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- uvmspace_share(): If p2 has a vmspace already, make sure to deactivate

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it and free it as appropriate.  Activate p2's new address space once
  it references p1's.
- uvm_fork(): Make sure the child's vmspace is NULL before calling
  uvmspace_share() (the child doens't have one already in this case).

These changes do not change the behavior for the current use of
uvmspace_share() (vfork(2)), but make it possible for an already
running process (such as a kernel thread) to properly attach to
another process's address space.
This commit is contained in:
thorpej 2000-10-11 17:27:58 +00:00
parent 47a2016cdc
commit 76589fafd4
2 changed files with 14 additions and 4 deletions
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7
sys/uvm/uvm_glue.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: uvm_glue.c,v 1.41 2000/09/23 00:43:10 enami Exp $ */
/* $NetBSD: uvm_glue.c,v 1.42 2000/10/11 17:27:59 thorpej Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@ -278,9 +278,10 @@ uvm_fork(p1, p2, shared, stack, stacksize, func, arg)
struct user *up = p2->p_addr;
int rv;
if (shared == TRUE)
if (shared == TRUE) {
p2->p_vmspace = NULL;
uvmspace_share(p1, p2); /* share vmspace */
else
} else
p2->p_vmspace = uvmspace_fork(p1->p_vmspace); /* fork vmspace */
/*

11
sys/uvm/uvm_map.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: uvm_map.c,v 1.82 2000/10/11 17:21:11 thorpej Exp $ */
/* $NetBSD: uvm_map.c,v 1.83 2000/10/11 17:27:58 thorpej Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@ -2779,8 +2779,17 @@ void
uvmspace_share(p1, p2)
struct proc *p1, *p2;
{
struct vmspace *ovm = p2->p_vmspace;
if (ovm != NULL)
pmap_deactivate(p2);
p2->p_vmspace = p1->p_vmspace;
p1->p_vmspace->vm_refcnt++;
pmap_activate(p2);
if (ovm != NULL)
uvmspace_free(ovm);
}
/*