2 * PPC64 code to handle Linux booting another kernel.
4 * Copyright (C) 2004-2005, IBM Corp.
6 * Created by: Milton D Miller II
8 * This source code is licensed under the GNU General Public License,
9 * Version 2. See the file COPYING for more details.
13 #include <linux/kexec.h>
14 #include <linux/smp.h>
15 #include <linux/thread_info.h>
16 #include <linux/init_task.h>
17 #include <linux/errno.h>
20 #include <asm/current.h>
21 #include <asm/machdep.h>
22 #include <asm/cacheflush.h>
25 #include <asm/sections.h> /* _end */
28 #include <asm/hw_breakpoint.h>
30 int default_machine_kexec_prepare(struct kimage
*image
)
33 unsigned long begin
, end
; /* limits of segment */
34 unsigned long low
, high
; /* limits of blocked memory range */
35 struct device_node
*node
;
36 const unsigned long *basep
;
37 const unsigned int *sizep
;
39 if (!ppc_md
.hpte_clear_all
)
43 * Since we use the kernel fault handlers and paging code to
44 * handle the virtual mode, we must make sure no destination
45 * overlaps kernel static data or bss.
47 for (i
= 0; i
< image
->nr_segments
; i
++)
48 if (image
->segment
[i
].mem
< __pa(_end
))
52 * For non-LPAR, we absolutely can not overwrite the mmu hash
53 * table, since we are still using the bolted entries in it to
54 * do the copy. Check that here.
56 * It is safe if the end is below the start of the blocked
57 * region (end <= low), or if the beginning is after the
58 * end of the blocked region (begin >= high). Use the
59 * boolean identity !(a || b) === (!a && !b).
62 low
= __pa(htab_address
);
63 high
= low
+ htab_size_bytes
;
65 for (i
= 0; i
< image
->nr_segments
; i
++) {
66 begin
= image
->segment
[i
].mem
;
67 end
= begin
+ image
->segment
[i
].memsz
;
69 if ((begin
< high
) && (end
> low
))
74 /* We also should not overwrite the tce tables */
75 for (node
= of_find_node_by_type(NULL
, "pci"); node
!= NULL
;
76 node
= of_find_node_by_type(node
, "pci")) {
77 basep
= of_get_property(node
, "linux,tce-base", NULL
);
78 sizep
= of_get_property(node
, "linux,tce-size", NULL
);
79 if (basep
== NULL
|| sizep
== NULL
)
83 high
= low
+ (*sizep
);
85 for (i
= 0; i
< image
->nr_segments
; i
++) {
86 begin
= image
->segment
[i
].mem
;
87 end
= begin
+ image
->segment
[i
].memsz
;
89 if ((begin
< high
) && (end
> low
))
97 #define IND_FLAGS (IND_DESTINATION | IND_INDIRECTION | IND_DONE | IND_SOURCE)
99 static void copy_segments(unsigned long ind
)
107 * We rely on kexec_load to create a lists that properly
108 * initializes these pointers before they are used.
109 * We will still crash if the list is wrong, but at least
110 * the compiler will be quiet.
115 for (entry
= ind
; !(entry
& IND_DONE
); entry
= *ptr
++) {
116 addr
= __va(entry
& PAGE_MASK
);
118 switch (entry
& IND_FLAGS
) {
119 case IND_DESTINATION
:
122 case IND_INDIRECTION
:
126 copy_page(dest
, addr
);
132 void kexec_copy_flush(struct kimage
*image
)
134 long i
, nr_segments
= image
->nr_segments
;
135 struct kexec_segment ranges
[KEXEC_SEGMENT_MAX
];
137 /* save the ranges on the stack to efficiently flush the icache */
138 memcpy(ranges
, image
->segment
, sizeof(ranges
));
141 * After this call we may not use anything allocated in dynamic
142 * memory, including *image.
144 * Only globals and the stack are allowed.
146 copy_segments(image
->head
);
149 * we need to clear the icache for all dest pages sometime,
150 * including ones that were in place on the original copy
152 for (i
= 0; i
< nr_segments
; i
++)
153 flush_icache_range((unsigned long)__va(ranges
[i
].mem
),
154 (unsigned long)__va(ranges
[i
].mem
+ ranges
[i
].memsz
));
159 static int kexec_all_irq_disabled
= 0;
161 static void kexec_smp_down(void *arg
)
164 mb(); /* make sure our irqs are disabled before we say they are */
165 get_paca()->kexec_state
= KEXEC_STATE_IRQS_OFF
;
166 while(kexec_all_irq_disabled
== 0)
168 mb(); /* make sure all irqs are disabled before this */
169 hw_breakpoint_disable();
171 * Now every CPU has IRQs off, we can clear out any pending
172 * IPIs and be sure that no more will come in after this.
174 if (ppc_md
.kexec_cpu_down
)
175 ppc_md
.kexec_cpu_down(0, 1);
181 static void kexec_prepare_cpus_wait(int wait_state
)
183 int my_cpu
, i
, notified
=-1;
185 hw_breakpoint_disable();
187 /* Make sure each CPU has atleast made it to the state we need */
188 for_each_online_cpu(i
) {
192 while (paca
[i
].kexec_state
< wait_state
) {
195 printk( "kexec: waiting for cpu %d (physical"
196 " %d) to enter %i state\n",
197 i
, paca
[i
].hw_cpu_id
, wait_state
);
205 static void kexec_prepare_cpus(void)
208 smp_call_function(kexec_smp_down
, NULL
, /* wait */0);
210 mb(); /* make sure IRQs are disabled before we say they are */
211 get_paca()->kexec_state
= KEXEC_STATE_IRQS_OFF
;
213 kexec_prepare_cpus_wait(KEXEC_STATE_IRQS_OFF
);
214 /* we are sure every CPU has IRQs off at this point */
215 kexec_all_irq_disabled
= 1;
217 /* after we tell the others to go down */
218 if (ppc_md
.kexec_cpu_down
)
219 ppc_md
.kexec_cpu_down(0, 0);
221 /* Before removing MMU mapings make sure all CPUs have entered real mode */
222 kexec_prepare_cpus_wait(KEXEC_STATE_REAL_MODE
);
229 static void kexec_prepare_cpus(void)
232 * move the secondarys to us so that we can copy
233 * the new kernel 0-0x100 safely
235 * do this if kexec in setup.c ?
237 * We need to release the cpus if we are ever going from an
238 * UP to an SMP kernel.
241 if (ppc_md
.kexec_cpu_down
)
242 ppc_md
.kexec_cpu_down(0, 0);
249 * kexec thread structure and stack.
251 * We need to make sure that this is 16384-byte aligned due to the
252 * way process stacks are handled. It also must be statically allocated
253 * or allocated as part of the kimage, because everything else may be
254 * overwritten when we copy the kexec image. We piggyback on the
255 * "init_task" linker section here to statically allocate a stack.
257 * We could use a smaller stack if we don't care about anything using
258 * current, but that audit has not been performed.
260 static union thread_union kexec_stack __init_task_data
=
263 /* Our assembly helper, in kexec_stub.S */
264 extern NORET_TYPE
void kexec_sequence(void *newstack
, unsigned long start
,
265 void *image
, void *control
,
266 void (*clear_all
)(void)) ATTRIB_NORET
;
268 /* too late to fail here */
269 void default_machine_kexec(struct kimage
*image
)
271 /* prepare control code if any */
274 * If the kexec boot is the normal one, need to shutdown other cpus
275 * into our wait loop and quiesce interrupts.
276 * Otherwise, in the case of crashed mode (crashing_cpu >= 0),
277 * stopping other CPUs and collecting their pt_regs is done before
278 * using debugger IPI.
281 if (crashing_cpu
== -1)
282 kexec_prepare_cpus();
284 /* switch to a staticly allocated stack. Based on irq stack code.
285 * XXX: the task struct will likely be invalid once we do the copy!
287 kexec_stack
.thread_info
.task
= current_thread_info()->task
;
288 kexec_stack
.thread_info
.flags
= 0;
290 /* Some things are best done in assembly. Finding globals with
291 * a toc is easier in C, so pass in what we can.
293 kexec_sequence(&kexec_stack
, image
->start
, image
,
294 page_address(image
->control_code_page
),
295 ppc_md
.hpte_clear_all
);
299 /* Values we need to export to the second kernel via the device tree. */
300 static unsigned long htab_base
;
302 static struct property htab_base_prop
= {
303 .name
= "linux,htab-base",
304 .length
= sizeof(unsigned long),
308 static struct property htab_size_prop
= {
309 .name
= "linux,htab-size",
310 .length
= sizeof(unsigned long),
311 .value
= &htab_size_bytes
,
314 static int __init
export_htab_values(void)
316 struct device_node
*node
;
317 struct property
*prop
;
319 /* On machines with no htab htab_address is NULL */
323 node
= of_find_node_by_path("/chosen");
327 /* remove any stale propertys so ours can be found */
328 prop
= of_find_property(node
, htab_base_prop
.name
, NULL
);
330 prom_remove_property(node
, prop
);
331 prop
= of_find_property(node
, htab_size_prop
.name
, NULL
);
333 prom_remove_property(node
, prop
);
335 htab_base
= __pa(htab_address
);
336 prom_add_property(node
, &htab_base_prop
);
337 prom_add_property(node
, &htab_size_prop
);
342 late_initcall(export_htab_values
);