Commit | Line | Data |
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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> | |
d9b2b2a2 | 16 | #include <linux/lmb.h> |
aaddd3ea | 17 | #include <asm/code-patching.h> |
0cc4746c | 18 | #include <asm/kdump.h> |
d9b2b2a2 | 19 | #include <asm/prom.h> |
0cc4746c | 20 | #include <asm/firmware.h> |
54c32021 | 21 | #include <asm/uaccess.h> |
0cc4746c ME |
22 | |
23 | #ifdef DEBUG | |
24 | #include <asm/udbg.h> | |
25 | #define DBG(fmt...) udbg_printf(fmt) | |
26 | #else | |
27 | #define DBG(fmt...) | |
28 | #endif | |
29 | ||
57cac4d1 VG |
30 | /* Stores the physical address of elf header of crash image. */ |
31 | unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX; | |
32 | ||
54622f10 | 33 | #ifndef CONFIG_RELOCATABLE |
d56c3aaa | 34 | void __init reserve_kdump_trampoline(void) |
47310413 ME |
35 | { |
36 | lmb_reserve(0, KDUMP_RESERVE_LIMIT); | |
37 | } | |
38 | ||
0cc4746c ME |
39 | static void __init create_trampoline(unsigned long addr) |
40 | { | |
e7a57273 ME |
41 | unsigned int *p = (unsigned int *)addr; |
42 | ||
0cc4746c ME |
43 | /* The maximum range of a single instruction branch, is the current |
44 | * instruction's address + (32 MB - 4) bytes. For the trampoline we | |
45 | * need to branch to current address + 32 MB. So we insert a nop at | |
46 | * the trampoline address, then the next instruction (+ 4 bytes) | |
47 | * does a branch to (32 MB - 4). The net effect is that when we | |
48 | * branch to "addr" we jump to ("addr" + 32 MB). Although it requires | |
49 | * two instructions it doesn't require any registers. | |
50 | */ | |
16c57b36 | 51 | patch_instruction(p, PPC_INST_NOP); |
e7a57273 | 52 | patch_branch(++p, addr + PHYSICAL_START, 0); |
0cc4746c ME |
53 | } |
54 | ||
47310413 | 55 | void __init setup_kdump_trampoline(void) |
0cc4746c ME |
56 | { |
57 | unsigned long i; | |
58 | ||
47310413 | 59 | DBG(" -> setup_kdump_trampoline()\n"); |
0cc4746c ME |
60 | |
61 | for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) { | |
62 | create_trampoline(i); | |
63 | } | |
64 | ||
9e4859ef | 65 | #ifdef CONFIG_PPC_PSERIES |
0cc4746c ME |
66 | create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START); |
67 | create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START); | |
9e4859ef | 68 | #endif /* CONFIG_PPC_PSERIES */ |
0cc4746c | 69 | |
47310413 | 70 | DBG(" <- setup_kdump_trampoline()\n"); |
0cc4746c | 71 | } |
54622f10 | 72 | #endif /* CONFIG_RELOCATABLE */ |
cc532915 | 73 | |
57cac4d1 VG |
74 | /* |
75 | * Note: elfcorehdr_addr is not just limited to vmcore. It is also used by | |
76 | * is_kdump_kernel() to determine if we are booting after a panic. Hence | |
77 | * ifdef it under CONFIG_CRASH_DUMP and not CONFIG_PROC_VMCORE. | |
78 | */ | |
cc532915 ME |
79 | static int __init parse_elfcorehdr(char *p) |
80 | { | |
81 | if (p) | |
82 | elfcorehdr_addr = memparse(p, &p); | |
83 | ||
9b41046c | 84 | return 1; |
cc532915 ME |
85 | } |
86 | __setup("elfcorehdr=", parse_elfcorehdr); | |
87 | ||
88 | static int __init parse_savemaxmem(char *p) | |
89 | { | |
90 | if (p) | |
91 | saved_max_pfn = (memparse(p, &p) >> PAGE_SHIFT) - 1; | |
92 | ||
9b41046c | 93 | return 1; |
cc532915 ME |
94 | } |
95 | __setup("savemaxmem=", parse_savemaxmem); | |
54c32021 | 96 | |
7230ced4 ME |
97 | |
98 | static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize, | |
99 | unsigned long offset, int userbuf) | |
100 | { | |
101 | if (userbuf) { | |
102 | if (copy_to_user((char __user *)buf, (vaddr + offset), csize)) | |
103 | return -EFAULT; | |
104 | } else | |
105 | memcpy(buf, (vaddr + offset), csize); | |
106 | ||
107 | return csize; | |
108 | } | |
109 | ||
40681b95 | 110 | /** |
54c32021 ME |
111 | * copy_oldmem_page - copy one page from "oldmem" |
112 | * @pfn: page frame number to be copied | |
113 | * @buf: target memory address for the copy; this can be in kernel address | |
114 | * space or user address space (see @userbuf) | |
115 | * @csize: number of bytes to copy | |
116 | * @offset: offset in bytes into the page (based on pfn) to begin the copy | |
117 | * @userbuf: if set, @buf is in user address space, use copy_to_user(), | |
118 | * otherwise @buf is in kernel address space, use memcpy(). | |
119 | * | |
120 | * Copy a page from "oldmem". For this page, there is no pte mapped | |
121 | * in the current kernel. We stitch up a pte, similar to kmap_atomic. | |
122 | */ | |
123 | ssize_t copy_oldmem_page(unsigned long pfn, char *buf, | |
124 | size_t csize, unsigned long offset, int userbuf) | |
125 | { | |
126 | void *vaddr; | |
127 | ||
128 | if (!csize) | |
129 | return 0; | |
130 | ||
7230ced4 | 131 | csize = min(csize, PAGE_SIZE); |
54c32021 | 132 | |
7230ced4 ME |
133 | if (pfn < max_pfn) { |
134 | vaddr = __va(pfn << PAGE_SHIFT); | |
135 | csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); | |
136 | } else { | |
137 | vaddr = __ioremap(pfn << PAGE_SHIFT, PAGE_SIZE, 0); | |
138 | csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); | |
139 | iounmap(vaddr); | |
140 | } | |
54c32021 | 141 | |
54c32021 ME |
142 | return csize; |
143 | } |