blob: 5fb667a60894dd6238b51db9c13b1caf93fc0253 [file] [log] [blame]
Michael Ellerman0cc47462005-12-04 18:39:37 +11001/*
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
Michael Ellermancc532912005-12-04 18:39:43 +110014#include <linux/crash_dump.h>
15#include <linux/bootmem.h>
David S. Millerd9b2b2a2008-02-13 16:56:49 -080016#include <linux/lmb.h>
Michael Ellermanaaddd3e2008-06-24 11:32:21 +100017#include <asm/code-patching.h>
Michael Ellerman0cc47462005-12-04 18:39:37 +110018#include <asm/kdump.h>
David S. Millerd9b2b2a2008-02-13 16:56:49 -080019#include <asm/prom.h>
Michael Ellerman0cc47462005-12-04 18:39:37 +110020#include <asm/firmware.h>
Michael Ellerman54c32022005-12-04 18:39:51 +110021#include <asm/uaccess.h>
Michael Ellerman0cc47462005-12-04 18:39:37 +110022
23#ifdef DEBUG
24#include <asm/udbg.h>
25#define DBG(fmt...) udbg_printf(fmt)
26#else
27#define DBG(fmt...)
28#endif
29
Vivek Goyal57cac4d2008-10-18 20:28:25 -070030/* Stores the physical address of elf header of crash image. */
31unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
32
Mohan Kumar M54622f12008-10-21 17:38:10 +000033#ifndef CONFIG_RELOCATABLE
Stephen Rothwelld56c3aa2007-08-15 20:53:26 +100034void __init reserve_kdump_trampoline(void)
Michael Ellerman47310412006-05-17 18:00:49 +100035{
36 lmb_reserve(0, KDUMP_RESERVE_LIMIT);
37}
38
Michael Ellerman0cc47462005-12-04 18:39:37 +110039static void __init create_trampoline(unsigned long addr)
40{
Michael Ellermane7a57272008-06-24 11:32:22 +100041 unsigned int *p = (unsigned int *)addr;
42
Michael Ellerman0cc47462005-12-04 18:39:37 +110043 /* 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 */
Kumar Gala16c57b32009-02-10 20:10:44 +000051 patch_instruction(p, PPC_INST_NOP);
Michael Ellermane7a57272008-06-24 11:32:22 +100052 patch_branch(++p, addr + PHYSICAL_START, 0);
Michael Ellerman0cc47462005-12-04 18:39:37 +110053}
54
Michael Ellerman47310412006-05-17 18:00:49 +100055void __init setup_kdump_trampoline(void)
Michael Ellerman0cc47462005-12-04 18:39:37 +110056{
57 unsigned long i;
58
Michael Ellerman47310412006-05-17 18:00:49 +100059 DBG(" -> setup_kdump_trampoline()\n");
Michael Ellerman0cc47462005-12-04 18:39:37 +110060
61 for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) {
62 create_trampoline(i);
63 }
64
Stephen Rothwell9e4859e2007-09-18 17:25:12 +100065#ifdef CONFIG_PPC_PSERIES
Michael Ellerman0cc47462005-12-04 18:39:37 +110066 create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START);
67 create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START);
Stephen Rothwell9e4859e2007-09-18 17:25:12 +100068#endif /* CONFIG_PPC_PSERIES */
Michael Ellerman0cc47462005-12-04 18:39:37 +110069
Michael Ellerman47310412006-05-17 18:00:49 +100070 DBG(" <- setup_kdump_trampoline()\n");
Michael Ellerman0cc47462005-12-04 18:39:37 +110071}
Mohan Kumar M54622f12008-10-21 17:38:10 +000072#endif /* CONFIG_RELOCATABLE */
Michael Ellermancc532912005-12-04 18:39:43 +110073
Vivek Goyal57cac4d2008-10-18 20:28:25 -070074/*
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 */
Michael Ellermancc532912005-12-04 18:39:43 +110079static int __init parse_elfcorehdr(char *p)
80{
81 if (p)
82 elfcorehdr_addr = memparse(p, &p);
83
OGAWA Hirofumi9b410462006-03-31 02:30:33 -080084 return 1;
Michael Ellermancc532912005-12-04 18:39:43 +110085}
86__setup("elfcorehdr=", parse_elfcorehdr);
87
88static int __init parse_savemaxmem(char *p)
89{
90 if (p)
91 saved_max_pfn = (memparse(p, &p) >> PAGE_SHIFT) - 1;
92
OGAWA Hirofumi9b410462006-03-31 02:30:33 -080093 return 1;
Michael Ellermancc532912005-12-04 18:39:43 +110094}
95__setup("savemaxmem=", parse_savemaxmem);
Michael Ellerman54c32022005-12-04 18:39:51 +110096
Michael Ellerman7230ced2008-07-31 16:54:28 +100097
98static 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
Michael Ellerman40681b92006-08-02 11:13:50 +1000110/**
Michael Ellerman54c32022005-12-04 18:39:51 +1100111 * 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 */
123ssize_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
Michael Ellerman7230ced2008-07-31 16:54:28 +1000131 csize = min(csize, PAGE_SIZE);
Michael Ellerman54c32022005-12-04 18:39:51 +1100132
Michael Ellerman7230ced2008-07-31 16:54:28 +1000133 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 }
Michael Ellerman54c32022005-12-04 18:39:51 +1100141
Michael Ellerman54c32022005-12-04 18:39:51 +1100142 return csize;
143}