* Copyright 1999, 2000, 2001, 2008 Bernie Innocenti <bernie@codewiz.org>
* -->
*
- * \brief Simple realtime multitasking scheduler.
- * Context switching is only done cooperatively.
+ * \brief Simple cooperative multitasking scheduler.
*
* \version $Id$
* \author Bernie Innocenti <bernie@codewiz.org>
#include "proc_p.h"
#include "proc.h"
-#include "cfg/cfg_arch.h" /* ARCH_EMUL */
-#include "cfg/cfg_kern.h"
+#include "cfg/cfg_arch.h" // ARCH_EMUL
+#include "cfg/cfg_proc.h"
+#include "cfg/cfg_monitor.h"
+#include <cfg/macros.h> // ROUND_UP2
#include <cfg/module.h>
+#include <cfg/depend.h> // CONFIG_DEPEND()
#include <cpu/irq.h>
#include <cpu/types.h>
#include <cpu/attr.h>
#include <cpu/frame.h>
-#include <string.h> /* memset() */
+#if CONFIG_KERN_HEAP
+ #include <struct/heap.h>
+#endif
+#include <string.h> /* memset() */
/*
* The scheduer tracks ready processes by enqueuing them in the
#if (ARCH & ARCH_EMUL)
/*
- * In hosted environments, we must emulate the stack on the real process stack.
+ * 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().
*/
-extern List StackFreeList;
+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()). */
#if CONFIG_KERN_SIGNALS
proc->sig_recv = 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);
{
LIST_INIT(&ProcReadyList);
+#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
* to do is create a PCB and make it current. We don't need to setup the stack
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;
- const 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
#if (ARCH & ARCH_EMUL)
/* Ignore stack provided by caller and use the large enough default instead. */
- PROC_ATOMIC(stack_base = (cpustack_t *)list_remHead(&StackFreeList));
+ PROC_ATOMIC(stack_base = (cpu_stack_t *)list_remHead(&StackFreeList));
+ ASSERT(stack_base);
stack_size = CONFIG_KERN_MINSTACKSIZE;
#elif CONFIG_KERN_HEAP
#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);
+ /*
+ * 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 */
{
proc = (Process *)stack_base;
proc->stack = stack_base + PROC_SIZE_WORDS;
+ // On some architecture stack should be aligned, so we do it.
+ proc->stack = (cpu_stack_t *)((uintptr_t)proc->stack + (sizeof(cpu_aligned_stack_t) - ((uintptr_t)proc->stack % sizeof(cpu_aligned_stack_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 = (cpu_stack_t *)((uintptr_t)proc - ((uintptr_t)proc % sizeof(cpu_aligned_stack_t)));
if (CPU_SP_ON_EMPTY_SLOT)
proc->stack--;
}
+ /* Ensure stack is aligned */
+ ASSERT((uintptr_t)proc->stack % sizeof(cpu_aligned_stack_t) == 0);
+ stack_size -= PROC_SIZE_WORDS * sizeof(cpu_stack_t);
proc_init_struct(proc);
proc->user_data = data;
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_stack.ss_size = stack_size - 1;
proc->context.uc_link = NULL;
makecontext(&proc->context, (void (*)(void))proc_entry, 1, entry);
#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));
- }
+
+ CPU_CREATE_NEW_STACK(proc->stack, entry, proc_exit);
+
#endif // CONFIG_KERN_PREEMPT
#if CONFIG_KERN_MONITOR
#endif
}
+
+#if CONFIG_KERN_PRI
+/**
+ * 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.
+ *
+ * To avoid interfering with system background activities such as input
+ * processing, application processes should remain within the range -10
+ * and +10.
+ */
+void proc_setPri(struct Process *proc, int pri)
+{
+ if (proc->link.pri == pri)
+ return;
+
+ proc->link.pri = pri;
+
+ if (proc != CurrentProcess)
+ {
+ proc_forbid();
+ ATOMIC(sched_reenqueue(proc));
+ proc_permit();
+ }
+}
+#endif // CONFIG_KERN_PRI
+
/**
* Terminate the current process
*/
#endif
#if (ARCH & ARCH_EMUL)
-#warning This is wrong
/* Reinsert process stack in free list */
- PROC_ATOMIC(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
#endif /* ARCH_EMUL */
CurrentProcess = NULL;
- proc_schedule();
+ proc_switch();
/* not reached */
}
-/**
- * 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
*/