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Make mmap(MAP_STACK) search for the available address space, similar

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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
This commit is contained in:
Konstantin Belousov 2014-06-09 03:37:41 +00:00
parent e41318fc7b
commit 4648ba0a0f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=267254
2 changed files with 68 additions and 40 deletions
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93
sys/vm/vm_map.c
View File

@ -136,6 +136,9 @@ static void vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry);
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 object, vm_ooffset_t offset,
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 object, vm_ooffset_t offset,
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 @@ vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
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);
@ -3346,12 +3365,44 @@ vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge)
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 addrbos, vm_size_t max_ssize,
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 addrbos, vm_size_t max_ssize,
* 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 addrbos, vm_size_t max_ssize,
new_entry->eflags |= MAP_ENTRY_GROWS_UP;
}
vm_map_unlock(map);
return (rv);
}

15
sys/vm/vm_mmap.c
View File

@ -1621,11 +1621,13 @@ vm_mmap(vm_map_t map, vm_offset_t *addr, vm_size_t size, vm_prot_t prot,
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, vm_size_t size, vm_prot_t prot,
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) {
/*