Author: alc
Date: Thu Jun 19 16:26:16 2014
New Revision: 267645
URL: http://svnweb.freebsd.org/changeset/base/267645
Log:
When MAP_STACK_GROWS_{DOWN,UP} are passed to vm_map_insert() set the
corresponding flag(s) in the new map entry. Previously, the caller was
responsible for setting them after vm_map_insert() returned.
Pass MAP_STACK_GROWS_DOWN to vm_map_insert() from vm_map_growstack() when
extending the stack in the downward direction.
Together these changes slightly simplify the caller's task when creating a
downward growing stack. In particular, the caller no longer needs to clip
the previous entry, because the new stack entry can't possibly coalesce
with the previous entry.
Reviewed by: kib
Sponsored by: EMC / Isilon Storage Division
Modified:
head/sys/vm/vm_map.c
Modified: head/sys/vm/vm_map.c
==============================================================================
--- head/sys/vm/vm_map.c Thu Jun 19 15:52:46 2014 (r267644)
+++ head/sys/vm/vm_map.c Thu Jun 19 16:26:16 2014 (r267645)
@@ -1159,6 +1159,10 @@ vm_map_insert(vm_map_t map, vm_object_t
protoeflags |= MAP_ENTRY_NOSYNC;
if (cow & MAP_DISABLE_COREDUMP)
protoeflags |= MAP_ENTRY_NOCOREDUMP;
+ if (cow & MAP_STACK_GROWS_DOWN)
+ protoeflags |= MAP_ENTRY_GROWS_DOWN;
+ if (cow & MAP_STACK_GROWS_UP)
+ protoeflags |= MAP_ENTRY_GROWS_UP;
if (cow & MAP_VN_WRITECOUNT)
protoeflags |= MAP_ENTRY_VN_WRITECNT;
if (cow & MAP_INHERIT_SHARE)
@@ -3445,17 +3449,17 @@ vm_map_stack_locked(vm_map_t map, vm_off
/* Now set the avail_ssize amount. */
if (rv == KERN_SUCCESS) {
- if (prev_entry != &map->header)
- vm_map_clip_end(map, prev_entry, bot);
new_entry = prev_entry->next;
if (new_entry->end != top || new_entry->start != bot)
panic("Bad entry start/end for new stack entry");
new_entry->avail_ssize = max_ssize - init_ssize;
- if (orient & MAP_STACK_GROWS_DOWN)
- new_entry->eflags |= MAP_ENTRY_GROWS_DOWN;
- if (orient & MAP_STACK_GROWS_UP)
- new_entry->eflags |= MAP_ENTRY_GROWS_UP;
+ KASSERT((orient & MAP_STACK_GROWS_DOWN) == 0 ||
+ (new_entry->eflags & MAP_ENTRY_GROWS_DOWN) != 0,
+ ("new entry lacks MAP_ENTRY_GROWS_DOWN"));
+ KASSERT((orient & MAP_STACK_GROWS_UP) == 0 ||
+ (new_entry->eflags & MAP_ENTRY_GROWS_UP) != 0,
+ ("new entry lacks MAP_ENTRY_GROWS_UP"));
}
return (rv);
@@ -3675,21 +3679,21 @@ Retry:
}
rv = vm_map_insert(map, NULL, 0, addr, stack_entry->start,
- next_entry->protection, next_entry->max_protection, 0);
+ next_entry->protection, next_entry->max_protection,
+ MAP_STACK_GROWS_DOWN);
/* Adjust the available stack space by the amount we grew. */
if (rv == KERN_SUCCESS) {
- if (prev_entry != &map->header)
- vm_map_clip_end(map, prev_entry, addr);
new_entry = prev_entry->next;
KASSERT(new_entry == stack_entry->prev, ("foo"));
KASSERT(new_entry->end == stack_entry->start, ("foo"));
KASSERT(new_entry->start == addr, ("foo"));
+ KASSERT((new_entry->eflags & MAP_ENTRY_GROWS_DOWN) !=
+ 0, ("new entry lacks MAP_ENTRY_GROWS_DOWN"));
grow_amount = new_entry->end - new_entry->start;
new_entry->avail_ssize = stack_entry->avail_ssize -
grow_amount;
stack_entry->eflags &= ~MAP_ENTRY_GROWS_DOWN;
- new_entry->eflags |= MAP_ENTRY_GROWS_DOWN;
}
} else {
/*
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