(void) @@ -409,59 +371,46 @@ struct Process *proc_current(void) return CurrentProcess; } - -#if 0 /* Simple testcase for the scheduler */ - -/*! - * Proc scheduling test subthread 1 +/** + * Get the pointer to the user data of the current process */ -static void NORETURN proc_test_thread1(void) +iptr_t proc_current_user_data(void) { - for (;;) - { - kputs(">task 1\n"); - timer_delay(50); - proc_switch(); - } + return CurrentProcess->user_data; } -/*! - * Proc scheduling test subthread 2 + +#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() */ -static void NORETURN proc_test_thread2(void) +void proc_forbid(void) { - for (;;) - { - kputs(">task 2\n"); - timer_delay(75); - proc_switch(); - } + /* No need to protect against interrupts here. */ + ++CurrentProcess->forbid_cnt; } -static cpustack_t proc_test_stack1[CONFIG_KERN_DEFSTACKSIZE/sizeof(cpustack_t)]; -static cpustack_t proc_test_stack2[CONFIG_KERN_DEFSTACKSIZE/sizeof(cpustack_t)]; - -/*! - * Proc scheduling test +/** + * Re-enable preemptive task switching. + * + * \sa proc_forbid() */ -void NORETURN proc_test(void) +void proc_permit(void) { - proc_new(proc_test_thread1, sizeof(proc_test_stack1), proc_test_stack1); - proc_new(proc_test_thread2, sizeof(proc_test_stack2), proc_test_stack2); - kputs("Created tasks\n"); - - kputs("stack1:\n"); - kdump(proc_test_stack1+sizeof(proc_test_stack1)-64, 64); - kputs("stack2:\n"); - kdump(proc_test_stack2+sizeof(proc_test_stack1)-64, 64); - - for (;;) - { - kputs(">main task\n"); - timer_delay(93); - proc_switch(); - } - - ASSERT(false); + /* No need to protect against interrupts here. */ + --CurrentProcess->forbid_cnt; } -#endif + +#endif /* CONFIG_KERN_PREEMPTIVE */