projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 60e64d46 | 1 | /* |
| 835c34a1 | 2 | * Memory preserving reboot related code. |
| 60e64d46 VG |
3 | * |
| 4 | * Created by: Hariprasad Nellitheertha (hari@in.ibm.com) | |
| 5 | * Copyright (C) IBM Corporation, 2004. All rights reserved | |
| 6 | */ | |
| 7 | ||
| 5a0e3ad6 | 8 | #include <linux/slab.h> |
| 60e64d46 | 9 | #include <linux/errno.h> |
| 60e64d46 VG |
10 | #include <linux/highmem.h> |
| 11 | #include <linux/crash_dump.h> | |
| 12 | ||
| 60e64d46 VG |
13 | #include <asm/uaccess.h> |
| 14 | ||
| 4ae362be | 15 | static void *kdump_buf_page; |
| 2030eae5 | 16 | |
| 57cac4d1 VG |
17 | /* Stores the physical address of elf header of crash image. */ |
| 18 | unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX; | |
| 19 | ||
| 72ed7de7 JS |
20 | static inline bool is_crashed_pfn_valid(unsigned long pfn) |
| 21 | { | |
| 22 | #ifndef CONFIG_X86_PAE | |
| 23 | /* | |
| 24 | * non-PAE kdump kernel executed from a PAE one will crop high pte | |
| 25 | * bits and poke unwanted space counting again from address 0, we | |
| 26 | * don't want that. pte must fit into unsigned long. In fact the | |
| 27 | * test checks high 12 bits for being zero (pfn will be shifted left | |
| 28 | * by PAGE_SHIFT). | |
| 29 | */ | |
| 30 | return pte_pfn(pfn_pte(pfn, __pgprot(0))) == pfn; | |
| 31 | #else | |
| 32 | return true; | |
| 33 | #endif | |
| 34 | } | |
| 35 | ||
| e77e1716 RD |
36 | /** |
| 37 | * copy_oldmem_page - copy one page from "oldmem" | |
| 38 | * @pfn: page frame number to be copied | |
| 39 | * @buf: target memory address for the copy; this can be in kernel address | |
| 40 | * space or user address space (see @userbuf) | |
| 41 | * @csize: number of bytes to copy | |
| 42 | * @offset: offset in bytes into the page (based on pfn) to begin the copy | |
| 43 | * @userbuf: if set, @buf is in user address space, use copy_to_user(), | |
| 44 | * otherwise @buf is in kernel address space, use memcpy(). | |
| 45 | * | |
| 60e64d46 VG |
46 | * Copy a page from "oldmem". For this page, there is no pte mapped |
| 47 | * in the current kernel. We stitch up a pte, similar to kmap_atomic. | |
| 4ae362be VG |
48 | * |
| 49 | * Calling copy_to_user() in atomic context is not desirable. Hence first | |
| 50 | * copying the data to a pre-allocated kernel page and then copying to user | |
| 51 | * space in non-atomic context. | |
| 60e64d46 VG |
52 | */ |
| 53 | ssize_t copy_oldmem_page(unsigned long pfn, char *buf, | |
| 4ae362be | 54 | size_t csize, unsigned long offset, int userbuf) |
| 60e64d46 | 55 | { |
| 4ae362be | 56 | void *vaddr; |
| 60e64d46 VG |
57 | |
| 58 | if (!csize) | |
| 59 | return 0; | |
| 60 | ||
| 72ed7de7 JS |
61 | if (!is_crashed_pfn_valid(pfn)) |
| 62 | return -EFAULT; | |
| 63 | ||
| 60e64d46 | 64 | vaddr = kmap_atomic_pfn(pfn, KM_PTE0); |
| 60e64d46 | 65 | |
| 4ae362be VG |
66 | if (!userbuf) { |
| 67 | memcpy(buf, (vaddr + offset), csize); | |
| 68 | kunmap_atomic(vaddr, KM_PTE0); | |
| 69 | } else { | |
| 70 | if (!kdump_buf_page) { | |
| 71 | printk(KERN_WARNING "Kdump: Kdump buffer page not" | |
| 72 | " allocated\n"); | |
| 22124c99 | 73 | kunmap_atomic(vaddr, KM_PTE0); |
| 60e64d46 VG |
74 | return -EFAULT; |
| 75 | } | |
| 4ae362be VG |
76 | copy_page(kdump_buf_page, vaddr); |
| 77 | kunmap_atomic(vaddr, KM_PTE0); | |
| 78 | if (copy_to_user(buf, (kdump_buf_page + offset), csize)) | |
| 79 | return -EFAULT; | |
| 60e64d46 VG |
80 | } |
| 81 | ||
| 60e64d46 VG |
82 | return csize; |
| 83 | } | |
| 4ae362be VG |
84 | |
| 85 | static int __init kdump_buf_page_init(void) | |
| 86 | { | |
| 87 | int ret = 0; | |
| 88 | ||
| 89 | kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL); | |
| 90 | if (!kdump_buf_page) { | |
| 91 | printk(KERN_WARNING "Kdump: Failed to allocate kdump buffer" | |
| 92 | " page\n"); | |
| 93 | ret = -ENOMEM; | |
| 94 | } | |
| 95 | ||
| 96 | return ret; | |
| 97 | } | |
| 98 | arch_initcall(kdump_buf_page_init); |