X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=kern%2Fproc.c;h=b8431b50e1b277317716b3b9f7f9f20defdb673f;hb=HEAD;hp=99f844bfaec3fe4205674a30e189399fd4024b4b;hpb=1ca35a617bc991a7eb1145bf15a19d00ea579882;p=bertos.git diff --git a/kern/proc.c b/kern/proc.c deleted file mode 100755 index 99f844bf..00000000 --- a/kern/proc.c +++ /dev/null @@ -1,367 +0,0 @@ -/*! - * \file - * - * - * \brief Simple realtime multitasking scheduler. - * Context switching is only done cooperatively. - * - * \version $Id$ - * - * \author Bernardo Innocenti - * \author Stefano Fedrigo - */ - -/* - * $Log$ - * 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 /* memset() */ - -/* CPU dependent context switching routines */ -extern void asm_switch_context(cpustack_t **new_sp, cpustack_t **save_sp); - -/* - * 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_TIMER - event_initSignal(&proc->proc_timer.expire, proc, SIG_SINGLE); -#endif - -#if CONFIG_KERN_SIGNALS - proc->sig_recv = 0; -#endif - -#if CONFIG_KERN_HEAP - proc->flags = 0; -#endif -} - -void proc_init(void) -{ - INITLIST(&ProcReadyList); - - /* 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; -} - - -/*! - * 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) -{ - 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 *)StackFreeList.head; - REMOVE((Node *)stack_base); - stacksize = DEF_STACKSIZE; -#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); - - /* 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 - -#ifdef _DEBUG - /* Fill-in the stack with a special marker to help debugging */ - memset(stack_base, CONFIG_KERN_STACKFILLCODE, stacksize / sizeof(cpustack_t)); -#endif /* _DEBUG */ - - /* 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); - -#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 */ - DISABLE_INTS; - SCHED_ENQUEUE(proc); - ENABLE_INTS; - - return proc; -} - - -/*! - * 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) -{ - /* 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; - - /* Remember old process to save its context later */ - old_process = CurrentProcess; - CurrentProcess = NULL; - - /* Poll on the ready queue for the first ready process - */ - for(;;) /* forever */ - { - /* Do CPU specific idle processing (ARGH, should be moved to the end of the loop!) */ - SCHEDULER_IDLE; - - DISABLE_INTS; - if (!ISLISTEMPTY(&ProcReadyList)) - { - /* Get process from ready list */ - CurrentProcess = (Process *)ProcReadyList.head; - REMOVE((Node *)CurrentProcess); - ENABLE_INTS; - break; - } - ENABLE_INTS; - } - - /* Optimization: don't switch contexts when the active - * process has not changed. - */ - if (CurrentProcess != old_process) - { - static 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_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) -#error This is wrong - /* Reinsert process stack in free list */ - ADDHEAD(&StackFreeList, (Node *)(CurrentProcess->stack - - (DEF_STACKSIZE / 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) -{ - DISABLE_INTS; - SCHED_ENQUEUE(CurrentProcess); - ENABLE_INTS; - proc_schedule(); -} - - -/*! - * Get the pointer to the current process - */ -struct Process *proc_current(void) -{ - return CurrentProcess; -} - - -#if 0 /* Simple testcase for the scheduler */ - -/*! - * Proc scheduling test subthread 1 - */ -static void NORETURN proc_test_thread1(void) -{ - for (;;) - { - kputs(">task 1\n"); - timer_delay(50); - proc_switch(); - } -} - -/*! - * Proc scheduling test subthread 2 - */ -static void NORETURN proc_test_thread2(void) -{ - for (;;) - { - kputs(">task 2\n"); - timer_delay(75); - proc_switch(); - } -} - -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 - */ -void NORETURN proc_test(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); -} -#endif