X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=bertos%2Fkern%2Fproc.c;h=6b1aaaff51fe97870b35a826ddaa96d4dd21d496;hb=83fc7933f968173822ed3f636d75860d4a747e76;hp=1d36ab0b16cdb482c65d894470d892e36f482a0d;hpb=e178e43b399c056990d8592f62385e1924b86b3c;p=bertos.git diff --git a/bertos/kern/proc.c b/bertos/kern/proc.c index 1d36ab0b..6b1aaaff 100644 --- a/bertos/kern/proc.c +++ b/bertos/kern/proc.c @@ -26,68 +26,65 @@ * 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 Simple realtime multitasking scheduler. - * Context switching is only done cooperatively. + * \brief Simple cooperative multitasking scheduler. * * \version $Id$ - * * \author Bernie Innocenti * \author Stefano Fedrigo */ - #include "proc_p.h" #include "proc.h" -#include "cfg/cfg_arch.h" /* ARCH_EMUL */ -#include +#include "cfg/cfg_arch.h" // ARCH_EMUL +#include "cfg/cfg_proc.h" +#include "cfg/cfg_monitor.h" +#include // ROUND_UP2 #include -#include /* ABS() */ +#include // CONFIG_DEPEND() #include #include #include +#include -#include +#if CONFIG_KERN_HEAP + #include +#endif #include /* memset() */ -/** - * CPU dependent context switching routines. +/* + * 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 some hosted environments, we must emulate the stack on the real + * process stack to satisfy consistency checks in system libraries and + * because some ABIs place trampolines on the stack. + * + * Access to this list must be protected by PROC_ATOMIC(). */ -uint16_t Quantum; -#endif - +List StackFreeList; -/* In Win32 we must emulate stack on the real process stack */ -#if (ARCH & ARCH_EMUL) -extern List StackFreeList; +#define NPROC 10 +cpu_stack_t proc_stacks[NPROC][(64 * 1024) / sizeof(cpu_stack_t)]; #endif /** The main process (the one that executes main()). */ @@ -101,15 +98,17 @@ static void proc_init_struct(Process *proc) #if CONFIG_KERN_SIGNALS proc->sig_recv = 0; -#endif - -#if CONFIG_KERN_PREEMPTIVE - proc->forbid_cnt = 0; + proc->sig_wait = 0; #endif #if CONFIG_KERN_HEAP proc->flags = 0; #endif + +#if CONFIG_KERN_PRI + proc->link.pri = 0; +#endif + } MOD_DEFINE(proc); @@ -118,50 +117,60 @@ void proc_init(void) { LIST_INIT(&ProcReadyList); -#if CONFIG_KERN_MONITOR - monitor_init(); +#if ARCH & ARCH_EMUL + LIST_INIT(&StackFreeList); + for (int i = 0; i < NPROC; i++) + ADDTAIL(&StackFreeList, (Node *)proc_stacks[i]); #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_PREEMPT + preempt_init(); +#endif + 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 stack_size, cpustack_t *stack_base) +struct Process *proc_new_with_name(UNUSED_ARG(const char *, name), void (*entry)(void), iptr_t data, size_t stack_size, cpu_stack_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 = ROUND_UP2(sizeof(Process), sizeof(cpu_stack_t)) / sizeof(cpu_stack_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_remHead(&StackFreeList); + PROC_ATOMIC(stack_base = (cpu_stack_t *)list_remHead(&StackFreeList)); + ASSERT(stack_base); - stack_size = CONFIG_PROC_DEFSTACKSIZE; + stack_size = CONFIG_KERN_MINSTACKSIZE; #elif CONFIG_KERN_HEAP /* Did the caller provide a stack for us? */ if (!stack_base) { /* Did the caller specify the desired stack size? */ if (!stack_size) - stack_size = CONFIG_PROC_DEFSTACKSIZE + sizeof(Process); + stack_size = CONFIG_KERN_MINSTACKSIZE; /* Allocate stack dinamically */ if (!(stack_base = heap_alloc(stack_size))) @@ -169,62 +178,111 @@ struct Process *proc_new_with_name(UNUSED(const char *, name), void (*entry)(voi free_stack = true; } -#else + +#else // !ARCH_EMUL && !CONFIG_KERN_HEAP + /* Stack must have been provided by the user */ - ASSERT(stack_base); + ASSERT_VALID_PTR(stack_base); ASSERT(stack_size); -#endif + +#endif // !ARCH_EMUL && !CONFIG_KERN_HEAP #if CONFIG_KERN_MONITOR - /* Fill-in the stack with a special marker to help debugging */ - memset(stack_base, CONFIG_KERN_STACKFILLCODE, stack_size / sizeof(cpustack_t)); + /* + * Fill-in the stack with a special marker to help debugging. + * On 64bit platforms, CONFIG_KERN_STACKFILLCODE is larger + * than an int, so the (int) cast is required to silence the + * warning for truncating its size. + */ + memset(stack_base, (int)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 = (Process *)stack_base; + proc->stack = stack_base + PROC_SIZE_WORDS; + // On some architecture stack should be aligned, so we do it. + proc->stack = (void *)proc->stack + (sizeof(cpu_aligned_stack_t) - ((long)proc->stack % sizeof(cpu_stack_aligned_t))); if (CPU_SP_ON_EMPTY_SLOT) proc->stack++; } else { - proc = (Process*)(stack_base + stack_size / sizeof(cpustack_t) - proc_size_words); - proc->stack = (cpustack_t*)proc; + proc = (Process *)(stack_base + stack_size / sizeof(cpu_stack_t) - PROC_SIZE_WORDS); + // On some architecture stack should be aligned, so we do it. + proc->stack = (void *)proc - ((long)proc % sizeof(cpu_aligned_stack_t)); if (CPU_SP_ON_EMPTY_SLOT) proc->stack--; } + stack_size = stack_size - PROC_SIZE_WORDS; 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); + #if CONFIG_KERN_PREEMPT + + getcontext(&proc->context); + proc->context.uc_stack.ss_sp = proc->stack; + proc->context.uc_stack.ss_size = stack_size - PROC_SIZE_WORDS - 1; + proc->context.uc_link = NULL; + makecontext(&proc->context, (void (*)(void))proc_entry, 1, 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)); + #else // !CONFIG_KERN_PREEMPT + { + size_t i; + + /* Initialize process stack frame */ + 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++) + CPU_PUSH_WORD(proc->stack, CPU_REG_INIT_VALUE(i)); + } + #endif // CONFIG_KERN_PREEMPT + + #if CONFIG_KERN_MONITOR + monitor_add(proc, name); + #endif /* Add to ready list */ ATOMIC(SCHED_ENQUEUE(proc)); -#if CONFIG_KERN_MONITOR - monitor_add(proc, name, stack_base, stack_size); -#endif - return proc; } -/** Rename a process */ +/** + * Return the name of the specified process. + * + * NULL is a legal argument and will return the name "". + */ +const char *proc_name(struct Process *proc) +{ + #if CONFIG_KERN_MONITOR + return proc ? proc->monitor.name : ""; + #else + (void)proc; + return "---"; + #endif +} + +/// Return the name of the currently running process +const char *proc_currentName(void) +{ + return proc_name(proc_current()); +} + +/// Rename a process void proc_rename(struct Process *proc, const char *name) { #if CONFIG_KERN_MONITOR @@ -235,85 +293,49 @@ void proc_rename(struct Process *proc, const char *name) } +#if CONFIG_KERN_PRI /** - * System scheduler: pass CPU control to the next process in - * the ready queue. + * Change the scheduling priority of a process. + * + * Process piorities are signed ints, whereas a larger integer value means + * higher scheduling priority. The default priority for new processes is 0. + * The idle process runs with the lowest possible priority: INT_MIN. + * + * A process with a higher priority always preempts lower priority processes. + * Processes of equal priority share the CPU time according to a simple + * round-robin policy. + * + * As a general rule to maximize responsiveness, compute-bound processes + * should be assigned negative priorities and tight, interactive processes + * should be assigned positive priorities. * - * Saving and restoring the context on the stack is done - * by a CPU-dependent support routine which must usually be - * written in assembly. + * To avoid interfering with system background activities such as input + * processing, application processes should remain within the range -10 + * and +10. */ -void proc_schedule(void) +void proc_setPri(struct Process *proc, int pri) { - 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, an interrupt can occur and it may - * 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); + if (proc->link.pri == pri) + return; - /* - * 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); - } + proc->link.pri = pri; - /* This RET resumes the execution on the new process */ + if (proc != CurrentProcess) + { + proc_forbid(); + ATOMIC(sched_reenqueue(proc)); + proc_permit(); + } } - +#endif // CONFIG_KERN_PRI /** * Terminate the current process */ void proc_exit(void) { + TRACEMSG("%p:%s", CurrentProcess, proc_currentName()); + #if CONFIG_KERN_MONITOR monitor_remove(CurrentProcess); #endif @@ -332,10 +354,8 @@ void proc_exit(void) #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)))); + PROC_ATOMIC(ADDHEAD(&StackFreeList, (Node *)CurrentProcess->stack_base)); /* * NOTE: At this point the first two words of what used @@ -345,74 +365,15 @@ void proc_exit(void) #endif /* ARCH_EMUL */ CurrentProcess = NULL; - proc_schedule(); + proc_switch(); /* 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) +iptr_t proc_currentUserData(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 */