diff options
Diffstat (limited to 'mm/vmalloc.c')
| -rw-r--r-- | mm/vmalloc.c | 223 |
1 files changed, 189 insertions, 34 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 204b8243d8ab..69511e663234 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -25,7 +25,7 @@ #include <linux/rcupdate.h> #include <linux/pfn.h> #include <linux/kmemleak.h> - +#include <linux/highmem.h> #include <asm/atomic.h> #include <asm/uaccess.h> #include <asm/tlbflush.h> @@ -168,11 +168,9 @@ static int vmap_page_range_noflush(unsigned long start, unsigned long end, next = pgd_addr_end(addr, end); err = vmap_pud_range(pgd, addr, next, prot, pages, &nr); if (err) - break; + return err; } while (pgd++, addr = next, addr != end); - if (unlikely(err)) - return err; return nr; } @@ -186,7 +184,7 @@ static int vmap_page_range(unsigned long start, unsigned long end, return ret; } -static inline int is_vmalloc_or_module_addr(const void *x) +int is_vmalloc_or_module_addr(const void *x) { /* * ARM, x86-64 and sparc64 put modules in a special place, @@ -1272,17 +1270,21 @@ struct vm_struct *remove_vm_area(const void *addr) if (va && va->flags & VM_VM_AREA) { struct vm_struct *vm = va->private; struct vm_struct *tmp, **p; - - vmap_debug_free_range(va->va_start, va->va_end); - free_unmap_vmap_area(va); - vm->size -= PAGE_SIZE; - + /* + * remove from list and disallow access to this vm_struct + * before unmap. (address range confliction is maintained by + * vmap.) + */ write_lock(&vmlist_lock); for (p = &vmlist; (tmp = *p) != vm; p = &tmp->next) ; *p = tmp->next; write_unlock(&vmlist_lock); + vmap_debug_free_range(va->va_start, va->va_end); + free_unmap_vmap_area(va); + vm->size -= PAGE_SIZE; + return vm; } return NULL; @@ -1384,7 +1386,7 @@ void *vmap(struct page **pages, unsigned int count, might_sleep(); - if (count > num_physpages) + if (count > totalram_pages) return NULL; area = get_vm_area_caller((count << PAGE_SHIFT), flags, @@ -1491,7 +1493,7 @@ static void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot, unsigned long real_size = size; size = PAGE_ALIGN(size); - if (!size || (size >> PAGE_SHIFT) > num_physpages) + if (!size || (size >> PAGE_SHIFT) > totalram_pages) return NULL; area = __get_vm_area_node(size, VM_ALLOC, VMALLOC_START, VMALLOC_END, @@ -1641,10 +1643,120 @@ void *vmalloc_32_user(unsigned long size) } EXPORT_SYMBOL(vmalloc_32_user); +/* + * small helper routine , copy contents to buf from addr. + * If the page is not present, fill zero. + */ + +static int aligned_vread(char *buf, char *addr, unsigned long count) +{ + struct page *p; + int copied = 0; + + while (count) { + unsigned long offset, length; + + offset = (unsigned long)addr & ~PAGE_MASK; + length = PAGE_SIZE - offset; + if (length > count) + length = count; + p = vmalloc_to_page(addr); + /* + * To do safe access to this _mapped_ area, we need + * lock. But adding lock here means that we need to add + * overhead of vmalloc()/vfree() calles for this _debug_ + * interface, rarely used. Instead of that, we'll use + * kmap() and get small overhead in this access function. + */ + if (p) { + /* + * we can expect USER0 is not used (see vread/vwrite's + * function description) + */ + void *map = kmap_atomic(p, KM_USER0); + memcpy(buf, map + offset, length); + kunmap_atomic(map, KM_USER0); + } else + memset(buf, 0, length); + + addr += length; + buf += length; + copied += length; + count -= length; + } + return copied; +} + +static int aligned_vwrite(char *buf, char *addr, unsigned long count) +{ + struct page *p; + int copied = 0; + + while (count) { + unsigned long offset, length; + + offset = (unsigned long)addr & ~PAGE_MASK; + length = PAGE_SIZE - offset; + if (length > count) + length = count; + p = vmalloc_to_page(addr); + /* + * To do safe access to this _mapped_ area, we need + * lock. But adding lock here means that we need to add + * overhead of vmalloc()/vfree() calles for this _debug_ + * interface, rarely used. Instead of that, we'll use + * kmap() and get small overhead in this access function. + */ + if (p) { + /* + * we can expect USER0 is not used (see vread/vwrite's + * function description) + */ + void *map = kmap_atomic(p, KM_USER0); + memcpy(map + offset, buf, length); + kunmap_atomic(map, KM_USER0); + } + addr += length; + buf += length; + copied += length; + count -= length; + } + return copied; +} + +/** + * vread() - read vmalloc area in a safe way. + * @buf: buffer for reading data + * @addr: vm address. + * @count: number of bytes to be read. + * + * Returns # of bytes which addr and buf should be increased. + * (same number to @count). Returns 0 if [addr...addr+count) doesn't + * includes any intersect with alive vmalloc area. + * + * This function checks that addr is a valid vmalloc'ed area, and + * copy data from that area to a given buffer. If the given memory range + * of [addr...addr+count) includes some valid address, data is copied to + * proper area of @buf. If there are memory holes, they'll be zero-filled. + * IOREMAP area is treated as memory hole and no copy is done. + * + * If [addr...addr+count) doesn't includes any intersects with alive + * vm_struct area, returns 0. + * @buf should be kernel's buffer. Because this function uses KM_USER0, + * the caller should guarantee KM_USER0 is not used. + * + * Note: In usual ops, vread() is never necessary because the caller + * should know vmalloc() area is valid and can use memcpy(). + * This is for routines which have to access vmalloc area without + * any informaion, as /dev/kmem. + * + */ + long vread(char *buf, char *addr, unsigned long count) { struct vm_struct *tmp; char *vaddr, *buf_start = buf; + unsigned long buflen = count; unsigned long n; /* Don't allow overflow */ @@ -1652,7 +1764,7 @@ long vread(char *buf, char *addr, unsigned long count) count = -(unsigned long) addr; read_lock(&vmlist_lock); - for (tmp = vmlist; tmp; tmp = tmp->next) { + for (tmp = vmlist; count && tmp; tmp = tmp->next) { vaddr = (char *) tmp->addr; if (addr >= vaddr + tmp->size - PAGE_SIZE) continue; @@ -1665,32 +1777,72 @@ long vread(char *buf, char *addr, unsigned long count) count--; } n = vaddr + tmp->size - PAGE_SIZE - addr; - do { - if (count == 0) - goto finished; - *buf = *addr; - buf++; - addr++; - count--; - } while (--n > 0); + if (n > count) + n = count; + if (!(tmp->flags & VM_IOREMAP)) + aligned_vread(buf, addr, n); + else /* IOREMAP area is treated as memory hole */ + memset(buf, 0, n); + buf += n; + addr += n; + count -= n; } finished: read_unlock(&vmlist_lock); - return buf - buf_start; + + if (buf == buf_start) + return 0; + /* zero-fill memory holes */ + if (buf != buf_start + buflen) + memset(buf, 0, buflen - (buf - buf_start)); + + return buflen; } +/** + * vwrite() - write vmalloc area in a safe way. + * @buf: buffer for source data + * @addr: vm address. + * @count: number of bytes to be read. + * + * Returns # of bytes which addr and buf should be incresed. + * (same number to @count). + * If [addr...addr+count) doesn't includes any intersect with valid + * vmalloc area, returns 0. + * + * This function checks that addr is a valid vmalloc'ed area, and + * copy data from a buffer to the given addr. If specified range of + * [addr...addr+count) includes some valid address, data is copied from + * proper area of @buf. If there are memory holes, no copy to hole. + * IOREMAP area is treated as memory hole and no copy is done. + * + * If [addr...addr+count) doesn't includes any intersects with alive + * vm_struct area, returns 0. + * @buf should be kernel's buffer. Because this function uses KM_USER0, + * the caller should guarantee KM_USER0 is not used. + * + * Note: In usual ops, vwrite() is never necessary because the caller + * should know vmalloc() area is valid and can use memcpy(). + * This is for routines which have to access vmalloc area without + * any informaion, as /dev/kmem. + * + * The caller should guarantee KM_USER1 is not used. + */ + long vwrite(char *buf, char *addr, unsigned long count) { struct vm_struct *tmp; - char *vaddr, *buf_start = buf; - unsigned long n; + char *vaddr; + unsigned long n, buflen; + int copied = 0; /* Don't allow overflow */ if ((unsigned long) addr + count < count) count = -(unsigned long) addr; + buflen = count; read_lock(&vmlist_lock); - for (tmp = vmlist; tmp; tmp = tmp->next) { + for (tmp = vmlist; count && tmp; tmp = tmp->next) { vaddr = (char *) tmp->addr; if (addr >= vaddr + tmp->size - PAGE_SIZE) continue; @@ -1702,18 +1854,21 @@ long vwrite(char *buf, char *addr, unsigned long count) count--; } n = vaddr + tmp->size - PAGE_SIZE - addr; - do { - if (count == 0) - goto finished; - *addr = *buf; - buf++; - addr++; - count--; - } while (--n > 0); + if (n > count) + n = count; + if (!(tmp->flags & VM_IOREMAP)) { + aligned_vwrite(buf, addr, n); + copied++; + } + buf += n; + addr += n; + count -= n; } finished: read_unlock(&vmlist_lock); - return buf - buf_start; + if (!copied) + return 0; + return buflen; } /** |