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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 | ||
47310413 ME |
28 | void reserve_kdump_trampoline(void) |
29 | { | |
30 | lmb_reserve(0, KDUMP_RESERVE_LIMIT); | |
31 | } | |
32 | ||
0cc4746c ME |
33 | static void __init create_trampoline(unsigned long addr) |
34 | { | |
35 | /* The maximum range of a single instruction branch, is the current | |
36 | * instruction's address + (32 MB - 4) bytes. For the trampoline we | |
37 | * need to branch to current address + 32 MB. So we insert a nop at | |
38 | * the trampoline address, then the next instruction (+ 4 bytes) | |
39 | * does a branch to (32 MB - 4). The net effect is that when we | |
40 | * branch to "addr" we jump to ("addr" + 32 MB). Although it requires | |
41 | * two instructions it doesn't require any registers. | |
42 | */ | |
43 | create_instruction(addr, 0x60000000); /* nop */ | |
44 | create_branch(addr + 4, addr + PHYSICAL_START, 0); | |
45 | } | |
46 | ||
47310413 | 47 | void __init setup_kdump_trampoline(void) |
0cc4746c ME |
48 | { |
49 | unsigned long i; | |
50 | ||
47310413 | 51 | DBG(" -> setup_kdump_trampoline()\n"); |
0cc4746c ME |
52 | |
53 | for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) { | |
54 | create_trampoline(i); | |
55 | } | |
56 | ||
57 | create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START); | |
58 | create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START); | |
59 | ||
47310413 | 60 | DBG(" <- setup_kdump_trampoline()\n"); |
0cc4746c | 61 | } |
cc532915 | 62 | |
6bac953f | 63 | #ifdef CONFIG_PROC_VMCORE |
cc532915 ME |
64 | static int __init parse_elfcorehdr(char *p) |
65 | { | |
66 | if (p) | |
67 | elfcorehdr_addr = memparse(p, &p); | |
68 | ||
9b41046c | 69 | return 1; |
cc532915 ME |
70 | } |
71 | __setup("elfcorehdr=", parse_elfcorehdr); | |
6bac953f | 72 | #endif |
cc532915 ME |
73 | |
74 | static int __init parse_savemaxmem(char *p) | |
75 | { | |
76 | if (p) | |
77 | saved_max_pfn = (memparse(p, &p) >> PAGE_SHIFT) - 1; | |
78 | ||
9b41046c | 79 | return 1; |
cc532915 ME |
80 | } |
81 | __setup("savemaxmem=", parse_savemaxmem); | |
54c32021 ME |
82 | |
83 | /* | |
84 | * copy_oldmem_page - copy one page from "oldmem" | |
85 | * @pfn: page frame number to be copied | |
86 | * @buf: target memory address for the copy; this can be in kernel address | |
87 | * space or user address space (see @userbuf) | |
88 | * @csize: number of bytes to copy | |
89 | * @offset: offset in bytes into the page (based on pfn) to begin the copy | |
90 | * @userbuf: if set, @buf is in user address space, use copy_to_user(), | |
91 | * otherwise @buf is in kernel address space, use memcpy(). | |
92 | * | |
93 | * Copy a page from "oldmem". For this page, there is no pte mapped | |
94 | * in the current kernel. We stitch up a pte, similar to kmap_atomic. | |
95 | */ | |
96 | ssize_t copy_oldmem_page(unsigned long pfn, char *buf, | |
97 | size_t csize, unsigned long offset, int userbuf) | |
98 | { | |
99 | void *vaddr; | |
100 | ||
101 | if (!csize) | |
102 | return 0; | |
103 | ||
104 | vaddr = __ioremap(pfn << PAGE_SHIFT, PAGE_SIZE, 0); | |
105 | ||
106 | if (userbuf) { | |
107 | if (copy_to_user((char __user *)buf, (vaddr + offset), csize)) { | |
108 | iounmap(vaddr); | |
109 | return -EFAULT; | |
110 | } | |
111 | } else | |
112 | memcpy(buf, (vaddr + offset), csize); | |
113 | ||
114 | iounmap(vaddr); | |
115 | return csize; | |
116 | } |