move pcb, stack copy to cpu_fork; copy only useful parts of user struct

[unix-history] / usr / src / sys / vm / vm_glue.c

diff --git a/usr/src/sys/vm/vm_glue.c b/usr/src/sys/vm/vm_glue.c
index 898ebe4..eb3f5dc 100644 (file)
--- a/usr/src/sys/vm/vm_glue.c
+++ b/usr/src/sys/vm/vm_glue.c
@@ -7,7 +7,7 @@
  *
  * %sccs.include.redist.c%
  *
  *
  * %sccs.include.redist.c%
  *

- *     @(#)vm_glue.c   7.3 (Berkeley) %G%
+ *     @(#)vm_glue.c   7.4 (Berkeley) %G%

  *
  *
  * Copyright (c) 1987, 1990 Carnegie-Mellon University.
  *
  *
  * Copyright (c) 1987, 1990 Carnegie-Mellon University.


@@ -74,7 +74,7 @@ useracc(addr, len, rw)
 
 #ifdef KGDB
 /*
 
 #ifdef KGDB
 /*

- * Change protections on kernel pages from addr to addr+size
+ * Change protections on kernel pages from addr to addr+len

  * (presumably so debugger can plant a breakpoint).
  * All addresses are assumed to reside in the Sysmap,
  */
  * (presumably so debugger can plant a breakpoint).
  * All addresses are assumed to reside in the Sysmap,
  */


@@ -109,13 +109,23 @@ vsunlock(addr, len, dirtied)
                        round_page(addr+len-1), TRUE);
 }
 
                        round_page(addr+len-1), TRUE);
 }
 

+/*
+ * Implement fork's actions on an address space.
+ * Here we arrange for the address space to be copied or referenced,
+ * allocate a user struct (pcb and kernel stack), then call the
+ * machine-dependent layer to fill those in and make the new process
+ * ready to run.
+ * NOTE: the kernel stack may be at a different location in the child
+ * process, and thus addresses of automatic variables may be invalid
+ * after cpu_fork returns in the child process.  We do nothing here
+ * after cpu_fork returns.
+ */

 vm_fork(p1, p2, isvfork)
        register struct proc *p1, *p2;
        int isvfork;
 {
        register struct user *up;
        vm_offset_t addr;
 vm_fork(p1, p2, isvfork)
        register struct proc *p1, *p2;
        int isvfork;
 {
        register struct user *up;
        vm_offset_t addr;

-       vm_size_t size;

 
        p2->p_vmspace = vmspace_fork(p1->p_vmspace);
 
 
        p2->p_vmspace = vmspace_fork(p1->p_vmspace);
 


@@ -125,49 +135,37 @@ vm_fork(p1, p2, isvfork)
 #endif
 
        /*
 #endif
 
        /*

-        * Allocate a wired-down (for now) u-area for the process
+        * Allocate a wired-down (for now) pcb and kernel stack for the process

         */
         */

-       size = round_page(ctob(UPAGES));
-       addr = kmem_alloc_pageable(kernel_map, size);
-       vm_map_pageable(kernel_map, addr, addr + size, FALSE);
-       p2->p_addr = (caddr_t)addr;
+       addr = kmem_alloc_pageable(kernel_map, ctob(UPAGES));
+       vm_map_pageable(kernel_map, addr, addr + ctob(UPAGES), FALSE);

        up = (struct user *)addr;
        up = (struct user *)addr;

+       p2->p_addr = up;

 
 

-       /*
-        * Update the current u-area and copy it to the new one
-        * THIS SHOULD BE DONE DIFFERENTLY, probably with a single
-        * machine-dependent call that copies and updates the pcb+stack,
-        * replacing the resume and savectx.
-        */
-       resume(pcbb(p1));
-       bcopy(p1->p_addr, p2->p_addr, size);

        /*
         * p_stats and p_sigacts currently point at fields
         * in the user struct but not at &u, instead at p_addr.
        /*
         * p_stats and p_sigacts currently point at fields
         * in the user struct but not at &u, instead at p_addr.

+        * Copy p_sigacts and parts of p_stats; zero the rest
+        * of p_stats (statistics).

         */
         */

-       p2->p_stats = &((struct user *)p2->p_addr)->u_stats;
-       p2->p_sigacts = &((struct user *)p2->p_addr)->u_sigacts;
+       p2->p_stats = &up->u_stats;
+       p2->p_sigacts = &up->u_sigacts;
+       up->u_sigacts = *p1->p_sigacts;
+       bzero(&up->u_stats.pstat_startzero,
+           (unsigned) ((caddr_t)&up->u_stats.pstat_endzero -
+           (caddr_t)&up->u_stats.pstat_startzero));
+       bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy,
+           ((caddr_t)&up->u_stats.pstat_endcopy -
+            (caddr_t)&up->u_stats.pstat_startcopy));

 
        /*
 
        /*

-        * Clear vm statistics of new process.
+        * cpu_fork will copy and update the kernel stack and pcb,
+        * and make the child ready to run.  It marks the child
+        * so that it can return differently than the parent.
+        * It returns twice, once in the parent process and
+        * once in the child.

         */
         */

-       bzero((caddr_t)&up->u_stats.p_ru, sizeof (struct rusage));
-       bzero((caddr_t)&up->u_stats.p_cru, sizeof (struct rusage));
-
-       PMAP_ACTIVATE(&p2->p_vmspace->vm_pmap, (struct pcb *)p2->p_addr, 0);
-
-       /*
-        * Arrange for a non-local goto when the new process
-        * is started, to resume here, returning nonzero from setjmp.
-        */
-       up->u_pcb.pcb_sswap = (int *)&u.u_ssave;
-       if (savectx(&up->u_ssave)) {
-               /*
-                * Return 1 in child.
-                */
-               return (1);
-       }
-       return (0);
+       return (cpu_fork(p1, p2));

 }
 
 /*
 }
 
 /*