machine_kexec.c revision 66c721e184e594d5761c5db804ade08fab81930d 
1/*
2 * Code to handle transition of Linux booting another kernel.
3 *
4 * Copyright (C) 2002-2003 Eric Biederman  <ebiederm@xmission.com>
5 * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
6 * Copyright (C) 2005 IBM Corporation.
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#include <linux/kexec.h>
13#include <linux/reboot.h>
14#include <linux/threads.h>
15#include <linux/lmb.h>
16#include <linux/of.h>
17#include <asm/machdep.h>
18#include <asm/prom.h>
19#include <asm/sections.h>
20
21void machine_crash_shutdown(struct pt_regs *regs)
22{
23	if (ppc_md.machine_crash_shutdown)
24		ppc_md.machine_crash_shutdown(regs);
25	else
26		default_machine_crash_shutdown(regs);
27}
28
29/*
30 * Do what every setup is needed on image and the
31 * reboot code buffer to allow us to avoid allocations
32 * later.
33 */
34int machine_kexec_prepare(struct kimage *image)
35{
36	if (ppc_md.machine_kexec_prepare)
37		return ppc_md.machine_kexec_prepare(image);
38	else
39		return default_machine_kexec_prepare(image);
40}
41
42void machine_kexec_cleanup(struct kimage *image)
43{
44	if (ppc_md.machine_kexec_cleanup)
45		ppc_md.machine_kexec_cleanup(image);
46}
47
48/*
49 * Do not allocate memory (or fail in any way) in machine_kexec().
50 * We are past the point of no return, committed to rebooting now.
51 */
52void machine_kexec(struct kimage *image)
53{
54	if (ppc_md.machine_kexec)
55		ppc_md.machine_kexec(image);
56	else
57		default_machine_kexec(image);
58
59	/* Fall back to normal restart if we're still alive. */
60	machine_restart(NULL);
61	for(;;);
62}
63
64void __init reserve_crashkernel(void)
65{
66	unsigned long long crash_size, crash_base;
67	int ret;
68
69	/* this is necessary because of lmb_phys_mem_size() */
70	lmb_analyze();
71
72	/* use common parsing */
73	ret = parse_crashkernel(boot_command_line, lmb_phys_mem_size(),
74			&crash_size, &crash_base);
75	if (ret == 0 && crash_size > 0) {
76		crashk_res.start = crash_base;
77		crashk_res.end = crash_base + crash_size - 1;
78	}
79
80	if (crashk_res.end == crashk_res.start) {
81		crashk_res.start = crashk_res.end = 0;
82		return;
83	}
84
85	/* We might have got these values via the command line or the
86	 * device tree, either way sanitise them now. */
87
88	crash_size = crashk_res.end - crashk_res.start + 1;
89
90#ifndef CONFIG_RELOCATABLE
91	if (crashk_res.start != KDUMP_KERNELBASE)
92		printk("Crash kernel location must be 0x%x\n",
93				KDUMP_KERNELBASE);
94
95	crashk_res.start = KDUMP_KERNELBASE;
96#else
97	if (!crashk_res.start) {
98		/*
99		 * unspecified address, choose a region of specified size
100		 * can overlap with initrd (ignoring corruption when retained)
101		 * ppc64 requires kernel and some stacks to be in first segemnt
102		 */
103		crashk_res.start = KDUMP_KERNELBASE;
104	}
105
106	crash_base = PAGE_ALIGN(crashk_res.start);
107	if (crash_base != crashk_res.start) {
108		printk("Crash kernel base must be aligned to 0x%lx\n",
109				PAGE_SIZE);
110		crashk_res.start = crash_base;
111	}
112
113#endif
114	crash_size = PAGE_ALIGN(crash_size);
115	crashk_res.end = crashk_res.start + crash_size - 1;
116
117	/* The crash region must not overlap the current kernel */
118	if (overlaps_crashkernel(__pa(_stext), _end - _stext)) {
119		printk(KERN_WARNING
120			"Crash kernel can not overlap current kernel\n");
121		crashk_res.start = crashk_res.end = 0;
122		return;
123	}
124
125	/* Crash kernel trumps memory limit */
126	if (memory_limit && memory_limit <= crashk_res.end) {
127		memory_limit = crashk_res.end + 1;
128		printk("Adjusted memory limit for crashkernel, now 0x%lx\n",
129				memory_limit);
130	}
131
132	printk(KERN_INFO "Reserving %ldMB of memory at %ldMB "
133			"for crashkernel (System RAM: %ldMB)\n",
134			(unsigned long)(crash_size >> 20),
135			(unsigned long)(crashk_res.start >> 20),
136			(unsigned long)(lmb_phys_mem_size() >> 20));
137
138	lmb_reserve(crashk_res.start, crash_size);
139}
140
141int overlaps_crashkernel(unsigned long start, unsigned long size)
142{
143	return (start + size) > crashk_res.start && start <= crashk_res.end;
144}
145
146/* Values we need to export to the second kernel via the device tree. */
147static unsigned long kernel_end;
148static unsigned long crashk_size;
149
150static struct property kernel_end_prop = {
151	.name = "linux,kernel-end",
152	.length = sizeof(unsigned long),
153	.value = &kernel_end,
154};
155
156static struct property crashk_base_prop = {
157	.name = "linux,crashkernel-base",
158	.length = sizeof(unsigned long),
159	.value = &crashk_res.start,
160};
161
162static struct property crashk_size_prop = {
163	.name = "linux,crashkernel-size",
164	.length = sizeof(unsigned long),
165	.value = &crashk_size,
166};
167
168static void __init export_crashk_values(struct device_node *node)
169{
170	struct property *prop;
171
172	/* There might be existing crash kernel properties, but we can't
173	 * be sure what's in them, so remove them. */
174	prop = of_find_property(node, "linux,crashkernel-base", NULL);
175	if (prop)
176		prom_remove_property(node, prop);
177
178	prop = of_find_property(node, "linux,crashkernel-size", NULL);
179	if (prop)
180		prom_remove_property(node, prop);
181
182	if (crashk_res.start != 0) {
183		prom_add_property(node, &crashk_base_prop);
184		crashk_size = crashk_res.end - crashk_res.start + 1;
185		prom_add_property(node, &crashk_size_prop);
186	}
187}
188
189static int __init kexec_setup(void)
190{
191	struct device_node *node;
192	struct property *prop;
193
194	node = of_find_node_by_path("/chosen");
195	if (!node)
196		return -ENOENT;
197
198	/* remove any stale properties so ours can be found */
199	prop = of_find_property(node, kernel_end_prop.name, NULL);
200	if (prop)
201		prom_remove_property(node, prop);
202
203	/* information needed by userspace when using default_machine_kexec */
204	kernel_end = __pa(_end);
205	prom_add_property(node, &kernel_end_prop);
206
207	export_crashk_values(node);
208
209	of_node_put(node);
210	return 0;
211}
212late_initcall(kexec_setup);
213