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fce0d574 S |
1 | /* |
2 | * machine_kexec.c - handle transition of Linux booting another kernel | |
3 | * | |
4 | * Copyright (C) 2004-2005, IBM Corp. | |
5 | * | |
6 | * Created by: Milton D Miller II | |
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 | ||
13 | #include <linux/cpumask.h> | |
14 | #include <linux/kexec.h> | |
15 | #include <linux/smp.h> | |
16 | #include <linux/thread_info.h> | |
17 | #include <linux/errno.h> | |
18 | ||
19 | #include <asm/page.h> | |
20 | #include <asm/current.h> | |
21 | #include <asm/machdep.h> | |
22 | #include <asm/cacheflush.h> | |
23 | #include <asm/paca.h> | |
24 | #include <asm/mmu.h> | |
25 | #include <asm/sections.h> /* _end */ | |
26 | #include <asm/prom.h> | |
2249ca9d | 27 | #include <asm/smp.h> |
fce0d574 S |
28 | |
29 | #define HASH_GROUP_SIZE 0x80 /* size of each hash group, asm/mmu.h */ | |
30 | ||
31 | /* Have this around till we move it into crash specific file */ | |
32 | note_buf_t crash_notes[NR_CPUS]; | |
33 | ||
34 | /* Dummy for now. Not sure if we need to have a crash shutdown in here | |
35 | * and if what it will achieve. Letting it be now to compile the code | |
36 | * in generic kexec environment | |
37 | */ | |
6e274d14 | 38 | void machine_crash_shutdown(struct pt_regs *regs) |
fce0d574 S |
39 | { |
40 | /* do nothing right now */ | |
41 | /* smp_relase_cpus() if we want smp on panic kernel */ | |
42 | /* cpu_irq_down to isolate us until we are ready */ | |
43 | } | |
44 | ||
45 | int machine_kexec_prepare(struct kimage *image) | |
46 | { | |
47 | int i; | |
48 | unsigned long begin, end; /* limits of segment */ | |
49 | unsigned long low, high; /* limits of blocked memory range */ | |
50 | struct device_node *node; | |
51 | unsigned long *basep; | |
52 | unsigned int *sizep; | |
53 | ||
54 | if (!ppc_md.hpte_clear_all) | |
55 | return -ENOENT; | |
56 | ||
57 | /* | |
58 | * Since we use the kernel fault handlers and paging code to | |
59 | * handle the virtual mode, we must make sure no destination | |
60 | * overlaps kernel static data or bss. | |
61 | */ | |
72414d3f | 62 | for (i = 0; i < image->nr_segments; i++) |
fce0d574 S |
63 | if (image->segment[i].mem < __pa(_end)) |
64 | return -ETXTBSY; | |
65 | ||
66 | /* | |
67 | * For non-LPAR, we absolutely can not overwrite the mmu hash | |
68 | * table, since we are still using the bolted entries in it to | |
69 | * do the copy. Check that here. | |
70 | * | |
71 | * It is safe if the end is below the start of the blocked | |
72 | * region (end <= low), or if the beginning is after the | |
73 | * end of the blocked region (begin >= high). Use the | |
74 | * boolean identity !(a || b) === (!a && !b). | |
75 | */ | |
76 | if (htab_address) { | |
77 | low = __pa(htab_address); | |
78 | high = low + (htab_hash_mask + 1) * HASH_GROUP_SIZE; | |
79 | ||
72414d3f | 80 | for (i = 0; i < image->nr_segments; i++) { |
fce0d574 S |
81 | begin = image->segment[i].mem; |
82 | end = begin + image->segment[i].memsz; | |
83 | ||
84 | if ((begin < high) && (end > low)) | |
85 | return -ETXTBSY; | |
86 | } | |
87 | } | |
88 | ||
89 | /* We also should not overwrite the tce tables */ | |
90 | for (node = of_find_node_by_type(NULL, "pci"); node != NULL; | |
91 | node = of_find_node_by_type(node, "pci")) { | |
92 | basep = (unsigned long *)get_property(node, "linux,tce-base", | |
93 | NULL); | |
94 | sizep = (unsigned int *)get_property(node, "linux,tce-size", | |
95 | NULL); | |
96 | if (basep == NULL || sizep == NULL) | |
97 | continue; | |
98 | ||
99 | low = *basep; | |
100 | high = low + (*sizep); | |
101 | ||
72414d3f | 102 | for (i = 0; i < image->nr_segments; i++) { |
fce0d574 S |
103 | begin = image->segment[i].mem; |
104 | end = begin + image->segment[i].memsz; | |
105 | ||
106 | if ((begin < high) && (end > low)) | |
107 | return -ETXTBSY; | |
108 | } | |
109 | } | |
110 | ||
111 | return 0; | |
112 | } | |
113 | ||
114 | void machine_kexec_cleanup(struct kimage *image) | |
115 | { | |
116 | /* we do nothing in prepare that needs to be undone */ | |
117 | } | |
118 | ||
119 | #define IND_FLAGS (IND_DESTINATION | IND_INDIRECTION | IND_DONE | IND_SOURCE) | |
120 | ||
121 | static void copy_segments(unsigned long ind) | |
122 | { | |
123 | unsigned long entry; | |
124 | unsigned long *ptr; | |
125 | void *dest; | |
126 | void *addr; | |
127 | ||
128 | /* | |
129 | * We rely on kexec_load to create a lists that properly | |
130 | * initializes these pointers before they are used. | |
131 | * We will still crash if the list is wrong, but at least | |
132 | * the compiler will be quiet. | |
133 | */ | |
134 | ptr = NULL; | |
135 | dest = NULL; | |
136 | ||
137 | for (entry = ind; !(entry & IND_DONE); entry = *ptr++) { | |
138 | addr = __va(entry & PAGE_MASK); | |
139 | ||
140 | switch (entry & IND_FLAGS) { | |
141 | case IND_DESTINATION: | |
142 | dest = addr; | |
143 | break; | |
144 | case IND_INDIRECTION: | |
145 | ptr = addr; | |
146 | break; | |
147 | case IND_SOURCE: | |
148 | copy_page(dest, addr); | |
149 | dest += PAGE_SIZE; | |
150 | } | |
151 | } | |
152 | } | |
153 | ||
154 | void kexec_copy_flush(struct kimage *image) | |
155 | { | |
156 | long i, nr_segments = image->nr_segments; | |
157 | struct kexec_segment ranges[KEXEC_SEGMENT_MAX]; | |
158 | ||
159 | /* save the ranges on the stack to efficiently flush the icache */ | |
160 | memcpy(ranges, image->segment, sizeof(ranges)); | |
161 | ||
162 | /* | |
163 | * After this call we may not use anything allocated in dynamic | |
164 | * memory, including *image. | |
165 | * | |
166 | * Only globals and the stack are allowed. | |
167 | */ | |
168 | copy_segments(image->head); | |
169 | ||
170 | /* | |
171 | * we need to clear the icache for all dest pages sometime, | |
172 | * including ones that were in place on the original copy | |
173 | */ | |
174 | for (i = 0; i < nr_segments; i++) | |
175 | flush_icache_range(ranges[i].mem + KERNELBASE, | |
176 | ranges[i].mem + KERNELBASE + | |
177 | ranges[i].memsz); | |
178 | } | |
179 | ||
180 | #ifdef CONFIG_SMP | |
181 | ||
182 | /* FIXME: we should schedule this function to be called on all cpus based | |
183 | * on calling the interrupts, but we would like to call it off irq level | |
184 | * so that the interrupt controller is clean. | |
185 | */ | |
186 | void kexec_smp_down(void *arg) | |
187 | { | |
188 | if (ppc_md.cpu_irq_down) | |
6d22d85a | 189 | ppc_md.cpu_irq_down(1); |
fce0d574 S |
190 | |
191 | local_irq_disable(); | |
192 | kexec_smp_wait(); | |
193 | /* NOTREACHED */ | |
194 | } | |
195 | ||
196 | static void kexec_prepare_cpus(void) | |
197 | { | |
198 | int my_cpu, i, notified=-1; | |
199 | ||
200 | smp_call_function(kexec_smp_down, NULL, 0, /* wait */0); | |
201 | my_cpu = get_cpu(); | |
202 | ||
203 | /* check the others cpus are now down (via paca hw cpu id == -1) */ | |
204 | for (i=0; i < NR_CPUS; i++) { | |
205 | if (i == my_cpu) | |
206 | continue; | |
207 | ||
208 | while (paca[i].hw_cpu_id != -1) { | |
b3ca8093 | 209 | barrier(); |
fce0d574 S |
210 | if (!cpu_possible(i)) { |
211 | printk("kexec: cpu %d hw_cpu_id %d is not" | |
212 | " possible, ignoring\n", | |
213 | i, paca[i].hw_cpu_id); | |
214 | break; | |
215 | } | |
216 | if (!cpu_online(i)) { | |
217 | /* Fixme: this can be spinning in | |
218 | * pSeries_secondary_wait with a paca | |
219 | * waiting for it to go online. | |
220 | */ | |
221 | printk("kexec: cpu %d hw_cpu_id %d is not" | |
222 | " online, ignoring\n", | |
223 | i, paca[i].hw_cpu_id); | |
224 | break; | |
225 | } | |
226 | if (i != notified) { | |
227 | printk( "kexec: waiting for cpu %d (physical" | |
228 | " %d) to go down\n", | |
229 | i, paca[i].hw_cpu_id); | |
230 | notified = i; | |
231 | } | |
232 | } | |
233 | } | |
234 | ||
235 | /* after we tell the others to go down */ | |
236 | if (ppc_md.cpu_irq_down) | |
6d22d85a | 237 | ppc_md.cpu_irq_down(0); |
fce0d574 S |
238 | |
239 | put_cpu(); | |
240 | ||
241 | local_irq_disable(); | |
242 | } | |
243 | ||
244 | #else /* ! SMP */ | |
245 | ||
246 | static void kexec_prepare_cpus(void) | |
247 | { | |
248 | /* | |
249 | * move the secondarys to us so that we can copy | |
250 | * the new kernel 0-0x100 safely | |
251 | * | |
252 | * do this if kexec in setup.c ? | |
75eedfed OJ |
253 | * |
254 | * We need to release the cpus if we are ever going from an | |
255 | * UP to an SMP kernel. | |
fce0d574 | 256 | */ |
75eedfed | 257 | smp_release_cpus(); |
fce0d574 | 258 | if (ppc_md.cpu_irq_down) |
6d22d85a | 259 | ppc_md.cpu_irq_down(0); |
fce0d574 S |
260 | local_irq_disable(); |
261 | } | |
262 | ||
263 | #endif /* SMP */ | |
264 | ||
265 | /* | |
266 | * kexec thread structure and stack. | |
267 | * | |
268 | * We need to make sure that this is 16384-byte aligned due to the | |
269 | * way process stacks are handled. It also must be statically allocated | |
270 | * or allocated as part of the kimage, because everything else may be | |
271 | * overwritten when we copy the kexec image. We piggyback on the | |
272 | * "init_task" linker section here to statically allocate a stack. | |
273 | * | |
274 | * We could use a smaller stack if we don't care about anything using | |
275 | * current, but that audit has not been performed. | |
276 | */ | |
277 | union thread_union kexec_stack | |
278 | __attribute__((__section__(".data.init_task"))) = { }; | |
279 | ||
280 | /* Our assembly helper, in kexec_stub.S */ | |
281 | extern NORET_TYPE void kexec_sequence(void *newstack, unsigned long start, | |
72414d3f MS |
282 | void *image, void *control, |
283 | void (*clear_all)(void)) ATTRIB_NORET; | |
fce0d574 S |
284 | |
285 | /* too late to fail here */ | |
286 | void machine_kexec(struct kimage *image) | |
287 | { | |
288 | ||
289 | /* prepare control code if any */ | |
290 | ||
291 | /* shutdown other cpus into our wait loop and quiesce interrupts */ | |
292 | kexec_prepare_cpus(); | |
293 | ||
294 | /* switch to a staticly allocated stack. Based on irq stack code. | |
295 | * XXX: the task struct will likely be invalid once we do the copy! | |
296 | */ | |
297 | kexec_stack.thread_info.task = current_thread_info()->task; | |
298 | kexec_stack.thread_info.flags = 0; | |
299 | ||
300 | /* Some things are best done in assembly. Finding globals with | |
301 | * a toc is easier in C, so pass in what we can. | |
302 | */ | |
303 | kexec_sequence(&kexec_stack, image->start, image, | |
304 | page_address(image->control_code_page), | |
305 | ppc_md.hpte_clear_all); | |
306 | /* NOTREACHED */ | |
307 | } |