minix/kernel/system.c
Tomas Hruby 1f89845bb2 SMP - can boot even if some cpus fail to boot
- EBADCPU is returned is scheduler tries to run a process on a CPU
  that either does not exist or isn't booted

- this change was originally meant to deal with stupid cpuid
  instruction which provides totally useless information about
  hyper-threading and MPS which does not deal with ht at all. ACPI
  provides correct information. If ht is turned off it looks like some
  CPUs failed to boot.  Nevertheless this patch may be handy for
  testing/benchmarking in the future.
2010-09-15 14:11:21 +00:00

700 lines
26 KiB
C

/* This task handles the interface between the kernel and user-level servers.
* System services can be accessed by doing a system call. System calls are
* transformed into request messages, which are handled by this task. By
* convention, a sys_call() is transformed in a SYS_CALL request message that
* is handled in a function named do_call().
*
* A private call vector is used to map all system calls to the functions that
* handle them. The actual handler functions are contained in separate files
* to keep this file clean. The call vector is used in the system task's main
* loop to handle all incoming requests.
*
* In addition to the main sys_task() entry point, which starts the main loop,
* there are several other minor entry points:
* get_priv: assign privilege structure to user or system process
* set_sendto_bit: allow a process to send messages to a new target
* unset_sendto_bit: disallow a process from sending messages to a target
* fill_sendto_mask: fill the target mask of a given process
* send_sig: send a signal directly to a system process
* cause_sig: take action to cause a signal to occur via a signal mgr
* sig_delay_done: tell PM that a process is not sending
* umap_bios: map virtual address in BIOS_SEG to physical
* get_randomness: accumulate randomness in a buffer
* clear_endpoint: remove a process' ability to send and receive messages
* sched_proc: schedule a process
*
* Changes:
* Nov 22, 2009 get_priv supports static priv ids (Cristiano Giuffrida)
* Aug 04, 2005 check if system call is allowed (Jorrit N. Herder)
* Jul 20, 2005 send signal to services with message (Jorrit N. Herder)
* Jan 15, 2005 new, generalized virtual copy function (Jorrit N. Herder)
* Oct 10, 2004 dispatch system calls from call vector (Jorrit N. Herder)
* Sep 30, 2004 source code documentation updated (Jorrit N. Herder)
*/
#include "debug.h"
#include "kernel.h"
#include "system.h"
#include "proc.h"
#include "vm.h"
#include "kernel/clock.h"
#include <stdlib.h>
#include <assert.h>
#include <signal.h>
#include <unistd.h>
#include <sys/sigcontext.h>
#include <minix/endpoint.h>
#include <minix/safecopies.h>
/* Declaration of the call vector that defines the mapping of system calls
* to handler functions. The vector is initialized in sys_init() with map(),
* which makes sure the system call numbers are ok. No space is allocated,
* because the dummy is declared extern. If an illegal call is given, the
* array size will be negative and this won't compile.
*/
PRIVATE int (*call_vec[NR_SYS_CALLS])(struct proc * caller, message *m_ptr);
#define map(call_nr, handler) \
{extern int dummy[NR_SYS_CALLS>(unsigned)(call_nr-KERNEL_CALL) ? 1:-1];} \
call_vec[(call_nr-KERNEL_CALL)] = (handler)
PRIVATE void kernel_call_finish(struct proc * caller, message *msg, int result)
{
if(result == VMSUSPEND) {
/* Special case: message has to be saved for handling
* until VM tells us it's allowed. VM has been notified
* and we must wait for its reply to restart the call.
*/
assert(RTS_ISSET(caller, RTS_VMREQUEST));
assert(caller->p_vmrequest.type == VMSTYPE_KERNELCALL);
caller->p_vmrequest.saved.reqmsg = *msg;
caller->p_misc_flags |= MF_KCALL_RESUME;
} else {
/*
* call is finished, we could have been suspended because of VM,
* remove the request message
*/
caller->p_vmrequest.saved.reqmsg.m_source = NONE;
if (result != EDONTREPLY) {
/* copy the result as a message to the original user buffer */
msg->m_source = SYSTEM;
msg->m_type = result; /* report status of call */
#if DEBUG_DUMPIPC
printmsgkresult(msg, caller);
#endif
if (copy_msg_to_user(caller, msg,
(message *)caller->p_delivermsg_vir)) {
printf("WARNING wrong user pointer 0x%08x from "
"process %s / %d\n",
caller->p_delivermsg_vir,
caller->p_name,
caller->p_endpoint);
}
}
}
}
PRIVATE int kernel_call_dispatch(struct proc * caller, message *msg)
{
int result = OK;
int call_nr;
#if DEBUG_DUMPIPC
printmsgkcall(msg, caller);
#endif
call_nr = msg->m_type - KERNEL_CALL;
/* See if the caller made a valid request and try to handle it. */
if (call_nr < 0 || call_nr >= NR_SYS_CALLS) { /* check call number */
printf("SYSTEM: illegal request %d from %d.\n",
call_nr,msg->m_source);
result = EBADREQUEST; /* illegal message type */
}
else if (!GET_BIT(priv(caller)->s_k_call_mask, call_nr)) {
printf("SYSTEM: denied request %d from %d.\n",
call_nr,msg->m_source);
result = ECALLDENIED; /* illegal message type */
} else {
/* handle the system call */
if (call_vec[call_nr])
result = (*call_vec[call_nr])(caller, msg);
else {
printf("Unused kernel call %d from %d\n",
call_nr, caller->p_endpoint);
result = EBADREQUEST;
}
}
return result;
}
/*===========================================================================*
* kernel_call *
*===========================================================================*/
/*
* this function checks the basic syscall parameters and if accepted it
* dispatches its handling to the right handler
*/
PUBLIC void kernel_call(message *m_user, struct proc * caller)
{
int result = OK;
message msg;
caller->p_delivermsg_vir = (vir_bytes) m_user;
/*
* the ldt and cr3 of the caller process is loaded because it just've trapped
* into the kernel or was already set in switch_to_user() before we resume
* execution of an interrupted kernel call
*/
if (copy_msg_from_user(caller, m_user, &msg) == 0) {
msg.m_source = caller->p_endpoint;
result = kernel_call_dispatch(caller, &msg);
}
else {
printf("WARNING wrong user pointer 0x%08x from process %s / %d\n",
m_user, caller->p_name, caller->p_endpoint);
result = EBADREQUEST;
}
kernel_call_finish(caller, &msg, result);
}
/*===========================================================================*
* initialize *
*===========================================================================*/
PUBLIC void system_init(void)
{
register struct priv *sp;
int i;
/* Initialize IRQ handler hooks. Mark all hooks available. */
for (i=0; i<NR_IRQ_HOOKS; i++) {
irq_hooks[i].proc_nr_e = NONE;
}
/* Initialize all alarm timers for all processes. */
for (sp=BEG_PRIV_ADDR; sp < END_PRIV_ADDR; sp++) {
tmr_inittimer(&(sp->s_alarm_timer));
}
/* Initialize the call vector to a safe default handler. Some system calls
* may be disabled or nonexistant. Then explicitely map known calls to their
* handler functions. This is done with a macro that gives a compile error
* if an illegal call number is used. The ordering is not important here.
*/
for (i=0; i<NR_SYS_CALLS; i++) {
call_vec[i] = NULL;
}
/* Process management. */
map(SYS_FORK, do_fork); /* a process forked a new process */
map(SYS_EXEC, do_exec); /* update process after execute */
map(SYS_CLEAR, do_clear); /* clean up after process exit */
map(SYS_EXIT, do_exit); /* a system process wants to exit */
map(SYS_PRIVCTL, do_privctl); /* system privileges control */
map(SYS_TRACE, do_trace); /* request a trace operation */
map(SYS_SETGRANT, do_setgrant); /* get/set own parameters */
map(SYS_RUNCTL, do_runctl); /* set/clear stop flag of a process */
map(SYS_UPDATE, do_update); /* update a process into another */
map(SYS_STATECTL, do_statectl); /* let a process control its state */
/* Signal handling. */
map(SYS_KILL, do_kill); /* cause a process to be signaled */
map(SYS_GETKSIG, do_getksig); /* signal manager checks for signals */
map(SYS_ENDKSIG, do_endksig); /* signal manager finished signal */
map(SYS_SIGSEND, do_sigsend); /* start POSIX-style signal */
map(SYS_SIGRETURN, do_sigreturn); /* return from POSIX-style signal */
/* Device I/O. */
map(SYS_IRQCTL, do_irqctl); /* interrupt control operations */
map(SYS_DEVIO, do_devio); /* inb, inw, inl, outb, outw, outl */
map(SYS_VDEVIO, do_vdevio); /* vector with devio requests */
/* Memory management. */
map(SYS_NEWMAP, do_newmap); /* set up a process memory map */
map(SYS_SEGCTL, do_segctl); /* add segment and get selector */
map(SYS_MEMSET, do_memset); /* write char to memory area */
map(SYS_VMCTL, do_vmctl); /* various VM process settings */
/* Copying. */
map(SYS_UMAP, do_umap); /* map virtual to physical address */
map(SYS_VIRCOPY, do_vircopy); /* use pure virtual addressing */
map(SYS_PHYSCOPY, do_copy); /* use physical addressing */
map(SYS_SAFECOPYFROM, do_safecopy_from);/* copy with pre-granted permission */
map(SYS_SAFECOPYTO, do_safecopy_to); /* copy with pre-granted permission */
map(SYS_VSAFECOPY, do_vsafecopy); /* vectored safecopy */
/* Mapping. */
map(SYS_SAFEMAP, do_safemap); /* map pages from other process */
map(SYS_SAFEREVMAP, do_saferevmap); /* grantor revokes the map grant */
map(SYS_SAFEUNMAP, do_safeunmap); /* requestor unmaps the mapped pages */
/* Clock functionality. */
map(SYS_TIMES, do_times); /* get uptime and process times */
map(SYS_SETALARM, do_setalarm); /* schedule a synchronous alarm */
map(SYS_STIME, do_stime); /* set the boottime */
map(SYS_VTIMER, do_vtimer); /* set or retrieve a virtual timer */
/* System control. */
map(SYS_ABORT, do_abort); /* abort MINIX */
map(SYS_GETINFO, do_getinfo); /* request system information */
map(SYS_SYSCTL, do_sysctl); /* misc system manipulation */
/* Profiling. */
map(SYS_SPROF, do_sprofile); /* start/stop statistical profiling */
map(SYS_CPROF, do_cprofile); /* get/reset call profiling data */
map(SYS_PROFBUF, do_profbuf); /* announce locations to kernel */
/* i386-specific. */
#if _MINIX_CHIP == _CHIP_INTEL
map(SYS_INT86, do_int86); /* real-mode BIOS calls */
map(SYS_READBIOS, do_readbios); /* read from BIOS locations */
map(SYS_IOPENABLE, do_iopenable); /* Enable I/O */
map(SYS_SDEVIO, do_sdevio); /* phys_insb, _insw, _outsb, _outsw */
/* Machine state switching. */
map(SYS_SETMCONTEXT, do_setmcontext); /* set machine context */
map(SYS_GETMCONTEXT, do_getmcontext); /* get machine context */
#endif
/* Scheduling */
map(SYS_SCHEDULE, do_schedule); /* reschedule a process */
map(SYS_SCHEDCTL, do_schedctl); /* change process scheduler */
}
/*===========================================================================*
* get_priv *
*===========================================================================*/
PUBLIC int get_priv(rc, priv_id)
register struct proc *rc; /* new (child) process pointer */
int priv_id; /* privilege id */
{
/* Allocate a new privilege structure for a system process. Privilege ids
* can be assigned either statically or dynamically.
*/
register struct priv *sp; /* privilege structure */
if(priv_id == NULL_PRIV_ID) { /* allocate slot dynamically */
for (sp = BEG_DYN_PRIV_ADDR; sp < END_DYN_PRIV_ADDR; ++sp)
if (sp->s_proc_nr == NONE) break;
if (sp >= END_DYN_PRIV_ADDR) return(ENOSPC);
}
else { /* allocate slot from id */
if(!is_static_priv_id(priv_id)) {
return EINVAL; /* invalid static priv id */
}
if(priv[priv_id].s_proc_nr != NONE) {
return EBUSY; /* slot already in use */
}
sp = &priv[priv_id];
}
rc->p_priv = sp; /* assign new slot */
rc->p_priv->s_proc_nr = proc_nr(rc); /* set association */
return(OK);
}
/*===========================================================================*
* set_sendto_bit *
*===========================================================================*/
PUBLIC void set_sendto_bit(const struct proc *rp, int id)
{
/* Allow a process to send messages to the process(es) associated with the
* system privilege structure with the given ID.
*/
/* Disallow the process from sending to a process privilege structure with no
* associated process, and disallow the process from sending to itself.
*/
if (id_to_nr(id) == NONE || priv_id(rp) == id) {
unset_sys_bit(priv(rp)->s_ipc_to, id);
return;
}
set_sys_bit(priv(rp)->s_ipc_to, id);
/* The process that this process can now send to, must be able to reply (or
* vice versa). Therefore, its send mask should be updated as well. Ignore
* receivers that don't support traps other than RECEIVE, they can't reply
* or send messages anyway.
*/
if (priv_addr(id)->s_trap_mask & ~((1 << RECEIVE)))
set_sys_bit(priv_addr(id)->s_ipc_to, priv_id(rp));
}
/*===========================================================================*
* unset_sendto_bit *
*===========================================================================*/
PUBLIC void unset_sendto_bit(const struct proc *rp, int id)
{
/* Prevent a process from sending to another process. Retain the send mask
* symmetry by also unsetting the bit for the other direction.
*/
unset_sys_bit(priv(rp)->s_ipc_to, id);
unset_sys_bit(priv_addr(id)->s_ipc_to, priv_id(rp));
}
/*===========================================================================*
* fill_sendto_mask *
*===========================================================================*/
PUBLIC void fill_sendto_mask(const struct proc *rp, int mask)
{
int i;
for (i=0; i < NR_SYS_PROCS; i++) {
if (mask & (1 << i))
set_sendto_bit(rp, i);
else
unset_sendto_bit(rp, i);
}
}
/*===========================================================================*
* send_sig *
*===========================================================================*/
PUBLIC void send_sig(endpoint_t ep, int sig_nr)
{
/* Notify a system process about a signal. This is straightforward. Simply
* set the signal that is to be delivered in the pending signals map and
* send a notification with source SYSTEM.
*/
register struct proc *rp;
int proc_nr;
if(!isokendpt(ep, &proc_nr) || isemptyn(proc_nr))
panic("send_sig to empty process: %d", ep);
rp = proc_addr(proc_nr);
(void) sigaddset(&priv(rp)->s_sig_pending, sig_nr);
mini_notify(proc_addr(SYSTEM), rp->p_endpoint);
}
/*===========================================================================*
* cause_sig *
*===========================================================================*/
PUBLIC void cause_sig(proc_nr, sig_nr)
proc_nr_t proc_nr; /* process to be signalled */
int sig_nr; /* signal to be sent */
{
/* A system process wants to send a signal to a process. Examples are:
* - HARDWARE wanting to cause a SIGSEGV after a CPU exception
* - TTY wanting to cause SIGINT upon getting a DEL
* - FS wanting to cause SIGPIPE for a broken pipe
* Signals are handled by sending a message to the signal manager assigned to
* the process. This function handles the signals and makes sure the signal
* manager gets them by sending a notification. The process being signaled
* is blocked while the signal manager has not finished all signals for it.
* Race conditions between calls to this function and the system calls that
* process pending kernel signals cannot exist. Signal related functions are
* only called when a user process causes a CPU exception and from the kernel
* process level, which runs to completion.
*/
register struct proc *rp, *sig_mgr_rp;
endpoint_t sig_mgr;
int sig_mgr_proc_nr;
/* Lookup signal manager. */
rp = proc_addr(proc_nr);
sig_mgr = priv(rp)->s_sig_mgr;
if(sig_mgr == SELF) sig_mgr = rp->p_endpoint;
/* If the target is the signal manager of itself, send the signal directly. */
if(rp->p_endpoint == sig_mgr) {
if(SIGS_IS_LETHAL(sig_nr)) {
/* If the signal is lethal, see if a backup signal manager exists. */
sig_mgr = priv(rp)->s_bak_sig_mgr;
if(sig_mgr != NONE && isokendpt(sig_mgr, &sig_mgr_proc_nr)) {
priv(rp)->s_sig_mgr = sig_mgr;
priv(rp)->s_bak_sig_mgr = NONE;
sig_mgr_rp = proc_addr(sig_mgr_proc_nr);
RTS_UNSET(sig_mgr_rp, RTS_NO_PRIV);
cause_sig(proc_nr, sig_nr); /* try again with the new sig mgr. */
return;
}
/* We are out of luck. Time to panic. */
proc_stacktrace(rp);
panic("cause_sig: sig manager %d gets lethal signal %d for itself",
rp->p_endpoint, sig_nr);
}
(void) sigaddset(&priv(rp)->s_sig_pending, sig_nr);
send_sig(rp->p_endpoint, SIGKSIGSM);
return;
}
/* Check if the signal is already pending. Process it otherwise. */
if (! sigismember(&rp->p_pending, sig_nr)) {
(void) sigaddset(&rp->p_pending, sig_nr);
if (! (RTS_ISSET(rp, RTS_SIGNALED))) { /* other pending */
RTS_SET(rp, RTS_SIGNALED | RTS_SIG_PENDING);
send_sig(sig_mgr, SIGKSIG);
}
}
}
/*===========================================================================*
* sig_delay_done *
*===========================================================================*/
PUBLIC void sig_delay_done(struct proc *rp)
{
/* A process is now known not to send any direct messages.
* Tell PM that the stop delay has ended, by sending a signal to the process.
* Used for actual signal delivery.
*/
rp->p_misc_flags &= ~MF_SIG_DELAY;
cause_sig(proc_nr(rp), SIGSNDELAY);
}
#if _MINIX_CHIP == _CHIP_INTEL
/*===========================================================================*
* umap_bios *
*===========================================================================*/
PUBLIC phys_bytes umap_bios(vir_addr, bytes)
vir_bytes vir_addr; /* virtual address in BIOS segment */
vir_bytes bytes; /* # of bytes to be copied */
{
/* Calculate the physical memory address at the BIOS. Note: currently, BIOS
* address zero (the first BIOS interrupt vector) is not considered as an
* error here, but since the physical address will be zero as well, the
* calling function will think an error occurred. This is not a problem,
* since no one uses the first BIOS interrupt vector.
*/
/* Check all acceptable ranges. */
if (vir_addr >= BIOS_MEM_BEGIN && vir_addr + bytes <= BIOS_MEM_END)
return (phys_bytes) vir_addr;
else if (vir_addr >= BASE_MEM_TOP && vir_addr + bytes <= UPPER_MEM_END)
return (phys_bytes) vir_addr;
printf("Warning, error in umap_bios, virtual address 0x%x\n", vir_addr);
return 0;
}
#endif
/*===========================================================================*
* umap_grant *
*===========================================================================*/
PUBLIC phys_bytes umap_grant(rp, grant, bytes)
struct proc *rp; /* pointer to proc table entry for process */
cp_grant_id_t grant; /* grant no. */
vir_bytes bytes; /* size */
{
int proc_nr;
vir_bytes offset, ret;
endpoint_t granter;
/* See if the grant in that process is sensible, and
* find out the virtual address and (optionally) new
* process for that address.
*
* Then convert that process to a slot number.
*/
if(verify_grant(rp->p_endpoint, ANY, grant, bytes, 0, 0,
&offset, &granter) != OK) {
printf("SYSTEM: umap_grant: verify_grant failed\n");
return 0;
}
if(!isokendpt(granter, &proc_nr)) {
printf("SYSTEM: umap_grant: isokendpt failed\n");
return 0;
}
/* Do the mapping from virtual to physical. */
ret = umap_virtual(proc_addr(proc_nr), D, offset, bytes);
if(!ret) {
printf("SYSTEM:umap_grant:umap_virtual failed; grant %s:%d -> %s: vir 0x%lx\n",
rp->p_name, grant,
proc_addr(proc_nr)->p_name, offset);
}
return ret;
}
/*===========================================================================*
* clear_ipc *
*===========================================================================*/
PRIVATE void clear_ipc(
register struct proc *rc /* slot of process to clean up */
)
{
/* Clear IPC data for a given process slot. */
struct proc **xpp; /* iterate over caller queue */
if (RTS_ISSET(rc, RTS_SENDING)) {
int target_proc;
okendpt(rc->p_sendto_e, &target_proc);
xpp = &proc_addr(target_proc)->p_caller_q; /* destination's queue */
while (*xpp) { /* check entire queue */
if (*xpp == rc) { /* process is on the queue */
*xpp = (*xpp)->p_q_link; /* replace by next process */
#if DEBUG_ENABLE_IPC_WARNINGS
printf("endpoint %d / %s removed from queue at %d\n",
rc->p_endpoint, rc->p_name, rc->p_sendto_e);
#endif
break; /* can only be queued once */
}
xpp = &(*xpp)->p_q_link; /* proceed to next queued */
}
rc->p_rts_flags &= ~RTS_SENDING;
}
rc->p_rts_flags &= ~RTS_RECEIVING;
}
/*===========================================================================*
* clear_endpoint *
*===========================================================================*/
PUBLIC void clear_endpoint(rc)
register struct proc *rc; /* slot of process to clean up */
{
if(isemptyp(rc)) panic("clear_proc: empty process: %d", rc->p_endpoint);
/* Make sure that the exiting process is no longer scheduled. */
RTS_SET(rc, RTS_NO_ENDPOINT);
if (priv(rc)->s_flags & SYS_PROC)
{
priv(rc)->s_asynsize= 0;
}
/* If the process happens to be queued trying to send a
* message, then it must be removed from the message queues.
*/
clear_ipc(rc);
/* Likewise, if another process was sending or receive a message to or from
* the exiting process, it must be alerted that process no longer is alive.
* Check all processes.
*/
clear_ipc_refs(rc, EDEADSRCDST);
}
/*===========================================================================*
* clear_ipc_refs *
*===========================================================================*/
PUBLIC void clear_ipc_refs(rc, caller_ret)
register struct proc *rc; /* slot of process to clean up */
int caller_ret; /* code to return on callers */
{
/* Clear IPC references for a given process slot. */
struct proc *rp; /* iterate over process table */
for (rp = BEG_PROC_ADDR; rp < END_PROC_ADDR; rp++) {
if(isemptyp(rp))
continue;
/* Unset pending notification bits. */
unset_sys_bit(priv(rp)->s_notify_pending, priv(rc)->s_id);
/* XXX FIXME: Cleanup should be done for senda() as well. For this to be
* done in a realistic way, we need a better implementation of senda
* with a bitmap similar to s_notify_pending for notify() rather than
* a single global MF_ASYNMSG flag. The current arrangement exposes
* several performance issues.
*/
/* Check if process depends on given process. */
if (P_BLOCKEDON(rp) == rc->p_endpoint) {
rp->p_reg.retreg = caller_ret; /* return requested code */
RTS_UNSET(rp, (RTS_RECEIVING|RTS_SENDING)); /* no longer blocking */
}
}
}
/*===========================================================================*
* kernel_call_resume *
*===========================================================================*/
PUBLIC void kernel_call_resume(struct proc *caller)
{
int result;
assert(!RTS_ISSET(caller, RTS_SLOT_FREE));
assert(!RTS_ISSET(caller, RTS_VMREQUEST));
assert(caller->p_vmrequest.saved.reqmsg.m_source == caller->p_endpoint);
/*
printf("KERNEL_CALL restart from %s / %d rts 0x%08x misc 0x%08x\n",
caller->p_name, caller->p_endpoint,
caller->p_rts_flags, caller->p_misc_flags);
*/
/* re-execute the kernel call, with MF_KCALL_RESUME still set so
* the call knows this is a retry.
*/
result = kernel_call_dispatch(caller, &caller->p_vmrequest.saved.reqmsg);
/*
* we are resuming the kernel call so we have to remove this flag so it
* can be set again
*/
caller->p_misc_flags &= ~MF_KCALL_RESUME;
kernel_call_finish(caller, &caller->p_vmrequest.saved.reqmsg, result);
}
/*===========================================================================*
* sched_proc *
*===========================================================================*/
PUBLIC int sched_proc(struct proc *p,
int priority,
int quantum,
int cpu)
{
/* Make sure the values given are within the allowed range.*/
if ((priority < TASK_Q && priority != -1) || priority > NR_SCHED_QUEUES)
return(EINVAL);
if (quantum < 1 && quantum != -1)
return(EINVAL);
#ifdef CONFIG_SMP
if ((cpu < 0 && cpu != -1) || (cpu > 0 && (unsigned) cpu >= ncpus))
return(EINVAL);
if (cpu != -1 && !(cpu_is_ready(cpu)))
return EBADCPU;
#endif
/* In some cases, we might be rescheduling a runnable process. In such
* a case (i.e. if we are updating the priority) we set the NO_QUANTUM
* flag before the generic unset to dequeue/enqueue the process
*/
/* FIXME this preempts the process, do we really want to do that ?*/
/* FIXME this is a problem for SMP if the processes currently runs on a
* different CPU */
if (proc_is_runnable(p)) {
#ifdef CONFIG_SMP
if (p->p_cpu != cpuid && cpu != -1 && cpu != p->p_cpu) {
printf("WARNING : changing cpu of a runnable process %d "
"on a different cpu!\n", p->p_endpoint);
return(EINVAL);
}
#endif
RTS_SET(p, RTS_NO_QUANTUM);
}
if (proc_is_runnable(p))
RTS_SET(p, RTS_NO_QUANTUM);
if (priority != -1)
p->p_priority = priority;
if (quantum != -1) {
p->p_quantum_size_ms = quantum;
p->p_cpu_time_left = ms_2_cpu_time(quantum);
}
#ifdef CONFIG_SMP
if (cpu != -1)
p->p_cpu = cpu;
#endif
/* Clear the scheduling bit and enqueue the process */
RTS_UNSET(p, RTS_NO_QUANTUM);
return OK;
}