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0cc4746c ME |
1 | /* |
2 | * Routines for doing kexec-based kdump. | |
3 | * | |
4 | * Copyright (C) 2005, IBM Corp. | |
5 | * | |
6 | * Created by: Michael Ellerman | |
7 | * | |
8 | * This source code is licensed under the GNU General Public License, | |
9 | * Version 2. See the file COPYING for more details. | |
10 | */ | |
11 | ||
12 | #undef DEBUG | |
13 | ||
cc532915 ME |
14 | #include <linux/crash_dump.h> |
15 | #include <linux/bootmem.h> | |
0cc4746c ME |
16 | #include <asm/kdump.h> |
17 | #include <asm/lmb.h> | |
18 | #include <asm/firmware.h> | |
54c32021 | 19 | #include <asm/uaccess.h> |
0cc4746c ME |
20 | |
21 | #ifdef DEBUG | |
22 | #include <asm/udbg.h> | |
23 | #define DBG(fmt...) udbg_printf(fmt) | |
24 | #else | |
25 | #define DBG(fmt...) | |
26 | #endif | |
27 | ||
28 | static void __init create_trampoline(unsigned long addr) | |
29 | { | |
30 | /* The maximum range of a single instruction branch, is the current | |
31 | * instruction's address + (32 MB - 4) bytes. For the trampoline we | |
32 | * need to branch to current address + 32 MB. So we insert a nop at | |
33 | * the trampoline address, then the next instruction (+ 4 bytes) | |
34 | * does a branch to (32 MB - 4). The net effect is that when we | |
35 | * branch to "addr" we jump to ("addr" + 32 MB). Although it requires | |
36 | * two instructions it doesn't require any registers. | |
37 | */ | |
38 | create_instruction(addr, 0x60000000); /* nop */ | |
39 | create_branch(addr + 4, addr + PHYSICAL_START, 0); | |
40 | } | |
41 | ||
42 | void __init kdump_setup(void) | |
43 | { | |
44 | unsigned long i; | |
45 | ||
46 | DBG(" -> kdump_setup()\n"); | |
47 | ||
48 | for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) { | |
49 | create_trampoline(i); | |
50 | } | |
51 | ||
52 | create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START); | |
53 | create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START); | |
54 | ||
55 | DBG(" <- kdump_setup()\n"); | |
56 | } | |
cc532915 | 57 | |
6bac953f | 58 | #ifdef CONFIG_PROC_VMCORE |
cc532915 ME |
59 | static int __init parse_elfcorehdr(char *p) |
60 | { | |
61 | if (p) | |
62 | elfcorehdr_addr = memparse(p, &p); | |
63 | ||
9b41046c | 64 | return 1; |
cc532915 ME |
65 | } |
66 | __setup("elfcorehdr=", parse_elfcorehdr); | |
6bac953f | 67 | #endif |
cc532915 ME |
68 | |
69 | static int __init parse_savemaxmem(char *p) | |
70 | { | |
71 | if (p) | |
72 | saved_max_pfn = (memparse(p, &p) >> PAGE_SHIFT) - 1; | |
73 | ||
9b41046c | 74 | return 1; |
cc532915 ME |
75 | } |
76 | __setup("savemaxmem=", parse_savemaxmem); | |
54c32021 ME |
77 | |
78 | /* | |
79 | * copy_oldmem_page - copy one page from "oldmem" | |
80 | * @pfn: page frame number to be copied | |
81 | * @buf: target memory address for the copy; this can be in kernel address | |
82 | * space or user address space (see @userbuf) | |
83 | * @csize: number of bytes to copy | |
84 | * @offset: offset in bytes into the page (based on pfn) to begin the copy | |
85 | * @userbuf: if set, @buf is in user address space, use copy_to_user(), | |
86 | * otherwise @buf is in kernel address space, use memcpy(). | |
87 | * | |
88 | * Copy a page from "oldmem". For this page, there is no pte mapped | |
89 | * in the current kernel. We stitch up a pte, similar to kmap_atomic. | |
90 | */ | |
91 | ssize_t copy_oldmem_page(unsigned long pfn, char *buf, | |
92 | size_t csize, unsigned long offset, int userbuf) | |
93 | { | |
94 | void *vaddr; | |
95 | ||
96 | if (!csize) | |
97 | return 0; | |
98 | ||
99 | vaddr = __ioremap(pfn << PAGE_SHIFT, PAGE_SIZE, 0); | |
100 | ||
101 | if (userbuf) { | |
102 | if (copy_to_user((char __user *)buf, (vaddr + offset), csize)) { | |
103 | iounmap(vaddr); | |
104 | return -EFAULT; | |
105 | } | |
106 | } else | |
107 | memcpy(buf, (vaddr + offset), csize); | |
108 | ||
109 | iounmap(vaddr); | |
110 | return csize; | |
111 | } |