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eb39c880 MS |
1 | /* |
2 | * Firmware Assisted dump: A robust mechanism to get reliable kernel crash | |
3 | * dump with assistance from firmware. This approach does not use kexec, | |
4 | * instead firmware assists in booting the kdump kernel while preserving | |
5 | * memory contents. The most of the code implementation has been adapted | |
6 | * from phyp assisted dump implementation written by Linas Vepstas and | |
7 | * Manish Ahuja | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License, or | |
12 | * (at your option) any later version. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License | |
20 | * along with this program; if not, write to the Free Software | |
21 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
22 | * | |
23 | * Copyright 2011 IBM Corporation | |
24 | * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> | |
25 | */ | |
26 | ||
27 | #undef DEBUG | |
28 | #define pr_fmt(fmt) "fadump: " fmt | |
29 | ||
30 | #include <linux/string.h> | |
31 | #include <linux/memblock.h> | |
32 | ||
33 | #include <asm/page.h> | |
34 | #include <asm/prom.h> | |
35 | #include <asm/rtas.h> | |
36 | #include <asm/fadump.h> | |
37 | ||
38 | static struct fw_dump fw_dump; | |
39 | ||
40 | /* Scan the Firmware Assisted dump configuration details. */ | |
41 | int __init early_init_dt_scan_fw_dump(unsigned long node, | |
42 | const char *uname, int depth, void *data) | |
43 | { | |
44 | __be32 *sections; | |
45 | int i, num_sections; | |
46 | unsigned long size; | |
47 | const int *token; | |
48 | ||
49 | if (depth != 1 || strcmp(uname, "rtas") != 0) | |
50 | return 0; | |
51 | ||
52 | /* | |
53 | * Check if Firmware Assisted dump is supported. if yes, check | |
54 | * if dump has been initiated on last reboot. | |
55 | */ | |
56 | token = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump", NULL); | |
57 | if (!token) | |
58 | return 0; | |
59 | ||
60 | fw_dump.fadump_supported = 1; | |
61 | fw_dump.ibm_configure_kernel_dump = *token; | |
62 | ||
63 | /* | |
64 | * The 'ibm,kernel-dump' rtas node is present only if there is | |
65 | * dump data waiting for us. | |
66 | */ | |
67 | if (of_get_flat_dt_prop(node, "ibm,kernel-dump", NULL)) | |
68 | fw_dump.dump_active = 1; | |
69 | ||
70 | /* Get the sizes required to store dump data for the firmware provided | |
71 | * dump sections. | |
72 | * For each dump section type supported, a 32bit cell which defines | |
73 | * the ID of a supported section followed by two 32 bit cells which | |
74 | * gives teh size of the section in bytes. | |
75 | */ | |
76 | sections = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump-sizes", | |
77 | &size); | |
78 | ||
79 | if (!sections) | |
80 | return 0; | |
81 | ||
82 | num_sections = size / (3 * sizeof(u32)); | |
83 | ||
84 | for (i = 0; i < num_sections; i++, sections += 3) { | |
85 | u32 type = (u32)of_read_number(sections, 1); | |
86 | ||
87 | switch (type) { | |
88 | case FADUMP_CPU_STATE_DATA: | |
89 | fw_dump.cpu_state_data_size = | |
90 | of_read_ulong(§ions[1], 2); | |
91 | break; | |
92 | case FADUMP_HPTE_REGION: | |
93 | fw_dump.hpte_region_size = | |
94 | of_read_ulong(§ions[1], 2); | |
95 | break; | |
96 | } | |
97 | } | |
98 | return 1; | |
99 | } | |
100 | ||
101 | /** | |
102 | * fadump_calculate_reserve_size(): reserve variable boot area 5% of System RAM | |
103 | * | |
104 | * Function to find the largest memory size we need to reserve during early | |
105 | * boot process. This will be the size of the memory that is required for a | |
106 | * kernel to boot successfully. | |
107 | * | |
108 | * This function has been taken from phyp-assisted dump feature implementation. | |
109 | * | |
110 | * returns larger of 256MB or 5% rounded down to multiples of 256MB. | |
111 | * | |
112 | * TODO: Come up with better approach to find out more accurate memory size | |
113 | * that is required for a kernel to boot successfully. | |
114 | * | |
115 | */ | |
116 | static inline unsigned long fadump_calculate_reserve_size(void) | |
117 | { | |
118 | unsigned long size; | |
119 | ||
120 | /* | |
121 | * Check if the size is specified through fadump_reserve_mem= cmdline | |
122 | * option. If yes, then use that. | |
123 | */ | |
124 | if (fw_dump.reserve_bootvar) | |
125 | return fw_dump.reserve_bootvar; | |
126 | ||
127 | /* divide by 20 to get 5% of value */ | |
128 | size = memblock_end_of_DRAM() / 20; | |
129 | ||
130 | /* round it down in multiples of 256 */ | |
131 | size = size & ~0x0FFFFFFFUL; | |
132 | ||
133 | /* Truncate to memory_limit. We don't want to over reserve the memory.*/ | |
134 | if (memory_limit && size > memory_limit) | |
135 | size = memory_limit; | |
136 | ||
137 | return (size > MIN_BOOT_MEM ? size : MIN_BOOT_MEM); | |
138 | } | |
139 | ||
140 | /* | |
141 | * Calculate the total memory size required to be reserved for | |
142 | * firmware-assisted dump registration. | |
143 | */ | |
144 | static unsigned long get_fadump_area_size(void) | |
145 | { | |
146 | unsigned long size = 0; | |
147 | ||
148 | size += fw_dump.cpu_state_data_size; | |
149 | size += fw_dump.hpte_region_size; | |
150 | size += fw_dump.boot_memory_size; | |
151 | ||
152 | size = PAGE_ALIGN(size); | |
153 | return size; | |
154 | } | |
155 | ||
156 | int __init fadump_reserve_mem(void) | |
157 | { | |
158 | unsigned long base, size, memory_boundary; | |
159 | ||
160 | if (!fw_dump.fadump_enabled) | |
161 | return 0; | |
162 | ||
163 | if (!fw_dump.fadump_supported) { | |
164 | printk(KERN_INFO "Firmware-assisted dump is not supported on" | |
165 | " this hardware\n"); | |
166 | fw_dump.fadump_enabled = 0; | |
167 | return 0; | |
168 | } | |
169 | /* Initialize boot memory size */ | |
170 | fw_dump.boot_memory_size = fadump_calculate_reserve_size(); | |
171 | ||
172 | /* | |
173 | * Calculate the memory boundary. | |
174 | * If memory_limit is less than actual memory boundary then reserve | |
175 | * the memory for fadump beyond the memory_limit and adjust the | |
176 | * memory_limit accordingly, so that the running kernel can run with | |
177 | * specified memory_limit. | |
178 | */ | |
179 | if (memory_limit && memory_limit < memblock_end_of_DRAM()) { | |
180 | size = get_fadump_area_size(); | |
181 | if ((memory_limit + size) < memblock_end_of_DRAM()) | |
182 | memory_limit += size; | |
183 | else | |
184 | memory_limit = memblock_end_of_DRAM(); | |
185 | printk(KERN_INFO "Adjusted memory_limit for firmware-assisted" | |
186 | " dump, now %#016llx\n", | |
187 | (unsigned long long)memory_limit); | |
188 | } | |
189 | if (memory_limit) | |
190 | memory_boundary = memory_limit; | |
191 | else | |
192 | memory_boundary = memblock_end_of_DRAM(); | |
193 | ||
194 | if (fw_dump.dump_active) { | |
195 | printk(KERN_INFO "Firmware-assisted dump is active.\n"); | |
196 | /* | |
197 | * If last boot has crashed then reserve all the memory | |
198 | * above boot_memory_size so that we don't touch it until | |
199 | * dump is written to disk by userspace tool. This memory | |
200 | * will be released for general use once the dump is saved. | |
201 | */ | |
202 | base = fw_dump.boot_memory_size; | |
203 | size = memory_boundary - base; | |
204 | memblock_reserve(base, size); | |
205 | printk(KERN_INFO "Reserved %ldMB of memory at %ldMB " | |
206 | "for saving crash dump\n", | |
207 | (unsigned long)(size >> 20), | |
208 | (unsigned long)(base >> 20)); | |
209 | } else { | |
210 | /* Reserve the memory at the top of memory. */ | |
211 | size = get_fadump_area_size(); | |
212 | base = memory_boundary - size; | |
213 | memblock_reserve(base, size); | |
214 | printk(KERN_INFO "Reserved %ldMB of memory at %ldMB " | |
215 | "for firmware-assisted dump\n", | |
216 | (unsigned long)(size >> 20), | |
217 | (unsigned long)(base >> 20)); | |
218 | } | |
219 | fw_dump.reserve_dump_area_start = base; | |
220 | fw_dump.reserve_dump_area_size = size; | |
221 | return 1; | |
222 | } | |
223 | ||
224 | /* Look for fadump= cmdline option. */ | |
225 | static int __init early_fadump_param(char *p) | |
226 | { | |
227 | if (!p) | |
228 | return 1; | |
229 | ||
230 | if (strncmp(p, "on", 2) == 0) | |
231 | fw_dump.fadump_enabled = 1; | |
232 | else if (strncmp(p, "off", 3) == 0) | |
233 | fw_dump.fadump_enabled = 0; | |
234 | ||
235 | return 0; | |
236 | } | |
237 | early_param("fadump", early_fadump_param); | |
238 | ||
239 | /* Look for fadump_reserve_mem= cmdline option */ | |
240 | static int __init early_fadump_reserve_mem(char *p) | |
241 | { | |
242 | if (p) | |
243 | fw_dump.reserve_bootvar = memparse(p, &p); | |
244 | return 0; | |
245 | } | |
246 | early_param("fadump_reserve_mem", early_fadump_reserve_mem); |