summaryrefslogtreecommitdiff
path: root/arch/powerpc/kernel/crash_dump.c
blob: 05745ddbd229dc1d9595bd825e099ce2ea5fdcd6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Routines for doing kexec-based kdump.
 *
 * Copyright (C) 2005, IBM Corp.
 *
 * Created by: Michael Ellerman
 */

#undef DEBUG

#include <linux/crash_dump.h>
#include <linux/io.h>
#include <linux/memblock.h>
#include <asm/code-patching.h>
#include <asm/kdump.h>
#include <asm/prom.h>
#include <asm/firmware.h>
#include <linux/uaccess.h>
#include <asm/rtas.h>

#ifdef DEBUG
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif

#ifndef CONFIG_NONSTATIC_KERNEL
void __init reserve_kdump_trampoline(void)
{
	memblock_reserve(0, KDUMP_RESERVE_LIMIT);
}

static void __init create_trampoline(unsigned long addr)
{
	unsigned int *p = (unsigned int *)addr;

	/* The maximum range of a single instruction branch, is the current
	 * instruction's address + (32 MB - 4) bytes. For the trampoline we
	 * need to branch to current address + 32 MB. So we insert a nop at
	 * the trampoline address, then the next instruction (+ 4 bytes)
	 * does a branch to (32 MB - 4). The net effect is that when we
	 * branch to "addr" we jump to ("addr" + 32 MB). Although it requires
	 * two instructions it doesn't require any registers.
	 */
	patch_instruction(p, PPC_INST_NOP);
	patch_branch(++p, addr + PHYSICAL_START, 0);
}

void __init setup_kdump_trampoline(void)
{
	unsigned long i;

	DBG(" -> setup_kdump_trampoline()\n");

	for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) {
		create_trampoline(i);
	}

#ifdef CONFIG_PPC_PSERIES
	create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START);
	create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START);
#endif /* CONFIG_PPC_PSERIES */

	DBG(" <- setup_kdump_trampoline()\n");
}
#endif /* CONFIG_NONSTATIC_KERNEL */

static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize,
                               unsigned long offset, int userbuf)
{
	if (userbuf) {
		if (copy_to_user((char __user *)buf, (vaddr + offset), csize))
			return -EFAULT;
	} else
		memcpy(buf, (vaddr + offset), csize);

	return csize;
}

/**
 * copy_oldmem_page - copy one page from "oldmem"
 * @pfn: page frame number to be copied
 * @buf: target memory address for the copy; this can be in kernel address
 *      space or user address space (see @userbuf)
 * @csize: number of bytes to copy
 * @offset: offset in bytes into the page (based on pfn) to begin the copy
 * @userbuf: if set, @buf is in user address space, use copy_to_user(),
 *      otherwise @buf is in kernel address space, use memcpy().
 *
 * Copy a page from "oldmem". For this page, there is no pte mapped
 * in the current kernel. We stitch up a pte, similar to kmap_atomic.
 */
ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
			size_t csize, unsigned long offset, int userbuf)
{
	void  *vaddr;
	phys_addr_t paddr;

	if (!csize)
		return 0;

	csize = min_t(size_t, csize, PAGE_SIZE);
	paddr = pfn << PAGE_SHIFT;

	if (memblock_is_region_memory(paddr, csize)) {
		vaddr = __va(paddr);
		csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
	} else {
		vaddr = ioremap_cache(paddr, PAGE_SIZE);
		csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
		iounmap(vaddr);
	}

	return csize;
}

#ifdef CONFIG_PPC_RTAS
/*
 * The crashkernel region will almost always overlap the RTAS region, so
 * we have to be careful when shrinking the crashkernel region.
 */
void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
{
	unsigned long addr;
	const __be32 *basep, *sizep;
	unsigned int rtas_start = 0, rtas_end = 0;

	basep = of_get_property(rtas.dev, "linux,rtas-base", NULL);
	sizep = of_get_property(rtas.dev, "rtas-size", NULL);

	if (basep && sizep) {
		rtas_start = be32_to_cpup(basep);
		rtas_end = rtas_start + be32_to_cpup(sizep);
	}

	for (addr = begin; addr < end; addr += PAGE_SIZE) {
		/* Does this page overlap with the RTAS region? */
		if (addr <= rtas_end && ((addr + PAGE_SIZE) > rtas_start))
			continue;

		free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
	}
}
#endif