projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 7aa1c8f4 RB |
1 | #include <linux/highmem.h> |
| 2 | #include <linux/bootmem.h> | |
| 3 | #include <linux/crash_dump.h> | |
| 4 | #include <asm/uaccess.h> | |
| 5 | ||
| 6 | unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX; | |
| 7 | ||
| 8 | static int __init parse_savemaxmem(char *p) | |
| 9 | { | |
| 10 | if (p) | |
| 11 | saved_max_pfn = (memparse(p, &p) >> PAGE_SHIFT) - 1; | |
| 12 | ||
| 13 | return 1; | |
| 14 | } | |
| 15 | __setup("savemaxmem=", parse_savemaxmem); | |
| 16 | ||
| 17 | ||
| 18 | static void *kdump_buf_page; | |
| 19 | ||
| 20 | /** | |
| 21 | * copy_oldmem_page - copy one page from "oldmem" | |
| 22 | * @pfn: page frame number to be copied | |
| 23 | * @buf: target memory address for the copy; this can be in kernel address | |
| 24 | * space or user address space (see @userbuf) | |
| 25 | * @csize: number of bytes to copy | |
| 26 | * @offset: offset in bytes into the page (based on pfn) to begin the copy | |
| 27 | * @userbuf: if set, @buf is in user address space, use copy_to_user(), | |
| 28 | * otherwise @buf is in kernel address space, use memcpy(). | |
| 29 | * | |
| 30 | * Copy a page from "oldmem". For this page, there is no pte mapped | |
| 31 | * in the current kernel. | |
| 32 | * | |
| 33 | * Calling copy_to_user() in atomic context is not desirable. Hence first | |
| 34 | * copying the data to a pre-allocated kernel page and then copying to user | |
| 35 | * space in non-atomic context. | |
| 36 | */ | |
| 37 | ssize_t copy_oldmem_page(unsigned long pfn, char *buf, | |
| 38 | size_t csize, unsigned long offset, int userbuf) | |
| 39 | { | |
| 40 | void *vaddr; | |
| 41 | ||
| 42 | if (!csize) | |
| 43 | return 0; | |
| 44 | ||
| 45 | vaddr = kmap_atomic_pfn(pfn); | |
| 46 | ||
| 47 | if (!userbuf) { | |
| 48 | memcpy(buf, (vaddr + offset), csize); | |
| 49 | kunmap_atomic(vaddr); | |
| 50 | } else { | |
| 51 | if (!kdump_buf_page) { | |
| 52 | pr_warning("Kdump: Kdump buffer page not allocated\n"); | |
| 53 | ||
| 54 | return -EFAULT; | |
| 55 | } | |
| 56 | copy_page(kdump_buf_page, vaddr); | |
| 57 | kunmap_atomic(vaddr); | |
| 58 | if (copy_to_user(buf, (kdump_buf_page + offset), csize)) | |
| 59 | return -EFAULT; | |
| 60 | } | |
| 61 | ||
| 62 | return csize; | |
| 63 | } | |
| 64 | ||
| 65 | static int __init kdump_buf_page_init(void) | |
| 66 | { | |
| 67 | int ret = 0; | |
| 68 | ||
| 69 | kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL); | |
| 70 | if (!kdump_buf_page) { | |
| 71 | pr_warning("Kdump: Failed to allocate kdump buffer page\n"); | |
| 72 | ret = -ENOMEM; | |
| 73 | } | |
| 74 | ||
| 75 | return ret; | |
| 76 | } | |
| 77 | arch_initcall(kdump_buf_page_init); |