1*1da177e4SLinus Torvalds /* 2*1da177e4SLinus Torvalds * mm/mmap.c 3*1da177e4SLinus Torvalds * 4*1da177e4SLinus Torvalds * Written by obz. 5*1da177e4SLinus Torvalds * 6*1da177e4SLinus Torvalds * Address space accounting code <alan@redhat.com> 7*1da177e4SLinus Torvalds */ 8*1da177e4SLinus Torvalds 9*1da177e4SLinus Torvalds #include <linux/slab.h> 10*1da177e4SLinus Torvalds #include <linux/mm.h> 11*1da177e4SLinus Torvalds #include <linux/shm.h> 12*1da177e4SLinus Torvalds #include <linux/mman.h> 13*1da177e4SLinus Torvalds #include <linux/pagemap.h> 14*1da177e4SLinus Torvalds #include <linux/swap.h> 15*1da177e4SLinus Torvalds #include <linux/syscalls.h> 16*1da177e4SLinus Torvalds #include <linux/init.h> 17*1da177e4SLinus Torvalds #include <linux/file.h> 18*1da177e4SLinus Torvalds #include <linux/fs.h> 19*1da177e4SLinus Torvalds #include <linux/personality.h> 20*1da177e4SLinus Torvalds #include <linux/security.h> 21*1da177e4SLinus Torvalds #include <linux/hugetlb.h> 22*1da177e4SLinus Torvalds #include <linux/profile.h> 23*1da177e4SLinus Torvalds #include <linux/module.h> 24*1da177e4SLinus Torvalds #include <linux/mount.h> 25*1da177e4SLinus Torvalds #include <linux/mempolicy.h> 26*1da177e4SLinus Torvalds #include <linux/rmap.h> 27*1da177e4SLinus Torvalds 28*1da177e4SLinus Torvalds #include <asm/uaccess.h> 29*1da177e4SLinus Torvalds #include <asm/cacheflush.h> 30*1da177e4SLinus Torvalds #include <asm/tlb.h> 31*1da177e4SLinus Torvalds 32*1da177e4SLinus Torvalds /* 33*1da177e4SLinus Torvalds * WARNING: the debugging will use recursive algorithms so never enable this 34*1da177e4SLinus Torvalds * unless you know what you are doing. 35*1da177e4SLinus Torvalds */ 36*1da177e4SLinus Torvalds #undef DEBUG_MM_RB 37*1da177e4SLinus Torvalds 38*1da177e4SLinus Torvalds /* description of effects of mapping type and prot in current implementation. 39*1da177e4SLinus Torvalds * this is due to the limited x86 page protection hardware. The expected 40*1da177e4SLinus Torvalds * behavior is in parens: 41*1da177e4SLinus Torvalds * 42*1da177e4SLinus Torvalds * map_type prot 43*1da177e4SLinus Torvalds * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC 44*1da177e4SLinus Torvalds * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes 45*1da177e4SLinus Torvalds * w: (no) no w: (no) no w: (yes) yes w: (no) no 46*1da177e4SLinus Torvalds * x: (no) no x: (no) yes x: (no) yes x: (yes) yes 47*1da177e4SLinus Torvalds * 48*1da177e4SLinus Torvalds * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes 49*1da177e4SLinus Torvalds * w: (no) no w: (no) no w: (copy) copy w: (no) no 50*1da177e4SLinus Torvalds * x: (no) no x: (no) yes x: (no) yes x: (yes) yes 51*1da177e4SLinus Torvalds * 52*1da177e4SLinus Torvalds */ 53*1da177e4SLinus Torvalds pgprot_t protection_map[16] = { 54*1da177e4SLinus Torvalds __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, 55*1da177e4SLinus Torvalds __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 56*1da177e4SLinus Torvalds }; 57*1da177e4SLinus Torvalds 58*1da177e4SLinus Torvalds int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ 59*1da177e4SLinus Torvalds int sysctl_overcommit_ratio = 50; /* default is 50% */ 60*1da177e4SLinus Torvalds int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT; 61*1da177e4SLinus Torvalds atomic_t vm_committed_space = ATOMIC_INIT(0); 62*1da177e4SLinus Torvalds 63*1da177e4SLinus Torvalds /* 64*1da177e4SLinus Torvalds * Check that a process has enough memory to allocate a new virtual 65*1da177e4SLinus Torvalds * mapping. 0 means there is enough memory for the allocation to 66*1da177e4SLinus Torvalds * succeed and -ENOMEM implies there is not. 67*1da177e4SLinus Torvalds * 68*1da177e4SLinus Torvalds * We currently support three overcommit policies, which are set via the 69*1da177e4SLinus Torvalds * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting 70*1da177e4SLinus Torvalds * 71*1da177e4SLinus Torvalds * Strict overcommit modes added 2002 Feb 26 by Alan Cox. 72*1da177e4SLinus Torvalds * Additional code 2002 Jul 20 by Robert Love. 73*1da177e4SLinus Torvalds * 74*1da177e4SLinus Torvalds * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. 75*1da177e4SLinus Torvalds * 76*1da177e4SLinus Torvalds * Note this is a helper function intended to be used by LSMs which 77*1da177e4SLinus Torvalds * wish to use this logic. 78*1da177e4SLinus Torvalds */ 79*1da177e4SLinus Torvalds int __vm_enough_memory(long pages, int cap_sys_admin) 80*1da177e4SLinus Torvalds { 81*1da177e4SLinus Torvalds unsigned long free, allowed; 82*1da177e4SLinus Torvalds 83*1da177e4SLinus Torvalds vm_acct_memory(pages); 84*1da177e4SLinus Torvalds 85*1da177e4SLinus Torvalds /* 86*1da177e4SLinus Torvalds * Sometimes we want to use more memory than we have 87*1da177e4SLinus Torvalds */ 88*1da177e4SLinus Torvalds if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) 89*1da177e4SLinus Torvalds return 0; 90*1da177e4SLinus Torvalds 91*1da177e4SLinus Torvalds if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { 92*1da177e4SLinus Torvalds unsigned long n; 93*1da177e4SLinus Torvalds 94*1da177e4SLinus Torvalds free = get_page_cache_size(); 95*1da177e4SLinus Torvalds free += nr_swap_pages; 96*1da177e4SLinus Torvalds 97*1da177e4SLinus Torvalds /* 98*1da177e4SLinus Torvalds * Any slabs which are created with the 99*1da177e4SLinus Torvalds * SLAB_RECLAIM_ACCOUNT flag claim to have contents 100*1da177e4SLinus Torvalds * which are reclaimable, under pressure. The dentry 101*1da177e4SLinus Torvalds * cache and most inode caches should fall into this 102*1da177e4SLinus Torvalds */ 103*1da177e4SLinus Torvalds free += atomic_read(&slab_reclaim_pages); 104*1da177e4SLinus Torvalds 105*1da177e4SLinus Torvalds /* 106*1da177e4SLinus Torvalds * Leave the last 3% for root 107*1da177e4SLinus Torvalds */ 108*1da177e4SLinus Torvalds if (!cap_sys_admin) 109*1da177e4SLinus Torvalds free -= free / 32; 110*1da177e4SLinus Torvalds 111*1da177e4SLinus Torvalds if (free > pages) 112*1da177e4SLinus Torvalds return 0; 113*1da177e4SLinus Torvalds 114*1da177e4SLinus Torvalds /* 115*1da177e4SLinus Torvalds * nr_free_pages() is very expensive on large systems, 116*1da177e4SLinus Torvalds * only call if we're about to fail. 117*1da177e4SLinus Torvalds */ 118*1da177e4SLinus Torvalds n = nr_free_pages(); 119*1da177e4SLinus Torvalds if (!cap_sys_admin) 120*1da177e4SLinus Torvalds n -= n / 32; 121*1da177e4SLinus Torvalds free += n; 122*1da177e4SLinus Torvalds 123*1da177e4SLinus Torvalds if (free > pages) 124*1da177e4SLinus Torvalds return 0; 125*1da177e4SLinus Torvalds vm_unacct_memory(pages); 126*1da177e4SLinus Torvalds return -ENOMEM; 127*1da177e4SLinus Torvalds } 128*1da177e4SLinus Torvalds 129*1da177e4SLinus Torvalds allowed = (totalram_pages - hugetlb_total_pages()) 130*1da177e4SLinus Torvalds * sysctl_overcommit_ratio / 100; 131*1da177e4SLinus Torvalds /* 132*1da177e4SLinus Torvalds * Leave the last 3% for root 133*1da177e4SLinus Torvalds */ 134*1da177e4SLinus Torvalds if (!cap_sys_admin) 135*1da177e4SLinus Torvalds allowed -= allowed / 32; 136*1da177e4SLinus Torvalds allowed += total_swap_pages; 137*1da177e4SLinus Torvalds 138*1da177e4SLinus Torvalds /* Don't let a single process grow too big: 139*1da177e4SLinus Torvalds leave 3% of the size of this process for other processes */ 140*1da177e4SLinus Torvalds allowed -= current->mm->total_vm / 32; 141*1da177e4SLinus Torvalds 142*1da177e4SLinus Torvalds if (atomic_read(&vm_committed_space) < allowed) 143*1da177e4SLinus Torvalds return 0; 144*1da177e4SLinus Torvalds 145*1da177e4SLinus Torvalds vm_unacct_memory(pages); 146*1da177e4SLinus Torvalds 147*1da177e4SLinus Torvalds return -ENOMEM; 148*1da177e4SLinus Torvalds } 149*1da177e4SLinus Torvalds 150*1da177e4SLinus Torvalds EXPORT_SYMBOL(sysctl_overcommit_memory); 151*1da177e4SLinus Torvalds EXPORT_SYMBOL(sysctl_overcommit_ratio); 152*1da177e4SLinus Torvalds EXPORT_SYMBOL(sysctl_max_map_count); 153*1da177e4SLinus Torvalds EXPORT_SYMBOL(vm_committed_space); 154*1da177e4SLinus Torvalds EXPORT_SYMBOL(__vm_enough_memory); 155*1da177e4SLinus Torvalds 156*1da177e4SLinus Torvalds /* 157*1da177e4SLinus Torvalds * Requires inode->i_mapping->i_mmap_lock 158*1da177e4SLinus Torvalds */ 159*1da177e4SLinus Torvalds static void __remove_shared_vm_struct(struct vm_area_struct *vma, 160*1da177e4SLinus Torvalds struct file *file, struct address_space *mapping) 161*1da177e4SLinus Torvalds { 162*1da177e4SLinus Torvalds if (vma->vm_flags & VM_DENYWRITE) 163*1da177e4SLinus Torvalds atomic_inc(&file->f_dentry->d_inode->i_writecount); 164*1da177e4SLinus Torvalds if (vma->vm_flags & VM_SHARED) 165*1da177e4SLinus Torvalds mapping->i_mmap_writable--; 166*1da177e4SLinus Torvalds 167*1da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 168*1da177e4SLinus Torvalds if (unlikely(vma->vm_flags & VM_NONLINEAR)) 169*1da177e4SLinus Torvalds list_del_init(&vma->shared.vm_set.list); 170*1da177e4SLinus Torvalds else 171*1da177e4SLinus Torvalds vma_prio_tree_remove(vma, &mapping->i_mmap); 172*1da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 173*1da177e4SLinus Torvalds } 174*1da177e4SLinus Torvalds 175*1da177e4SLinus Torvalds /* 176*1da177e4SLinus Torvalds * Remove one vm structure and free it. 177*1da177e4SLinus Torvalds */ 178*1da177e4SLinus Torvalds static void remove_vm_struct(struct vm_area_struct *vma) 179*1da177e4SLinus Torvalds { 180*1da177e4SLinus Torvalds struct file *file = vma->vm_file; 181*1da177e4SLinus Torvalds 182*1da177e4SLinus Torvalds might_sleep(); 183*1da177e4SLinus Torvalds if (file) { 184*1da177e4SLinus Torvalds struct address_space *mapping = file->f_mapping; 185*1da177e4SLinus Torvalds spin_lock(&mapping->i_mmap_lock); 186*1da177e4SLinus Torvalds __remove_shared_vm_struct(vma, file, mapping); 187*1da177e4SLinus Torvalds spin_unlock(&mapping->i_mmap_lock); 188*1da177e4SLinus Torvalds } 189*1da177e4SLinus Torvalds if (vma->vm_ops && vma->vm_ops->close) 190*1da177e4SLinus Torvalds vma->vm_ops->close(vma); 191*1da177e4SLinus Torvalds if (file) 192*1da177e4SLinus Torvalds fput(file); 193*1da177e4SLinus Torvalds anon_vma_unlink(vma); 194*1da177e4SLinus Torvalds mpol_free(vma_policy(vma)); 195*1da177e4SLinus Torvalds kmem_cache_free(vm_area_cachep, vma); 196*1da177e4SLinus Torvalds } 197*1da177e4SLinus Torvalds 198*1da177e4SLinus Torvalds /* 199*1da177e4SLinus Torvalds * sys_brk() for the most part doesn't need the global kernel 200*1da177e4SLinus Torvalds * lock, except when an application is doing something nasty 201*1da177e4SLinus Torvalds * like trying to un-brk an area that has already been mapped 202*1da177e4SLinus Torvalds * to a regular file. in this case, the unmapping will need 203*1da177e4SLinus Torvalds * to invoke file system routines that need the global lock. 204*1da177e4SLinus Torvalds */ 205*1da177e4SLinus Torvalds asmlinkage unsigned long sys_brk(unsigned long brk) 206*1da177e4SLinus Torvalds { 207*1da177e4SLinus Torvalds unsigned long rlim, retval; 208*1da177e4SLinus Torvalds unsigned long newbrk, oldbrk; 209*1da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 210*1da177e4SLinus Torvalds 211*1da177e4SLinus Torvalds down_write(&mm->mmap_sem); 212*1da177e4SLinus Torvalds 213*1da177e4SLinus Torvalds if (brk < mm->end_code) 214*1da177e4SLinus Torvalds goto out; 215*1da177e4SLinus Torvalds newbrk = PAGE_ALIGN(brk); 216*1da177e4SLinus Torvalds oldbrk = PAGE_ALIGN(mm->brk); 217*1da177e4SLinus Torvalds if (oldbrk == newbrk) 218*1da177e4SLinus Torvalds goto set_brk; 219*1da177e4SLinus Torvalds 220*1da177e4SLinus Torvalds /* Always allow shrinking brk. */ 221*1da177e4SLinus Torvalds if (brk <= mm->brk) { 222*1da177e4SLinus Torvalds if (!do_munmap(mm, newbrk, oldbrk-newbrk)) 223*1da177e4SLinus Torvalds goto set_brk; 224*1da177e4SLinus Torvalds goto out; 225*1da177e4SLinus Torvalds } 226*1da177e4SLinus Torvalds 227*1da177e4SLinus Torvalds /* Check against rlimit.. */ 228*1da177e4SLinus Torvalds rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur; 229*1da177e4SLinus Torvalds if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim) 230*1da177e4SLinus Torvalds goto out; 231*1da177e4SLinus Torvalds 232*1da177e4SLinus Torvalds /* Check against existing mmap mappings. */ 233*1da177e4SLinus Torvalds if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) 234*1da177e4SLinus Torvalds goto out; 235*1da177e4SLinus Torvalds 236*1da177e4SLinus Torvalds /* Ok, looks good - let it rip. */ 237*1da177e4SLinus Torvalds if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) 238*1da177e4SLinus Torvalds goto out; 239*1da177e4SLinus Torvalds set_brk: 240*1da177e4SLinus Torvalds mm->brk = brk; 241*1da177e4SLinus Torvalds out: 242*1da177e4SLinus Torvalds retval = mm->brk; 243*1da177e4SLinus Torvalds up_write(&mm->mmap_sem); 244*1da177e4SLinus Torvalds return retval; 245*1da177e4SLinus Torvalds } 246*1da177e4SLinus Torvalds 247*1da177e4SLinus Torvalds #ifdef DEBUG_MM_RB 248*1da177e4SLinus Torvalds static int browse_rb(struct rb_root *root) 249*1da177e4SLinus Torvalds { 250*1da177e4SLinus Torvalds int i = 0, j; 251*1da177e4SLinus Torvalds struct rb_node *nd, *pn = NULL; 252*1da177e4SLinus Torvalds unsigned long prev = 0, pend = 0; 253*1da177e4SLinus Torvalds 254*1da177e4SLinus Torvalds for (nd = rb_first(root); nd; nd = rb_next(nd)) { 255*1da177e4SLinus Torvalds struct vm_area_struct *vma; 256*1da177e4SLinus Torvalds vma = rb_entry(nd, struct vm_area_struct, vm_rb); 257*1da177e4SLinus Torvalds if (vma->vm_start < prev) 258*1da177e4SLinus Torvalds printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1; 259*1da177e4SLinus Torvalds if (vma->vm_start < pend) 260*1da177e4SLinus Torvalds printk("vm_start %lx pend %lx\n", vma->vm_start, pend); 261*1da177e4SLinus Torvalds if (vma->vm_start > vma->vm_end) 262*1da177e4SLinus Torvalds printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); 263*1da177e4SLinus Torvalds i++; 264*1da177e4SLinus Torvalds pn = nd; 265*1da177e4SLinus Torvalds } 266*1da177e4SLinus Torvalds j = 0; 267*1da177e4SLinus Torvalds for (nd = pn; nd; nd = rb_prev(nd)) { 268*1da177e4SLinus Torvalds j++; 269*1da177e4SLinus Torvalds } 270*1da177e4SLinus Torvalds if (i != j) 271*1da177e4SLinus Torvalds printk("backwards %d, forwards %d\n", j, i), i = 0; 272*1da177e4SLinus Torvalds return i; 273*1da177e4SLinus Torvalds } 274*1da177e4SLinus Torvalds 275*1da177e4SLinus Torvalds void validate_mm(struct mm_struct *mm) 276*1da177e4SLinus Torvalds { 277*1da177e4SLinus Torvalds int bug = 0; 278*1da177e4SLinus Torvalds int i = 0; 279*1da177e4SLinus Torvalds struct vm_area_struct *tmp = mm->mmap; 280*1da177e4SLinus Torvalds while (tmp) { 281*1da177e4SLinus Torvalds tmp = tmp->vm_next; 282*1da177e4SLinus Torvalds i++; 283*1da177e4SLinus Torvalds } 284*1da177e4SLinus Torvalds if (i != mm->map_count) 285*1da177e4SLinus Torvalds printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1; 286*1da177e4SLinus Torvalds i = browse_rb(&mm->mm_rb); 287*1da177e4SLinus Torvalds if (i != mm->map_count) 288*1da177e4SLinus Torvalds printk("map_count %d rb %d\n", mm->map_count, i), bug = 1; 289*1da177e4SLinus Torvalds if (bug) 290*1da177e4SLinus Torvalds BUG(); 291*1da177e4SLinus Torvalds } 292*1da177e4SLinus Torvalds #else 293*1da177e4SLinus Torvalds #define validate_mm(mm) do { } while (0) 294*1da177e4SLinus Torvalds #endif 295*1da177e4SLinus Torvalds 296*1da177e4SLinus Torvalds static struct vm_area_struct * 297*1da177e4SLinus Torvalds find_vma_prepare(struct mm_struct *mm, unsigned long addr, 298*1da177e4SLinus Torvalds struct vm_area_struct **pprev, struct rb_node ***rb_link, 299*1da177e4SLinus Torvalds struct rb_node ** rb_parent) 300*1da177e4SLinus Torvalds { 301*1da177e4SLinus Torvalds struct vm_area_struct * vma; 302*1da177e4SLinus Torvalds struct rb_node ** __rb_link, * __rb_parent, * rb_prev; 303*1da177e4SLinus Torvalds 304*1da177e4SLinus Torvalds __rb_link = &mm->mm_rb.rb_node; 305*1da177e4SLinus Torvalds rb_prev = __rb_parent = NULL; 306*1da177e4SLinus Torvalds vma = NULL; 307*1da177e4SLinus Torvalds 308*1da177e4SLinus Torvalds while (*__rb_link) { 309*1da177e4SLinus Torvalds struct vm_area_struct *vma_tmp; 310*1da177e4SLinus Torvalds 311*1da177e4SLinus Torvalds __rb_parent = *__rb_link; 312*1da177e4SLinus Torvalds vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); 313*1da177e4SLinus Torvalds 314*1da177e4SLinus Torvalds if (vma_tmp->vm_end > addr) { 315*1da177e4SLinus Torvalds vma = vma_tmp; 316*1da177e4SLinus Torvalds if (vma_tmp->vm_start <= addr) 317*1da177e4SLinus Torvalds return vma; 318*1da177e4SLinus Torvalds __rb_link = &__rb_parent->rb_left; 319*1da177e4SLinus Torvalds } else { 320*1da177e4SLinus Torvalds rb_prev = __rb_parent; 321*1da177e4SLinus Torvalds __rb_link = &__rb_parent->rb_right; 322*1da177e4SLinus Torvalds } 323*1da177e4SLinus Torvalds } 324*1da177e4SLinus Torvalds 325*1da177e4SLinus Torvalds *pprev = NULL; 326*1da177e4SLinus Torvalds if (rb_prev) 327*1da177e4SLinus Torvalds *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); 328*1da177e4SLinus Torvalds *rb_link = __rb_link; 329*1da177e4SLinus Torvalds *rb_parent = __rb_parent; 330*1da177e4SLinus Torvalds return vma; 331*1da177e4SLinus Torvalds } 332*1da177e4SLinus Torvalds 333*1da177e4SLinus Torvalds static inline void 334*1da177e4SLinus Torvalds __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, 335*1da177e4SLinus Torvalds struct vm_area_struct *prev, struct rb_node *rb_parent) 336*1da177e4SLinus Torvalds { 337*1da177e4SLinus Torvalds if (prev) { 338*1da177e4SLinus Torvalds vma->vm_next = prev->vm_next; 339*1da177e4SLinus Torvalds prev->vm_next = vma; 340*1da177e4SLinus Torvalds } else { 341*1da177e4SLinus Torvalds mm->mmap = vma; 342*1da177e4SLinus Torvalds if (rb_parent) 343*1da177e4SLinus Torvalds vma->vm_next = rb_entry(rb_parent, 344*1da177e4SLinus Torvalds struct vm_area_struct, vm_rb); 345*1da177e4SLinus Torvalds else 346*1da177e4SLinus Torvalds vma->vm_next = NULL; 347*1da177e4SLinus Torvalds } 348*1da177e4SLinus Torvalds } 349*1da177e4SLinus Torvalds 350*1da177e4SLinus Torvalds void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, 351*1da177e4SLinus Torvalds struct rb_node **rb_link, struct rb_node *rb_parent) 352*1da177e4SLinus Torvalds { 353*1da177e4SLinus Torvalds rb_link_node(&vma->vm_rb, rb_parent, rb_link); 354*1da177e4SLinus Torvalds rb_insert_color(&vma->vm_rb, &mm->mm_rb); 355*1da177e4SLinus Torvalds } 356*1da177e4SLinus Torvalds 357*1da177e4SLinus Torvalds static inline void __vma_link_file(struct vm_area_struct *vma) 358*1da177e4SLinus Torvalds { 359*1da177e4SLinus Torvalds struct file * file; 360*1da177e4SLinus Torvalds 361*1da177e4SLinus Torvalds file = vma->vm_file; 362*1da177e4SLinus Torvalds if (file) { 363*1da177e4SLinus Torvalds struct address_space *mapping = file->f_mapping; 364*1da177e4SLinus Torvalds 365*1da177e4SLinus Torvalds if (vma->vm_flags & VM_DENYWRITE) 366*1da177e4SLinus Torvalds atomic_dec(&file->f_dentry->d_inode->i_writecount); 367*1da177e4SLinus Torvalds if (vma->vm_flags & VM_SHARED) 368*1da177e4SLinus Torvalds mapping->i_mmap_writable++; 369*1da177e4SLinus Torvalds 370*1da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 371*1da177e4SLinus Torvalds if (unlikely(vma->vm_flags & VM_NONLINEAR)) 372*1da177e4SLinus Torvalds vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); 373*1da177e4SLinus Torvalds else 374*1da177e4SLinus Torvalds vma_prio_tree_insert(vma, &mapping->i_mmap); 375*1da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 376*1da177e4SLinus Torvalds } 377*1da177e4SLinus Torvalds } 378*1da177e4SLinus Torvalds 379*1da177e4SLinus Torvalds static void 380*1da177e4SLinus Torvalds __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, 381*1da177e4SLinus Torvalds struct vm_area_struct *prev, struct rb_node **rb_link, 382*1da177e4SLinus Torvalds struct rb_node *rb_parent) 383*1da177e4SLinus Torvalds { 384*1da177e4SLinus Torvalds __vma_link_list(mm, vma, prev, rb_parent); 385*1da177e4SLinus Torvalds __vma_link_rb(mm, vma, rb_link, rb_parent); 386*1da177e4SLinus Torvalds __anon_vma_link(vma); 387*1da177e4SLinus Torvalds } 388*1da177e4SLinus Torvalds 389*1da177e4SLinus Torvalds static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, 390*1da177e4SLinus Torvalds struct vm_area_struct *prev, struct rb_node **rb_link, 391*1da177e4SLinus Torvalds struct rb_node *rb_parent) 392*1da177e4SLinus Torvalds { 393*1da177e4SLinus Torvalds struct address_space *mapping = NULL; 394*1da177e4SLinus Torvalds 395*1da177e4SLinus Torvalds if (vma->vm_file) 396*1da177e4SLinus Torvalds mapping = vma->vm_file->f_mapping; 397*1da177e4SLinus Torvalds 398*1da177e4SLinus Torvalds if (mapping) { 399*1da177e4SLinus Torvalds spin_lock(&mapping->i_mmap_lock); 400*1da177e4SLinus Torvalds vma->vm_truncate_count = mapping->truncate_count; 401*1da177e4SLinus Torvalds } 402*1da177e4SLinus Torvalds anon_vma_lock(vma); 403*1da177e4SLinus Torvalds 404*1da177e4SLinus Torvalds __vma_link(mm, vma, prev, rb_link, rb_parent); 405*1da177e4SLinus Torvalds __vma_link_file(vma); 406*1da177e4SLinus Torvalds 407*1da177e4SLinus Torvalds anon_vma_unlock(vma); 408*1da177e4SLinus Torvalds if (mapping) 409*1da177e4SLinus Torvalds spin_unlock(&mapping->i_mmap_lock); 410*1da177e4SLinus Torvalds 411*1da177e4SLinus Torvalds mm->map_count++; 412*1da177e4SLinus Torvalds validate_mm(mm); 413*1da177e4SLinus Torvalds } 414*1da177e4SLinus Torvalds 415*1da177e4SLinus Torvalds /* 416*1da177e4SLinus Torvalds * Helper for vma_adjust in the split_vma insert case: 417*1da177e4SLinus Torvalds * insert vm structure into list and rbtree and anon_vma, 418*1da177e4SLinus Torvalds * but it has already been inserted into prio_tree earlier. 419*1da177e4SLinus Torvalds */ 420*1da177e4SLinus Torvalds static void 421*1da177e4SLinus Torvalds __insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) 422*1da177e4SLinus Torvalds { 423*1da177e4SLinus Torvalds struct vm_area_struct * __vma, * prev; 424*1da177e4SLinus Torvalds struct rb_node ** rb_link, * rb_parent; 425*1da177e4SLinus Torvalds 426*1da177e4SLinus Torvalds __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent); 427*1da177e4SLinus Torvalds if (__vma && __vma->vm_start < vma->vm_end) 428*1da177e4SLinus Torvalds BUG(); 429*1da177e4SLinus Torvalds __vma_link(mm, vma, prev, rb_link, rb_parent); 430*1da177e4SLinus Torvalds mm->map_count++; 431*1da177e4SLinus Torvalds } 432*1da177e4SLinus Torvalds 433*1da177e4SLinus Torvalds static inline void 434*1da177e4SLinus Torvalds __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, 435*1da177e4SLinus Torvalds struct vm_area_struct *prev) 436*1da177e4SLinus Torvalds { 437*1da177e4SLinus Torvalds prev->vm_next = vma->vm_next; 438*1da177e4SLinus Torvalds rb_erase(&vma->vm_rb, &mm->mm_rb); 439*1da177e4SLinus Torvalds if (mm->mmap_cache == vma) 440*1da177e4SLinus Torvalds mm->mmap_cache = prev; 441*1da177e4SLinus Torvalds } 442*1da177e4SLinus Torvalds 443*1da177e4SLinus Torvalds /* 444*1da177e4SLinus Torvalds * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that 445*1da177e4SLinus Torvalds * is already present in an i_mmap tree without adjusting the tree. 446*1da177e4SLinus Torvalds * The following helper function should be used when such adjustments 447*1da177e4SLinus Torvalds * are necessary. The "insert" vma (if any) is to be inserted 448*1da177e4SLinus Torvalds * before we drop the necessary locks. 449*1da177e4SLinus Torvalds */ 450*1da177e4SLinus Torvalds void vma_adjust(struct vm_area_struct *vma, unsigned long start, 451*1da177e4SLinus Torvalds unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) 452*1da177e4SLinus Torvalds { 453*1da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 454*1da177e4SLinus Torvalds struct vm_area_struct *next = vma->vm_next; 455*1da177e4SLinus Torvalds struct vm_area_struct *importer = NULL; 456*1da177e4SLinus Torvalds struct address_space *mapping = NULL; 457*1da177e4SLinus Torvalds struct prio_tree_root *root = NULL; 458*1da177e4SLinus Torvalds struct file *file = vma->vm_file; 459*1da177e4SLinus Torvalds struct anon_vma *anon_vma = NULL; 460*1da177e4SLinus Torvalds long adjust_next = 0; 461*1da177e4SLinus Torvalds int remove_next = 0; 462*1da177e4SLinus Torvalds 463*1da177e4SLinus Torvalds if (next && !insert) { 464*1da177e4SLinus Torvalds if (end >= next->vm_end) { 465*1da177e4SLinus Torvalds /* 466*1da177e4SLinus Torvalds * vma expands, overlapping all the next, and 467*1da177e4SLinus Torvalds * perhaps the one after too (mprotect case 6). 468*1da177e4SLinus Torvalds */ 469*1da177e4SLinus Torvalds again: remove_next = 1 + (end > next->vm_end); 470*1da177e4SLinus Torvalds end = next->vm_end; 471*1da177e4SLinus Torvalds anon_vma = next->anon_vma; 472*1da177e4SLinus Torvalds importer = vma; 473*1da177e4SLinus Torvalds } else if (end > next->vm_start) { 474*1da177e4SLinus Torvalds /* 475*1da177e4SLinus Torvalds * vma expands, overlapping part of the next: 476*1da177e4SLinus Torvalds * mprotect case 5 shifting the boundary up. 477*1da177e4SLinus Torvalds */ 478*1da177e4SLinus Torvalds adjust_next = (end - next->vm_start) >> PAGE_SHIFT; 479*1da177e4SLinus Torvalds anon_vma = next->anon_vma; 480*1da177e4SLinus Torvalds importer = vma; 481*1da177e4SLinus Torvalds } else if (end < vma->vm_end) { 482*1da177e4SLinus Torvalds /* 483*1da177e4SLinus Torvalds * vma shrinks, and !insert tells it's not 484*1da177e4SLinus Torvalds * split_vma inserting another: so it must be 485*1da177e4SLinus Torvalds * mprotect case 4 shifting the boundary down. 486*1da177e4SLinus Torvalds */ 487*1da177e4SLinus Torvalds adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); 488*1da177e4SLinus Torvalds anon_vma = next->anon_vma; 489*1da177e4SLinus Torvalds importer = next; 490*1da177e4SLinus Torvalds } 491*1da177e4SLinus Torvalds } 492*1da177e4SLinus Torvalds 493*1da177e4SLinus Torvalds if (file) { 494*1da177e4SLinus Torvalds mapping = file->f_mapping; 495*1da177e4SLinus Torvalds if (!(vma->vm_flags & VM_NONLINEAR)) 496*1da177e4SLinus Torvalds root = &mapping->i_mmap; 497*1da177e4SLinus Torvalds spin_lock(&mapping->i_mmap_lock); 498*1da177e4SLinus Torvalds if (importer && 499*1da177e4SLinus Torvalds vma->vm_truncate_count != next->vm_truncate_count) { 500*1da177e4SLinus Torvalds /* 501*1da177e4SLinus Torvalds * unmap_mapping_range might be in progress: 502*1da177e4SLinus Torvalds * ensure that the expanding vma is rescanned. 503*1da177e4SLinus Torvalds */ 504*1da177e4SLinus Torvalds importer->vm_truncate_count = 0; 505*1da177e4SLinus Torvalds } 506*1da177e4SLinus Torvalds if (insert) { 507*1da177e4SLinus Torvalds insert->vm_truncate_count = vma->vm_truncate_count; 508*1da177e4SLinus Torvalds /* 509*1da177e4SLinus Torvalds * Put into prio_tree now, so instantiated pages 510*1da177e4SLinus Torvalds * are visible to arm/parisc __flush_dcache_page 511*1da177e4SLinus Torvalds * throughout; but we cannot insert into address 512*1da177e4SLinus Torvalds * space until vma start or end is updated. 513*1da177e4SLinus Torvalds */ 514*1da177e4SLinus Torvalds __vma_link_file(insert); 515*1da177e4SLinus Torvalds } 516*1da177e4SLinus Torvalds } 517*1da177e4SLinus Torvalds 518*1da177e4SLinus Torvalds /* 519*1da177e4SLinus Torvalds * When changing only vma->vm_end, we don't really need 520*1da177e4SLinus Torvalds * anon_vma lock: but is that case worth optimizing out? 521*1da177e4SLinus Torvalds */ 522*1da177e4SLinus Torvalds if (vma->anon_vma) 523*1da177e4SLinus Torvalds anon_vma = vma->anon_vma; 524*1da177e4SLinus Torvalds if (anon_vma) { 525*1da177e4SLinus Torvalds spin_lock(&anon_vma->lock); 526*1da177e4SLinus Torvalds /* 527*1da177e4SLinus Torvalds * Easily overlooked: when mprotect shifts the boundary, 528*1da177e4SLinus Torvalds * make sure the expanding vma has anon_vma set if the 529*1da177e4SLinus Torvalds * shrinking vma had, to cover any anon pages imported. 530*1da177e4SLinus Torvalds */ 531*1da177e4SLinus Torvalds if (importer && !importer->anon_vma) { 532*1da177e4SLinus Torvalds importer->anon_vma = anon_vma; 533*1da177e4SLinus Torvalds __anon_vma_link(importer); 534*1da177e4SLinus Torvalds } 535*1da177e4SLinus Torvalds } 536*1da177e4SLinus Torvalds 537*1da177e4SLinus Torvalds if (root) { 538*1da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 539*1da177e4SLinus Torvalds vma_prio_tree_remove(vma, root); 540*1da177e4SLinus Torvalds if (adjust_next) 541*1da177e4SLinus Torvalds vma_prio_tree_remove(next, root); 542*1da177e4SLinus Torvalds } 543*1da177e4SLinus Torvalds 544*1da177e4SLinus Torvalds vma->vm_start = start; 545*1da177e4SLinus Torvalds vma->vm_end = end; 546*1da177e4SLinus Torvalds vma->vm_pgoff = pgoff; 547*1da177e4SLinus Torvalds if (adjust_next) { 548*1da177e4SLinus Torvalds next->vm_start += adjust_next << PAGE_SHIFT; 549*1da177e4SLinus Torvalds next->vm_pgoff += adjust_next; 550*1da177e4SLinus Torvalds } 551*1da177e4SLinus Torvalds 552*1da177e4SLinus Torvalds if (root) { 553*1da177e4SLinus Torvalds if (adjust_next) 554*1da177e4SLinus Torvalds vma_prio_tree_insert(next, root); 555*1da177e4SLinus Torvalds vma_prio_tree_insert(vma, root); 556*1da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 557*1da177e4SLinus Torvalds } 558*1da177e4SLinus Torvalds 559*1da177e4SLinus Torvalds if (remove_next) { 560*1da177e4SLinus Torvalds /* 561*1da177e4SLinus Torvalds * vma_merge has merged next into vma, and needs 562*1da177e4SLinus Torvalds * us to remove next before dropping the locks. 563*1da177e4SLinus Torvalds */ 564*1da177e4SLinus Torvalds __vma_unlink(mm, next, vma); 565*1da177e4SLinus Torvalds if (file) 566*1da177e4SLinus Torvalds __remove_shared_vm_struct(next, file, mapping); 567*1da177e4SLinus Torvalds if (next->anon_vma) 568*1da177e4SLinus Torvalds __anon_vma_merge(vma, next); 569*1da177e4SLinus Torvalds } else if (insert) { 570*1da177e4SLinus Torvalds /* 571*1da177e4SLinus Torvalds * split_vma has split insert from vma, and needs 572*1da177e4SLinus Torvalds * us to insert it before dropping the locks 573*1da177e4SLinus Torvalds * (it may either follow vma or precede it). 574*1da177e4SLinus Torvalds */ 575*1da177e4SLinus Torvalds __insert_vm_struct(mm, insert); 576*1da177e4SLinus Torvalds } 577*1da177e4SLinus Torvalds 578*1da177e4SLinus Torvalds if (anon_vma) 579*1da177e4SLinus Torvalds spin_unlock(&anon_vma->lock); 580*1da177e4SLinus Torvalds if (mapping) 581*1da177e4SLinus Torvalds spin_unlock(&mapping->i_mmap_lock); 582*1da177e4SLinus Torvalds 583*1da177e4SLinus Torvalds if (remove_next) { 584*1da177e4SLinus Torvalds if (file) 585*1da177e4SLinus Torvalds fput(file); 586*1da177e4SLinus Torvalds mm->map_count--; 587*1da177e4SLinus Torvalds mpol_free(vma_policy(next)); 588*1da177e4SLinus Torvalds kmem_cache_free(vm_area_cachep, next); 589*1da177e4SLinus Torvalds /* 590*1da177e4SLinus Torvalds * In mprotect's case 6 (see comments on vma_merge), 591*1da177e4SLinus Torvalds * we must remove another next too. It would clutter 592*1da177e4SLinus Torvalds * up the code too much to do both in one go. 593*1da177e4SLinus Torvalds */ 594*1da177e4SLinus Torvalds if (remove_next == 2) { 595*1da177e4SLinus Torvalds next = vma->vm_next; 596*1da177e4SLinus Torvalds goto again; 597*1da177e4SLinus Torvalds } 598*1da177e4SLinus Torvalds } 599*1da177e4SLinus Torvalds 600*1da177e4SLinus Torvalds validate_mm(mm); 601*1da177e4SLinus Torvalds } 602*1da177e4SLinus Torvalds 603*1da177e4SLinus Torvalds /* 604*1da177e4SLinus Torvalds * If the vma has a ->close operation then the driver probably needs to release 605*1da177e4SLinus Torvalds * per-vma resources, so we don't attempt to merge those. 606*1da177e4SLinus Torvalds */ 607*1da177e4SLinus Torvalds #define VM_SPECIAL (VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_RESERVED) 608*1da177e4SLinus Torvalds 609*1da177e4SLinus Torvalds static inline int is_mergeable_vma(struct vm_area_struct *vma, 610*1da177e4SLinus Torvalds struct file *file, unsigned long vm_flags) 611*1da177e4SLinus Torvalds { 612*1da177e4SLinus Torvalds if (vma->vm_flags != vm_flags) 613*1da177e4SLinus Torvalds return 0; 614*1da177e4SLinus Torvalds if (vma->vm_file != file) 615*1da177e4SLinus Torvalds return 0; 616*1da177e4SLinus Torvalds if (vma->vm_ops && vma->vm_ops->close) 617*1da177e4SLinus Torvalds return 0; 618*1da177e4SLinus Torvalds return 1; 619*1da177e4SLinus Torvalds } 620*1da177e4SLinus Torvalds 621*1da177e4SLinus Torvalds static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, 622*1da177e4SLinus Torvalds struct anon_vma *anon_vma2) 623*1da177e4SLinus Torvalds { 624*1da177e4SLinus Torvalds return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2); 625*1da177e4SLinus Torvalds } 626*1da177e4SLinus Torvalds 627*1da177e4SLinus Torvalds /* 628*1da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 629*1da177e4SLinus Torvalds * in front of (at a lower virtual address and file offset than) the vma. 630*1da177e4SLinus Torvalds * 631*1da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 632*1da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 633*1da177e4SLinus Torvalds * 634*1da177e4SLinus Torvalds * We don't check here for the merged mmap wrapping around the end of pagecache 635*1da177e4SLinus Torvalds * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which 636*1da177e4SLinus Torvalds * wrap, nor mmaps which cover the final page at index -1UL. 637*1da177e4SLinus Torvalds */ 638*1da177e4SLinus Torvalds static int 639*1da177e4SLinus Torvalds can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, 640*1da177e4SLinus Torvalds struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) 641*1da177e4SLinus Torvalds { 642*1da177e4SLinus Torvalds if (is_mergeable_vma(vma, file, vm_flags) && 643*1da177e4SLinus Torvalds is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { 644*1da177e4SLinus Torvalds if (vma->vm_pgoff == vm_pgoff) 645*1da177e4SLinus Torvalds return 1; 646*1da177e4SLinus Torvalds } 647*1da177e4SLinus Torvalds return 0; 648*1da177e4SLinus Torvalds } 649*1da177e4SLinus Torvalds 650*1da177e4SLinus Torvalds /* 651*1da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 652*1da177e4SLinus Torvalds * beyond (at a higher virtual address and file offset than) the vma. 653*1da177e4SLinus Torvalds * 654*1da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 655*1da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 656*1da177e4SLinus Torvalds */ 657*1da177e4SLinus Torvalds static int 658*1da177e4SLinus Torvalds can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, 659*1da177e4SLinus Torvalds struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) 660*1da177e4SLinus Torvalds { 661*1da177e4SLinus Torvalds if (is_mergeable_vma(vma, file, vm_flags) && 662*1da177e4SLinus Torvalds is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { 663*1da177e4SLinus Torvalds pgoff_t vm_pglen; 664*1da177e4SLinus Torvalds vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; 665*1da177e4SLinus Torvalds if (vma->vm_pgoff + vm_pglen == vm_pgoff) 666*1da177e4SLinus Torvalds return 1; 667*1da177e4SLinus Torvalds } 668*1da177e4SLinus Torvalds return 0; 669*1da177e4SLinus Torvalds } 670*1da177e4SLinus Torvalds 671*1da177e4SLinus Torvalds /* 672*1da177e4SLinus Torvalds * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out 673*1da177e4SLinus Torvalds * whether that can be merged with its predecessor or its successor. 674*1da177e4SLinus Torvalds * Or both (it neatly fills a hole). 675*1da177e4SLinus Torvalds * 676*1da177e4SLinus Torvalds * In most cases - when called for mmap, brk or mremap - [addr,end) is 677*1da177e4SLinus Torvalds * certain not to be mapped by the time vma_merge is called; but when 678*1da177e4SLinus Torvalds * called for mprotect, it is certain to be already mapped (either at 679*1da177e4SLinus Torvalds * an offset within prev, or at the start of next), and the flags of 680*1da177e4SLinus Torvalds * this area are about to be changed to vm_flags - and the no-change 681*1da177e4SLinus Torvalds * case has already been eliminated. 682*1da177e4SLinus Torvalds * 683*1da177e4SLinus Torvalds * The following mprotect cases have to be considered, where AAAA is 684*1da177e4SLinus Torvalds * the area passed down from mprotect_fixup, never extending beyond one 685*1da177e4SLinus Torvalds * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: 686*1da177e4SLinus Torvalds * 687*1da177e4SLinus Torvalds * AAAA AAAA AAAA AAAA 688*1da177e4SLinus Torvalds * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX 689*1da177e4SLinus Torvalds * cannot merge might become might become might become 690*1da177e4SLinus Torvalds * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or 691*1da177e4SLinus Torvalds * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or 692*1da177e4SLinus Torvalds * mremap move: PPPPNNNNNNNN 8 693*1da177e4SLinus Torvalds * AAAA 694*1da177e4SLinus Torvalds * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN 695*1da177e4SLinus Torvalds * might become case 1 below case 2 below case 3 below 696*1da177e4SLinus Torvalds * 697*1da177e4SLinus Torvalds * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: 698*1da177e4SLinus Torvalds * mprotect_fixup updates vm_flags & vm_page_prot on successful return. 699*1da177e4SLinus Torvalds */ 700*1da177e4SLinus Torvalds struct vm_area_struct *vma_merge(struct mm_struct *mm, 701*1da177e4SLinus Torvalds struct vm_area_struct *prev, unsigned long addr, 702*1da177e4SLinus Torvalds unsigned long end, unsigned long vm_flags, 703*1da177e4SLinus Torvalds struct anon_vma *anon_vma, struct file *file, 704*1da177e4SLinus Torvalds pgoff_t pgoff, struct mempolicy *policy) 705*1da177e4SLinus Torvalds { 706*1da177e4SLinus Torvalds pgoff_t pglen = (end - addr) >> PAGE_SHIFT; 707*1da177e4SLinus Torvalds struct vm_area_struct *area, *next; 708*1da177e4SLinus Torvalds 709*1da177e4SLinus Torvalds /* 710*1da177e4SLinus Torvalds * We later require that vma->vm_flags == vm_flags, 711*1da177e4SLinus Torvalds * so this tests vma->vm_flags & VM_SPECIAL, too. 712*1da177e4SLinus Torvalds */ 713*1da177e4SLinus Torvalds if (vm_flags & VM_SPECIAL) 714*1da177e4SLinus Torvalds return NULL; 715*1da177e4SLinus Torvalds 716*1da177e4SLinus Torvalds if (prev) 717*1da177e4SLinus Torvalds next = prev->vm_next; 718*1da177e4SLinus Torvalds else 719*1da177e4SLinus Torvalds next = mm->mmap; 720*1da177e4SLinus Torvalds area = next; 721*1da177e4SLinus Torvalds if (next && next->vm_end == end) /* cases 6, 7, 8 */ 722*1da177e4SLinus Torvalds next = next->vm_next; 723*1da177e4SLinus Torvalds 724*1da177e4SLinus Torvalds /* 725*1da177e4SLinus Torvalds * Can it merge with the predecessor? 726*1da177e4SLinus Torvalds */ 727*1da177e4SLinus Torvalds if (prev && prev->vm_end == addr && 728*1da177e4SLinus Torvalds mpol_equal(vma_policy(prev), policy) && 729*1da177e4SLinus Torvalds can_vma_merge_after(prev, vm_flags, 730*1da177e4SLinus Torvalds anon_vma, file, pgoff)) { 731*1da177e4SLinus Torvalds /* 732*1da177e4SLinus Torvalds * OK, it can. Can we now merge in the successor as well? 733*1da177e4SLinus Torvalds */ 734*1da177e4SLinus Torvalds if (next && end == next->vm_start && 735*1da177e4SLinus Torvalds mpol_equal(policy, vma_policy(next)) && 736*1da177e4SLinus Torvalds can_vma_merge_before(next, vm_flags, 737*1da177e4SLinus Torvalds anon_vma, file, pgoff+pglen) && 738*1da177e4SLinus Torvalds is_mergeable_anon_vma(prev->anon_vma, 739*1da177e4SLinus Torvalds next->anon_vma)) { 740*1da177e4SLinus Torvalds /* cases 1, 6 */ 741*1da177e4SLinus Torvalds vma_adjust(prev, prev->vm_start, 742*1da177e4SLinus Torvalds next->vm_end, prev->vm_pgoff, NULL); 743*1da177e4SLinus Torvalds } else /* cases 2, 5, 7 */ 744*1da177e4SLinus Torvalds vma_adjust(prev, prev->vm_start, 745*1da177e4SLinus Torvalds end, prev->vm_pgoff, NULL); 746*1da177e4SLinus Torvalds return prev; 747*1da177e4SLinus Torvalds } 748*1da177e4SLinus Torvalds 749*1da177e4SLinus Torvalds /* 750*1da177e4SLinus Torvalds * Can this new request be merged in front of next? 751*1da177e4SLinus Torvalds */ 752*1da177e4SLinus Torvalds if (next && end == next->vm_start && 753*1da177e4SLinus Torvalds mpol_equal(policy, vma_policy(next)) && 754*1da177e4SLinus Torvalds can_vma_merge_before(next, vm_flags, 755*1da177e4SLinus Torvalds anon_vma, file, pgoff+pglen)) { 756*1da177e4SLinus Torvalds if (prev && addr < prev->vm_end) /* case 4 */ 757*1da177e4SLinus Torvalds vma_adjust(prev, prev->vm_start, 758*1da177e4SLinus Torvalds addr, prev->vm_pgoff, NULL); 759*1da177e4SLinus Torvalds else /* cases 3, 8 */ 760*1da177e4SLinus Torvalds vma_adjust(area, addr, next->vm_end, 761*1da177e4SLinus Torvalds next->vm_pgoff - pglen, NULL); 762*1da177e4SLinus Torvalds return area; 763*1da177e4SLinus Torvalds } 764*1da177e4SLinus Torvalds 765*1da177e4SLinus Torvalds return NULL; 766*1da177e4SLinus Torvalds } 767*1da177e4SLinus Torvalds 768*1da177e4SLinus Torvalds /* 769*1da177e4SLinus Torvalds * find_mergeable_anon_vma is used by anon_vma_prepare, to check 770*1da177e4SLinus Torvalds * neighbouring vmas for a suitable anon_vma, before it goes off 771*1da177e4SLinus Torvalds * to allocate a new anon_vma. It checks because a repetitive 772*1da177e4SLinus Torvalds * sequence of mprotects and faults may otherwise lead to distinct 773*1da177e4SLinus Torvalds * anon_vmas being allocated, preventing vma merge in subsequent 774*1da177e4SLinus Torvalds * mprotect. 775*1da177e4SLinus Torvalds */ 776*1da177e4SLinus Torvalds struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) 777*1da177e4SLinus Torvalds { 778*1da177e4SLinus Torvalds struct vm_area_struct *near; 779*1da177e4SLinus Torvalds unsigned long vm_flags; 780*1da177e4SLinus Torvalds 781*1da177e4SLinus Torvalds near = vma->vm_next; 782*1da177e4SLinus Torvalds if (!near) 783*1da177e4SLinus Torvalds goto try_prev; 784*1da177e4SLinus Torvalds 785*1da177e4SLinus Torvalds /* 786*1da177e4SLinus Torvalds * Since only mprotect tries to remerge vmas, match flags 787*1da177e4SLinus Torvalds * which might be mprotected into each other later on. 788*1da177e4SLinus Torvalds * Neither mlock nor madvise tries to remerge at present, 789*1da177e4SLinus Torvalds * so leave their flags as obstructing a merge. 790*1da177e4SLinus Torvalds */ 791*1da177e4SLinus Torvalds vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); 792*1da177e4SLinus Torvalds vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); 793*1da177e4SLinus Torvalds 794*1da177e4SLinus Torvalds if (near->anon_vma && vma->vm_end == near->vm_start && 795*1da177e4SLinus Torvalds mpol_equal(vma_policy(vma), vma_policy(near)) && 796*1da177e4SLinus Torvalds can_vma_merge_before(near, vm_flags, 797*1da177e4SLinus Torvalds NULL, vma->vm_file, vma->vm_pgoff + 798*1da177e4SLinus Torvalds ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT))) 799*1da177e4SLinus Torvalds return near->anon_vma; 800*1da177e4SLinus Torvalds try_prev: 801*1da177e4SLinus Torvalds /* 802*1da177e4SLinus Torvalds * It is potentially slow to have to call find_vma_prev here. 803*1da177e4SLinus Torvalds * But it's only on the first write fault on the vma, not 804*1da177e4SLinus Torvalds * every time, and we could devise a way to avoid it later 805*1da177e4SLinus Torvalds * (e.g. stash info in next's anon_vma_node when assigning 806*1da177e4SLinus Torvalds * an anon_vma, or when trying vma_merge). Another time. 807*1da177e4SLinus Torvalds */ 808*1da177e4SLinus Torvalds if (find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma) 809*1da177e4SLinus Torvalds BUG(); 810*1da177e4SLinus Torvalds if (!near) 811*1da177e4SLinus Torvalds goto none; 812*1da177e4SLinus Torvalds 813*1da177e4SLinus Torvalds vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); 814*1da177e4SLinus Torvalds vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); 815*1da177e4SLinus Torvalds 816*1da177e4SLinus Torvalds if (near->anon_vma && near->vm_end == vma->vm_start && 817*1da177e4SLinus Torvalds mpol_equal(vma_policy(near), vma_policy(vma)) && 818*1da177e4SLinus Torvalds can_vma_merge_after(near, vm_flags, 819*1da177e4SLinus Torvalds NULL, vma->vm_file, vma->vm_pgoff)) 820*1da177e4SLinus Torvalds return near->anon_vma; 821*1da177e4SLinus Torvalds none: 822*1da177e4SLinus Torvalds /* 823*1da177e4SLinus Torvalds * There's no absolute need to look only at touching neighbours: 824*1da177e4SLinus Torvalds * we could search further afield for "compatible" anon_vmas. 825*1da177e4SLinus Torvalds * But it would probably just be a waste of time searching, 826*1da177e4SLinus Torvalds * or lead to too many vmas hanging off the same anon_vma. 827*1da177e4SLinus Torvalds * We're trying to allow mprotect remerging later on, 828*1da177e4SLinus Torvalds * not trying to minimize memory used for anon_vmas. 829*1da177e4SLinus Torvalds */ 830*1da177e4SLinus Torvalds return NULL; 831*1da177e4SLinus Torvalds } 832*1da177e4SLinus Torvalds 833*1da177e4SLinus Torvalds #ifdef CONFIG_PROC_FS 834*1da177e4SLinus Torvalds void __vm_stat_account(struct mm_struct *mm, unsigned long flags, 835*1da177e4SLinus Torvalds struct file *file, long pages) 836*1da177e4SLinus Torvalds { 837*1da177e4SLinus Torvalds const unsigned long stack_flags 838*1da177e4SLinus Torvalds = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); 839*1da177e4SLinus Torvalds 840*1da177e4SLinus Torvalds #ifdef CONFIG_HUGETLB 841*1da177e4SLinus Torvalds if (flags & VM_HUGETLB) { 842*1da177e4SLinus Torvalds if (!(flags & VM_DONTCOPY)) 843*1da177e4SLinus Torvalds mm->shared_vm += pages; 844*1da177e4SLinus Torvalds return; 845*1da177e4SLinus Torvalds } 846*1da177e4SLinus Torvalds #endif /* CONFIG_HUGETLB */ 847*1da177e4SLinus Torvalds 848*1da177e4SLinus Torvalds if (file) { 849*1da177e4SLinus Torvalds mm->shared_vm += pages; 850*1da177e4SLinus Torvalds if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) 851*1da177e4SLinus Torvalds mm->exec_vm += pages; 852*1da177e4SLinus Torvalds } else if (flags & stack_flags) 853*1da177e4SLinus Torvalds mm->stack_vm += pages; 854*1da177e4SLinus Torvalds if (flags & (VM_RESERVED|VM_IO)) 855*1da177e4SLinus Torvalds mm->reserved_vm += pages; 856*1da177e4SLinus Torvalds } 857*1da177e4SLinus Torvalds #endif /* CONFIG_PROC_FS */ 858*1da177e4SLinus Torvalds 859*1da177e4SLinus Torvalds /* 860*1da177e4SLinus Torvalds * The caller must hold down_write(current->mm->mmap_sem). 861*1da177e4SLinus Torvalds */ 862*1da177e4SLinus Torvalds 863*1da177e4SLinus Torvalds unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, 864*1da177e4SLinus Torvalds unsigned long len, unsigned long prot, 865*1da177e4SLinus Torvalds unsigned long flags, unsigned long pgoff) 866*1da177e4SLinus Torvalds { 867*1da177e4SLinus Torvalds struct mm_struct * mm = current->mm; 868*1da177e4SLinus Torvalds struct vm_area_struct * vma, * prev; 869*1da177e4SLinus Torvalds struct inode *inode; 870*1da177e4SLinus Torvalds unsigned int vm_flags; 871*1da177e4SLinus Torvalds int correct_wcount = 0; 872*1da177e4SLinus Torvalds int error; 873*1da177e4SLinus Torvalds struct rb_node ** rb_link, * rb_parent; 874*1da177e4SLinus Torvalds int accountable = 1; 875*1da177e4SLinus Torvalds unsigned long charged = 0, reqprot = prot; 876*1da177e4SLinus Torvalds 877*1da177e4SLinus Torvalds if (file) { 878*1da177e4SLinus Torvalds if (is_file_hugepages(file)) 879*1da177e4SLinus Torvalds accountable = 0; 880*1da177e4SLinus Torvalds 881*1da177e4SLinus Torvalds if (!file->f_op || !file->f_op->mmap) 882*1da177e4SLinus Torvalds return -ENODEV; 883*1da177e4SLinus Torvalds 884*1da177e4SLinus Torvalds if ((prot & PROT_EXEC) && 885*1da177e4SLinus Torvalds (file->f_vfsmnt->mnt_flags & MNT_NOEXEC)) 886*1da177e4SLinus Torvalds return -EPERM; 887*1da177e4SLinus Torvalds } 888*1da177e4SLinus Torvalds /* 889*1da177e4SLinus Torvalds * Does the application expect PROT_READ to imply PROT_EXEC? 890*1da177e4SLinus Torvalds * 891*1da177e4SLinus Torvalds * (the exception is when the underlying filesystem is noexec 892*1da177e4SLinus Torvalds * mounted, in which case we dont add PROT_EXEC.) 893*1da177e4SLinus Torvalds */ 894*1da177e4SLinus Torvalds if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) 895*1da177e4SLinus Torvalds if (!(file && (file->f_vfsmnt->mnt_flags & MNT_NOEXEC))) 896*1da177e4SLinus Torvalds prot |= PROT_EXEC; 897*1da177e4SLinus Torvalds 898*1da177e4SLinus Torvalds if (!len) 899*1da177e4SLinus Torvalds return -EINVAL; 900*1da177e4SLinus Torvalds 901*1da177e4SLinus Torvalds /* Careful about overflows.. */ 902*1da177e4SLinus Torvalds len = PAGE_ALIGN(len); 903*1da177e4SLinus Torvalds if (!len || len > TASK_SIZE) 904*1da177e4SLinus Torvalds return -ENOMEM; 905*1da177e4SLinus Torvalds 906*1da177e4SLinus Torvalds /* offset overflow? */ 907*1da177e4SLinus Torvalds if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) 908*1da177e4SLinus Torvalds return -EOVERFLOW; 909*1da177e4SLinus Torvalds 910*1da177e4SLinus Torvalds /* Too many mappings? */ 911*1da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 912*1da177e4SLinus Torvalds return -ENOMEM; 913*1da177e4SLinus Torvalds 914*1da177e4SLinus Torvalds /* Obtain the address to map to. we verify (or select) it and ensure 915*1da177e4SLinus Torvalds * that it represents a valid section of the address space. 916*1da177e4SLinus Torvalds */ 917*1da177e4SLinus Torvalds addr = get_unmapped_area(file, addr, len, pgoff, flags); 918*1da177e4SLinus Torvalds if (addr & ~PAGE_MASK) 919*1da177e4SLinus Torvalds return addr; 920*1da177e4SLinus Torvalds 921*1da177e4SLinus Torvalds /* Do simple checking here so the lower-level routines won't have 922*1da177e4SLinus Torvalds * to. we assume access permissions have been handled by the open 923*1da177e4SLinus Torvalds * of the memory object, so we don't do any here. 924*1da177e4SLinus Torvalds */ 925*1da177e4SLinus Torvalds vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | 926*1da177e4SLinus Torvalds mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; 927*1da177e4SLinus Torvalds 928*1da177e4SLinus Torvalds if (flags & MAP_LOCKED) { 929*1da177e4SLinus Torvalds if (!can_do_mlock()) 930*1da177e4SLinus Torvalds return -EPERM; 931*1da177e4SLinus Torvalds vm_flags |= VM_LOCKED; 932*1da177e4SLinus Torvalds } 933*1da177e4SLinus Torvalds /* mlock MCL_FUTURE? */ 934*1da177e4SLinus Torvalds if (vm_flags & VM_LOCKED) { 935*1da177e4SLinus Torvalds unsigned long locked, lock_limit; 936*1da177e4SLinus Torvalds locked = mm->locked_vm << PAGE_SHIFT; 937*1da177e4SLinus Torvalds lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; 938*1da177e4SLinus Torvalds locked += len; 939*1da177e4SLinus Torvalds if (locked > lock_limit && !capable(CAP_IPC_LOCK)) 940*1da177e4SLinus Torvalds return -EAGAIN; 941*1da177e4SLinus Torvalds } 942*1da177e4SLinus Torvalds 943*1da177e4SLinus Torvalds inode = file ? file->f_dentry->d_inode : NULL; 944*1da177e4SLinus Torvalds 945*1da177e4SLinus Torvalds if (file) { 946*1da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 947*1da177e4SLinus Torvalds case MAP_SHARED: 948*1da177e4SLinus Torvalds if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) 949*1da177e4SLinus Torvalds return -EACCES; 950*1da177e4SLinus Torvalds 951*1da177e4SLinus Torvalds /* 952*1da177e4SLinus Torvalds * Make sure we don't allow writing to an append-only 953*1da177e4SLinus Torvalds * file.. 954*1da177e4SLinus Torvalds */ 955*1da177e4SLinus Torvalds if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) 956*1da177e4SLinus Torvalds return -EACCES; 957*1da177e4SLinus Torvalds 958*1da177e4SLinus Torvalds /* 959*1da177e4SLinus Torvalds * Make sure there are no mandatory locks on the file. 960*1da177e4SLinus Torvalds */ 961*1da177e4SLinus Torvalds if (locks_verify_locked(inode)) 962*1da177e4SLinus Torvalds return -EAGAIN; 963*1da177e4SLinus Torvalds 964*1da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 965*1da177e4SLinus Torvalds if (!(file->f_mode & FMODE_WRITE)) 966*1da177e4SLinus Torvalds vm_flags &= ~(VM_MAYWRITE | VM_SHARED); 967*1da177e4SLinus Torvalds 968*1da177e4SLinus Torvalds /* fall through */ 969*1da177e4SLinus Torvalds case MAP_PRIVATE: 970*1da177e4SLinus Torvalds if (!(file->f_mode & FMODE_READ)) 971*1da177e4SLinus Torvalds return -EACCES; 972*1da177e4SLinus Torvalds break; 973*1da177e4SLinus Torvalds 974*1da177e4SLinus Torvalds default: 975*1da177e4SLinus Torvalds return -EINVAL; 976*1da177e4SLinus Torvalds } 977*1da177e4SLinus Torvalds } else { 978*1da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 979*1da177e4SLinus Torvalds case MAP_SHARED: 980*1da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 981*1da177e4SLinus Torvalds break; 982*1da177e4SLinus Torvalds case MAP_PRIVATE: 983*1da177e4SLinus Torvalds /* 984*1da177e4SLinus Torvalds * Set pgoff according to addr for anon_vma. 985*1da177e4SLinus Torvalds */ 986*1da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 987*1da177e4SLinus Torvalds break; 988*1da177e4SLinus Torvalds default: 989*1da177e4SLinus Torvalds return -EINVAL; 990*1da177e4SLinus Torvalds } 991*1da177e4SLinus Torvalds } 992*1da177e4SLinus Torvalds 993*1da177e4SLinus Torvalds error = security_file_mmap(file, reqprot, prot, flags); 994*1da177e4SLinus Torvalds if (error) 995*1da177e4SLinus Torvalds return error; 996*1da177e4SLinus Torvalds 997*1da177e4SLinus Torvalds /* Clear old maps */ 998*1da177e4SLinus Torvalds error = -ENOMEM; 999*1da177e4SLinus Torvalds munmap_back: 1000*1da177e4SLinus Torvalds vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); 1001*1da177e4SLinus Torvalds if (vma && vma->vm_start < addr + len) { 1002*1da177e4SLinus Torvalds if (do_munmap(mm, addr, len)) 1003*1da177e4SLinus Torvalds return -ENOMEM; 1004*1da177e4SLinus Torvalds goto munmap_back; 1005*1da177e4SLinus Torvalds } 1006*1da177e4SLinus Torvalds 1007*1da177e4SLinus Torvalds /* Check against address space limit. */ 1008*1da177e4SLinus Torvalds if ((mm->total_vm << PAGE_SHIFT) + len 1009*1da177e4SLinus Torvalds > current->signal->rlim[RLIMIT_AS].rlim_cur) 1010*1da177e4SLinus Torvalds return -ENOMEM; 1011*1da177e4SLinus Torvalds 1012*1da177e4SLinus Torvalds if (accountable && (!(flags & MAP_NORESERVE) || 1013*1da177e4SLinus Torvalds sysctl_overcommit_memory == OVERCOMMIT_NEVER)) { 1014*1da177e4SLinus Torvalds if (vm_flags & VM_SHARED) { 1015*1da177e4SLinus Torvalds /* Check memory availability in shmem_file_setup? */ 1016*1da177e4SLinus Torvalds vm_flags |= VM_ACCOUNT; 1017*1da177e4SLinus Torvalds } else if (vm_flags & VM_WRITE) { 1018*1da177e4SLinus Torvalds /* 1019*1da177e4SLinus Torvalds * Private writable mapping: check memory availability 1020*1da177e4SLinus Torvalds */ 1021*1da177e4SLinus Torvalds charged = len >> PAGE_SHIFT; 1022*1da177e4SLinus Torvalds if (security_vm_enough_memory(charged)) 1023*1da177e4SLinus Torvalds return -ENOMEM; 1024*1da177e4SLinus Torvalds vm_flags |= VM_ACCOUNT; 1025*1da177e4SLinus Torvalds } 1026*1da177e4SLinus Torvalds } 1027*1da177e4SLinus Torvalds 1028*1da177e4SLinus Torvalds /* 1029*1da177e4SLinus Torvalds * Can we just expand an old private anonymous mapping? 1030*1da177e4SLinus Torvalds * The VM_SHARED test is necessary because shmem_zero_setup 1031*1da177e4SLinus Torvalds * will create the file object for a shared anonymous map below. 1032*1da177e4SLinus Torvalds */ 1033*1da177e4SLinus Torvalds if (!file && !(vm_flags & VM_SHARED) && 1034*1da177e4SLinus Torvalds vma_merge(mm, prev, addr, addr + len, vm_flags, 1035*1da177e4SLinus Torvalds NULL, NULL, pgoff, NULL)) 1036*1da177e4SLinus Torvalds goto out; 1037*1da177e4SLinus Torvalds 1038*1da177e4SLinus Torvalds /* 1039*1da177e4SLinus Torvalds * Determine the object being mapped and call the appropriate 1040*1da177e4SLinus Torvalds * specific mapper. the address has already been validated, but 1041*1da177e4SLinus Torvalds * not unmapped, but the maps are removed from the list. 1042*1da177e4SLinus Torvalds */ 1043*1da177e4SLinus Torvalds vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); 1044*1da177e4SLinus Torvalds if (!vma) { 1045*1da177e4SLinus Torvalds error = -ENOMEM; 1046*1da177e4SLinus Torvalds goto unacct_error; 1047*1da177e4SLinus Torvalds } 1048*1da177e4SLinus Torvalds memset(vma, 0, sizeof(*vma)); 1049*1da177e4SLinus Torvalds 1050*1da177e4SLinus Torvalds vma->vm_mm = mm; 1051*1da177e4SLinus Torvalds vma->vm_start = addr; 1052*1da177e4SLinus Torvalds vma->vm_end = addr + len; 1053*1da177e4SLinus Torvalds vma->vm_flags = vm_flags; 1054*1da177e4SLinus Torvalds vma->vm_page_prot = protection_map[vm_flags & 0x0f]; 1055*1da177e4SLinus Torvalds vma->vm_pgoff = pgoff; 1056*1da177e4SLinus Torvalds 1057*1da177e4SLinus Torvalds if (file) { 1058*1da177e4SLinus Torvalds error = -EINVAL; 1059*1da177e4SLinus Torvalds if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 1060*1da177e4SLinus Torvalds goto free_vma; 1061*1da177e4SLinus Torvalds if (vm_flags & VM_DENYWRITE) { 1062*1da177e4SLinus Torvalds error = deny_write_access(file); 1063*1da177e4SLinus Torvalds if (error) 1064*1da177e4SLinus Torvalds goto free_vma; 1065*1da177e4SLinus Torvalds correct_wcount = 1; 1066*1da177e4SLinus Torvalds } 1067*1da177e4SLinus Torvalds vma->vm_file = file; 1068*1da177e4SLinus Torvalds get_file(file); 1069*1da177e4SLinus Torvalds error = file->f_op->mmap(file, vma); 1070*1da177e4SLinus Torvalds if (error) 1071*1da177e4SLinus Torvalds goto unmap_and_free_vma; 1072*1da177e4SLinus Torvalds } else if (vm_flags & VM_SHARED) { 1073*1da177e4SLinus Torvalds error = shmem_zero_setup(vma); 1074*1da177e4SLinus Torvalds if (error) 1075*1da177e4SLinus Torvalds goto free_vma; 1076*1da177e4SLinus Torvalds } 1077*1da177e4SLinus Torvalds 1078*1da177e4SLinus Torvalds /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform 1079*1da177e4SLinus Torvalds * shmem_zero_setup (perhaps called through /dev/zero's ->mmap) 1080*1da177e4SLinus Torvalds * that memory reservation must be checked; but that reservation 1081*1da177e4SLinus Torvalds * belongs to shared memory object, not to vma: so now clear it. 1082*1da177e4SLinus Torvalds */ 1083*1da177e4SLinus Torvalds if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT)) 1084*1da177e4SLinus Torvalds vma->vm_flags &= ~VM_ACCOUNT; 1085*1da177e4SLinus Torvalds 1086*1da177e4SLinus Torvalds /* Can addr have changed?? 1087*1da177e4SLinus Torvalds * 1088*1da177e4SLinus Torvalds * Answer: Yes, several device drivers can do it in their 1089*1da177e4SLinus Torvalds * f_op->mmap method. -DaveM 1090*1da177e4SLinus Torvalds */ 1091*1da177e4SLinus Torvalds addr = vma->vm_start; 1092*1da177e4SLinus Torvalds pgoff = vma->vm_pgoff; 1093*1da177e4SLinus Torvalds vm_flags = vma->vm_flags; 1094*1da177e4SLinus Torvalds 1095*1da177e4SLinus Torvalds if (!file || !vma_merge(mm, prev, addr, vma->vm_end, 1096*1da177e4SLinus Torvalds vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) { 1097*1da177e4SLinus Torvalds file = vma->vm_file; 1098*1da177e4SLinus Torvalds vma_link(mm, vma, prev, rb_link, rb_parent); 1099*1da177e4SLinus Torvalds if (correct_wcount) 1100*1da177e4SLinus Torvalds atomic_inc(&inode->i_writecount); 1101*1da177e4SLinus Torvalds } else { 1102*1da177e4SLinus Torvalds if (file) { 1103*1da177e4SLinus Torvalds if (correct_wcount) 1104*1da177e4SLinus Torvalds atomic_inc(&inode->i_writecount); 1105*1da177e4SLinus Torvalds fput(file); 1106*1da177e4SLinus Torvalds } 1107*1da177e4SLinus Torvalds mpol_free(vma_policy(vma)); 1108*1da177e4SLinus Torvalds kmem_cache_free(vm_area_cachep, vma); 1109*1da177e4SLinus Torvalds } 1110*1da177e4SLinus Torvalds out: 1111*1da177e4SLinus Torvalds mm->total_vm += len >> PAGE_SHIFT; 1112*1da177e4SLinus Torvalds __vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); 1113*1da177e4SLinus Torvalds if (vm_flags & VM_LOCKED) { 1114*1da177e4SLinus Torvalds mm->locked_vm += len >> PAGE_SHIFT; 1115*1da177e4SLinus Torvalds make_pages_present(addr, addr + len); 1116*1da177e4SLinus Torvalds } 1117*1da177e4SLinus Torvalds if (flags & MAP_POPULATE) { 1118*1da177e4SLinus Torvalds up_write(&mm->mmap_sem); 1119*1da177e4SLinus Torvalds sys_remap_file_pages(addr, len, 0, 1120*1da177e4SLinus Torvalds pgoff, flags & MAP_NONBLOCK); 1121*1da177e4SLinus Torvalds down_write(&mm->mmap_sem); 1122*1da177e4SLinus Torvalds } 1123*1da177e4SLinus Torvalds return addr; 1124*1da177e4SLinus Torvalds 1125*1da177e4SLinus Torvalds unmap_and_free_vma: 1126*1da177e4SLinus Torvalds if (correct_wcount) 1127*1da177e4SLinus Torvalds atomic_inc(&inode->i_writecount); 1128*1da177e4SLinus Torvalds vma->vm_file = NULL; 1129*1da177e4SLinus Torvalds fput(file); 1130*1da177e4SLinus Torvalds 1131*1da177e4SLinus Torvalds /* Undo any partial mapping done by a device driver. */ 1132*1da177e4SLinus Torvalds zap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, NULL); 1133*1da177e4SLinus Torvalds free_vma: 1134*1da177e4SLinus Torvalds kmem_cache_free(vm_area_cachep, vma); 1135*1da177e4SLinus Torvalds unacct_error: 1136*1da177e4SLinus Torvalds if (charged) 1137*1da177e4SLinus Torvalds vm_unacct_memory(charged); 1138*1da177e4SLinus Torvalds return error; 1139*1da177e4SLinus Torvalds } 1140*1da177e4SLinus Torvalds 1141*1da177e4SLinus Torvalds EXPORT_SYMBOL(do_mmap_pgoff); 1142*1da177e4SLinus Torvalds 1143*1da177e4SLinus Torvalds /* Get an address range which is currently unmapped. 1144*1da177e4SLinus Torvalds * For shmat() with addr=0. 1145*1da177e4SLinus Torvalds * 1146*1da177e4SLinus Torvalds * Ugly calling convention alert: 1147*1da177e4SLinus Torvalds * Return value with the low bits set means error value, 1148*1da177e4SLinus Torvalds * ie 1149*1da177e4SLinus Torvalds * if (ret & ~PAGE_MASK) 1150*1da177e4SLinus Torvalds * error = ret; 1151*1da177e4SLinus Torvalds * 1152*1da177e4SLinus Torvalds * This function "knows" that -ENOMEM has the bits set. 1153*1da177e4SLinus Torvalds */ 1154*1da177e4SLinus Torvalds #ifndef HAVE_ARCH_UNMAPPED_AREA 1155*1da177e4SLinus Torvalds unsigned long 1156*1da177e4SLinus Torvalds arch_get_unmapped_area(struct file *filp, unsigned long addr, 1157*1da177e4SLinus Torvalds unsigned long len, unsigned long pgoff, unsigned long flags) 1158*1da177e4SLinus Torvalds { 1159*1da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1160*1da177e4SLinus Torvalds struct vm_area_struct *vma; 1161*1da177e4SLinus Torvalds unsigned long start_addr; 1162*1da177e4SLinus Torvalds 1163*1da177e4SLinus Torvalds if (len > TASK_SIZE) 1164*1da177e4SLinus Torvalds return -ENOMEM; 1165*1da177e4SLinus Torvalds 1166*1da177e4SLinus Torvalds if (addr) { 1167*1da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 1168*1da177e4SLinus Torvalds vma = find_vma(mm, addr); 1169*1da177e4SLinus Torvalds if (TASK_SIZE - len >= addr && 1170*1da177e4SLinus Torvalds (!vma || addr + len <= vma->vm_start)) 1171*1da177e4SLinus Torvalds return addr; 1172*1da177e4SLinus Torvalds } 1173*1da177e4SLinus Torvalds start_addr = addr = mm->free_area_cache; 1174*1da177e4SLinus Torvalds 1175*1da177e4SLinus Torvalds full_search: 1176*1da177e4SLinus Torvalds for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { 1177*1da177e4SLinus Torvalds /* At this point: (!vma || addr < vma->vm_end). */ 1178*1da177e4SLinus Torvalds if (TASK_SIZE - len < addr) { 1179*1da177e4SLinus Torvalds /* 1180*1da177e4SLinus Torvalds * Start a new search - just in case we missed 1181*1da177e4SLinus Torvalds * some holes. 1182*1da177e4SLinus Torvalds */ 1183*1da177e4SLinus Torvalds if (start_addr != TASK_UNMAPPED_BASE) { 1184*1da177e4SLinus Torvalds start_addr = addr = TASK_UNMAPPED_BASE; 1185*1da177e4SLinus Torvalds goto full_search; 1186*1da177e4SLinus Torvalds } 1187*1da177e4SLinus Torvalds return -ENOMEM; 1188*1da177e4SLinus Torvalds } 1189*1da177e4SLinus Torvalds if (!vma || addr + len <= vma->vm_start) { 1190*1da177e4SLinus Torvalds /* 1191*1da177e4SLinus Torvalds * Remember the place where we stopped the search: 1192*1da177e4SLinus Torvalds */ 1193*1da177e4SLinus Torvalds mm->free_area_cache = addr + len; 1194*1da177e4SLinus Torvalds return addr; 1195*1da177e4SLinus Torvalds } 1196*1da177e4SLinus Torvalds addr = vma->vm_end; 1197*1da177e4SLinus Torvalds } 1198*1da177e4SLinus Torvalds } 1199*1da177e4SLinus Torvalds #endif 1200*1da177e4SLinus Torvalds 1201*1da177e4SLinus Torvalds void arch_unmap_area(struct vm_area_struct *area) 1202*1da177e4SLinus Torvalds { 1203*1da177e4SLinus Torvalds /* 1204*1da177e4SLinus Torvalds * Is this a new hole at the lowest possible address? 1205*1da177e4SLinus Torvalds */ 1206*1da177e4SLinus Torvalds if (area->vm_start >= TASK_UNMAPPED_BASE && 1207*1da177e4SLinus Torvalds area->vm_start < area->vm_mm->free_area_cache) 1208*1da177e4SLinus Torvalds area->vm_mm->free_area_cache = area->vm_start; 1209*1da177e4SLinus Torvalds } 1210*1da177e4SLinus Torvalds 1211*1da177e4SLinus Torvalds /* 1212*1da177e4SLinus Torvalds * This mmap-allocator allocates new areas top-down from below the 1213*1da177e4SLinus Torvalds * stack's low limit (the base): 1214*1da177e4SLinus Torvalds */ 1215*1da177e4SLinus Torvalds #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN 1216*1da177e4SLinus Torvalds unsigned long 1217*1da177e4SLinus Torvalds arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 1218*1da177e4SLinus Torvalds const unsigned long len, const unsigned long pgoff, 1219*1da177e4SLinus Torvalds const unsigned long flags) 1220*1da177e4SLinus Torvalds { 1221*1da177e4SLinus Torvalds struct vm_area_struct *vma; 1222*1da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1223*1da177e4SLinus Torvalds unsigned long addr = addr0; 1224*1da177e4SLinus Torvalds 1225*1da177e4SLinus Torvalds /* requested length too big for entire address space */ 1226*1da177e4SLinus Torvalds if (len > TASK_SIZE) 1227*1da177e4SLinus Torvalds return -ENOMEM; 1228*1da177e4SLinus Torvalds 1229*1da177e4SLinus Torvalds /* requesting a specific address */ 1230*1da177e4SLinus Torvalds if (addr) { 1231*1da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 1232*1da177e4SLinus Torvalds vma = find_vma(mm, addr); 1233*1da177e4SLinus Torvalds if (TASK_SIZE - len >= addr && 1234*1da177e4SLinus Torvalds (!vma || addr + len <= vma->vm_start)) 1235*1da177e4SLinus Torvalds return addr; 1236*1da177e4SLinus Torvalds } 1237*1da177e4SLinus Torvalds 1238*1da177e4SLinus Torvalds /* either no address requested or can't fit in requested address hole */ 1239*1da177e4SLinus Torvalds addr = mm->free_area_cache; 1240*1da177e4SLinus Torvalds 1241*1da177e4SLinus Torvalds /* make sure it can fit in the remaining address space */ 1242*1da177e4SLinus Torvalds if (addr >= len) { 1243*1da177e4SLinus Torvalds vma = find_vma(mm, addr-len); 1244*1da177e4SLinus Torvalds if (!vma || addr <= vma->vm_start) 1245*1da177e4SLinus Torvalds /* remember the address as a hint for next time */ 1246*1da177e4SLinus Torvalds return (mm->free_area_cache = addr-len); 1247*1da177e4SLinus Torvalds } 1248*1da177e4SLinus Torvalds 1249*1da177e4SLinus Torvalds addr = mm->mmap_base-len; 1250*1da177e4SLinus Torvalds 1251*1da177e4SLinus Torvalds do { 1252*1da177e4SLinus Torvalds /* 1253*1da177e4SLinus Torvalds * Lookup failure means no vma is above this address, 1254*1da177e4SLinus Torvalds * else if new region fits below vma->vm_start, 1255*1da177e4SLinus Torvalds * return with success: 1256*1da177e4SLinus Torvalds */ 1257*1da177e4SLinus Torvalds vma = find_vma(mm, addr); 1258*1da177e4SLinus Torvalds if (!vma || addr+len <= vma->vm_start) 1259*1da177e4SLinus Torvalds /* remember the address as a hint for next time */ 1260*1da177e4SLinus Torvalds return (mm->free_area_cache = addr); 1261*1da177e4SLinus Torvalds 1262*1da177e4SLinus Torvalds /* try just below the current vma->vm_start */ 1263*1da177e4SLinus Torvalds addr = vma->vm_start-len; 1264*1da177e4SLinus Torvalds } while (len <= vma->vm_start); 1265*1da177e4SLinus Torvalds 1266*1da177e4SLinus Torvalds /* 1267*1da177e4SLinus Torvalds * A failed mmap() very likely causes application failure, 1268*1da177e4SLinus Torvalds * so fall back to the bottom-up function here. This scenario 1269*1da177e4SLinus Torvalds * can happen with large stack limits and large mmap() 1270*1da177e4SLinus Torvalds * allocations. 1271*1da177e4SLinus Torvalds */ 1272*1da177e4SLinus Torvalds mm->free_area_cache = TASK_UNMAPPED_BASE; 1273*1da177e4SLinus Torvalds addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); 1274*1da177e4SLinus Torvalds /* 1275*1da177e4SLinus Torvalds * Restore the topdown base: 1276*1da177e4SLinus Torvalds */ 1277*1da177e4SLinus Torvalds mm->free_area_cache = mm->mmap_base; 1278*1da177e4SLinus Torvalds 1279*1da177e4SLinus Torvalds return addr; 1280*1da177e4SLinus Torvalds } 1281*1da177e4SLinus Torvalds #endif 1282*1da177e4SLinus Torvalds 1283*1da177e4SLinus Torvalds void arch_unmap_area_topdown(struct vm_area_struct *area) 1284*1da177e4SLinus Torvalds { 1285*1da177e4SLinus Torvalds /* 1286*1da177e4SLinus Torvalds * Is this a new hole at the highest possible address? 1287*1da177e4SLinus Torvalds */ 1288*1da177e4SLinus Torvalds if (area->vm_end > area->vm_mm->free_area_cache) 1289*1da177e4SLinus Torvalds area->vm_mm->free_area_cache = area->vm_end; 1290*1da177e4SLinus Torvalds 1291*1da177e4SLinus Torvalds /* dont allow allocations above current base */ 1292*1da177e4SLinus Torvalds if (area->vm_mm->free_area_cache > area->vm_mm->mmap_base) 1293*1da177e4SLinus Torvalds area->vm_mm->free_area_cache = area->vm_mm->mmap_base; 1294*1da177e4SLinus Torvalds } 1295*1da177e4SLinus Torvalds 1296*1da177e4SLinus Torvalds unsigned long 1297*1da177e4SLinus Torvalds get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, 1298*1da177e4SLinus Torvalds unsigned long pgoff, unsigned long flags) 1299*1da177e4SLinus Torvalds { 1300*1da177e4SLinus Torvalds if (flags & MAP_FIXED) { 1301*1da177e4SLinus Torvalds unsigned long ret; 1302*1da177e4SLinus Torvalds 1303*1da177e4SLinus Torvalds if (addr > TASK_SIZE - len) 1304*1da177e4SLinus Torvalds return -ENOMEM; 1305*1da177e4SLinus Torvalds if (addr & ~PAGE_MASK) 1306*1da177e4SLinus Torvalds return -EINVAL; 1307*1da177e4SLinus Torvalds if (file && is_file_hugepages(file)) { 1308*1da177e4SLinus Torvalds /* 1309*1da177e4SLinus Torvalds * Check if the given range is hugepage aligned, and 1310*1da177e4SLinus Torvalds * can be made suitable for hugepages. 1311*1da177e4SLinus Torvalds */ 1312*1da177e4SLinus Torvalds ret = prepare_hugepage_range(addr, len); 1313*1da177e4SLinus Torvalds } else { 1314*1da177e4SLinus Torvalds /* 1315*1da177e4SLinus Torvalds * Ensure that a normal request is not falling in a 1316*1da177e4SLinus Torvalds * reserved hugepage range. For some archs like IA-64, 1317*1da177e4SLinus Torvalds * there is a separate region for hugepages. 1318*1da177e4SLinus Torvalds */ 1319*1da177e4SLinus Torvalds ret = is_hugepage_only_range(current->mm, addr, len); 1320*1da177e4SLinus Torvalds } 1321*1da177e4SLinus Torvalds if (ret) 1322*1da177e4SLinus Torvalds return -EINVAL; 1323*1da177e4SLinus Torvalds return addr; 1324*1da177e4SLinus Torvalds } 1325*1da177e4SLinus Torvalds 1326*1da177e4SLinus Torvalds if (file && file->f_op && file->f_op->get_unmapped_area) 1327*1da177e4SLinus Torvalds return file->f_op->get_unmapped_area(file, addr, len, 1328*1da177e4SLinus Torvalds pgoff, flags); 1329*1da177e4SLinus Torvalds 1330*1da177e4SLinus Torvalds return current->mm->get_unmapped_area(file, addr, len, pgoff, flags); 1331*1da177e4SLinus Torvalds } 1332*1da177e4SLinus Torvalds 1333*1da177e4SLinus Torvalds EXPORT_SYMBOL(get_unmapped_area); 1334*1da177e4SLinus Torvalds 1335*1da177e4SLinus Torvalds /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ 1336*1da177e4SLinus Torvalds struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr) 1337*1da177e4SLinus Torvalds { 1338*1da177e4SLinus Torvalds struct vm_area_struct *vma = NULL; 1339*1da177e4SLinus Torvalds 1340*1da177e4SLinus Torvalds if (mm) { 1341*1da177e4SLinus Torvalds /* Check the cache first. */ 1342*1da177e4SLinus Torvalds /* (Cache hit rate is typically around 35%.) */ 1343*1da177e4SLinus Torvalds vma = mm->mmap_cache; 1344*1da177e4SLinus Torvalds if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { 1345*1da177e4SLinus Torvalds struct rb_node * rb_node; 1346*1da177e4SLinus Torvalds 1347*1da177e4SLinus Torvalds rb_node = mm->mm_rb.rb_node; 1348*1da177e4SLinus Torvalds vma = NULL; 1349*1da177e4SLinus Torvalds 1350*1da177e4SLinus Torvalds while (rb_node) { 1351*1da177e4SLinus Torvalds struct vm_area_struct * vma_tmp; 1352*1da177e4SLinus Torvalds 1353*1da177e4SLinus Torvalds vma_tmp = rb_entry(rb_node, 1354*1da177e4SLinus Torvalds struct vm_area_struct, vm_rb); 1355*1da177e4SLinus Torvalds 1356*1da177e4SLinus Torvalds if (vma_tmp->vm_end > addr) { 1357*1da177e4SLinus Torvalds vma = vma_tmp; 1358*1da177e4SLinus Torvalds if (vma_tmp->vm_start <= addr) 1359*1da177e4SLinus Torvalds break; 1360*1da177e4SLinus Torvalds rb_node = rb_node->rb_left; 1361*1da177e4SLinus Torvalds } else 1362*1da177e4SLinus Torvalds rb_node = rb_node->rb_right; 1363*1da177e4SLinus Torvalds } 1364*1da177e4SLinus Torvalds if (vma) 1365*1da177e4SLinus Torvalds mm->mmap_cache = vma; 1366*1da177e4SLinus Torvalds } 1367*1da177e4SLinus Torvalds } 1368*1da177e4SLinus Torvalds return vma; 1369*1da177e4SLinus Torvalds } 1370*1da177e4SLinus Torvalds 1371*1da177e4SLinus Torvalds EXPORT_SYMBOL(find_vma); 1372*1da177e4SLinus Torvalds 1373*1da177e4SLinus Torvalds /* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */ 1374*1da177e4SLinus Torvalds struct vm_area_struct * 1375*1da177e4SLinus Torvalds find_vma_prev(struct mm_struct *mm, unsigned long addr, 1376*1da177e4SLinus Torvalds struct vm_area_struct **pprev) 1377*1da177e4SLinus Torvalds { 1378*1da177e4SLinus Torvalds struct vm_area_struct *vma = NULL, *prev = NULL; 1379*1da177e4SLinus Torvalds struct rb_node * rb_node; 1380*1da177e4SLinus Torvalds if (!mm) 1381*1da177e4SLinus Torvalds goto out; 1382*1da177e4SLinus Torvalds 1383*1da177e4SLinus Torvalds /* Guard against addr being lower than the first VMA */ 1384*1da177e4SLinus Torvalds vma = mm->mmap; 1385*1da177e4SLinus Torvalds 1386*1da177e4SLinus Torvalds /* Go through the RB tree quickly. */ 1387*1da177e4SLinus Torvalds rb_node = mm->mm_rb.rb_node; 1388*1da177e4SLinus Torvalds 1389*1da177e4SLinus Torvalds while (rb_node) { 1390*1da177e4SLinus Torvalds struct vm_area_struct *vma_tmp; 1391*1da177e4SLinus Torvalds vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb); 1392*1da177e4SLinus Torvalds 1393*1da177e4SLinus Torvalds if (addr < vma_tmp->vm_end) { 1394*1da177e4SLinus Torvalds rb_node = rb_node->rb_left; 1395*1da177e4SLinus Torvalds } else { 1396*1da177e4SLinus Torvalds prev = vma_tmp; 1397*1da177e4SLinus Torvalds if (!prev->vm_next || (addr < prev->vm_next->vm_end)) 1398*1da177e4SLinus Torvalds break; 1399*1da177e4SLinus Torvalds rb_node = rb_node->rb_right; 1400*1da177e4SLinus Torvalds } 1401*1da177e4SLinus Torvalds } 1402*1da177e4SLinus Torvalds 1403*1da177e4SLinus Torvalds out: 1404*1da177e4SLinus Torvalds *pprev = prev; 1405*1da177e4SLinus Torvalds return prev ? prev->vm_next : vma; 1406*1da177e4SLinus Torvalds } 1407*1da177e4SLinus Torvalds 1408*1da177e4SLinus Torvalds /* 1409*1da177e4SLinus Torvalds * Verify that the stack growth is acceptable and 1410*1da177e4SLinus Torvalds * update accounting. This is shared with both the 1411*1da177e4SLinus Torvalds * grow-up and grow-down cases. 1412*1da177e4SLinus Torvalds */ 1413*1da177e4SLinus Torvalds static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow) 1414*1da177e4SLinus Torvalds { 1415*1da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 1416*1da177e4SLinus Torvalds struct rlimit *rlim = current->signal->rlim; 1417*1da177e4SLinus Torvalds 1418*1da177e4SLinus Torvalds /* address space limit tests */ 1419*1da177e4SLinus Torvalds if (mm->total_vm + grow > rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT) 1420*1da177e4SLinus Torvalds return -ENOMEM; 1421*1da177e4SLinus Torvalds 1422*1da177e4SLinus Torvalds /* Stack limit test */ 1423*1da177e4SLinus Torvalds if (size > rlim[RLIMIT_STACK].rlim_cur) 1424*1da177e4SLinus Torvalds return -ENOMEM; 1425*1da177e4SLinus Torvalds 1426*1da177e4SLinus Torvalds /* mlock limit tests */ 1427*1da177e4SLinus Torvalds if (vma->vm_flags & VM_LOCKED) { 1428*1da177e4SLinus Torvalds unsigned long locked; 1429*1da177e4SLinus Torvalds unsigned long limit; 1430*1da177e4SLinus Torvalds locked = mm->locked_vm + grow; 1431*1da177e4SLinus Torvalds limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT; 1432*1da177e4SLinus Torvalds if (locked > limit && !capable(CAP_IPC_LOCK)) 1433*1da177e4SLinus Torvalds return -ENOMEM; 1434*1da177e4SLinus Torvalds } 1435*1da177e4SLinus Torvalds 1436*1da177e4SLinus Torvalds /* 1437*1da177e4SLinus Torvalds * Overcommit.. This must be the final test, as it will 1438*1da177e4SLinus Torvalds * update security statistics. 1439*1da177e4SLinus Torvalds */ 1440*1da177e4SLinus Torvalds if (security_vm_enough_memory(grow)) 1441*1da177e4SLinus Torvalds return -ENOMEM; 1442*1da177e4SLinus Torvalds 1443*1da177e4SLinus Torvalds /* Ok, everything looks good - let it rip */ 1444*1da177e4SLinus Torvalds mm->total_vm += grow; 1445*1da177e4SLinus Torvalds if (vma->vm_flags & VM_LOCKED) 1446*1da177e4SLinus Torvalds mm->locked_vm += grow; 1447*1da177e4SLinus Torvalds __vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); 1448*1da177e4SLinus Torvalds return 0; 1449*1da177e4SLinus Torvalds } 1450*1da177e4SLinus Torvalds 1451*1da177e4SLinus Torvalds #ifdef CONFIG_STACK_GROWSUP 1452*1da177e4SLinus Torvalds /* 1453*1da177e4SLinus Torvalds * vma is the first one with address > vma->vm_end. Have to extend vma. 1454*1da177e4SLinus Torvalds */ 1455*1da177e4SLinus Torvalds int expand_stack(struct vm_area_struct * vma, unsigned long address) 1456*1da177e4SLinus Torvalds { 1457*1da177e4SLinus Torvalds int error; 1458*1da177e4SLinus Torvalds 1459*1da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSUP)) 1460*1da177e4SLinus Torvalds return -EFAULT; 1461*1da177e4SLinus Torvalds 1462*1da177e4SLinus Torvalds /* 1463*1da177e4SLinus Torvalds * We must make sure the anon_vma is allocated 1464*1da177e4SLinus Torvalds * so that the anon_vma locking is not a noop. 1465*1da177e4SLinus Torvalds */ 1466*1da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 1467*1da177e4SLinus Torvalds return -ENOMEM; 1468*1da177e4SLinus Torvalds anon_vma_lock(vma); 1469*1da177e4SLinus Torvalds 1470*1da177e4SLinus Torvalds /* 1471*1da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 1472*1da177e4SLinus Torvalds * is required to hold the mmap_sem in read mode. We need the 1473*1da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 1474*1da177e4SLinus Torvalds */ 1475*1da177e4SLinus Torvalds address += 4 + PAGE_SIZE - 1; 1476*1da177e4SLinus Torvalds address &= PAGE_MASK; 1477*1da177e4SLinus Torvalds error = 0; 1478*1da177e4SLinus Torvalds 1479*1da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 1480*1da177e4SLinus Torvalds if (address > vma->vm_end) { 1481*1da177e4SLinus Torvalds unsigned long size, grow; 1482*1da177e4SLinus Torvalds 1483*1da177e4SLinus Torvalds size = address - vma->vm_start; 1484*1da177e4SLinus Torvalds grow = (address - vma->vm_end) >> PAGE_SHIFT; 1485*1da177e4SLinus Torvalds 1486*1da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 1487*1da177e4SLinus Torvalds if (!error) 1488*1da177e4SLinus Torvalds vma->vm_end = address; 1489*1da177e4SLinus Torvalds } 1490*1da177e4SLinus Torvalds anon_vma_unlock(vma); 1491*1da177e4SLinus Torvalds return error; 1492*1da177e4SLinus Torvalds } 1493*1da177e4SLinus Torvalds 1494*1da177e4SLinus Torvalds struct vm_area_struct * 1495*1da177e4SLinus Torvalds find_extend_vma(struct mm_struct *mm, unsigned long addr) 1496*1da177e4SLinus Torvalds { 1497*1da177e4SLinus Torvalds struct vm_area_struct *vma, *prev; 1498*1da177e4SLinus Torvalds 1499*1da177e4SLinus Torvalds addr &= PAGE_MASK; 1500*1da177e4SLinus Torvalds vma = find_vma_prev(mm, addr, &prev); 1501*1da177e4SLinus Torvalds if (vma && (vma->vm_start <= addr)) 1502*1da177e4SLinus Torvalds return vma; 1503*1da177e4SLinus Torvalds if (!prev || expand_stack(prev, addr)) 1504*1da177e4SLinus Torvalds return NULL; 1505*1da177e4SLinus Torvalds if (prev->vm_flags & VM_LOCKED) { 1506*1da177e4SLinus Torvalds make_pages_present(addr, prev->vm_end); 1507*1da177e4SLinus Torvalds } 1508*1da177e4SLinus Torvalds return prev; 1509*1da177e4SLinus Torvalds } 1510*1da177e4SLinus Torvalds #else 1511*1da177e4SLinus Torvalds /* 1512*1da177e4SLinus Torvalds * vma is the first one with address < vma->vm_start. Have to extend vma. 1513*1da177e4SLinus Torvalds */ 1514*1da177e4SLinus Torvalds int expand_stack(struct vm_area_struct *vma, unsigned long address) 1515*1da177e4SLinus Torvalds { 1516*1da177e4SLinus Torvalds int error; 1517*1da177e4SLinus Torvalds 1518*1da177e4SLinus Torvalds /* 1519*1da177e4SLinus Torvalds * We must make sure the anon_vma is allocated 1520*1da177e4SLinus Torvalds * so that the anon_vma locking is not a noop. 1521*1da177e4SLinus Torvalds */ 1522*1da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 1523*1da177e4SLinus Torvalds return -ENOMEM; 1524*1da177e4SLinus Torvalds anon_vma_lock(vma); 1525*1da177e4SLinus Torvalds 1526*1da177e4SLinus Torvalds /* 1527*1da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 1528*1da177e4SLinus Torvalds * is required to hold the mmap_sem in read mode. We need the 1529*1da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 1530*1da177e4SLinus Torvalds */ 1531*1da177e4SLinus Torvalds address &= PAGE_MASK; 1532*1da177e4SLinus Torvalds error = 0; 1533*1da177e4SLinus Torvalds 1534*1da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 1535*1da177e4SLinus Torvalds if (address < vma->vm_start) { 1536*1da177e4SLinus Torvalds unsigned long size, grow; 1537*1da177e4SLinus Torvalds 1538*1da177e4SLinus Torvalds size = vma->vm_end - address; 1539*1da177e4SLinus Torvalds grow = (vma->vm_start - address) >> PAGE_SHIFT; 1540*1da177e4SLinus Torvalds 1541*1da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 1542*1da177e4SLinus Torvalds if (!error) { 1543*1da177e4SLinus Torvalds vma->vm_start = address; 1544*1da177e4SLinus Torvalds vma->vm_pgoff -= grow; 1545*1da177e4SLinus Torvalds } 1546*1da177e4SLinus Torvalds } 1547*1da177e4SLinus Torvalds anon_vma_unlock(vma); 1548*1da177e4SLinus Torvalds return error; 1549*1da177e4SLinus Torvalds } 1550*1da177e4SLinus Torvalds 1551*1da177e4SLinus Torvalds struct vm_area_struct * 1552*1da177e4SLinus Torvalds find_extend_vma(struct mm_struct * mm, unsigned long addr) 1553*1da177e4SLinus Torvalds { 1554*1da177e4SLinus Torvalds struct vm_area_struct * vma; 1555*1da177e4SLinus Torvalds unsigned long start; 1556*1da177e4SLinus Torvalds 1557*1da177e4SLinus Torvalds addr &= PAGE_MASK; 1558*1da177e4SLinus Torvalds vma = find_vma(mm,addr); 1559*1da177e4SLinus Torvalds if (!vma) 1560*1da177e4SLinus Torvalds return NULL; 1561*1da177e4SLinus Torvalds if (vma->vm_start <= addr) 1562*1da177e4SLinus Torvalds return vma; 1563*1da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 1564*1da177e4SLinus Torvalds return NULL; 1565*1da177e4SLinus Torvalds start = vma->vm_start; 1566*1da177e4SLinus Torvalds if (expand_stack(vma, addr)) 1567*1da177e4SLinus Torvalds return NULL; 1568*1da177e4SLinus Torvalds if (vma->vm_flags & VM_LOCKED) { 1569*1da177e4SLinus Torvalds make_pages_present(addr, start); 1570*1da177e4SLinus Torvalds } 1571*1da177e4SLinus Torvalds return vma; 1572*1da177e4SLinus Torvalds } 1573*1da177e4SLinus Torvalds #endif 1574*1da177e4SLinus Torvalds 1575*1da177e4SLinus Torvalds /* 1576*1da177e4SLinus Torvalds * Try to free as many page directory entries as we can, 1577*1da177e4SLinus Torvalds * without having to work very hard at actually scanning 1578*1da177e4SLinus Torvalds * the page tables themselves. 1579*1da177e4SLinus Torvalds * 1580*1da177e4SLinus Torvalds * Right now we try to free page tables if we have a nice 1581*1da177e4SLinus Torvalds * PGDIR-aligned area that got free'd up. We could be more 1582*1da177e4SLinus Torvalds * granular if we want to, but this is fast and simple, 1583*1da177e4SLinus Torvalds * and covers the bad cases. 1584*1da177e4SLinus Torvalds * 1585*1da177e4SLinus Torvalds * "prev", if it exists, points to a vma before the one 1586*1da177e4SLinus Torvalds * we just free'd - but there's no telling how much before. 1587*1da177e4SLinus Torvalds */ 1588*1da177e4SLinus Torvalds static void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *prev, 1589*1da177e4SLinus Torvalds unsigned long start, unsigned long end) 1590*1da177e4SLinus Torvalds { 1591*1da177e4SLinus Torvalds unsigned long first = start & PGDIR_MASK; 1592*1da177e4SLinus Torvalds unsigned long last = end + PGDIR_SIZE - 1; 1593*1da177e4SLinus Torvalds struct mm_struct *mm = tlb->mm; 1594*1da177e4SLinus Torvalds 1595*1da177e4SLinus Torvalds if (last > MM_VM_SIZE(mm) || last < end) 1596*1da177e4SLinus Torvalds last = MM_VM_SIZE(mm); 1597*1da177e4SLinus Torvalds 1598*1da177e4SLinus Torvalds if (!prev) { 1599*1da177e4SLinus Torvalds prev = mm->mmap; 1600*1da177e4SLinus Torvalds if (!prev) 1601*1da177e4SLinus Torvalds goto no_mmaps; 1602*1da177e4SLinus Torvalds if (prev->vm_end > start) { 1603*1da177e4SLinus Torvalds if (last > prev->vm_start) 1604*1da177e4SLinus Torvalds last = prev->vm_start; 1605*1da177e4SLinus Torvalds goto no_mmaps; 1606*1da177e4SLinus Torvalds } 1607*1da177e4SLinus Torvalds } 1608*1da177e4SLinus Torvalds for (;;) { 1609*1da177e4SLinus Torvalds struct vm_area_struct *next = prev->vm_next; 1610*1da177e4SLinus Torvalds 1611*1da177e4SLinus Torvalds if (next) { 1612*1da177e4SLinus Torvalds if (next->vm_start < start) { 1613*1da177e4SLinus Torvalds prev = next; 1614*1da177e4SLinus Torvalds continue; 1615*1da177e4SLinus Torvalds } 1616*1da177e4SLinus Torvalds if (last > next->vm_start) 1617*1da177e4SLinus Torvalds last = next->vm_start; 1618*1da177e4SLinus Torvalds } 1619*1da177e4SLinus Torvalds if (prev->vm_end > first) 1620*1da177e4SLinus Torvalds first = prev->vm_end; 1621*1da177e4SLinus Torvalds break; 1622*1da177e4SLinus Torvalds } 1623*1da177e4SLinus Torvalds no_mmaps: 1624*1da177e4SLinus Torvalds if (last < first) /* for arches with discontiguous pgd indices */ 1625*1da177e4SLinus Torvalds return; 1626*1da177e4SLinus Torvalds if (first < FIRST_USER_PGD_NR * PGDIR_SIZE) 1627*1da177e4SLinus Torvalds first = FIRST_USER_PGD_NR * PGDIR_SIZE; 1628*1da177e4SLinus Torvalds /* No point trying to free anything if we're in the same pte page */ 1629*1da177e4SLinus Torvalds if ((first & PMD_MASK) < (last & PMD_MASK)) { 1630*1da177e4SLinus Torvalds clear_page_range(tlb, first, last); 1631*1da177e4SLinus Torvalds flush_tlb_pgtables(mm, first, last); 1632*1da177e4SLinus Torvalds } 1633*1da177e4SLinus Torvalds } 1634*1da177e4SLinus Torvalds 1635*1da177e4SLinus Torvalds /* Normal function to fix up a mapping 1636*1da177e4SLinus Torvalds * This function is the default for when an area has no specific 1637*1da177e4SLinus Torvalds * function. This may be used as part of a more specific routine. 1638*1da177e4SLinus Torvalds * 1639*1da177e4SLinus Torvalds * By the time this function is called, the area struct has been 1640*1da177e4SLinus Torvalds * removed from the process mapping list. 1641*1da177e4SLinus Torvalds */ 1642*1da177e4SLinus Torvalds static void unmap_vma(struct mm_struct *mm, struct vm_area_struct *area) 1643*1da177e4SLinus Torvalds { 1644*1da177e4SLinus Torvalds size_t len = area->vm_end - area->vm_start; 1645*1da177e4SLinus Torvalds 1646*1da177e4SLinus Torvalds area->vm_mm->total_vm -= len >> PAGE_SHIFT; 1647*1da177e4SLinus Torvalds if (area->vm_flags & VM_LOCKED) 1648*1da177e4SLinus Torvalds area->vm_mm->locked_vm -= len >> PAGE_SHIFT; 1649*1da177e4SLinus Torvalds vm_stat_unaccount(area); 1650*1da177e4SLinus Torvalds area->vm_mm->unmap_area(area); 1651*1da177e4SLinus Torvalds remove_vm_struct(area); 1652*1da177e4SLinus Torvalds } 1653*1da177e4SLinus Torvalds 1654*1da177e4SLinus Torvalds /* 1655*1da177e4SLinus Torvalds * Update the VMA and inode share lists. 1656*1da177e4SLinus Torvalds * 1657*1da177e4SLinus Torvalds * Ok - we have the memory areas we should free on the 'free' list, 1658*1da177e4SLinus Torvalds * so release them, and do the vma updates. 1659*1da177e4SLinus Torvalds */ 1660*1da177e4SLinus Torvalds static void unmap_vma_list(struct mm_struct *mm, 1661*1da177e4SLinus Torvalds struct vm_area_struct *mpnt) 1662*1da177e4SLinus Torvalds { 1663*1da177e4SLinus Torvalds do { 1664*1da177e4SLinus Torvalds struct vm_area_struct *next = mpnt->vm_next; 1665*1da177e4SLinus Torvalds unmap_vma(mm, mpnt); 1666*1da177e4SLinus Torvalds mpnt = next; 1667*1da177e4SLinus Torvalds } while (mpnt != NULL); 1668*1da177e4SLinus Torvalds validate_mm(mm); 1669*1da177e4SLinus Torvalds } 1670*1da177e4SLinus Torvalds 1671*1da177e4SLinus Torvalds /* 1672*1da177e4SLinus Torvalds * Get rid of page table information in the indicated region. 1673*1da177e4SLinus Torvalds * 1674*1da177e4SLinus Torvalds * Called with the page table lock held. 1675*1da177e4SLinus Torvalds */ 1676*1da177e4SLinus Torvalds static void unmap_region(struct mm_struct *mm, 1677*1da177e4SLinus Torvalds struct vm_area_struct *vma, 1678*1da177e4SLinus Torvalds struct vm_area_struct *prev, 1679*1da177e4SLinus Torvalds unsigned long start, 1680*1da177e4SLinus Torvalds unsigned long end) 1681*1da177e4SLinus Torvalds { 1682*1da177e4SLinus Torvalds struct mmu_gather *tlb; 1683*1da177e4SLinus Torvalds unsigned long nr_accounted = 0; 1684*1da177e4SLinus Torvalds 1685*1da177e4SLinus Torvalds lru_add_drain(); 1686*1da177e4SLinus Torvalds tlb = tlb_gather_mmu(mm, 0); 1687*1da177e4SLinus Torvalds unmap_vmas(&tlb, mm, vma, start, end, &nr_accounted, NULL); 1688*1da177e4SLinus Torvalds vm_unacct_memory(nr_accounted); 1689*1da177e4SLinus Torvalds 1690*1da177e4SLinus Torvalds if (is_hugepage_only_range(mm, start, end - start)) 1691*1da177e4SLinus Torvalds hugetlb_free_pgtables(tlb, prev, start, end); 1692*1da177e4SLinus Torvalds else 1693*1da177e4SLinus Torvalds free_pgtables(tlb, prev, start, end); 1694*1da177e4SLinus Torvalds tlb_finish_mmu(tlb, start, end); 1695*1da177e4SLinus Torvalds } 1696*1da177e4SLinus Torvalds 1697*1da177e4SLinus Torvalds /* 1698*1da177e4SLinus Torvalds * Create a list of vma's touched by the unmap, removing them from the mm's 1699*1da177e4SLinus Torvalds * vma list as we go.. 1700*1da177e4SLinus Torvalds */ 1701*1da177e4SLinus Torvalds static void 1702*1da177e4SLinus Torvalds detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, 1703*1da177e4SLinus Torvalds struct vm_area_struct *prev, unsigned long end) 1704*1da177e4SLinus Torvalds { 1705*1da177e4SLinus Torvalds struct vm_area_struct **insertion_point; 1706*1da177e4SLinus Torvalds struct vm_area_struct *tail_vma = NULL; 1707*1da177e4SLinus Torvalds 1708*1da177e4SLinus Torvalds insertion_point = (prev ? &prev->vm_next : &mm->mmap); 1709*1da177e4SLinus Torvalds do { 1710*1da177e4SLinus Torvalds rb_erase(&vma->vm_rb, &mm->mm_rb); 1711*1da177e4SLinus Torvalds mm->map_count--; 1712*1da177e4SLinus Torvalds tail_vma = vma; 1713*1da177e4SLinus Torvalds vma = vma->vm_next; 1714*1da177e4SLinus Torvalds } while (vma && vma->vm_start < end); 1715*1da177e4SLinus Torvalds *insertion_point = vma; 1716*1da177e4SLinus Torvalds tail_vma->vm_next = NULL; 1717*1da177e4SLinus Torvalds mm->mmap_cache = NULL; /* Kill the cache. */ 1718*1da177e4SLinus Torvalds } 1719*1da177e4SLinus Torvalds 1720*1da177e4SLinus Torvalds /* 1721*1da177e4SLinus Torvalds * Split a vma into two pieces at address 'addr', a new vma is allocated 1722*1da177e4SLinus Torvalds * either for the first part or the the tail. 1723*1da177e4SLinus Torvalds */ 1724*1da177e4SLinus Torvalds int split_vma(struct mm_struct * mm, struct vm_area_struct * vma, 1725*1da177e4SLinus Torvalds unsigned long addr, int new_below) 1726*1da177e4SLinus Torvalds { 1727*1da177e4SLinus Torvalds struct mempolicy *pol; 1728*1da177e4SLinus Torvalds struct vm_area_struct *new; 1729*1da177e4SLinus Torvalds 1730*1da177e4SLinus Torvalds if (is_vm_hugetlb_page(vma) && (addr & ~HPAGE_MASK)) 1731*1da177e4SLinus Torvalds return -EINVAL; 1732*1da177e4SLinus Torvalds 1733*1da177e4SLinus Torvalds if (mm->map_count >= sysctl_max_map_count) 1734*1da177e4SLinus Torvalds return -ENOMEM; 1735*1da177e4SLinus Torvalds 1736*1da177e4SLinus Torvalds new = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); 1737*1da177e4SLinus Torvalds if (!new) 1738*1da177e4SLinus Torvalds return -ENOMEM; 1739*1da177e4SLinus Torvalds 1740*1da177e4SLinus Torvalds /* most fields are the same, copy all, and then fixup */ 1741*1da177e4SLinus Torvalds *new = *vma; 1742*1da177e4SLinus Torvalds 1743*1da177e4SLinus Torvalds if (new_below) 1744*1da177e4SLinus Torvalds new->vm_end = addr; 1745*1da177e4SLinus Torvalds else { 1746*1da177e4SLinus Torvalds new->vm_start = addr; 1747*1da177e4SLinus Torvalds new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); 1748*1da177e4SLinus Torvalds } 1749*1da177e4SLinus Torvalds 1750*1da177e4SLinus Torvalds pol = mpol_copy(vma_policy(vma)); 1751*1da177e4SLinus Torvalds if (IS_ERR(pol)) { 1752*1da177e4SLinus Torvalds kmem_cache_free(vm_area_cachep, new); 1753*1da177e4SLinus Torvalds return PTR_ERR(pol); 1754*1da177e4SLinus Torvalds } 1755*1da177e4SLinus Torvalds vma_set_policy(new, pol); 1756*1da177e4SLinus Torvalds 1757*1da177e4SLinus Torvalds if (new->vm_file) 1758*1da177e4SLinus Torvalds get_file(new->vm_file); 1759*1da177e4SLinus Torvalds 1760*1da177e4SLinus Torvalds if (new->vm_ops && new->vm_ops->open) 1761*1da177e4SLinus Torvalds new->vm_ops->open(new); 1762*1da177e4SLinus Torvalds 1763*1da177e4SLinus Torvalds if (new_below) 1764*1da177e4SLinus Torvalds vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + 1765*1da177e4SLinus Torvalds ((addr - new->vm_start) >> PAGE_SHIFT), new); 1766*1da177e4SLinus Torvalds else 1767*1da177e4SLinus Torvalds vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); 1768*1da177e4SLinus Torvalds 1769*1da177e4SLinus Torvalds return 0; 1770*1da177e4SLinus Torvalds } 1771*1da177e4SLinus Torvalds 1772*1da177e4SLinus Torvalds /* Munmap is split into 2 main parts -- this part which finds 1773*1da177e4SLinus Torvalds * what needs doing, and the areas themselves, which do the 1774*1da177e4SLinus Torvalds * work. This now handles partial unmappings. 1775*1da177e4SLinus Torvalds * Jeremy Fitzhardinge <jeremy@goop.org> 1776*1da177e4SLinus Torvalds */ 1777*1da177e4SLinus Torvalds int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) 1778*1da177e4SLinus Torvalds { 1779*1da177e4SLinus Torvalds unsigned long end; 1780*1da177e4SLinus Torvalds struct vm_area_struct *mpnt, *prev, *last; 1781*1da177e4SLinus Torvalds 1782*1da177e4SLinus Torvalds if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) 1783*1da177e4SLinus Torvalds return -EINVAL; 1784*1da177e4SLinus Torvalds 1785*1da177e4SLinus Torvalds if ((len = PAGE_ALIGN(len)) == 0) 1786*1da177e4SLinus Torvalds return -EINVAL; 1787*1da177e4SLinus Torvalds 1788*1da177e4SLinus Torvalds /* Find the first overlapping VMA */ 1789*1da177e4SLinus Torvalds mpnt = find_vma_prev(mm, start, &prev); 1790*1da177e4SLinus Torvalds if (!mpnt) 1791*1da177e4SLinus Torvalds return 0; 1792*1da177e4SLinus Torvalds /* we have start < mpnt->vm_end */ 1793*1da177e4SLinus Torvalds 1794*1da177e4SLinus Torvalds /* if it doesn't overlap, we have nothing.. */ 1795*1da177e4SLinus Torvalds end = start + len; 1796*1da177e4SLinus Torvalds if (mpnt->vm_start >= end) 1797*1da177e4SLinus Torvalds return 0; 1798*1da177e4SLinus Torvalds 1799*1da177e4SLinus Torvalds /* 1800*1da177e4SLinus Torvalds * If we need to split any vma, do it now to save pain later. 1801*1da177e4SLinus Torvalds * 1802*1da177e4SLinus Torvalds * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially 1803*1da177e4SLinus Torvalds * unmapped vm_area_struct will remain in use: so lower split_vma 1804*1da177e4SLinus Torvalds * places tmp vma above, and higher split_vma places tmp vma below. 1805*1da177e4SLinus Torvalds */ 1806*1da177e4SLinus Torvalds if (start > mpnt->vm_start) { 1807*1da177e4SLinus Torvalds int error = split_vma(mm, mpnt, start, 0); 1808*1da177e4SLinus Torvalds if (error) 1809*1da177e4SLinus Torvalds return error; 1810*1da177e4SLinus Torvalds prev = mpnt; 1811*1da177e4SLinus Torvalds } 1812*1da177e4SLinus Torvalds 1813*1da177e4SLinus Torvalds /* Does it split the last one? */ 1814*1da177e4SLinus Torvalds last = find_vma(mm, end); 1815*1da177e4SLinus Torvalds if (last && end > last->vm_start) { 1816*1da177e4SLinus Torvalds int error = split_vma(mm, last, end, 1); 1817*1da177e4SLinus Torvalds if (error) 1818*1da177e4SLinus Torvalds return error; 1819*1da177e4SLinus Torvalds } 1820*1da177e4SLinus Torvalds mpnt = prev? prev->vm_next: mm->mmap; 1821*1da177e4SLinus Torvalds 1822*1da177e4SLinus Torvalds /* 1823*1da177e4SLinus Torvalds * Remove the vma's, and unmap the actual pages 1824*1da177e4SLinus Torvalds */ 1825*1da177e4SLinus Torvalds detach_vmas_to_be_unmapped(mm, mpnt, prev, end); 1826*1da177e4SLinus Torvalds spin_lock(&mm->page_table_lock); 1827*1da177e4SLinus Torvalds unmap_region(mm, mpnt, prev, start, end); 1828*1da177e4SLinus Torvalds spin_unlock(&mm->page_table_lock); 1829*1da177e4SLinus Torvalds 1830*1da177e4SLinus Torvalds /* Fix up all other VM information */ 1831*1da177e4SLinus Torvalds unmap_vma_list(mm, mpnt); 1832*1da177e4SLinus Torvalds 1833*1da177e4SLinus Torvalds return 0; 1834*1da177e4SLinus Torvalds } 1835*1da177e4SLinus Torvalds 1836*1da177e4SLinus Torvalds EXPORT_SYMBOL(do_munmap); 1837*1da177e4SLinus Torvalds 1838*1da177e4SLinus Torvalds asmlinkage long sys_munmap(unsigned long addr, size_t len) 1839*1da177e4SLinus Torvalds { 1840*1da177e4SLinus Torvalds int ret; 1841*1da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1842*1da177e4SLinus Torvalds 1843*1da177e4SLinus Torvalds profile_munmap(addr); 1844*1da177e4SLinus Torvalds 1845*1da177e4SLinus Torvalds down_write(&mm->mmap_sem); 1846*1da177e4SLinus Torvalds ret = do_munmap(mm, addr, len); 1847*1da177e4SLinus Torvalds up_write(&mm->mmap_sem); 1848*1da177e4SLinus Torvalds return ret; 1849*1da177e4SLinus Torvalds } 1850*1da177e4SLinus Torvalds 1851*1da177e4SLinus Torvalds static inline void verify_mm_writelocked(struct mm_struct *mm) 1852*1da177e4SLinus Torvalds { 1853*1da177e4SLinus Torvalds #ifdef CONFIG_DEBUG_KERNEL 1854*1da177e4SLinus Torvalds if (unlikely(down_read_trylock(&mm->mmap_sem))) { 1855*1da177e4SLinus Torvalds WARN_ON(1); 1856*1da177e4SLinus Torvalds up_read(&mm->mmap_sem); 1857*1da177e4SLinus Torvalds } 1858*1da177e4SLinus Torvalds #endif 1859*1da177e4SLinus Torvalds } 1860*1da177e4SLinus Torvalds 1861*1da177e4SLinus Torvalds /* 1862*1da177e4SLinus Torvalds * this is really a simplified "do_mmap". it only handles 1863*1da177e4SLinus Torvalds * anonymous maps. eventually we may be able to do some 1864*1da177e4SLinus Torvalds * brk-specific accounting here. 1865*1da177e4SLinus Torvalds */ 1866*1da177e4SLinus Torvalds unsigned long do_brk(unsigned long addr, unsigned long len) 1867*1da177e4SLinus Torvalds { 1868*1da177e4SLinus Torvalds struct mm_struct * mm = current->mm; 1869*1da177e4SLinus Torvalds struct vm_area_struct * vma, * prev; 1870*1da177e4SLinus Torvalds unsigned long flags; 1871*1da177e4SLinus Torvalds struct rb_node ** rb_link, * rb_parent; 1872*1da177e4SLinus Torvalds pgoff_t pgoff = addr >> PAGE_SHIFT; 1873*1da177e4SLinus Torvalds 1874*1da177e4SLinus Torvalds len = PAGE_ALIGN(len); 1875*1da177e4SLinus Torvalds if (!len) 1876*1da177e4SLinus Torvalds return addr; 1877*1da177e4SLinus Torvalds 1878*1da177e4SLinus Torvalds if ((addr + len) > TASK_SIZE || (addr + len) < addr) 1879*1da177e4SLinus Torvalds return -EINVAL; 1880*1da177e4SLinus Torvalds 1881*1da177e4SLinus Torvalds /* 1882*1da177e4SLinus Torvalds * mlock MCL_FUTURE? 1883*1da177e4SLinus Torvalds */ 1884*1da177e4SLinus Torvalds if (mm->def_flags & VM_LOCKED) { 1885*1da177e4SLinus Torvalds unsigned long locked, lock_limit; 1886*1da177e4SLinus Torvalds locked = mm->locked_vm << PAGE_SHIFT; 1887*1da177e4SLinus Torvalds lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; 1888*1da177e4SLinus Torvalds locked += len; 1889*1da177e4SLinus Torvalds if (locked > lock_limit && !capable(CAP_IPC_LOCK)) 1890*1da177e4SLinus Torvalds return -EAGAIN; 1891*1da177e4SLinus Torvalds } 1892*1da177e4SLinus Torvalds 1893*1da177e4SLinus Torvalds /* 1894*1da177e4SLinus Torvalds * mm->mmap_sem is required to protect against another thread 1895*1da177e4SLinus Torvalds * changing the mappings in case we sleep. 1896*1da177e4SLinus Torvalds */ 1897*1da177e4SLinus Torvalds verify_mm_writelocked(mm); 1898*1da177e4SLinus Torvalds 1899*1da177e4SLinus Torvalds /* 1900*1da177e4SLinus Torvalds * Clear old maps. this also does some error checking for us 1901*1da177e4SLinus Torvalds */ 1902*1da177e4SLinus Torvalds munmap_back: 1903*1da177e4SLinus Torvalds vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); 1904*1da177e4SLinus Torvalds if (vma && vma->vm_start < addr + len) { 1905*1da177e4SLinus Torvalds if (do_munmap(mm, addr, len)) 1906*1da177e4SLinus Torvalds return -ENOMEM; 1907*1da177e4SLinus Torvalds goto munmap_back; 1908*1da177e4SLinus Torvalds } 1909*1da177e4SLinus Torvalds 1910*1da177e4SLinus Torvalds /* Check against address space limits *after* clearing old maps... */ 1911*1da177e4SLinus Torvalds if ((mm->total_vm << PAGE_SHIFT) + len 1912*1da177e4SLinus Torvalds > current->signal->rlim[RLIMIT_AS].rlim_cur) 1913*1da177e4SLinus Torvalds return -ENOMEM; 1914*1da177e4SLinus Torvalds 1915*1da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 1916*1da177e4SLinus Torvalds return -ENOMEM; 1917*1da177e4SLinus Torvalds 1918*1da177e4SLinus Torvalds if (security_vm_enough_memory(len >> PAGE_SHIFT)) 1919*1da177e4SLinus Torvalds return -ENOMEM; 1920*1da177e4SLinus Torvalds 1921*1da177e4SLinus Torvalds flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; 1922*1da177e4SLinus Torvalds 1923*1da177e4SLinus Torvalds /* Can we just expand an old private anonymous mapping? */ 1924*1da177e4SLinus Torvalds if (vma_merge(mm, prev, addr, addr + len, flags, 1925*1da177e4SLinus Torvalds NULL, NULL, pgoff, NULL)) 1926*1da177e4SLinus Torvalds goto out; 1927*1da177e4SLinus Torvalds 1928*1da177e4SLinus Torvalds /* 1929*1da177e4SLinus Torvalds * create a vma struct for an anonymous mapping 1930*1da177e4SLinus Torvalds */ 1931*1da177e4SLinus Torvalds vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); 1932*1da177e4SLinus Torvalds if (!vma) { 1933*1da177e4SLinus Torvalds vm_unacct_memory(len >> PAGE_SHIFT); 1934*1da177e4SLinus Torvalds return -ENOMEM; 1935*1da177e4SLinus Torvalds } 1936*1da177e4SLinus Torvalds memset(vma, 0, sizeof(*vma)); 1937*1da177e4SLinus Torvalds 1938*1da177e4SLinus Torvalds vma->vm_mm = mm; 1939*1da177e4SLinus Torvalds vma->vm_start = addr; 1940*1da177e4SLinus Torvalds vma->vm_end = addr + len; 1941*1da177e4SLinus Torvalds vma->vm_pgoff = pgoff; 1942*1da177e4SLinus Torvalds vma->vm_flags = flags; 1943*1da177e4SLinus Torvalds vma->vm_page_prot = protection_map[flags & 0x0f]; 1944*1da177e4SLinus Torvalds vma_link(mm, vma, prev, rb_link, rb_parent); 1945*1da177e4SLinus Torvalds out: 1946*1da177e4SLinus Torvalds mm->total_vm += len >> PAGE_SHIFT; 1947*1da177e4SLinus Torvalds if (flags & VM_LOCKED) { 1948*1da177e4SLinus Torvalds mm->locked_vm += len >> PAGE_SHIFT; 1949*1da177e4SLinus Torvalds make_pages_present(addr, addr + len); 1950*1da177e4SLinus Torvalds } 1951*1da177e4SLinus Torvalds return addr; 1952*1da177e4SLinus Torvalds } 1953*1da177e4SLinus Torvalds 1954*1da177e4SLinus Torvalds EXPORT_SYMBOL(do_brk); 1955*1da177e4SLinus Torvalds 1956*1da177e4SLinus Torvalds /* Release all mmaps. */ 1957*1da177e4SLinus Torvalds void exit_mmap(struct mm_struct *mm) 1958*1da177e4SLinus Torvalds { 1959*1da177e4SLinus Torvalds struct mmu_gather *tlb; 1960*1da177e4SLinus Torvalds struct vm_area_struct *vma; 1961*1da177e4SLinus Torvalds unsigned long nr_accounted = 0; 1962*1da177e4SLinus Torvalds 1963*1da177e4SLinus Torvalds lru_add_drain(); 1964*1da177e4SLinus Torvalds 1965*1da177e4SLinus Torvalds spin_lock(&mm->page_table_lock); 1966*1da177e4SLinus Torvalds 1967*1da177e4SLinus Torvalds tlb = tlb_gather_mmu(mm, 1); 1968*1da177e4SLinus Torvalds flush_cache_mm(mm); 1969*1da177e4SLinus Torvalds /* Use ~0UL here to ensure all VMAs in the mm are unmapped */ 1970*1da177e4SLinus Torvalds mm->map_count -= unmap_vmas(&tlb, mm, mm->mmap, 0, 1971*1da177e4SLinus Torvalds ~0UL, &nr_accounted, NULL); 1972*1da177e4SLinus Torvalds vm_unacct_memory(nr_accounted); 1973*1da177e4SLinus Torvalds BUG_ON(mm->map_count); /* This is just debugging */ 1974*1da177e4SLinus Torvalds clear_page_range(tlb, FIRST_USER_PGD_NR * PGDIR_SIZE, MM_VM_SIZE(mm)); 1975*1da177e4SLinus Torvalds 1976*1da177e4SLinus Torvalds tlb_finish_mmu(tlb, 0, MM_VM_SIZE(mm)); 1977*1da177e4SLinus Torvalds 1978*1da177e4SLinus Torvalds vma = mm->mmap; 1979*1da177e4SLinus Torvalds mm->mmap = mm->mmap_cache = NULL; 1980*1da177e4SLinus Torvalds mm->mm_rb = RB_ROOT; 1981*1da177e4SLinus Torvalds set_mm_counter(mm, rss, 0); 1982*1da177e4SLinus Torvalds mm->total_vm = 0; 1983*1da177e4SLinus Torvalds mm->locked_vm = 0; 1984*1da177e4SLinus Torvalds 1985*1da177e4SLinus Torvalds spin_unlock(&mm->page_table_lock); 1986*1da177e4SLinus Torvalds 1987*1da177e4SLinus Torvalds /* 1988*1da177e4SLinus Torvalds * Walk the list again, actually closing and freeing it 1989*1da177e4SLinus Torvalds * without holding any MM locks. 1990*1da177e4SLinus Torvalds */ 1991*1da177e4SLinus Torvalds while (vma) { 1992*1da177e4SLinus Torvalds struct vm_area_struct *next = vma->vm_next; 1993*1da177e4SLinus Torvalds remove_vm_struct(vma); 1994*1da177e4SLinus Torvalds vma = next; 1995*1da177e4SLinus Torvalds } 1996*1da177e4SLinus Torvalds } 1997*1da177e4SLinus Torvalds 1998*1da177e4SLinus Torvalds /* Insert vm structure into process list sorted by address 1999*1da177e4SLinus Torvalds * and into the inode's i_mmap tree. If vm_file is non-NULL 2000*1da177e4SLinus Torvalds * then i_mmap_lock is taken here. 2001*1da177e4SLinus Torvalds */ 2002*1da177e4SLinus Torvalds int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) 2003*1da177e4SLinus Torvalds { 2004*1da177e4SLinus Torvalds struct vm_area_struct * __vma, * prev; 2005*1da177e4SLinus Torvalds struct rb_node ** rb_link, * rb_parent; 2006*1da177e4SLinus Torvalds 2007*1da177e4SLinus Torvalds /* 2008*1da177e4SLinus Torvalds * The vm_pgoff of a purely anonymous vma should be irrelevant 2009*1da177e4SLinus Torvalds * until its first write fault, when page's anon_vma and index 2010*1da177e4SLinus Torvalds * are set. But now set the vm_pgoff it will almost certainly 2011*1da177e4SLinus Torvalds * end up with (unless mremap moves it elsewhere before that 2012*1da177e4SLinus Torvalds * first wfault), so /proc/pid/maps tells a consistent story. 2013*1da177e4SLinus Torvalds * 2014*1da177e4SLinus Torvalds * By setting it to reflect the virtual start address of the 2015*1da177e4SLinus Torvalds * vma, merges and splits can happen in a seamless way, just 2016*1da177e4SLinus Torvalds * using the existing file pgoff checks and manipulations. 2017*1da177e4SLinus Torvalds * Similarly in do_mmap_pgoff and in do_brk. 2018*1da177e4SLinus Torvalds */ 2019*1da177e4SLinus Torvalds if (!vma->vm_file) { 2020*1da177e4SLinus Torvalds BUG_ON(vma->anon_vma); 2021*1da177e4SLinus Torvalds vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; 2022*1da177e4SLinus Torvalds } 2023*1da177e4SLinus Torvalds __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent); 2024*1da177e4SLinus Torvalds if (__vma && __vma->vm_start < vma->vm_end) 2025*1da177e4SLinus Torvalds return -ENOMEM; 2026*1da177e4SLinus Torvalds vma_link(mm, vma, prev, rb_link, rb_parent); 2027*1da177e4SLinus Torvalds return 0; 2028*1da177e4SLinus Torvalds } 2029*1da177e4SLinus Torvalds 2030*1da177e4SLinus Torvalds /* 2031*1da177e4SLinus Torvalds * Copy the vma structure to a new location in the same mm, 2032*1da177e4SLinus Torvalds * prior to moving page table entries, to effect an mremap move. 2033*1da177e4SLinus Torvalds */ 2034*1da177e4SLinus Torvalds struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, 2035*1da177e4SLinus Torvalds unsigned long addr, unsigned long len, pgoff_t pgoff) 2036*1da177e4SLinus Torvalds { 2037*1da177e4SLinus Torvalds struct vm_area_struct *vma = *vmap; 2038*1da177e4SLinus Torvalds unsigned long vma_start = vma->vm_start; 2039*1da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 2040*1da177e4SLinus Torvalds struct vm_area_struct *new_vma, *prev; 2041*1da177e4SLinus Torvalds struct rb_node **rb_link, *rb_parent; 2042*1da177e4SLinus Torvalds struct mempolicy *pol; 2043*1da177e4SLinus Torvalds 2044*1da177e4SLinus Torvalds /* 2045*1da177e4SLinus Torvalds * If anonymous vma has not yet been faulted, update new pgoff 2046*1da177e4SLinus Torvalds * to match new location, to increase its chance of merging. 2047*1da177e4SLinus Torvalds */ 2048*1da177e4SLinus Torvalds if (!vma->vm_file && !vma->anon_vma) 2049*1da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 2050*1da177e4SLinus Torvalds 2051*1da177e4SLinus Torvalds find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); 2052*1da177e4SLinus Torvalds new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, 2053*1da177e4SLinus Torvalds vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); 2054*1da177e4SLinus Torvalds if (new_vma) { 2055*1da177e4SLinus Torvalds /* 2056*1da177e4SLinus Torvalds * Source vma may have been merged into new_vma 2057*1da177e4SLinus Torvalds */ 2058*1da177e4SLinus Torvalds if (vma_start >= new_vma->vm_start && 2059*1da177e4SLinus Torvalds vma_start < new_vma->vm_end) 2060*1da177e4SLinus Torvalds *vmap = new_vma; 2061*1da177e4SLinus Torvalds } else { 2062*1da177e4SLinus Torvalds new_vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); 2063*1da177e4SLinus Torvalds if (new_vma) { 2064*1da177e4SLinus Torvalds *new_vma = *vma; 2065*1da177e4SLinus Torvalds pol = mpol_copy(vma_policy(vma)); 2066*1da177e4SLinus Torvalds if (IS_ERR(pol)) { 2067*1da177e4SLinus Torvalds kmem_cache_free(vm_area_cachep, new_vma); 2068*1da177e4SLinus Torvalds return NULL; 2069*1da177e4SLinus Torvalds } 2070*1da177e4SLinus Torvalds vma_set_policy(new_vma, pol); 2071*1da177e4SLinus Torvalds new_vma->vm_start = addr; 2072*1da177e4SLinus Torvalds new_vma->vm_end = addr + len; 2073*1da177e4SLinus Torvalds new_vma->vm_pgoff = pgoff; 2074*1da177e4SLinus Torvalds if (new_vma->vm_file) 2075*1da177e4SLinus Torvalds get_file(new_vma->vm_file); 2076*1da177e4SLinus Torvalds if (new_vma->vm_ops && new_vma->vm_ops->open) 2077*1da177e4SLinus Torvalds new_vma->vm_ops->open(new_vma); 2078*1da177e4SLinus Torvalds vma_link(mm, new_vma, prev, rb_link, rb_parent); 2079*1da177e4SLinus Torvalds } 2080*1da177e4SLinus Torvalds } 2081*1da177e4SLinus Torvalds return new_vma; 2082*1da177e4SLinus Torvalds } 2083