projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1ac2e6ca RR |
1 | /* |
| 2 | * User address space access functions. | |
| 3 | * | |
| 4 | * For licencing details see kernel-base/COPYING | |
| 5 | */ | |
| 6 | ||
| 7 | #include <linux/highmem.h> | |
| 8 | #include <linux/module.h> | |
| 9 | ||
| 92ae03f2 | 10 | #include <asm/word-at-a-time.h> |
| db0dc75d | 11 | #include <linux/sched.h> |
| 92ae03f2 | 12 | |
| 1ac2e6ca RR |
13 | /* |
| 14 | * best effort, GUP based copy_from_user() that is NMI-safe | |
| 15 | */ | |
| 16 | unsigned long | |
| 17 | copy_from_user_nmi(void *to, const void __user *from, unsigned long n) | |
| 18 | { | |
| 19 | unsigned long offset, addr = (unsigned long)from; | |
| 20 | unsigned long size, len = 0; | |
| 21 | struct page *page; | |
| 22 | void *map; | |
| 23 | int ret; | |
| 24 | ||
| 25f42985 | 25 | if (__range_not_ok(from, n, TASK_SIZE)) |
| db0dc75d AS |
26 | return len; |
| 27 | ||
| 1ac2e6ca RR |
28 | do { |
| 29 | ret = __get_user_pages_fast(addr, 1, 0, &page); | |
| 30 | if (!ret) | |
| 31 | break; | |
| 32 | ||
| 33 | offset = addr & (PAGE_SIZE - 1); | |
| 34 | size = min(PAGE_SIZE - offset, n - len); | |
| 35 | ||
| 36 | map = kmap_atomic(page); | |
| 37 | memcpy(to, map+offset, size); | |
| 38 | kunmap_atomic(map); | |
| 39 | put_page(page); | |
| 40 | ||
| 41 | len += size; | |
| 42 | to += size; | |
| 43 | addr += size; | |
| 44 | ||
| 45 | } while (len < n); | |
| 46 | ||
| 47 | return len; | |
| 48 | } | |
| 49 | EXPORT_SYMBOL_GPL(copy_from_user_nmi); |