Author: kib
Date: Mon Jun 9 03:37:41 2014
New Revision: 267254
URL: http://svnweb.freebsd.org/changeset/base/267254
Log:
Make mmap(MAP_STACK) search for the available address space, similar
to !MAP_STACK mapping requests. For MAP_STACK | MAP_FIXED, clear any
mappings which could previously exist in the used range.
For this, teach vm_map_find() and vm_map_fixed() to handle
MAP_STACK_GROWS_DOWN or _UP cow flags, by calling a new
vm_map_stack_locked() helper, which is factored out from
vm_map_stack().
The side effect of the change is that MAP_STACK started obeying
MAP_ALIGNMENT and MAP_32BIT flags.
Reported by: rwatson
Reviewed by: alc
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Modified:
head/sys/vm/vm_map.c
head/sys/vm/vm_mmap.c
Modified: head/sys/vm/vm_map.c
==============================================================================
--- head/sys/vm/vm_map.c Mon Jun 9 02:45:53 2014 (r267253)
+++ head/sys/vm/vm_map.c Mon Jun 9 03:37:41 2014 (r267254)
@@ -136,6 +136,9 @@ static void vm_map_entry_dispose(vm_map_
static void vm_map_zdtor(void *mem, int size, void *arg);
static void vmspace_zdtor(void *mem, int size, void *arg);
#endif
+static int vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos,
+ vm_size_t max_ssize, vm_size_t growsize, vm_prot_t prot, vm_prot_t max,
+ int cow);
#define ENTRY_CHARGED(e) ((e)->cred != NULL || \
((e)->object.vm_object != NULL && (e)->object.vm_object->cred != NULL && \
@@ -1399,11 +1402,19 @@ vm_map_fixed(vm_map_t map, vm_object_t o
int result;
end = start + length;
+ KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 ||
+ object == NULL,
+ ("vm_map_fixed: non-NULL backing object for stack"));
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
(void) vm_map_delete(map, start, end);
- result = vm_map_insert(map, object, offset, start, end, prot,
- max, cow);
+ if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) {
+ result = vm_map_stack_locked(map, start, length, sgrowsiz,
+ prot, max, cow);
+ } else {
+ result = vm_map_insert(map, object, offset, start, end,
+ prot, max, cow);
+ }
vm_map_unlock(map);
return (result);
}
@@ -1426,6 +1437,9 @@ vm_map_find(vm_map_t map, vm_object_t ob
vm_offset_t alignment, initial_addr, start;
int result;
+ KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 ||
+ object == NULL,
+ ("vm_map_find: non-NULL backing object for stack"));
if (find_space == VMFS_OPTIMAL_SPACE && (object == NULL ||
(object->flags & OBJ_COLORED) == 0))
find_space = VMFS_ANY_SPACE;
@@ -1467,8 +1481,13 @@ again:
start = *addr;
}
- result = vm_map_insert(map, object, offset, start, start +
- length, prot, max, cow);
+ if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) {
+ result = vm_map_stack_locked(map, start, length,
+ sgrowsiz, prot, max, cow);
+ } else {
+ result = vm_map_insert(map, object, offset, start,
+ start + length, prot, max, cow);
+ }
} while (result == KERN_NO_SPACE && find_space != VMFS_NO_SPACE &&
find_space != VMFS_ANY_SPACE);
vm_map_unlock(map);
@@ -3347,11 +3366,43 @@ int
vm_map_stack(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
vm_prot_t prot, vm_prot_t max, int cow)
{
+ vm_size_t growsize, init_ssize;
+ rlim_t lmemlim, vmemlim;
+ int rv;
+
+ growsize = sgrowsiz;
+ init_ssize = (max_ssize < growsize) ? max_ssize : growsize;
+ vm_map_lock(map);
+ PROC_LOCK(curproc);
+ lmemlim = lim_cur(curproc, RLIMIT_MEMLOCK);
+ vmemlim = lim_cur(curproc, RLIMIT_VMEM);
+ PROC_UNLOCK(curproc);
+ if (!old_mlock && map->flags & MAP_WIREFUTURE) {
+ if (ptoa(pmap_wired_count(map->pmap)) + init_ssize > lmemlim) {
+ rv = KERN_NO_SPACE;
+ goto out;
+ }
+ }
+ /* If we would blow our VMEM resource limit, no go */
+ if (map->size + init_ssize > vmemlim) {
+ rv = KERN_NO_SPACE;
+ goto out;
+ }
+ rv = vm_map_stack_locked(map, addrbos, max_ssize, sgrowsiz, prot,
+ max, cow);
+out:
+ vm_map_unlock(map);
+ return (rv);
+}
+
+static int
+vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
+ vm_size_t growsize, vm_prot_t prot, vm_prot_t max, int cow)
+{
vm_map_entry_t new_entry, prev_entry;
vm_offset_t bot, top;
- vm_size_t growsize, init_ssize;
+ vm_size_t init_ssize;
int orient, rv;
- rlim_t lmemlim, vmemlim;
/*
* The stack orientation is piggybacked with the cow argument.
@@ -3367,34 +3418,11 @@ vm_map_stack(vm_map_t map, vm_offset_t a
addrbos + max_ssize < addrbos)
return (KERN_NO_SPACE);
- growsize = sgrowsiz;
init_ssize = (max_ssize < growsize) ? max_ssize : growsize;
- PROC_LOCK(curproc);
- lmemlim = lim_cur(curproc, RLIMIT_MEMLOCK);
- vmemlim = lim_cur(curproc, RLIMIT_VMEM);
- PROC_UNLOCK(curproc);
-
- vm_map_lock(map);
-
/* If addr is already mapped, no go */
- if (vm_map_lookup_entry(map, addrbos, &prev_entry)) {
- vm_map_unlock(map);
+ if (vm_map_lookup_entry(map, addrbos, &prev_entry))
return (KERN_NO_SPACE);
- }
-
- if (!old_mlock && map->flags & MAP_WIREFUTURE) {
- if (ptoa(pmap_wired_count(map->pmap)) + init_ssize > lmemlim) {
- vm_map_unlock(map);
- return (KERN_NO_SPACE);
- }
- }
-
- /* If we would blow our VMEM resource limit, no go */
- if (map->size + init_ssize > vmemlim) {
- vm_map_unlock(map);
- return (KERN_NO_SPACE);
- }
/*
* If we can't accomodate max_ssize in the current mapping, no go.
@@ -3406,10 +3434,8 @@ vm_map_stack(vm_map_t map, vm_offset_t a
* grow the stack.
*/
if ((prev_entry->next != &map->header) &&
- (prev_entry->next->start < addrbos + max_ssize)) {
- vm_map_unlock(map);
+ (prev_entry->next->start < addrbos + max_ssize))
return (KERN_NO_SPACE);
- }
/*
* We initially map a stack of only init_ssize. We will grow as
@@ -3445,7 +3471,6 @@ vm_map_stack(vm_map_t map, vm_offset_t a
new_entry->eflags |= MAP_ENTRY_GROWS_UP;
}
- vm_map_unlock(map);
return (rv);
}
Modified: head/sys/vm/vm_mmap.c
==============================================================================
--- head/sys/vm/vm_mmap.c Mon Jun 9 02:45:53 2014 (r267253)
+++ head/sys/vm/vm_mmap.c Mon Jun 9 03:37:41 2014 (r267254)
@@ -1621,11 +1621,13 @@ vm_mmap(vm_map_t map, vm_offset_t *addr,
docow |= MAP_INHERIT_SHARE;
if (writecounted)
docow |= MAP_VN_WRITECOUNT;
+ if (flags & MAP_STACK) {
+ if (object != NULL)
+ return (EINVAL);
+ docow |= MAP_STACK_GROWS_DOWN;
+ }
- if (flags & MAP_STACK)
- rv = vm_map_stack(map, *addr, size, prot, maxprot,
- docow | MAP_STACK_GROWS_DOWN);
- else if (fitit) {
+ if (fitit) {
if ((flags & MAP_ALIGNMENT_MASK) == MAP_ALIGNED_SUPER)
findspace = VMFS_SUPER_SPACE;
else if ((flags & MAP_ALIGNMENT_MASK) != 0)
@@ -1638,9 +1640,10 @@ vm_mmap(vm_map_t map, vm_offset_t *addr,
flags & MAP_32BIT ? MAP_32BIT_MAX_ADDR :
#endif
0, findspace, prot, maxprot, docow);
- } else
+ } else {
rv = vm_map_fixed(map, object, foff, *addr, size,
- prot, maxprot, docow);
+ prot, maxprot, docow);
+ }
if (rv == KERN_SUCCESS) {
/*
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