4 * (C) Copyright 1995 Linus Torvalds
5 * (C) Copyright 2002 Christoph Hellwig
8 #include <linux/capability.h>
9 #include <linux/mman.h>
11 #include <linux/mempolicy.h>
12 #include <linux/syscalls.h>
13 #include <linux/vs_memory.h>
16 static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
17 unsigned long start, unsigned long end, unsigned int newflags)
19 struct mm_struct * mm = vma->vm_mm;
24 if (newflags == vma->vm_flags) {
29 pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
30 *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
31 vma->vm_file, pgoff, vma_policy(vma));
39 if (start != vma->vm_start) {
40 ret = split_vma(mm, vma, start, 1);
45 if (end != vma->vm_end) {
46 ret = split_vma(mm, vma, end, 0);
53 * vm_flags is protected by the mmap_sem held in write mode.
54 * It's okay if try_to_unmap_one unmaps a page just after we
55 * set VM_LOCKED, make_pages_present below will bring it back.
57 vma->vm_flags = newflags;
60 * Keep track of amount of locked VM.
62 pages = (end - start) >> PAGE_SHIFT;
63 if (newflags & VM_LOCKED) {
65 if (!(newflags & VM_IO))
66 ret = make_pages_present(start, end);
69 vx_vmlocked_sub(vma->vm_mm, pages);
76 static int do_mlock(unsigned long start, size_t len, int on)
78 unsigned long nstart, end, tmp;
79 struct vm_area_struct * vma, * prev;
82 len = PAGE_ALIGN(len);
88 vma = find_vma_prev(current->mm, start, &prev);
89 if (!vma || vma->vm_start > start)
92 if (start > vma->vm_start)
95 for (nstart = start ; ; ) {
96 unsigned int newflags;
98 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
100 newflags = vma->vm_flags | VM_LOCKED;
102 newflags &= ~VM_LOCKED;
107 error = mlock_fixup(vma, &prev, nstart, tmp, newflags);
111 if (nstart < prev->vm_end)
112 nstart = prev->vm_end;
117 if (!vma || vma->vm_start != nstart) {
125 asmlinkage long sys_mlock(unsigned long start, size_t len)
127 unsigned long locked, grow;
128 unsigned long lock_limit;
134 down_write(¤t->mm->mmap_sem);
135 len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
138 grow = len >> PAGE_SHIFT;
139 if (!vx_vmlocked_avail(current->mm, grow))
141 locked = current->mm->locked_vm + grow;
143 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
144 lock_limit >>= PAGE_SHIFT;
146 /* check against resource limits */
147 if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
148 error = do_mlock(start, len, 1);
150 up_write(¤t->mm->mmap_sem);
154 asmlinkage long sys_munlock(unsigned long start, size_t len)
158 down_write(¤t->mm->mmap_sem);
159 len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
161 ret = do_mlock(start, len, 0);
162 up_write(¤t->mm->mmap_sem);
166 static int do_mlockall(int flags)
168 struct vm_area_struct * vma, * prev = NULL;
169 unsigned int def_flags = 0;
171 if (flags & MCL_FUTURE)
172 def_flags = VM_LOCKED;
173 current->mm->def_flags = def_flags;
174 if (flags == MCL_FUTURE)
177 for (vma = current->mm->mmap; vma ; vma = prev->vm_next) {
178 unsigned int newflags;
180 newflags = vma->vm_flags | VM_LOCKED;
181 if (!(flags & MCL_CURRENT))
182 newflags &= ~VM_LOCKED;
185 mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
191 asmlinkage long sys_mlockall(int flags)
193 unsigned long lock_limit;
196 if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE)))
203 down_write(¤t->mm->mmap_sem);
205 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
206 lock_limit >>= PAGE_SHIFT;
209 if (!vx_vmlocked_avail(current->mm, current->mm->total_vm))
211 if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
212 capable(CAP_IPC_LOCK))
213 ret = do_mlockall(flags);
214 up_write(¤t->mm->mmap_sem);
219 asmlinkage long sys_munlockall(void)
223 down_write(¤t->mm->mmap_sem);
224 ret = do_mlockall(0);
225 up_write(¤t->mm->mmap_sem);
230 * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB
231 * shm segments) get accounted against the user_struct instead.
233 static DEFINE_SPINLOCK(shmlock_user_lock);
235 int user_shm_lock(size_t size, struct user_struct *user)
237 unsigned long lock_limit, locked;
240 locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
241 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
242 lock_limit >>= PAGE_SHIFT;
243 spin_lock(&shmlock_user_lock);
244 if (locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
247 user->locked_shm += locked;
250 spin_unlock(&shmlock_user_lock);
254 void user_shm_unlock(size_t size, struct user_struct *user)
256 spin_lock(&shmlock_user_lock);
257 user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
258 spin_unlock(&shmlock_user_lock);