cb9faaebfd
- as the idle task is never placed on any run queue, we don't need any special idle queue. - one more queue available for user processes
1522 lines
47 KiB
C
1522 lines
47 KiB
C
/* This file contains essentially all of the process and message handling.
|
|
* Together with "mpx.s" it forms the lowest layer of the MINIX kernel.
|
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* There is one entry point from the outside:
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*
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* sys_call: a system call, i.e., the kernel is trapped with an INT
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*
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* As well as several entry points used from the interrupt and task level:
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*
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* lock_send: send a message to a process
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*
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* Changes:
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* Aug 19, 2005 rewrote scheduling code (Jorrit N. Herder)
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* Jul 25, 2005 rewrote system call handling (Jorrit N. Herder)
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* May 26, 2005 rewrote message passing functions (Jorrit N. Herder)
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* May 24, 2005 new notification system call (Jorrit N. Herder)
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* Oct 28, 2004 nonblocking send and receive calls (Jorrit N. Herder)
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*
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* The code here is critical to make everything work and is important for the
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* overall performance of the system. A large fraction of the code deals with
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* list manipulation. To make this both easy to understand and fast to execute
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* pointer pointers are used throughout the code. Pointer pointers prevent
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* exceptions for the head or tail of a linked list.
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*
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* node_t *queue, *new_node; // assume these as global variables
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* node_t **xpp = &queue; // get pointer pointer to head of queue
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* while (*xpp != NULL) // find last pointer of the linked list
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* xpp = &(*xpp)->next; // get pointer to next pointer
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* *xpp = new_node; // now replace the end (the NULL pointer)
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* new_node->next = NULL; // and mark the new end of the list
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*
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* For example, when adding a new node to the end of the list, one normally
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* makes an exception for an empty list and looks up the end of the list for
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* nonempty lists. As shown above, this is not required with pointer pointers.
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*/
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#include <minix/com.h>
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#include <minix/callnr.h>
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#include <minix/endpoint.h>
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#include <stddef.h>
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#include <signal.h>
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#include <minix/portio.h>
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#include <minix/u64.h>
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|
|
|
#include "debug.h"
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#include "kernel.h"
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#include "proc.h"
|
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#include "vm.h"
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|
|
|
/* Scheduling and message passing functions. The functions are available to
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* other parts of the kernel through lock_...(). The lock temporarily disables
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* interrupts to prevent race conditions.
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*/
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FORWARD _PROTOTYPE( int mini_send, (struct proc *caller_ptr, int dst_e,
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message *m_ptr, int flags));
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FORWARD _PROTOTYPE( int mini_receive, (struct proc *caller_ptr, int src,
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message *m_ptr, int flags));
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|
FORWARD _PROTOTYPE( int mini_senda, (struct proc *caller_ptr,
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asynmsg_t *table, size_t size));
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|
FORWARD _PROTOTYPE( int deadlock, (int function,
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register struct proc *caller, int src_dst));
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|
FORWARD _PROTOTYPE( int try_async, (struct proc *caller_ptr));
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|
FORWARD _PROTOTYPE( int try_one, (struct proc *src_ptr, struct proc *dst_ptr,
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int *postponed));
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FORWARD _PROTOTYPE( void sched, (struct proc *rp, int *queue, int *front));
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FORWARD _PROTOTYPE( struct proc * pick_proc, (void));
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FORWARD _PROTOTYPE( void enqueue_head, (struct proc *rp));
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#define PICK_ANY 1
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#define PICK_HIGHERONLY 2
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|
|
#define BuildNotifyMessage(m_ptr, src, dst_ptr) \
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(m_ptr)->m_type = NOTIFY_FROM(src); \
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(m_ptr)->NOTIFY_TIMESTAMP = get_uptime(); \
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switch (src) { \
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case HARDWARE: \
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(m_ptr)->NOTIFY_ARG = priv(dst_ptr)->s_int_pending; \
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priv(dst_ptr)->s_int_pending = 0; \
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break; \
|
|
case SYSTEM: \
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(m_ptr)->NOTIFY_ARG = priv(dst_ptr)->s_sig_pending; \
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priv(dst_ptr)->s_sig_pending = 0; \
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|
break; \
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* QueueMess *
|
|
*===========================================================================*/
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|
PRIVATE int QueueMess(endpoint_t ep, vir_bytes msg_lin, struct proc *dst)
|
|
{
|
|
int k;
|
|
phys_bytes addr;
|
|
NOREC_ENTER(queuemess);
|
|
/* Queue a message from the src process (in memory) to the dst
|
|
* process (using dst process table entry). Do actual copy to
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* kernel here; it's an error if the copy fails into kernel.
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|
*/
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|
vmassert(!(dst->p_misc_flags & MF_DELIVERMSG));
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|
vmassert(dst->p_delivermsg_lin);
|
|
vmassert(isokendpt(ep, &k));
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|
|
|
#if 0
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|
if(INMEMORY(dst)) {
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|
PHYS_COPY_CATCH(msg_lin, dst->p_delivermsg_lin,
|
|
sizeof(message), addr);
|
|
if(!addr) {
|
|
PHYS_COPY_CATCH(vir2phys(&ep), dst->p_delivermsg_lin,
|
|
sizeof(ep), addr);
|
|
if(!addr) {
|
|
NOREC_RETURN(queuemess, OK);
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
PHYS_COPY_CATCH(msg_lin, vir2phys(&dst->p_delivermsg), sizeof(message), addr);
|
|
if(addr) {
|
|
NOREC_RETURN(queuemess, EFAULT);
|
|
}
|
|
|
|
dst->p_delivermsg.m_source = ep;
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|
dst->p_misc_flags |= MF_DELIVERMSG;
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|
|
|
NOREC_RETURN(queuemess, OK);
|
|
}
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|
|
|
/*===========================================================================*
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|
* schedcheck *
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|
*===========================================================================*/
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|
PUBLIC struct proc * schedcheck(void)
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|
{
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|
/* This function is called an instant before proc_ptr is
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|
* to be scheduled again.
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|
*/
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|
NOREC_ENTER(schedch);
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vmassert(intr_disabled());
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|
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|
/*
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* if the current process is still runnable check the misc flags and let
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* it run unless it becomes not runnable in the meantime
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*/
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if (proc_is_runnable(proc_ptr))
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goto check_misc_flags;
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|
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|
/*
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* if a process becomes not runnable while handling the misc flags, we
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* need to pick a new one here and start from scratch. Also if the
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* current process wasn' runnable, we pick a new one here
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*/
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not_runnable_pick_new:
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if (proc_is_preempted(proc_ptr)) {
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proc_ptr->p_rts_flags &= ~RTS_PREEMPTED;
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if (proc_is_runnable(proc_ptr))
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enqueue_head(proc_ptr);
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|
}
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|
/* this enqueues the process again */
|
|
if (proc_no_quantum(proc_ptr))
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RTS_UNSET(proc_ptr, RTS_NO_QUANTUM);
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|
|
|
/*
|
|
* if we have no process to run, set IDLE as the current process for
|
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* time accounting and put the cpu in and idle state. After the next
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* timer interrupt the execution resumes here and we can pick another
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* process. If there is still nothing runnable we "schedule" IDLE again
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*/
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|
while (!(proc_ptr = pick_proc())) {
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proc_ptr = proc_addr(IDLE);
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if (priv(proc_ptr)->s_flags & BILLABLE)
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bill_ptr = proc_ptr;
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halt_cpu();
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|
}
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|
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|
check_misc_flags:
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|
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|
vmassert(proc_ptr);
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vmassert(proc_is_runnable(proc_ptr));
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while (proc_ptr->p_misc_flags &
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(MF_DELIVERMSG | MF_SC_DEFER | MF_SC_TRACE | MF_SC_ACTIVE)) {
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|
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|
vmassert(proc_is_runnable(proc_ptr));
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if (proc_ptr->p_misc_flags & MF_DELIVERMSG) {
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TRACE(VF_SCHEDULING, printf("delivering to %s / %d\n",
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proc_ptr->p_name, proc_ptr->p_endpoint););
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if(delivermsg(proc_ptr) == VMSUSPEND) {
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|
TRACE(VF_SCHEDULING,
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printf("suspending %s / %d\n",
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proc_ptr->p_name,
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proc_ptr->p_endpoint););
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vmassert(!proc_is_runnable(proc_ptr));
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}
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}
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else if (proc_ptr->p_misc_flags & MF_SC_DEFER) {
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/* Perform the system call that we deferred earlier. */
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|
#if DEBUG_SCHED_CHECK
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if (proc_ptr->p_misc_flags & MF_SC_ACTIVE)
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minix_panic("MF_SC_ACTIVE and MF_SC_DEFER set",
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NO_NUM);
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#endif
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arch_do_syscall(proc_ptr);
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|
/* If the process is stopped for signal delivery, and
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* not blocked sending a message after the system call,
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* inform PM.
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*/
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if ((proc_ptr->p_misc_flags & MF_SIG_DELAY) &&
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!RTS_ISSET(proc_ptr, RTS_SENDING))
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sig_delay_done(proc_ptr);
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}
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else if (proc_ptr->p_misc_flags & MF_SC_TRACE) {
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/* Trigger a system call leave event if this was a
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* system call. We must do this after processing the
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* other flags above, both for tracing correctness and
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* to be able to use 'break'.
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*/
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if (!(proc_ptr->p_misc_flags & MF_SC_ACTIVE))
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break;
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|
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|
proc_ptr->p_misc_flags &=
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~(MF_SC_TRACE | MF_SC_ACTIVE);
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|
/* Signal the "leave system call" event.
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* Block the process.
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|
*/
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cause_sig(proc_nr(proc_ptr), SIGTRAP);
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}
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else if (proc_ptr->p_misc_flags & MF_SC_ACTIVE) {
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/* If MF_SC_ACTIVE was set, remove it now:
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* we're leaving the system call.
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*/
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proc_ptr->p_misc_flags &= ~MF_SC_ACTIVE;
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break;
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}
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|
|
/*
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* the selected process might not be runnable anymore. We have
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* to checkit and schedule another one
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*/
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if (!proc_is_runnable(proc_ptr))
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goto not_runnable_pick_new;
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}
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TRACE(VF_SCHEDULING, printf("starting %s / %d\n",
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proc_ptr->p_name, proc_ptr->p_endpoint););
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#if DEBUG_TRACE
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proc_ptr->p_schedules++;
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#endif
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|
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|
proc_ptr = arch_finish_schedcheck();
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|
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|
NOREC_RETURN(schedch, proc_ptr);
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|
}
|
|
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|
/*===========================================================================*
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|
* sys_call *
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*===========================================================================*/
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PUBLIC int sys_call(call_nr, src_dst_e, m_ptr, bit_map)
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int call_nr; /* system call number and flags */
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int src_dst_e; /* src to receive from or dst to send to */
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message *m_ptr; /* pointer to message in the caller's space */
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long bit_map; /* notification event set or flags */
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{
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/* System calls are done by trapping to the kernel with an INT instruction.
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* The trap is caught and sys_call() is called to send or receive a message
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* (or both). The caller is always given by 'proc_ptr'.
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*/
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register struct proc *caller_ptr = proc_ptr; /* get pointer to caller */
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int mask_entry; /* bit to check in send mask */
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int group_size; /* used for deadlock check */
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int result; /* the system call's result */
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int src_dst_p; /* Process slot number */
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size_t msg_size;
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|
|
|
/* If this process is subject to system call tracing, handle that first. */
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if (caller_ptr->p_misc_flags & (MF_SC_TRACE | MF_SC_DEFER)) {
|
|
/* Are we tracing this process, and is it the first sys_call entry? */
|
|
if ((caller_ptr->p_misc_flags & (MF_SC_TRACE | MF_SC_DEFER)) ==
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MF_SC_TRACE) {
|
|
/* We must notify the tracer before processing the actual
|
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* system call. If we don't, the tracer could not obtain the
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* input message. Postpone the entire system call.
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|
*/
|
|
caller_ptr->p_misc_flags &= ~MF_SC_TRACE;
|
|
caller_ptr->p_misc_flags |= MF_SC_DEFER;
|
|
|
|
/* Signal the "enter system call" event. Block the process. */
|
|
cause_sig(proc_nr(caller_ptr), SIGTRAP);
|
|
|
|
/* Preserve the return register's value. */
|
|
return caller_ptr->p_reg.retreg;
|
|
}
|
|
|
|
/* If the MF_SC_DEFER flag is set, the syscall is now being resumed. */
|
|
caller_ptr->p_misc_flags &= ~MF_SC_DEFER;
|
|
|
|
#if DEBUG_SCHED_CHECK
|
|
if (caller_ptr->p_misc_flags & MF_SC_ACTIVE)
|
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minix_panic("MF_SC_ACTIVE already set", NO_NUM);
|
|
#endif
|
|
|
|
/* Set a flag to allow reliable tracing of leaving the system call. */
|
|
caller_ptr->p_misc_flags |= MF_SC_ACTIVE;
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}
|
|
|
|
#if DEBUG_SCHED_CHECK
|
|
if(caller_ptr->p_misc_flags & MF_DELIVERMSG) {
|
|
kprintf("sys_call: MF_DELIVERMSG on for %s / %d\n",
|
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caller_ptr->p_name, caller_ptr->p_endpoint);
|
|
minix_panic("MF_DELIVERMSG on", NO_NUM);
|
|
}
|
|
#endif
|
|
|
|
#if 0
|
|
if(src_dst_e != 4 && src_dst_e != 5 &&
|
|
caller_ptr->p_endpoint != 4 && caller_ptr->p_endpoint != 5) {
|
|
if(call_nr == SEND)
|
|
kprintf("(%d SEND to %d) ", caller_ptr->p_endpoint, src_dst_e);
|
|
else if(call_nr == RECEIVE)
|
|
kprintf("(%d RECEIVE from %d) ", caller_ptr->p_endpoint, src_dst_e);
|
|
else if(call_nr == SENDREC)
|
|
kprintf("(%d SENDREC to %d) ", caller_ptr->p_endpoint, src_dst_e);
|
|
else
|
|
kprintf("(%d %d to/from %d) ", caller_ptr->p_endpoint, call_nr, src_dst_e);
|
|
}
|
|
#endif
|
|
|
|
#if DEBUG_SCHED_CHECK
|
|
if (RTS_ISSET(caller_ptr, RTS_SLOT_FREE))
|
|
{
|
|
kprintf("called by the dead?!?\n");
|
|
return EINVAL;
|
|
}
|
|
#endif
|
|
|
|
/* Check destination. SENDA is special because its argument is a table and
|
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* not a single destination. RECEIVE is the only call that accepts ANY (in
|
|
* addition to a real endpoint). The other calls (SEND, SENDREC,
|
|
* and NOTIFY) require an endpoint to corresponds to a process. In addition,
|
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* it is necessary to check whether a process is allowed to send to a given
|
|
* destination.
|
|
*/
|
|
if (call_nr == SENDA)
|
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{
|
|
/* No destination argument */
|
|
}
|
|
else if (src_dst_e == ANY)
|
|
{
|
|
if (call_nr != RECEIVE)
|
|
{
|
|
#if 0
|
|
kprintf("sys_call: trap %d by %d with bad endpoint %d\n",
|
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call_nr, proc_nr(caller_ptr), src_dst_e);
|
|
#endif
|
|
return EINVAL;
|
|
}
|
|
src_dst_p = src_dst_e;
|
|
}
|
|
else
|
|
{
|
|
/* Require a valid source and/or destination process. */
|
|
if(!isokendpt(src_dst_e, &src_dst_p)) {
|
|
#if 0
|
|
kprintf("sys_call: trap %d by %d with bad endpoint %d\n",
|
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call_nr, proc_nr(caller_ptr), src_dst_e);
|
|
#endif
|
|
return EDEADSRCDST;
|
|
}
|
|
|
|
/* If the call is to send to a process, i.e., for SEND, SENDNB,
|
|
* SENDREC or NOTIFY, verify that the caller is allowed to send to
|
|
* the given destination.
|
|
*/
|
|
if (call_nr != RECEIVE)
|
|
{
|
|
if (!may_send_to(caller_ptr, src_dst_p)) {
|
|
#if DEBUG_ENABLE_IPC_WARNINGS
|
|
kprintf(
|
|
"sys_call: ipc mask denied trap %d from %d to %d\n",
|
|
call_nr, caller_ptr->p_endpoint, src_dst_e);
|
|
#endif
|
|
return(ECALLDENIED); /* call denied by ipc mask */
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Only allow non-negative call_nr values less than 32 */
|
|
if (call_nr < 0 || call_nr >= 32)
|
|
{
|
|
#if DEBUG_ENABLE_IPC_WARNINGS
|
|
kprintf("sys_call: trap %d not allowed, caller %d, src_dst %d\n",
|
|
call_nr, proc_nr(caller_ptr), src_dst_p);
|
|
#endif
|
|
return(ETRAPDENIED); /* trap denied by mask or kernel */
|
|
}
|
|
|
|
/* Check if the process has privileges for the requested call. Calls to the
|
|
* kernel may only be SENDREC, because tasks always reply and may not block
|
|
* if the caller doesn't do receive().
|
|
*/
|
|
if (!(priv(caller_ptr)->s_trap_mask & (1 << call_nr))) {
|
|
#if DEBUG_ENABLE_IPC_WARNINGS
|
|
kprintf("sys_call: trap %d not allowed, caller %d, src_dst %d\n",
|
|
call_nr, proc_nr(caller_ptr), src_dst_p);
|
|
#endif
|
|
return(ETRAPDENIED); /* trap denied by mask or kernel */
|
|
}
|
|
|
|
if ((iskerneln(src_dst_p) && call_nr != SENDREC && call_nr != RECEIVE)) {
|
|
#if DEBUG_ENABLE_IPC_WARNINGS
|
|
kprintf("sys_call: trap %d not allowed, caller %d, src_dst %d\n",
|
|
call_nr, proc_nr(caller_ptr), src_dst_e);
|
|
#endif
|
|
return(ETRAPDENIED); /* trap denied by mask or kernel */
|
|
}
|
|
|
|
/* Get and check the size of the argument in bytes.
|
|
* Normally this is just the size of a regular message, but in the
|
|
* case of SENDA the argument is a table.
|
|
*/
|
|
if(call_nr == SENDA) {
|
|
msg_size = (size_t) src_dst_e;
|
|
|
|
/* Limit size to something reasonable. An arbitrary choice is 16
|
|
* times the number of process table entries.
|
|
*/
|
|
if (msg_size > 16*(NR_TASKS + NR_PROCS))
|
|
return EDOM;
|
|
msg_size *= sizeof(asynmsg_t); /* convert to bytes */
|
|
} else {
|
|
msg_size = sizeof(*m_ptr);
|
|
}
|
|
|
|
/* Check for a possible deadlock for blocking SEND(REC) and RECEIVE. */
|
|
if (call_nr == SEND || call_nr == SENDREC || call_nr == RECEIVE) {
|
|
if (group_size = deadlock(call_nr, caller_ptr, src_dst_p)) {
|
|
#if 0
|
|
kprintf("sys_call: trap %d from %d to %d deadlocked, group size %d\n",
|
|
call_nr, proc_nr(caller_ptr), src_dst_p, group_size);
|
|
#endif
|
|
return(ELOCKED);
|
|
}
|
|
}
|
|
|
|
/* Now check if the call is known and try to perform the request. The only
|
|
* system calls that exist in MINIX are sending and receiving messages.
|
|
* - SENDREC: combines SEND and RECEIVE in a single system call
|
|
* - SEND: sender blocks until its message has been delivered
|
|
* - RECEIVE: receiver blocks until an acceptable message has arrived
|
|
* - NOTIFY: asynchronous call; deliver notification or mark pending
|
|
* - SENDA: list of asynchronous send requests
|
|
*/
|
|
switch(call_nr) {
|
|
case SENDREC:
|
|
/* A flag is set so that notifications cannot interrupt SENDREC. */
|
|
caller_ptr->p_misc_flags |= MF_REPLY_PEND;
|
|
/* fall through */
|
|
case SEND:
|
|
result = mini_send(caller_ptr, src_dst_e, m_ptr, 0);
|
|
if (call_nr == SEND || result != OK)
|
|
break; /* done, or SEND failed */
|
|
/* fall through for SENDREC */
|
|
case RECEIVE:
|
|
if (call_nr == RECEIVE)
|
|
caller_ptr->p_misc_flags &= ~MF_REPLY_PEND;
|
|
result = mini_receive(caller_ptr, src_dst_e, m_ptr, 0);
|
|
break;
|
|
case NOTIFY:
|
|
result = mini_notify(caller_ptr, src_dst_e);
|
|
break;
|
|
case SENDNB:
|
|
result = mini_send(caller_ptr, src_dst_e, m_ptr, NON_BLOCKING);
|
|
break;
|
|
case SENDA:
|
|
result = mini_senda(caller_ptr, (asynmsg_t *)m_ptr, (size_t)src_dst_e);
|
|
break;
|
|
default:
|
|
result = EBADCALL; /* illegal system call */
|
|
}
|
|
|
|
/* Now, return the result of the system call to the caller. */
|
|
return(result);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* deadlock *
|
|
*===========================================================================*/
|
|
PRIVATE int deadlock(function, cp, src_dst)
|
|
int function; /* trap number */
|
|
register struct proc *cp; /* pointer to caller */
|
|
int src_dst; /* src or dst process */
|
|
{
|
|
/* Check for deadlock. This can happen if 'caller_ptr' and 'src_dst' have
|
|
* a cyclic dependency of blocking send and receive calls. The only cyclic
|
|
* depency that is not fatal is if the caller and target directly SEND(REC)
|
|
* and RECEIVE to each other. If a deadlock is found, the group size is
|
|
* returned. Otherwise zero is returned.
|
|
*/
|
|
register struct proc *xp; /* process pointer */
|
|
int group_size = 1; /* start with only caller */
|
|
int trap_flags;
|
|
#if DEBUG_ENABLE_IPC_WARNINGS
|
|
static struct proc *processes[NR_PROCS + NR_TASKS];
|
|
processes[0] = cp;
|
|
#endif
|
|
|
|
while (src_dst != ANY) { /* check while process nr */
|
|
int src_dst_e;
|
|
xp = proc_addr(src_dst); /* follow chain of processes */
|
|
#if DEBUG_ENABLE_IPC_WARNINGS
|
|
processes[group_size] = xp;
|
|
#endif
|
|
group_size ++; /* extra process in group */
|
|
|
|
/* Check whether the last process in the chain has a dependency. If it
|
|
* has not, the cycle cannot be closed and we are done.
|
|
*/
|
|
if (RTS_ISSET(xp, RTS_RECEIVING)) { /* xp has dependency */
|
|
if(xp->p_getfrom_e == ANY) src_dst = ANY;
|
|
else okendpt(xp->p_getfrom_e, &src_dst);
|
|
} else if (RTS_ISSET(xp, RTS_SENDING)) { /* xp has dependency */
|
|
okendpt(xp->p_sendto_e, &src_dst);
|
|
} else {
|
|
return(0); /* not a deadlock */
|
|
}
|
|
|
|
/* Now check if there is a cyclic dependency. For group sizes of two,
|
|
* a combination of SEND(REC) and RECEIVE is not fatal. Larger groups
|
|
* or other combinations indicate a deadlock.
|
|
*/
|
|
if (src_dst == proc_nr(cp)) { /* possible deadlock */
|
|
if (group_size == 2) { /* caller and src_dst */
|
|
/* The function number is magically converted to flags. */
|
|
if ((xp->p_rts_flags ^ (function << 2)) & RTS_SENDING) {
|
|
return(0); /* not a deadlock */
|
|
}
|
|
}
|
|
#if DEBUG_ENABLE_IPC_WARNINGS
|
|
{
|
|
int i;
|
|
kprintf("deadlock between these processes:\n");
|
|
for(i = 0; i < group_size; i++) {
|
|
kprintf(" %10s ", processes[i]->p_name);
|
|
proc_stacktrace(processes[i]);
|
|
}
|
|
}
|
|
#endif
|
|
return(group_size); /* deadlock found */
|
|
}
|
|
}
|
|
return(0); /* not a deadlock */
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* mini_send *
|
|
*===========================================================================*/
|
|
PRIVATE int mini_send(caller_ptr, dst_e, m_ptr, flags)
|
|
register struct proc *caller_ptr; /* who is trying to send a message? */
|
|
int dst_e; /* to whom is message being sent? */
|
|
message *m_ptr; /* pointer to message buffer */
|
|
int flags;
|
|
{
|
|
/* Send a message from 'caller_ptr' to 'dst'. If 'dst' is blocked waiting
|
|
* for this message, copy the message to it and unblock 'dst'. If 'dst' is
|
|
* not waiting at all, or is waiting for another source, queue 'caller_ptr'.
|
|
*/
|
|
register struct proc *dst_ptr;
|
|
register struct proc **xpp;
|
|
int dst_p;
|
|
phys_bytes linaddr;
|
|
vir_bytes addr;
|
|
int r;
|
|
|
|
if(!(linaddr = umap_local(caller_ptr, D, (vir_bytes) m_ptr,
|
|
sizeof(message)))) {
|
|
return EFAULT;
|
|
}
|
|
dst_p = _ENDPOINT_P(dst_e);
|
|
dst_ptr = proc_addr(dst_p);
|
|
|
|
if (RTS_ISSET(dst_ptr, RTS_NO_ENDPOINT))
|
|
{
|
|
return EDSTDIED;
|
|
}
|
|
|
|
/* Check if 'dst' is blocked waiting for this message. The destination's
|
|
* RTS_SENDING flag may be set when its SENDREC call blocked while sending.
|
|
*/
|
|
if (WILLRECEIVE(dst_ptr, caller_ptr->p_endpoint)) {
|
|
/* Destination is indeed waiting for this message. */
|
|
vmassert(!(dst_ptr->p_misc_flags & MF_DELIVERMSG));
|
|
if((r=QueueMess(caller_ptr->p_endpoint, linaddr, dst_ptr)) != OK)
|
|
return r;
|
|
RTS_UNSET(dst_ptr, RTS_RECEIVING);
|
|
} else {
|
|
if(flags & NON_BLOCKING) {
|
|
return(ENOTREADY);
|
|
}
|
|
|
|
/* Destination is not waiting. Block and dequeue caller. */
|
|
PHYS_COPY_CATCH(linaddr, vir2phys(&caller_ptr->p_sendmsg),
|
|
sizeof(message), addr);
|
|
|
|
if(addr) { return EFAULT; }
|
|
RTS_SET(caller_ptr, RTS_SENDING);
|
|
caller_ptr->p_sendto_e = dst_e;
|
|
|
|
/* Process is now blocked. Put in on the destination's queue. */
|
|
xpp = &dst_ptr->p_caller_q; /* find end of list */
|
|
while (*xpp != NIL_PROC) xpp = &(*xpp)->p_q_link;
|
|
*xpp = caller_ptr; /* add caller to end */
|
|
caller_ptr->p_q_link = NIL_PROC; /* mark new end of list */
|
|
}
|
|
return(OK);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* mini_receive *
|
|
*===========================================================================*/
|
|
PRIVATE int mini_receive(caller_ptr, src_e, m_ptr, flags)
|
|
register struct proc *caller_ptr; /* process trying to get message */
|
|
int src_e; /* which message source is wanted */
|
|
message *m_ptr; /* pointer to message buffer */
|
|
int flags;
|
|
{
|
|
/* A process or task wants to get a message. If a message is already queued,
|
|
* acquire it and deblock the sender. If no message from the desired source
|
|
* is available block the caller.
|
|
*/
|
|
register struct proc **xpp;
|
|
register struct notification **ntf_q_pp;
|
|
message m;
|
|
int bit_nr;
|
|
sys_map_t *map;
|
|
bitchunk_t *chunk;
|
|
int i, r, src_id, src_proc_nr, src_p;
|
|
phys_bytes linaddr;
|
|
|
|
vmassert(!(caller_ptr->p_misc_flags & MF_DELIVERMSG));
|
|
|
|
if(!(linaddr = umap_local(caller_ptr, D, (vir_bytes) m_ptr,
|
|
sizeof(message)))) {
|
|
return EFAULT;
|
|
}
|
|
|
|
/* This is where we want our message. */
|
|
caller_ptr->p_delivermsg_lin = linaddr;
|
|
caller_ptr->p_delivermsg_vir = (vir_bytes) m_ptr;
|
|
|
|
if(src_e == ANY) src_p = ANY;
|
|
else
|
|
{
|
|
okendpt(src_e, &src_p);
|
|
if (RTS_ISSET(proc_addr(src_p), RTS_NO_ENDPOINT))
|
|
{
|
|
return ESRCDIED;
|
|
}
|
|
}
|
|
|
|
|
|
/* Check to see if a message from desired source is already available. The
|
|
* caller's RTS_SENDING flag may be set if SENDREC couldn't send. If it is
|
|
* set, the process should be blocked.
|
|
*/
|
|
if (!RTS_ISSET(caller_ptr, RTS_SENDING)) {
|
|
|
|
/* Check if there are pending notifications, except for SENDREC. */
|
|
if (! (caller_ptr->p_misc_flags & MF_REPLY_PEND)) {
|
|
|
|
map = &priv(caller_ptr)->s_notify_pending;
|
|
for (chunk=&map->chunk[0]; chunk<&map->chunk[NR_SYS_CHUNKS]; chunk++) {
|
|
endpoint_t hisep;
|
|
|
|
/* Find a pending notification from the requested source. */
|
|
if (! *chunk) continue; /* no bits in chunk */
|
|
for (i=0; ! (*chunk & (1<<i)); ++i) {} /* look up the bit */
|
|
src_id = (chunk - &map->chunk[0]) * BITCHUNK_BITS + i;
|
|
if (src_id >= NR_SYS_PROCS) break; /* out of range */
|
|
src_proc_nr = id_to_nr(src_id); /* get source proc */
|
|
#if DEBUG_ENABLE_IPC_WARNINGS
|
|
if(src_proc_nr == NONE) {
|
|
kprintf("mini_receive: sending notify from NONE\n");
|
|
}
|
|
#endif
|
|
if (src_e!=ANY && src_p != src_proc_nr) continue;/* source not ok */
|
|
*chunk &= ~(1 << i); /* no longer pending */
|
|
|
|
/* Found a suitable source, deliver the notification message. */
|
|
BuildNotifyMessage(&m, src_proc_nr, caller_ptr); /* assemble message */
|
|
hisep = proc_addr(src_proc_nr)->p_endpoint;
|
|
vmassert(!(caller_ptr->p_misc_flags & MF_DELIVERMSG));
|
|
vmassert(src_e == ANY || hisep == src_e);
|
|
if((r=QueueMess(hisep, vir2phys(&m), caller_ptr)) != OK) {
|
|
minix_panic("mini_receive: local QueueMess failed", NO_NUM);
|
|
}
|
|
return(OK); /* report success */
|
|
}
|
|
}
|
|
|
|
/* Check caller queue. Use pointer pointers to keep code simple. */
|
|
xpp = &caller_ptr->p_caller_q;
|
|
while (*xpp != NIL_PROC) {
|
|
if (src_e == ANY || src_p == proc_nr(*xpp)) {
|
|
#if DEBUG_SCHED_CHECK
|
|
if (RTS_ISSET(*xpp, RTS_SLOT_FREE) || RTS_ISSET(*xpp, RTS_NO_ENDPOINT))
|
|
{
|
|
kprintf("%d: receive from %d; found dead %d (%s)?\n",
|
|
caller_ptr->p_endpoint, src_e, (*xpp)->p_endpoint,
|
|
(*xpp)->p_name);
|
|
return EINVAL;
|
|
}
|
|
#endif
|
|
|
|
/* Found acceptable message. Copy it and update status. */
|
|
vmassert(!(caller_ptr->p_misc_flags & MF_DELIVERMSG));
|
|
QueueMess((*xpp)->p_endpoint,
|
|
vir2phys(&(*xpp)->p_sendmsg), caller_ptr);
|
|
if ((*xpp)->p_misc_flags & MF_SIG_DELAY)
|
|
sig_delay_done(*xpp);
|
|
RTS_UNSET(*xpp, RTS_SENDING);
|
|
*xpp = (*xpp)->p_q_link; /* remove from queue */
|
|
return(OK); /* report success */
|
|
}
|
|
xpp = &(*xpp)->p_q_link; /* proceed to next */
|
|
}
|
|
|
|
if (caller_ptr->p_misc_flags & MF_ASYNMSG)
|
|
{
|
|
if (src_e != ANY)
|
|
r= try_one(proc_addr(src_p), caller_ptr, NULL);
|
|
else
|
|
r= try_async(caller_ptr);
|
|
|
|
if (r == OK)
|
|
return OK; /* Got a message */
|
|
}
|
|
}
|
|
|
|
/* No suitable message is available or the caller couldn't send in SENDREC.
|
|
* Block the process trying to receive, unless the flags tell otherwise.
|
|
*/
|
|
if ( ! (flags & NON_BLOCKING)) {
|
|
caller_ptr->p_getfrom_e = src_e;
|
|
RTS_SET(caller_ptr, RTS_RECEIVING);
|
|
return(OK);
|
|
} else {
|
|
return(ENOTREADY);
|
|
}
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* mini_notify *
|
|
*===========================================================================*/
|
|
PUBLIC int mini_notify(caller_ptr, dst_e)
|
|
register struct proc *caller_ptr; /* sender of the notification */
|
|
endpoint_t dst_e; /* which process to notify */
|
|
{
|
|
register struct proc *dst_ptr;
|
|
int src_id; /* source id for late delivery */
|
|
message m; /* the notification message */
|
|
int r;
|
|
int proc_nr;
|
|
int dst_p;
|
|
|
|
vmassert(intr_disabled());
|
|
|
|
if (!isokendpt(dst_e, &dst_p)) {
|
|
util_stacktrace();
|
|
kprintf("mini_notify: bogus endpoint %d\n", dst_e);
|
|
return EDEADSRCDST;
|
|
}
|
|
|
|
dst_ptr = proc_addr(dst_p);
|
|
|
|
/* Check to see if target is blocked waiting for this message. A process
|
|
* can be both sending and receiving during a SENDREC system call.
|
|
*/
|
|
if (WILLRECEIVE(dst_ptr, caller_ptr->p_endpoint) &&
|
|
! (dst_ptr->p_misc_flags & MF_REPLY_PEND)) {
|
|
/* Destination is indeed waiting for a message. Assemble a notification
|
|
* message and deliver it. Copy from pseudo-source HARDWARE, since the
|
|
* message is in the kernel's address space.
|
|
*/
|
|
BuildNotifyMessage(&m, proc_nr(caller_ptr), dst_ptr);
|
|
vmassert(!(dst_ptr->p_misc_flags & MF_DELIVERMSG));
|
|
if((r=QueueMess(caller_ptr->p_endpoint, vir2phys(&m), dst_ptr)) != OK) {
|
|
minix_panic("mini_notify: local QueueMess failed", NO_NUM);
|
|
}
|
|
RTS_UNSET(dst_ptr, RTS_RECEIVING);
|
|
return(OK);
|
|
}
|
|
|
|
/* Destination is not ready to receive the notification. Add it to the
|
|
* bit map with pending notifications. Note the indirectness: the system id
|
|
* instead of the process number is used in the pending bit map.
|
|
*/
|
|
src_id = priv(caller_ptr)->s_id;
|
|
set_sys_bit(priv(dst_ptr)->s_notify_pending, src_id);
|
|
return(OK);
|
|
}
|
|
|
|
#define ASCOMPLAIN(caller, entry, field) \
|
|
kprintf("kernel:%s:%d: asyn failed for %s in %s " \
|
|
"(%d/%d, tab 0x%lx)\n",__FILE__,__LINE__, \
|
|
field, caller->p_name, entry, priv(caller)->s_asynsize, priv(caller)->s_asyntab)
|
|
|
|
#define A_RETRIEVE(entry, field) \
|
|
if(data_copy(caller_ptr->p_endpoint, \
|
|
table_v + (entry)*sizeof(asynmsg_t) + offsetof(struct asynmsg,field),\
|
|
SYSTEM, (vir_bytes) &tabent.field, \
|
|
sizeof(tabent.field)) != OK) {\
|
|
ASCOMPLAIN(caller_ptr, entry, #field); \
|
|
return EFAULT; \
|
|
}
|
|
|
|
#define A_INSERT(entry, field) \
|
|
if(data_copy(SYSTEM, (vir_bytes) &tabent.field, \
|
|
caller_ptr->p_endpoint, \
|
|
table_v + (entry)*sizeof(asynmsg_t) + offsetof(struct asynmsg,field),\
|
|
sizeof(tabent.field)) != OK) {\
|
|
ASCOMPLAIN(caller_ptr, entry, #field); \
|
|
return EFAULT; \
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* mini_senda *
|
|
*===========================================================================*/
|
|
PRIVATE int mini_senda(caller_ptr, table, size)
|
|
struct proc *caller_ptr;
|
|
asynmsg_t *table;
|
|
size_t size;
|
|
{
|
|
int i, dst_p, done, do_notify, r;
|
|
unsigned flags;
|
|
struct proc *dst_ptr;
|
|
struct priv *privp;
|
|
message *m_ptr;
|
|
asynmsg_t tabent;
|
|
vir_bytes table_v = (vir_bytes) table;
|
|
vir_bytes linaddr;
|
|
|
|
privp= priv(caller_ptr);
|
|
if (!(privp->s_flags & SYS_PROC))
|
|
{
|
|
kprintf(
|
|
"mini_senda: warning caller has no privilege structure\n");
|
|
return EPERM;
|
|
}
|
|
|
|
/* Clear table */
|
|
privp->s_asyntab= -1;
|
|
privp->s_asynsize= 0;
|
|
|
|
if (size == 0)
|
|
{
|
|
/* Nothing to do, just return */
|
|
return OK;
|
|
}
|
|
|
|
if(!(linaddr = umap_local(caller_ptr, D, (vir_bytes) table,
|
|
size * sizeof(*table)))) {
|
|
printf("mini_senda: umap_local failed; 0x%lx len 0x%lx\n",
|
|
table, size * sizeof(*table));
|
|
return EFAULT;
|
|
}
|
|
|
|
/* Limit size to something reasonable. An arbitrary choice is 16
|
|
* times the number of process table entries.
|
|
*
|
|
* (this check has been duplicated in sys_call but is left here
|
|
* as a sanity check)
|
|
*/
|
|
if (size > 16*(NR_TASKS + NR_PROCS))
|
|
{
|
|
return EDOM;
|
|
}
|
|
|
|
/* Scan the table */
|
|
do_notify= FALSE;
|
|
done= TRUE;
|
|
for (i= 0; i<size; i++)
|
|
{
|
|
|
|
/* Read status word */
|
|
A_RETRIEVE(i, flags);
|
|
flags= tabent.flags;
|
|
|
|
/* Skip empty entries */
|
|
if (flags == 0)
|
|
continue;
|
|
|
|
/* Check for reserved bits in the flags field */
|
|
if (flags & ~(AMF_VALID|AMF_DONE|AMF_NOTIFY|AMF_NOREPLY) ||
|
|
!(flags & AMF_VALID))
|
|
{
|
|
return EINVAL;
|
|
}
|
|
|
|
/* Skip entry if AMF_DONE is already set */
|
|
if (flags & AMF_DONE)
|
|
continue;
|
|
|
|
/* Get destination */
|
|
A_RETRIEVE(i, dst);
|
|
|
|
if (!isokendpt(tabent.dst, &dst_p))
|
|
{
|
|
/* Bad destination, report the error */
|
|
tabent.result= EDEADSRCDST;
|
|
A_INSERT(i, result);
|
|
tabent.flags= flags | AMF_DONE;
|
|
A_INSERT(i, flags);
|
|
|
|
if (flags & AMF_NOTIFY)
|
|
do_notify= 1;
|
|
continue;
|
|
}
|
|
|
|
if (!may_send_to(caller_ptr, dst_p))
|
|
{
|
|
/* Send denied by IPC mask */
|
|
tabent.result= ECALLDENIED;
|
|
A_INSERT(i, result);
|
|
tabent.flags= flags | AMF_DONE;
|
|
A_INSERT(i, flags);
|
|
|
|
if (flags & AMF_NOTIFY)
|
|
do_notify= 1;
|
|
continue;
|
|
}
|
|
|
|
#if 0
|
|
kprintf("mini_senda: entry[%d]: flags 0x%x dst %d/%d\n",
|
|
i, tabent.flags, tabent.dst, dst_p);
|
|
#endif
|
|
|
|
dst_ptr = proc_addr(dst_p);
|
|
|
|
/* RTS_NO_ENDPOINT should be removed */
|
|
if (dst_ptr->p_rts_flags & RTS_NO_ENDPOINT)
|
|
{
|
|
tabent.result= EDSTDIED;
|
|
A_INSERT(i, result);
|
|
tabent.flags= flags | AMF_DONE;
|
|
A_INSERT(i, flags);
|
|
|
|
if (flags & AMF_NOTIFY)
|
|
do_notify= TRUE;
|
|
continue;
|
|
}
|
|
|
|
/* Check if 'dst' is blocked waiting for this message.
|
|
* If AMF_NOREPLY is set, do not satisfy the receiving part of
|
|
* a SENDREC.
|
|
*/
|
|
if (WILLRECEIVE(dst_ptr, caller_ptr->p_endpoint) &&
|
|
(!(flags & AMF_NOREPLY) ||
|
|
!(dst_ptr->p_misc_flags & MF_REPLY_PEND)))
|
|
{
|
|
/* Destination is indeed waiting for this message. */
|
|
m_ptr= &table[i].msg; /* Note: pointer in the
|
|
* caller's address space.
|
|
*/
|
|
/* Copy message from sender. */
|
|
tabent.result= QueueMess(caller_ptr->p_endpoint,
|
|
linaddr + (vir_bytes) &table[i].msg -
|
|
(vir_bytes) table, dst_ptr);
|
|
if(tabent.result == OK)
|
|
RTS_UNSET(dst_ptr, RTS_RECEIVING);
|
|
|
|
A_INSERT(i, result);
|
|
tabent.flags= flags | AMF_DONE;
|
|
A_INSERT(i, flags);
|
|
|
|
if (flags & AMF_NOTIFY)
|
|
do_notify= 1;
|
|
continue;
|
|
}
|
|
else
|
|
{
|
|
/* Should inform receiver that something is pending */
|
|
dst_ptr->p_misc_flags |= MF_ASYNMSG;
|
|
done= FALSE;
|
|
continue;
|
|
}
|
|
}
|
|
if (do_notify)
|
|
kprintf("mini_senda: should notify caller\n");
|
|
if (!done)
|
|
{
|
|
privp->s_asyntab= (vir_bytes)table;
|
|
privp->s_asynsize= size;
|
|
}
|
|
return OK;
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* try_async *
|
|
*===========================================================================*/
|
|
PRIVATE int try_async(caller_ptr)
|
|
struct proc *caller_ptr;
|
|
{
|
|
int r;
|
|
struct priv *privp;
|
|
struct proc *src_ptr;
|
|
int postponed = FALSE;
|
|
|
|
/* Try all privilege structures */
|
|
for (privp = BEG_PRIV_ADDR; privp < END_PRIV_ADDR; ++privp)
|
|
{
|
|
if (privp->s_proc_nr == NONE)
|
|
continue;
|
|
|
|
src_ptr= proc_addr(privp->s_proc_nr);
|
|
|
|
vmassert(!(caller_ptr->p_misc_flags & MF_DELIVERMSG));
|
|
r= try_one(src_ptr, caller_ptr, &postponed);
|
|
if (r == OK)
|
|
return r;
|
|
}
|
|
|
|
/* Nothing found, clear MF_ASYNMSG unless messages were postponed */
|
|
if (postponed == FALSE)
|
|
caller_ptr->p_misc_flags &= ~MF_ASYNMSG;
|
|
|
|
return ESRCH;
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* try_one *
|
|
*===========================================================================*/
|
|
PRIVATE int try_one(src_ptr, dst_ptr, postponed)
|
|
struct proc *src_ptr;
|
|
struct proc *dst_ptr;
|
|
int *postponed;
|
|
{
|
|
int i, do_notify, done;
|
|
unsigned flags;
|
|
size_t size;
|
|
endpoint_t dst_e;
|
|
asynmsg_t *table_ptr;
|
|
message *m_ptr;
|
|
struct priv *privp;
|
|
asynmsg_t tabent;
|
|
vir_bytes table_v;
|
|
struct proc *caller_ptr;
|
|
int r;
|
|
|
|
privp= priv(src_ptr);
|
|
|
|
/* Basic validity checks */
|
|
if (privp->s_id == USER_PRIV_ID) return EAGAIN;
|
|
if (privp->s_asynsize == 0) return EAGAIN;
|
|
if (!may_send_to(src_ptr, proc_nr(dst_ptr))) return EAGAIN;
|
|
|
|
size= privp->s_asynsize;
|
|
table_v = privp->s_asyntab;
|
|
caller_ptr = src_ptr;
|
|
|
|
dst_e= dst_ptr->p_endpoint;
|
|
|
|
/* Scan the table */
|
|
do_notify= FALSE;
|
|
done= TRUE;
|
|
for (i= 0; i<size; i++)
|
|
{
|
|
/* Read status word */
|
|
A_RETRIEVE(i, flags);
|
|
flags= tabent.flags;
|
|
|
|
/* Skip empty entries */
|
|
if (flags == 0)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
/* Check for reserved bits in the flags field */
|
|
if (flags & ~(AMF_VALID|AMF_DONE|AMF_NOTIFY|AMF_NOREPLY) ||
|
|
!(flags & AMF_VALID))
|
|
{
|
|
kprintf("try_one: bad bits in table\n");
|
|
privp->s_asynsize= 0;
|
|
return EINVAL;
|
|
}
|
|
|
|
/* Skip entry is AMF_DONE is already set */
|
|
if (flags & AMF_DONE)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
/* Clear done. We are done when all entries are either empty
|
|
* or done at the start of the call.
|
|
*/
|
|
done= FALSE;
|
|
|
|
/* Get destination */
|
|
A_RETRIEVE(i, dst);
|
|
|
|
if (tabent.dst != dst_e)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
/* If AMF_NOREPLY is set, do not satisfy the receiving part of
|
|
* a SENDREC. Do not unset MF_ASYNMSG later because of this,
|
|
* though: this message is still to be delivered later.
|
|
*/
|
|
if ((flags & AMF_NOREPLY) &&
|
|
(dst_ptr->p_misc_flags & MF_REPLY_PEND))
|
|
{
|
|
if (postponed != NULL)
|
|
*postponed = TRUE;
|
|
|
|
continue;
|
|
}
|
|
|
|
/* Deliver message */
|
|
table_ptr= (asynmsg_t *)privp->s_asyntab;
|
|
m_ptr= &table_ptr[i].msg; /* Note: pointer in the
|
|
* caller's address space.
|
|
*/
|
|
A_RETRIEVE(i, msg);
|
|
r = QueueMess(src_ptr->p_endpoint, vir2phys(&tabent.msg),
|
|
dst_ptr);
|
|
|
|
tabent.result= r;
|
|
A_INSERT(i, result);
|
|
tabent.flags= flags | AMF_DONE;
|
|
A_INSERT(i, flags);
|
|
|
|
if (flags & AMF_NOTIFY)
|
|
{
|
|
kprintf("try_one: should notify caller\n");
|
|
}
|
|
return OK;
|
|
}
|
|
if (done)
|
|
privp->s_asynsize= 0;
|
|
return EAGAIN;
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* lock_notify *
|
|
*===========================================================================*/
|
|
PUBLIC int lock_notify(src_e, dst_e)
|
|
int src_e; /* (endpoint) sender of the notification */
|
|
int dst_e; /* (endpoint) who is to be notified */
|
|
{
|
|
/* Safe gateway to mini_notify() for tasks and interrupt handlers. The sender
|
|
* is explicitely given to prevent confusion where the call comes from. MINIX
|
|
* kernel is not reentrant, which means to interrupts are disabled after
|
|
* the first kernel entry (hardware interrupt, trap, or exception). Locking
|
|
* is done by temporarily disabling interrupts.
|
|
*/
|
|
int result, src_p;
|
|
|
|
vmassert(!intr_disabled());
|
|
|
|
if (!isokendpt(src_e, &src_p)) {
|
|
kprintf("lock_notify: bogus src: %d\n", src_e);
|
|
return EDEADSRCDST;
|
|
}
|
|
|
|
lock;
|
|
vmassert(intr_disabled());
|
|
result = mini_notify(proc_addr(src_p), dst_e);
|
|
vmassert(intr_disabled());
|
|
unlock;
|
|
vmassert(!intr_disabled());
|
|
|
|
return(result);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* enqueue *
|
|
*===========================================================================*/
|
|
PUBLIC void enqueue(rp)
|
|
register struct proc *rp; /* this process is now runnable */
|
|
{
|
|
/* Add 'rp' to one of the queues of runnable processes. This function is
|
|
* responsible for inserting a process into one of the scheduling queues.
|
|
* The mechanism is implemented here. The actual scheduling policy is
|
|
* defined in sched() and pick_proc().
|
|
*/
|
|
int q; /* scheduling queue to use */
|
|
int front; /* add to front or back */
|
|
|
|
NOREC_ENTER(enqueuefunc);
|
|
|
|
#if DEBUG_SCHED_CHECK
|
|
if(!intr_disabled()) { minix_panic("enqueue with interrupts enabled", NO_NUM); }
|
|
if (rp->p_ready) minix_panic("enqueue already ready process", NO_NUM);
|
|
#endif
|
|
|
|
/* Determine where to insert to process. */
|
|
sched(rp, &q, &front);
|
|
|
|
vmassert(q >= 0);
|
|
|
|
/* Now add the process to the queue. */
|
|
if (rdy_head[q] == NIL_PROC) { /* add to empty queue */
|
|
rdy_head[q] = rdy_tail[q] = rp; /* create a new queue */
|
|
rp->p_nextready = NIL_PROC; /* mark new end */
|
|
}
|
|
else if (front) { /* add to head of queue */
|
|
rp->p_nextready = rdy_head[q]; /* chain head of queue */
|
|
rdy_head[q] = rp; /* set new queue head */
|
|
}
|
|
else { /* add to tail of queue */
|
|
rdy_tail[q]->p_nextready = rp; /* chain tail of queue */
|
|
rdy_tail[q] = rp; /* set new queue tail */
|
|
rp->p_nextready = NIL_PROC; /* mark new end */
|
|
}
|
|
|
|
#if DEBUG_SCHED_CHECK
|
|
rp->p_ready = 1;
|
|
CHECK_RUNQUEUES;
|
|
#endif
|
|
|
|
/*
|
|
* enqueueing a process with a higher priority than the current one, it gets
|
|
* preempted. The current process must be preemptible. Testing the priority
|
|
* also makes sure that a process does not preempt itself
|
|
*/
|
|
vmassert(proc_ptr);
|
|
if ((proc_ptr->p_priority > rp->p_priority) &&
|
|
(priv(proc_ptr)->s_flags & PREEMPTIBLE))
|
|
RTS_SET(proc_ptr, RTS_PREEMPTED); /* calls dequeue() */
|
|
|
|
#if DEBUG_SCHED_CHECK
|
|
CHECK_RUNQUEUES;
|
|
#endif
|
|
|
|
NOREC_RETURN(enqueuefunc, );
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* enqueue_head *
|
|
*===========================================================================*/
|
|
/*
|
|
* put a process at the front of its run queue. It comes handy when a process is
|
|
* preempted and removed from run queue to not to have a currently not-runnable
|
|
* process on a run queue. We have to put this process back at the fron to be
|
|
* fair
|
|
*/
|
|
PRIVATE void enqueue_head(struct proc *rp)
|
|
{
|
|
int q; /* scheduling queue to use */
|
|
|
|
#if DEBUG_SCHED_CHECK
|
|
if(!intr_disabled()) { minix_panic("enqueue with interrupts enabled", NO_NUM); }
|
|
if (rp->p_ready) minix_panic("enqueue already ready process", NO_NUM);
|
|
#endif
|
|
|
|
/*
|
|
* the process was runnable without its quantum expired when dequeued. A
|
|
* process with no time left should vahe been handled else and differently
|
|
*/
|
|
vmassert(rp->p_ticks_left);
|
|
|
|
vmassert(q >= 0);
|
|
|
|
q = rp->p_priority;
|
|
|
|
/* Now add the process to the queue. */
|
|
if (rdy_head[q] == NIL_PROC) { /* add to empty queue */
|
|
rdy_head[q] = rdy_tail[q] = rp; /* create a new queue */
|
|
rp->p_nextready = NIL_PROC; /* mark new end */
|
|
}
|
|
else /* add to head of queue */
|
|
rp->p_nextready = rdy_head[q]; /* chain head of queue */
|
|
rdy_head[q] = rp; /* set new queue head */
|
|
|
|
#if DEBUG_SCHED_CHECK
|
|
rp->p_ready = 1;
|
|
CHECK_RUNQUEUES;
|
|
#endif
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* dequeue *
|
|
*===========================================================================*/
|
|
PUBLIC void dequeue(rp)
|
|
register struct proc *rp; /* this process is no longer runnable */
|
|
{
|
|
/* A process must be removed from the scheduling queues, for example, because
|
|
* it has blocked. If the currently active process is removed, a new process
|
|
* is picked to run by calling pick_proc().
|
|
*/
|
|
register int q = rp->p_priority; /* queue to use */
|
|
register struct proc **xpp; /* iterate over queue */
|
|
register struct proc *prev_xp;
|
|
|
|
NOREC_ENTER(dequeuefunc);
|
|
|
|
#if DEBUG_STACK_CHECK
|
|
/* Side-effect for kernel: check if the task's stack still is ok? */
|
|
if (iskernelp(rp)) {
|
|
if (*priv(rp)->s_stack_guard != STACK_GUARD)
|
|
minix_panic("stack overrun by task", proc_nr(rp));
|
|
}
|
|
#endif
|
|
|
|
#if DEBUG_SCHED_CHECK
|
|
if(!intr_disabled()) { minix_panic("dequeue with interrupts enabled", NO_NUM); }
|
|
if (! rp->p_ready) minix_panic("dequeue() already unready process", NO_NUM);
|
|
#endif
|
|
|
|
/* Now make sure that the process is not in its ready queue. Remove the
|
|
* process if it is found. A process can be made unready even if it is not
|
|
* running by being sent a signal that kills it.
|
|
*/
|
|
prev_xp = NIL_PROC;
|
|
for (xpp = &rdy_head[q]; *xpp != NIL_PROC; xpp = &(*xpp)->p_nextready) {
|
|
|
|
if (*xpp == rp) { /* found process to remove */
|
|
*xpp = (*xpp)->p_nextready; /* replace with next chain */
|
|
if (rp == rdy_tail[q]) /* queue tail removed */
|
|
rdy_tail[q] = prev_xp; /* set new tail */
|
|
|
|
#if DEBUG_SCHED_CHECK
|
|
rp->p_ready = 0;
|
|
CHECK_RUNQUEUES;
|
|
#endif
|
|
break;
|
|
}
|
|
prev_xp = *xpp; /* save previous in chain */
|
|
}
|
|
|
|
#if DEBUG_SCHED_CHECK
|
|
CHECK_RUNQUEUES;
|
|
#endif
|
|
|
|
NOREC_RETURN(dequeuefunc, );
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* sched *
|
|
*===========================================================================*/
|
|
PRIVATE void sched(rp, queue, front)
|
|
register struct proc *rp; /* process to be scheduled */
|
|
int *queue; /* return: queue to use */
|
|
int *front; /* return: front or back */
|
|
{
|
|
/* This function determines the scheduling policy. It is called whenever a
|
|
* process must be added to one of the scheduling queues to decide where to
|
|
* insert it. As a side-effect the process' priority may be updated.
|
|
*/
|
|
int time_left = (rp->p_ticks_left > 0); /* quantum fully consumed */
|
|
|
|
/* Check whether the process has time left. Otherwise give a new quantum
|
|
* and lower the process' priority, unless the process already is in the
|
|
* lowest queue.
|
|
*/
|
|
if (! time_left) { /* quantum consumed ? */
|
|
rp->p_ticks_left = rp->p_quantum_size; /* give new quantum */
|
|
if (rp->p_priority < (NR_SCHED_QUEUES-1)) {
|
|
rp->p_priority += 1; /* lower priority */
|
|
}
|
|
}
|
|
|
|
/* If there is time left, the process is added to the front of its queue,
|
|
* so that it can immediately run. The queue to use simply is always the
|
|
* process' current priority.
|
|
*/
|
|
*queue = rp->p_priority;
|
|
*front = time_left;
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* pick_proc *
|
|
*===========================================================================*/
|
|
PRIVATE struct proc * pick_proc(void)
|
|
{
|
|
/* Decide who to run now. A new process is selected an returned.
|
|
* When a billable process is selected, record it in 'bill_ptr', so that the
|
|
* clock task can tell who to bill for system time.
|
|
*/
|
|
register struct proc *rp; /* process to run */
|
|
int q; /* iterate over queues */
|
|
|
|
/* Check each of the scheduling queues for ready processes. The number of
|
|
* queues is defined in proc.h, and priorities are set in the task table.
|
|
* The lowest queue contains IDLE, which is always ready.
|
|
*/
|
|
for (q=0; q < NR_SCHED_QUEUES; q++) {
|
|
int found = 0;
|
|
if(!(rp = rdy_head[q])) {
|
|
TRACE(VF_PICKPROC, printf("queue %d empty\n", q););
|
|
continue;
|
|
}
|
|
TRACE(VF_PICKPROC, printf("found %s / %d on queue %d\n",
|
|
rp->p_name, rp->p_endpoint, q););
|
|
vmassert(!proc_is_runnable(rp));
|
|
if (priv(rp)->s_flags & BILLABLE)
|
|
bill_ptr = rp; /* bill for system time */
|
|
return rp;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* balance_queues *
|
|
*===========================================================================*/
|
|
#define Q_BALANCE_TICKS 100
|
|
PUBLIC void balance_queues(tp)
|
|
timer_t *tp; /* watchdog timer pointer */
|
|
{
|
|
/* Check entire process table and give all process a higher priority. This
|
|
* effectively means giving a new quantum. If a process already is at its
|
|
* maximum priority, its quantum will be renewed.
|
|
*/
|
|
static timer_t queue_timer; /* timer structure to use */
|
|
register struct proc* rp; /* process table pointer */
|
|
clock_t next_period; /* time of next period */
|
|
int ticks_added = 0; /* total time added */
|
|
|
|
vmassert(!intr_disabled());
|
|
|
|
lock;
|
|
for (rp=BEG_PROC_ADDR; rp<END_PROC_ADDR; rp++) {
|
|
if (! isemptyp(rp)) { /* check slot use */
|
|
if (rp->p_priority > rp->p_max_priority) { /* update priority? */
|
|
if (proc_is_runnable(rp)) dequeue(rp); /* take off queue */
|
|
ticks_added += rp->p_quantum_size; /* do accounting */
|
|
rp->p_priority -= 1; /* raise priority */
|
|
if (proc_is_runnable(rp)) enqueue(rp); /* put on queue */
|
|
}
|
|
else {
|
|
ticks_added += rp->p_quantum_size - rp->p_ticks_left;
|
|
rp->p_ticks_left = rp->p_quantum_size; /* give new quantum */
|
|
}
|
|
}
|
|
}
|
|
unlock;
|
|
|
|
/* Now schedule a new watchdog timer to balance the queues again. The
|
|
* period depends on the total amount of quantum ticks added.
|
|
*/
|
|
next_period = MAX(Q_BALANCE_TICKS, ticks_added); /* calculate next */
|
|
set_timer(&queue_timer, get_uptime() + next_period, balance_queues);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* lock_send *
|
|
*===========================================================================*/
|
|
PUBLIC int lock_send(dst_e, m_ptr)
|
|
int dst_e; /* to whom is message being sent? */
|
|
message *m_ptr; /* pointer to message buffer */
|
|
{
|
|
/* Safe gateway to mini_send() for tasks. */
|
|
int result;
|
|
lock;
|
|
result = mini_send(proc_ptr, dst_e, m_ptr, 0);
|
|
unlock;
|
|
return(result);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* endpoint_lookup *
|
|
*===========================================================================*/
|
|
PUBLIC struct proc *endpoint_lookup(endpoint_t e)
|
|
{
|
|
int n;
|
|
|
|
if(!isokendpt(e, &n)) return NULL;
|
|
|
|
return proc_addr(n);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* isokendpt_f *
|
|
*===========================================================================*/
|
|
#if DEBUG_ENABLE_IPC_WARNINGS
|
|
PUBLIC int isokendpt_f(file, line, e, p, fatalflag)
|
|
char *file;
|
|
int line;
|
|
#else
|
|
PUBLIC int isokendpt_f(e, p, fatalflag)
|
|
#endif
|
|
endpoint_t e;
|
|
int *p, fatalflag;
|
|
{
|
|
int ok = 0;
|
|
/* Convert an endpoint number into a process number.
|
|
* Return nonzero if the process is alive with the corresponding
|
|
* generation number, zero otherwise.
|
|
*
|
|
* This function is called with file and line number by the
|
|
* isokendpt_d macro if DEBUG_ENABLE_IPC_WARNINGS is defined,
|
|
* otherwise without. This allows us to print the where the
|
|
* conversion was attempted, making the errors verbose without
|
|
* adding code for that at every call.
|
|
*
|
|
* If fatalflag is nonzero, we must panic if the conversion doesn't
|
|
* succeed.
|
|
*/
|
|
*p = _ENDPOINT_P(e);
|
|
if(!isokprocn(*p)) {
|
|
#if DEBUG_ENABLE_IPC_WARNINGS
|
|
kprintf("kernel:%s:%d: bad endpoint %d: proc %d out of range\n",
|
|
file, line, e, *p);
|
|
#endif
|
|
} else if(isemptyn(*p)) {
|
|
#if 0
|
|
kprintf("kernel:%s:%d: bad endpoint %d: proc %d empty\n", file, line, e, *p);
|
|
#endif
|
|
} else if(proc_addr(*p)->p_endpoint != e) {
|
|
#if DEBUG_ENABLE_IPC_WARNINGS
|
|
kprintf("kernel:%s:%d: bad endpoint %d: proc %d has ept %d (generation %d vs. %d)\n", file, line,
|
|
e, *p, proc_addr(*p)->p_endpoint,
|
|
_ENDPOINT_G(e), _ENDPOINT_G(proc_addr(*p)->p_endpoint));
|
|
#endif
|
|
} else ok = 1;
|
|
if(!ok && fatalflag) {
|
|
minix_panic("invalid endpoint ", e);
|
|
}
|
|
return ok;
|
|
}
|
|
|