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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>
Yinghai Lu95f72d12010-07-12 14:36:09 +100016#include <linux/memblock.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>
Anton Blanchardd72e0632010-08-24 14:23:44 +000022#include <asm/rtas.h>
Michael Ellerman0cc47462005-12-04 18:39:37 +110023
24#ifdef DEBUG
25#include <asm/udbg.h>
26#define DBG(fmt...) udbg_printf(fmt)
27#else
28#define DBG(fmt...)
29#endif
30
Mohan Kumar M54622f12008-10-21 17:38:10 +000031#ifndef CONFIG_RELOCATABLE
Stephen Rothwelld56c3aa2007-08-15 20:53:26 +100032void __init reserve_kdump_trampoline(void)
Michael Ellerman47310412006-05-17 18:00:49 +100033{
Yinghai Lu95f72d12010-07-12 14:36:09 +100034 memblock_reserve(0, KDUMP_RESERVE_LIMIT);
Michael Ellerman47310412006-05-17 18:00:49 +100035}
36
Michael Ellerman0cc47462005-12-04 18:39:37 +110037static void __init create_trampoline(unsigned long addr)
38{
Michael Ellermane7a572732008-06-24 11:32:22 +100039 unsigned int *p = (unsigned int *)addr;
40
Michael Ellerman0cc47462005-12-04 18:39:37 +110041 /* The maximum range of a single instruction branch, is the current
42 * instruction's address + (32 MB - 4) bytes. For the trampoline we
43 * need to branch to current address + 32 MB. So we insert a nop at
44 * the trampoline address, then the next instruction (+ 4 bytes)
45 * does a branch to (32 MB - 4). The net effect is that when we
46 * branch to "addr" we jump to ("addr" + 32 MB). Although it requires
47 * two instructions it doesn't require any registers.
48 */
Kumar Gala16c57b32009-02-10 20:10:44 +000049 patch_instruction(p, PPC_INST_NOP);
Michael Ellermane7a572732008-06-24 11:32:22 +100050 patch_branch(++p, addr + PHYSICAL_START, 0);
Michael Ellerman0cc47462005-12-04 18:39:37 +110051}
52
Michael Ellerman47310412006-05-17 18:00:49 +100053void __init setup_kdump_trampoline(void)
Michael Ellerman0cc47462005-12-04 18:39:37 +110054{
55 unsigned long i;
56
Michael Ellerman47310412006-05-17 18:00:49 +100057 DBG(" -> setup_kdump_trampoline()\n");
Michael Ellerman0cc47462005-12-04 18:39:37 +110058
59 for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) {
60 create_trampoline(i);
61 }
62
Stephen Rothwell9e4859e2007-09-18 17:25:12 +100063#ifdef CONFIG_PPC_PSERIES
Michael Ellerman0cc47462005-12-04 18:39:37 +110064 create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START);
65 create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START);
Stephen Rothwell9e4859e2007-09-18 17:25:12 +100066#endif /* CONFIG_PPC_PSERIES */
Michael Ellerman0cc47462005-12-04 18:39:37 +110067
Michael Ellerman47310412006-05-17 18:00:49 +100068 DBG(" <- setup_kdump_trampoline()\n");
Michael Ellerman0cc47462005-12-04 18:39:37 +110069}
Mohan Kumar M54622f12008-10-21 17:38:10 +000070#endif /* CONFIG_RELOCATABLE */
Michael Ellermancc532912005-12-04 18:39:43 +110071
Michael Ellermancc532912005-12-04 18:39:43 +110072static int __init parse_savemaxmem(char *p)
73{
74 if (p)
75 saved_max_pfn = (memparse(p, &p) >> PAGE_SHIFT) - 1;
76
OGAWA Hirofumi9b410462006-03-31 02:30:33 -080077 return 1;
Michael Ellermancc532912005-12-04 18:39:43 +110078}
79__setup("savemaxmem=", parse_savemaxmem);
Michael Ellerman54c32022005-12-04 18:39:51 +110080
Michael Ellerman7230ced2008-07-31 16:54:28 +100081
82static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize,
83 unsigned long offset, int userbuf)
84{
85 if (userbuf) {
86 if (copy_to_user((char __user *)buf, (vaddr + offset), csize))
87 return -EFAULT;
88 } else
89 memcpy(buf, (vaddr + offset), csize);
90
91 return csize;
92}
93
Michael Ellerman40681b92006-08-02 11:13:50 +100094/**
Michael Ellerman54c32022005-12-04 18:39:51 +110095 * copy_oldmem_page - copy one page from "oldmem"
96 * @pfn: page frame number to be copied
97 * @buf: target memory address for the copy; this can be in kernel address
98 * space or user address space (see @userbuf)
99 * @csize: number of bytes to copy
100 * @offset: offset in bytes into the page (based on pfn) to begin the copy
101 * @userbuf: if set, @buf is in user address space, use copy_to_user(),
102 * otherwise @buf is in kernel address space, use memcpy().
103 *
104 * Copy a page from "oldmem". For this page, there is no pte mapped
105 * in the current kernel. We stitch up a pte, similar to kmap_atomic.
106 */
107ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
108 size_t csize, unsigned long offset, int userbuf)
109{
110 void *vaddr;
111
112 if (!csize)
113 return 0;
114
Matthew McClintockbbc8e302010-07-21 11:14:54 +0000115 csize = min_t(size_t, csize, PAGE_SIZE);
Michael Ellerman54c32022005-12-04 18:39:51 +1100116
Matthew McClintockbbc8e302010-07-21 11:14:54 +0000117 if ((min_low_pfn < pfn) && (pfn < max_pfn)) {
Michael Ellerman7230ced2008-07-31 16:54:28 +1000118 vaddr = __va(pfn << PAGE_SHIFT);
119 csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
120 } else {
121 vaddr = __ioremap(pfn << PAGE_SHIFT, PAGE_SIZE, 0);
122 csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
123 iounmap(vaddr);
124 }
Michael Ellerman54c32022005-12-04 18:39:51 +1100125
Michael Ellerman54c32022005-12-04 18:39:51 +1100126 return csize;
127}
Anton Blanchardd72e0632010-08-24 14:23:44 +0000128
129#ifdef CONFIG_PPC_RTAS
130/*
131 * The crashkernel region will almost always overlap the RTAS region, so
132 * we have to be careful when shrinking the crashkernel region.
133 */
134void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
135{
136 unsigned long addr;
137 const u32 *basep, *sizep;
138 unsigned int rtas_start = 0, rtas_end = 0;
139
140 basep = of_get_property(rtas.dev, "linux,rtas-base", NULL);
141 sizep = of_get_property(rtas.dev, "rtas-size", NULL);
142
143 if (basep && sizep) {
144 rtas_start = *basep;
145 rtas_end = *basep + *sizep;
146 }
147
148 for (addr = begin; addr < end; addr += PAGE_SIZE) {
149 /* Does this page overlap with the RTAS region? */
150 if (addr <= rtas_end && ((addr + PAGE_SIZE) > rtas_start))
151 continue;
152
153 ClearPageReserved(pfn_to_page(addr >> PAGE_SHIFT));
154 init_page_count(pfn_to_page(addr >> PAGE_SHIFT));
155 free_page((unsigned long)__va(addr));
156 totalram_pages++;
157 }
158}
159#endif