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minix/kernel/system.c
Ben Gras cd8b915ed9 Primary goal for these changes is: 
- no longer have kernel have its own page table that is loaded
    on every kernel entry (trap, interrupt, exception). the primary
    purpose is to reduce the number of required reloads.
Result:
  - kernel can only access memory of process that was running when
    kernel was entered
  - kernel must be mapped into every process page table, so traps to
    kernel keep working
Problem:
  - kernel must often access memory of arbitrary processes (e.g. send
    arbitrary processes messages); this can't happen directly any more;
    usually because that process' page table isn't loaded at all, sometimes
    because that memory isn't mapped in at all, sometimes because it isn't
    mapped in read-write.
So:
  - kernel must be able to map in memory of any process, in its own
    address space.
Implementation:
  - VM and kernel share a range of memory in which addresses of
    all page tables of all processes are available. This has two purposes:
      . Kernel has to know what data to copy in order to map in a range
      . Kernel has to know where to write the data in order to map it in
    That last point is because kernel has to write in the currently loaded
    page table.
  - Processes and kernel are separated through segments; kernel segments
    haven't changed.
  - The kernel keeps the process whose page table is currently loaded
    in 'ptproc.'
  - If it wants to map in a range of memory, it writes the value of the
    page directory entry for that range into the page directory entry
    in the currently loaded map. There is a slot reserved for such
    purposes. The kernel can then access this memory directly.
  - In order to do this, its segment has been increased (and the
    segments of processes start where it ends).
  - In the pagefault handler, detect if the kernel is doing
    'trappable' memory access (i.e. a pagefault isn't a fatal
     error) and if so,
       - set the saved instruction pointer to phys_copy_fault,
	 breaking out of phys_copy
       - set the saved eax register to the address of the page
	 fault, both for sanity checking and for checking in
	 which of the two ranges that phys_copy was called
	 with the fault occured
  - Some boot-time processes do not have their own page table,
    and are mapped in with the kernel, and separated with
    segments. The kernel detects this using HASPT. If such a
    process has to be scheduled, any page table will work and
    no page table switch is done.

Major changes in kernel are
  - When accessing user processes memory, kernel no longer
    explicitly checks before it does so if that memory is OK.
    It simply makes the mapping (if necessary), tries to do the
    operation, and traps the pagefault if that memory isn't present;
    if that happens, the copy function returns EFAULT.
    So all of the CHECKRANGE_OR_SUSPEND macros are gone.
  - Kernel no longer has to copy/read and parse page tables.
  - A message copying optimisation: when messages are copied, and
    the recipient isn't mapped in, they are copied into a buffer
    in the kernel. This is done in QueueMess. The next time
    the recipient is scheduled, this message is copied into
    its memory. This happens in schedcheck().
    This eliminates the mapping/copying step for messages, and makes
    it easier to deliver messages. This eliminates soft_notify.
  - Kernel no longer creates a page table at all, so the vm_setbuf
    and pagetable writing in memory.c is gone.

Minor changes in kernel are
  - ipc_stats thrown out, wasn't used
  - misc flags all renamed to MF_*
  - NOREC_* macros to enter and leave functions that should not
    be called recursively; just sanity checks really
  - code to fully decode segment selectors and descriptors
    to print on exceptions
  - lots of vmassert()s added, only executed if DEBUG_VMASSERT is 1
2009-09-21 14:31:52 +00:00

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/* 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
* send_sig: send a signal directly to a system process
* cause_sig: take action to cause a signal to occur via PM
* 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
*
* Changes:
* 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 <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <string.h>
#include <sys/sigcontext.h>
#include <minix/endpoint.h>
#include <minix/safecopies.h>
#include <minix/portio.h>
#include <minix/u64.h>
#include <sys/vm_i386.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.
*/
PUBLIC int (*call_vec[NR_SYS_CALLS])(message *m_ptr);
char *callnames[NR_SYS_CALLS];
#define map(call_nr, handler) \
{extern int dummy[NR_SYS_CALLS>(unsigned)(call_nr-KERNEL_CALL) ? 1:-1];} \
callnames[(call_nr-KERNEL_CALL)] = #call_nr; \
call_vec[(call_nr-KERNEL_CALL)] = (handler)
FORWARD _PROTOTYPE( void initialize, (void));
FORWARD _PROTOTYPE( struct proc *vmrestart_check, (message *));
/*===========================================================================*
* sys_task *
*===========================================================================*/
PUBLIC void sys_task()
{
/* Main entry point of sys_task. Get the message and dispatch on type. */
static message m;
register int result;
register struct proc *caller_ptr;
int s;
int call_nr;
int n = 0;
/* Initialize the system task. */
initialize();
while (TRUE) {
struct proc *restarting;
restarting = vmrestart_check(&m);
if(!restarting) {
int r;
/* Get work. Block and wait until a request message arrives. */
if((r=receive(ANY, &m)) != OK)
minix_panic("receive() failed", r);
}
sys_call_code = (unsigned) m.m_type;
call_nr = sys_call_code - KERNEL_CALL;
who_e = m.m_source;
okendpt(who_e, &who_p);
caller_ptr = proc_addr(who_p);
/* 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 */
kprintf("SYSTEM: illegal request %d from %d.\n",
call_nr,m.m_source);
result = EBADREQUEST; /* illegal message type */
}
else if (!GET_BIT(priv(caller_ptr)->s_k_call_mask, call_nr)) {
result = ECALLDENIED; /* illegal message type */
}
else {
result = (*call_vec[call_nr])(&m); /* handle the system call */
}
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.
*/
vmassert(RTS_ISSET(caller_ptr, VMREQUEST));
vmassert(caller_ptr->p_vmrequest.type == VMSTYPE_KERNELCALL);
memcpy(&caller_ptr->p_vmrequest.saved.reqmsg, &m, sizeof(m));
} else if (result != EDONTREPLY) {
/* Send a reply, unless inhibited by a handler function.
* Use the kernel function lock_send() to prevent a system
* call trap.
*/
if(restarting) {
vmassert(!RTS_ISSET(restarting, VMREQUEST));
#if 0
vmassert(!RTS_ISSET(restarting, VMREQTARGET));
#endif
}
m.m_type = result; /* report status of call */
if(WILLRECEIVE(caller_ptr, SYSTEM)) {
if (OK != (s=lock_send(m.m_source, &m))) {
kprintf("SYSTEM, reply to %d failed: %d\n",
m.m_source, s);
}
} else {
kprintf("SYSTEM: not replying to %d; not ready\n",
caller_ptr->p_endpoint);
}
}
}
}
/*===========================================================================*
* initialize *
*===========================================================================*/
PRIVATE void initialize(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] = do_unused;
callnames[i] = "unused";
}
/* Process management. */
map(SYS_FORK, do_fork); /* a process forked a new process */
map(SYS_EXEC, do_exec); /* update process after execute */
map(SYS_EXIT, do_exit); /* clean up after process exit */
map(SYS_NICE, do_nice); /* set scheduling priority */
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 */
/* Signal handling. */
map(SYS_KILL, do_kill); /* cause a process to be signaled */
map(SYS_GETKSIG, do_getksig); /* PM checks for pending signals */
map(SYS_ENDKSIG, do_endksig); /* PM finished processing 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_VIRVCOPY, do_virvcopy); /* vector with copy requests */
map(SYS_PHYSVCOPY, do_vcopy); /* vector with copy requests */
map(SYS_SAFECOPYFROM, do_safecopy); /* copy with pre-granted permission */
map(SYS_SAFECOPYTO, do_safecopy); /* copy with pre-granted permission */
map(SYS_VSAFECOPY, do_vsafecopy); /* vectored safecopy */
/* 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 */
map(SYS_MAPDMA, do_mapdma);
#endif
}
/*===========================================================================*
* get_priv *
*===========================================================================*/
PUBLIC int get_priv(rc, proc_type)
register struct proc *rc; /* new (child) process pointer */
int proc_type; /* system or user process flag */
{
/* Get a privilege structure. All user processes share the same privilege
* structure. System processes get their own privilege structure.
*/
register struct priv *sp; /* privilege structure */
if (proc_type == SYS_PROC) { /* find a new slot */
for (sp = BEG_PRIV_ADDR; sp < END_PRIV_ADDR; ++sp)
if (sp->s_proc_nr == NONE && sp->s_id != USER_PRIV_ID) break;
if (sp >= END_PRIV_ADDR) return(ENOSPC);
rc->p_priv = sp; /* assign new slot */
rc->p_priv->s_proc_nr = proc_nr(rc); /* set association */
rc->p_priv->s_flags = SYS_PROC; /* mark as privileged */
/* Clear some fields */
sp->s_asyntab= -1;
sp->s_asynsize= 0;
} else {
rc->p_priv = &priv[USER_PRIV_ID]; /* use shared slot */
rc->p_priv->s_proc_nr = INIT_PROC_NR; /* set association */
/* s_flags of this shared structure are to be once at system startup. */
}
return(OK);
}
/*===========================================================================*
* set_sendto_bit *
*===========================================================================*/
PUBLIC void set_sendto_bit(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.
*/
struct proc *rrp; /* receiver process */
/* Disallow the process from sending to a system privilege structure with no
* associated process, and disallow the process from sending to itself.
*/
if (id_to_nr(id) == NONE || priv_id(rp) == 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.
* Therefore, its send mask should be updated as well.
*/
rrp = proc_addr(id_to_nr(id));
if (!iskernelp(rrp))
set_sys_bit(priv(rrp)->s_ipc_to, priv_id(rp));
}
/*===========================================================================*
* unset_sendto_bit *
*===========================================================================*/
PUBLIC void unset_sendto_bit(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));
}
/*===========================================================================*
* send_sig *
*===========================================================================*/
PUBLIC void send_sig(int proc_nr, 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;
static int n;
if(!isokprocn(proc_nr) || isemptyn(proc_nr))
minix_panic("send_sig to empty process", proc_nr);
rp = proc_addr(proc_nr);
sigaddset(&priv(rp)->s_sig_pending, sig_nr);
if(!intr_disabled()) {
lock_notify(SYSTEM, rp->p_endpoint);
} else {
mini_notify(proc_addr(SYSTEM), rp->p_endpoint);
}
}
/*===========================================================================*
* cause_sig *
*===========================================================================*/
PUBLIC void cause_sig(proc_nr, sig_nr)
int proc_nr; /* process to be signalled */
int sig_nr; /* signal to be sent, 1 to _NSIG */
{
/* 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 PM. This function handles the
* signals and makes sure the PM gets them by sending a notification. The
* process being signaled is blocked while PM 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;
if (proc_nr == PM_PROC_NR)
minix_panic("cause_sig: PM gets signal", NO_NUM);
/* Check if the signal is already pending. Process it otherwise. */
rp = proc_addr(proc_nr);
if (! sigismember(&rp->p_pending, sig_nr)) {
sigaddset(&rp->p_pending, sig_nr);
if (! (RTS_ISSET(rp, SIGNALED))) { /* other pending */
RTS_LOCK_SET(rp, SIGNALED | SIG_PENDING);
send_sig(PM_PROC_NR, SIGKSIG);
}
}
}
#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;
kprintf("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) {
kprintf("SYSTEM: umap_grant: verify_grant failed\n");
return 0;
}
if(!isokendpt(granter, &proc_nr)) {
kprintf("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) {
kprintf("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_endpoint *
*===========================================================================*/
PUBLIC void clear_endpoint(rc)
register struct proc *rc; /* slot of process to clean up */
{
register struct proc *rp; /* iterate over process table */
register struct proc **xpp; /* iterate over caller queue */
struct proc *np;
if(isemptyp(rc)) minix_panic("clear_proc: empty process", rc->p_endpoint);
if(rc->p_endpoint == PM_PROC_NR || rc->p_endpoint == VFS_PROC_NR ||
rc->p_endpoint == VM_PROC_NR)
{
/* This test is great for debugging system processes dying,
* but as this happens normally on reboot, not good permanent code.
*/
kprintf("process %s / %d died; stack: ", rc->p_name, rc->p_endpoint);
proc_stacktrace(rc);
kprintf("kernel trace: ");
util_stacktrace();
minix_panic("clear_proc: system process died", rc->p_endpoint);
}
/* Make sure that the exiting process is no longer scheduled. */
RTS_LOCK_SET(rc, NO_ENDPOINT);
if (priv(rc)->s_flags & SYS_PROC)
{
if (priv(rc)->s_asynsize) {
kprintf("clear_endpoint: clearing s_asynsize of %s / %d\n",
rc->p_name, rc->p_endpoint);
proc_stacktrace(rc);
}
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.
*/
if (RTS_ISSET(rc, SENDING)) {
int target_proc;
okendpt(rc->p_sendto_e, &target_proc);
xpp = &proc_addr(target_proc)->p_caller_q; /* destination's queue */
while (*xpp != NIL_PROC) { /* 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
kprintf("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 &= ~SENDING;
}
rc->p_rts_flags &= ~RECEIVING;
/* 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.
*/
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);
/* Check if process is receiving from exiting process. */
if (RTS_ISSET(rp, RECEIVING) && rp->p_getfrom_e == rc->p_endpoint) {
rp->p_reg.retreg = ESRCDIED; /* report source died */
RTS_LOCK_UNSET(rp, RECEIVING); /* no longer receiving */
#if DEBUG_ENABLE_IPC_WARNINGS
kprintf("endpoint %d / %s receiving from dead src ep %d / %s\n",
rp->p_endpoint, rp->p_name, rc->p_endpoint, rc->p_name);
#endif
}
if (RTS_ISSET(rp, SENDING) &&
rp->p_sendto_e == rc->p_endpoint) {
rp->p_reg.retreg = EDSTDIED; /* report destination died */
RTS_LOCK_UNSET(rp, SENDING);
#if DEBUG_ENABLE_IPC_WARNINGS
kprintf("endpoint %d / %s send to dying dst ep %d (%s)\n",
rp->p_endpoint, rp->p_name, rc->p_endpoint, rc->p_name);
#endif
}
}
}
/*===========================================================================*
* umap_verify_grant *
*===========================================================================*/
PUBLIC phys_bytes umap_verify_grant(rp, grantee, grant, offset, bytes, access)
struct proc *rp; /* pointer to proc table entry for process */
endpoint_t grantee; /* who wants to do this */
cp_grant_id_t grant; /* grant no. */
vir_bytes offset; /* offset into grant */
vir_bytes bytes; /* size */
int access; /* does grantee want to CPF_READ or _WRITE? */
{
int proc_nr;
vir_bytes v_offset;
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, grantee, grant, bytes, access, offset,
&v_offset, &granter) != OK
|| !isokendpt(granter, &proc_nr)) {
return 0;
}
/* Do the mapping from virtual to physical. */
return umap_virtual(proc_addr(proc_nr), D, v_offset, bytes);
}
/*===========================================================================*
* vmrestart_check *
*===========================================================================*/
PRIVATE struct proc *vmrestart_check(message *m)
{
int type, r;
struct proc *restarting;
/* Anyone waiting to be vm-restarted? */
if(!(restarting = vmrestart))
return NULL;
vmassert(!RTS_ISSET(restarting, SLOT_FREE));
vmassert(RTS_ISSET(restarting, VMREQUEST));
type = restarting->p_vmrequest.type;
restarting->p_vmrequest.type = VMSTYPE_SYS_NONE;
vmrestart = restarting->p_vmrequest.nextrestart;
switch(type) {
case VMSTYPE_KERNELCALL:
memcpy(m, &restarting->p_vmrequest.saved.reqmsg, sizeof(*m));
restarting->p_vmrequest.saved.reqmsg.m_source = NONE;
vmassert(m->m_source == restarting->p_endpoint);
/* Original caller could've disappeared in the meantime. */
if(!isokendpt(m->m_source, &who_p)) {
kprintf("SYSTEM: ignoring call %d from dead %d\n",
m->m_type, m->m_source);
return NULL;
}
{ int i;
i = m->m_type - KERNEL_CALL;
if(i >= 0 && i < NR_SYS_CALLS) {
#if 0
kprintf("SYSTEM: restart %s from %d\n",
callnames[i], m->m_source);
#endif
} else {
minix_panic("call number out of range", i);
}
}
return restarting;
default:
minix_panic("strange restart type", type);
}
minix_panic("fell out of switch", NO_NUM);
}
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