1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Code to handle transition of Linux booting another kernel.
4 *
5 * Copyright (C) 2002-2003 Eric Biederman <ebiederm@xmission.com>
6 * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
7 * Copyright (C) 2005 IBM Corporation.
8 */
9
10 #include <linux/kexec.h>
11 #include <linux/reboot.h>
12 #include <linux/threads.h>
13 #include <linux/memblock.h>
14 #include <linux/of.h>
15 #include <linux/irq.h>
16 #include <linux/ftrace.h>
17
18 #include <asm/kdump.h>
19 #include <asm/machdep.h>
20 #include <asm/pgalloc.h>
21 #include <asm/sections.h>
22 #include <asm/setup.h>
23 #include <asm/firmware.h>
24
25 #ifdef CONFIG_CRASH_DUMP
machine_crash_shutdown(struct pt_regs * regs)26 void machine_crash_shutdown(struct pt_regs *regs)
27 {
28 default_machine_crash_shutdown(regs);
29 }
30 #endif
31
machine_kexec_cleanup(struct kimage * image)32 void machine_kexec_cleanup(struct kimage *image)
33 {
34 }
35
36 /*
37 * Do not allocate memory (or fail in any way) in machine_kexec().
38 * We are past the point of no return, committed to rebooting now.
39 */
machine_kexec(struct kimage * image)40 void machine_kexec(struct kimage *image)
41 {
42 int save_ftrace_enabled;
43
44 save_ftrace_enabled = __ftrace_enabled_save();
45 this_cpu_disable_ftrace();
46
47 if (ppc_md.machine_kexec)
48 ppc_md.machine_kexec(image);
49 else
50 default_machine_kexec(image);
51
52 this_cpu_enable_ftrace();
53 __ftrace_enabled_restore(save_ftrace_enabled);
54
55 /* Fall back to normal restart if we're still alive. */
56 machine_restart(NULL);
57 for(;;);
58 }
59
60 #ifdef CONFIG_CRASH_RESERVE
61
get_crash_base(unsigned long long crash_base)62 static unsigned long long __init get_crash_base(unsigned long long crash_base)
63 {
64
65 #ifndef CONFIG_NONSTATIC_KERNEL
66 if (crash_base != KDUMP_KERNELBASE)
67 printk("Crash kernel location must be 0x%x\n",
68 KDUMP_KERNELBASE);
69
70 return KDUMP_KERNELBASE;
71 #else
72 unsigned long long crash_base_align;
73
74 if (!crash_base) {
75 #ifdef CONFIG_PPC64
76 /*
77 * On the LPAR platform place the crash kernel to mid of
78 * RMA size (max. of 512MB) to ensure the crash kernel
79 * gets enough space to place itself and some stack to be
80 * in the first segment. At the same time normal kernel
81 * also get enough space to allocate memory for essential
82 * system resource in the first segment. Keep the crash
83 * kernel starts at 128MB offset on other platforms.
84 */
85 if (firmware_has_feature(FW_FEATURE_LPAR))
86 crash_base = min_t(u64, ppc64_rma_size / 2, SZ_512M);
87 else
88 crash_base = min_t(u64, ppc64_rma_size / 2, SZ_128M);
89 #else
90 crash_base = KDUMP_KERNELBASE;
91 #endif
92 }
93
94 crash_base_align = PAGE_ALIGN(crash_base);
95 if (crash_base != crash_base_align)
96 pr_warn("Crash kernel base must be aligned to 0x%lx\n", PAGE_SIZE);
97
98 return crash_base_align;
99 #endif
100 }
101
arch_reserve_crashkernel(void)102 void __init arch_reserve_crashkernel(void)
103 {
104 unsigned long long crash_size, crash_base, crash_end;
105 unsigned long long kernel_start, kernel_size;
106 unsigned long long total_mem_sz;
107 int ret;
108
109 total_mem_sz = memory_limit ? memory_limit : memblock_phys_mem_size();
110
111 /* use common parsing */
112 ret = parse_crashkernel(boot_command_line, total_mem_sz, &crash_size,
113 &crash_base, NULL, NULL);
114
115 if (ret)
116 return;
117
118 crash_base = get_crash_base(crash_base);
119 crash_end = crash_base + crash_size - 1;
120
121 kernel_start = __pa(_stext);
122 kernel_size = _end - _stext;
123
124 /* The crash region must not overlap the current kernel */
125 if ((kernel_start + kernel_size > crash_base) && (kernel_start <= crash_end)) {
126 pr_warn("Crash kernel can not overlap current kernel\n");
127 return;
128 }
129
130 reserve_crashkernel_generic(crash_size, crash_base, 0, false);
131 }
132
overlaps_crashkernel(unsigned long start,unsigned long size)133 int __init overlaps_crashkernel(unsigned long start, unsigned long size)
134 {
135 return (start + size) > crashk_res.start && start <= crashk_res.end;
136 }
137
138 /* Values we need to export to the second kernel via the device tree. */
139 static phys_addr_t kernel_end;
140 static phys_addr_t crashk_base;
141 static phys_addr_t crashk_size;
142 static unsigned long long mem_limit;
143
144 static struct property kernel_end_prop = {
145 .name = "linux,kernel-end",
146 .length = sizeof(phys_addr_t),
147 .value = &kernel_end,
148 };
149
150 static struct property crashk_base_prop = {
151 .name = "linux,crashkernel-base",
152 .length = sizeof(phys_addr_t),
153 .value = &crashk_base
154 };
155
156 static struct property crashk_size_prop = {
157 .name = "linux,crashkernel-size",
158 .length = sizeof(phys_addr_t),
159 .value = &crashk_size,
160 };
161
162 static struct property memory_limit_prop = {
163 .name = "linux,memory-limit",
164 .length = sizeof(unsigned long long),
165 .value = &mem_limit,
166 };
167
168 #define cpu_to_be_ulong __PASTE(cpu_to_be, BITS_PER_LONG)
169
export_crashk_values(struct device_node * node)170 static void __init export_crashk_values(struct device_node *node)
171 {
172 /* There might be existing crash kernel properties, but we can't
173 * be sure what's in them, so remove them. */
174 of_remove_property(node, of_find_property(node,
175 "linux,crashkernel-base", NULL));
176 of_remove_property(node, of_find_property(node,
177 "linux,crashkernel-size", NULL));
178
179 if (crashk_res.start != 0) {
180 crashk_base = cpu_to_be_ulong(crashk_res.start),
181 of_add_property(node, &crashk_base_prop);
182 crashk_size = cpu_to_be_ulong(resource_size(&crashk_res));
183 of_add_property(node, &crashk_size_prop);
184 }
185
186 /*
187 * memory_limit is required by the kexec-tools to limit the
188 * crash regions to the actual memory used.
189 */
190 mem_limit = cpu_to_be_ulong(memory_limit);
191 of_update_property(node, &memory_limit_prop);
192 }
193
kexec_setup(void)194 static int __init kexec_setup(void)
195 {
196 struct device_node *node;
197
198 node = of_find_node_by_path("/chosen");
199 if (!node)
200 return -ENOENT;
201
202 /* remove any stale properties so ours can be found */
203 of_remove_property(node, of_find_property(node, kernel_end_prop.name, NULL));
204
205 /* information needed by userspace when using default_machine_kexec */
206 kernel_end = cpu_to_be_ulong(__pa(_end));
207 of_add_property(node, &kernel_end_prop);
208
209 export_crashk_values(node);
210
211 of_node_put(node);
212 return 0;
213 }
214 late_initcall(kexec_setup);
215 #endif /* CONFIG_CRASH_RESERVE */
216