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>
18 #include <linux/kernel.h>
19 #include <linux/cpu.h>
20 #include <linux/hardirq.h>
23 #include <asm/current.h>
24 #include <asm/machdep.h>
25 #include <asm/cacheflush.h>
26 #include <asm/firmware.h>
29 #include <asm/sections.h> /* _end */
32 #include <asm/hw_breakpoint.h>
33 #include <asm/asm-prototypes.h>
35 int default_machine_kexec_prepare(struct kimage
*image
)
38 unsigned long begin
, end
; /* limits of segment */
39 unsigned long low
, high
; /* limits of blocked memory range */
40 struct device_node
*node
;
41 const unsigned long *basep
;
42 const unsigned int *sizep
;
45 * Since we use the kernel fault handlers and paging code to
46 * handle the virtual mode, we must make sure no destination
47 * overlaps kernel static data or bss.
49 for (i
= 0; i
< image
->nr_segments
; i
++)
50 if (image
->segment
[i
].mem
< __pa(_end
))
53 /* We also should not overwrite the tce tables */
54 for_each_node_by_type(node
, "pci") {
55 basep
= of_get_property(node
, "linux,tce-base", NULL
);
56 sizep
= of_get_property(node
, "linux,tce-size", NULL
);
57 if (basep
== NULL
|| sizep
== NULL
)
61 high
= low
+ (*sizep
);
63 for (i
= 0; i
< image
->nr_segments
; i
++) {
64 begin
= image
->segment
[i
].mem
;
65 end
= begin
+ image
->segment
[i
].memsz
;
67 if ((begin
< high
) && (end
> low
))
75 static void copy_segments(unsigned long ind
)
83 * We rely on kexec_load to create a lists that properly
84 * initializes these pointers before they are used.
85 * We will still crash if the list is wrong, but at least
86 * the compiler will be quiet.
91 for (entry
= ind
; !(entry
& IND_DONE
); entry
= *ptr
++) {
92 addr
= __va(entry
& PAGE_MASK
);
94 switch (entry
& IND_FLAGS
) {
102 copy_page(dest
, addr
);
108 void kexec_copy_flush(struct kimage
*image
)
110 long i
, nr_segments
= image
->nr_segments
;
111 struct kexec_segment ranges
[KEXEC_SEGMENT_MAX
];
113 /* save the ranges on the stack to efficiently flush the icache */
114 memcpy(ranges
, image
->segment
, sizeof(ranges
));
117 * After this call we may not use anything allocated in dynamic
118 * memory, including *image.
120 * Only globals and the stack are allowed.
122 copy_segments(image
->head
);
125 * we need to clear the icache for all dest pages sometime,
126 * including ones that were in place on the original copy
128 for (i
= 0; i
< nr_segments
; i
++)
129 flush_icache_range((unsigned long)__va(ranges
[i
].mem
),
130 (unsigned long)__va(ranges
[i
].mem
+ ranges
[i
].memsz
));
135 static int kexec_all_irq_disabled
= 0;
137 static void kexec_smp_down(void *arg
)
142 mb(); /* make sure our irqs are disabled before we say they are */
143 get_paca()->kexec_state
= KEXEC_STATE_IRQS_OFF
;
144 while(kexec_all_irq_disabled
== 0)
146 mb(); /* make sure all irqs are disabled before this */
147 hw_breakpoint_disable();
149 * Now every CPU has IRQs off, we can clear out any pending
150 * IPIs and be sure that no more will come in after this.
152 if (ppc_md
.kexec_cpu_down
)
153 ppc_md
.kexec_cpu_down(0, 1);
159 static void kexec_prepare_cpus_wait(int wait_state
)
161 int my_cpu
, i
, notified
=-1;
163 hw_breakpoint_disable();
165 /* Make sure each CPU has at least made it to the state we need.
167 * FIXME: There is a (slim) chance of a problem if not all of the CPUs
168 * are correctly onlined. If somehow we start a CPU on boot with RTAS
169 * start-cpu, but somehow that CPU doesn't write callin_cpu_map[] in
170 * time, the boot CPU will timeout. If it does eventually execute
171 * stuff, the secondary will start up (paca[].cpu_start was written) and
172 * get into a peculiar state. If the platform supports
173 * smp_ops->take_timebase(), the secondary CPU will probably be spinning
174 * in there. If not (i.e. pseries), the secondary will continue on and
175 * try to online itself/idle/etc. If it survives that, we need to find
176 * these possible-but-not-online-but-should-be CPUs and chaperone them
177 * into kexec_smp_wait().
179 for_each_online_cpu(i
) {
183 while (paca
[i
].kexec_state
< wait_state
) {
186 printk(KERN_INFO
"kexec: waiting for cpu %d "
187 "(physical %d) to enter %i state\n",
188 i
, paca
[i
].hw_cpu_id
, wait_state
);
197 * We need to make sure each present CPU is online. The next kernel will scan
198 * the device tree and assume primary threads are online and query secondary
199 * threads via RTAS to online them if required. If we don't online primary
200 * threads, they will be stuck. However, we also online secondary threads as we
201 * may be using 'cede offline'. In this case RTAS doesn't see the secondary
202 * threads as offline -- and again, these CPUs will be stuck.
204 * So, we online all CPUs that should be running, including secondary threads.
206 static void wake_offline_cpus(void)
210 for_each_present_cpu(cpu
) {
211 if (!cpu_online(cpu
)) {
212 printk(KERN_INFO
"kexec: Waking offline cpu %d.\n",
214 WARN_ON(cpu_up(cpu
));
219 static void kexec_prepare_cpus(void)
222 smp_call_function(kexec_smp_down
, NULL
, /* wait */0);
226 mb(); /* make sure IRQs are disabled before we say they are */
227 get_paca()->kexec_state
= KEXEC_STATE_IRQS_OFF
;
229 kexec_prepare_cpus_wait(KEXEC_STATE_IRQS_OFF
);
230 /* we are sure every CPU has IRQs off at this point */
231 kexec_all_irq_disabled
= 1;
233 /* after we tell the others to go down */
234 if (ppc_md
.kexec_cpu_down
)
235 ppc_md
.kexec_cpu_down(0, 0);
238 * Before removing MMU mappings make sure all CPUs have entered real
241 kexec_prepare_cpus_wait(KEXEC_STATE_REAL_MODE
);
248 static void kexec_prepare_cpus(void)
251 * move the secondarys to us so that we can copy
252 * the new kernel 0-0x100 safely
254 * do this if kexec in setup.c ?
256 * We need to release the cpus if we are ever going from an
257 * UP to an SMP kernel.
260 if (ppc_md
.kexec_cpu_down
)
261 ppc_md
.kexec_cpu_down(0, 0);
269 * kexec thread structure and stack.
271 * We need to make sure that this is 16384-byte aligned due to the
272 * way process stacks are handled. It also must be statically allocated
273 * or allocated as part of the kimage, because everything else may be
274 * overwritten when we copy the kexec image. We piggyback on the
275 * "init_task" linker section here to statically allocate a stack.
277 * We could use a smaller stack if we don't care about anything using
278 * current, but that audit has not been performed.
280 static union thread_union kexec_stack __init_task_data
=
284 * For similar reasons to the stack above, the kexecing CPU needs to be on a
285 * static PACA; we switch to kexec_paca.
287 struct paca_struct kexec_paca
;
289 /* Our assembly helper, in misc_64.S */
290 extern void kexec_sequence(void *newstack
, unsigned long start
,
291 void *image
, void *control
,
292 void (*clear_all
)(void),
293 bool copy_with_mmu_off
) __noreturn
;
295 /* too late to fail here */
296 void default_machine_kexec(struct kimage
*image
)
298 bool copy_with_mmu_off
;
300 /* prepare control code if any */
303 * If the kexec boot is the normal one, need to shutdown other cpus
304 * into our wait loop and quiesce interrupts.
305 * Otherwise, in the case of crashed mode (crashing_cpu >= 0),
306 * stopping other CPUs and collecting their pt_regs is done before
307 * using debugger IPI.
310 if (!kdump_in_progress())
311 kexec_prepare_cpus();
313 printk("kexec: Starting switchover sequence.\n");
315 /* switch to a staticly allocated stack. Based on irq stack code.
316 * We setup preempt_count to avoid using VMX in memcpy.
317 * XXX: the task struct will likely be invalid once we do the copy!
319 kexec_stack
.thread_info
.task
= current_thread_info()->task
;
320 kexec_stack
.thread_info
.flags
= 0;
321 kexec_stack
.thread_info
.preempt_count
= HARDIRQ_OFFSET
;
322 kexec_stack
.thread_info
.cpu
= current_thread_info()->cpu
;
324 /* We need a static PACA, too; copy this CPU's PACA over and switch to
325 * it. Also poison per_cpu_offset to catch anyone using non-static
328 memcpy(&kexec_paca
, get_paca(), sizeof(struct paca_struct
));
329 kexec_paca
.data_offset
= 0xedeaddeadeeeeeeeUL
;
330 paca
= (struct paca_struct
*)RELOC_HIDE(&kexec_paca
, 0) -
331 kexec_paca
.paca_index
;
332 setup_paca(&kexec_paca
);
334 /* XXX: If anyone does 'dynamic lppacas' this will also need to be
335 * switched to a static version!
338 * On Book3S, the copy must happen with the MMU off if we are either
339 * using Radix page tables or we are not in an LPAR since we can
340 * overwrite the page tables while copying.
342 * In an LPAR, we keep the MMU on otherwise we can't access beyond
343 * the RMA. On BookE there is no real MMU off mode, so we have to
344 * keep it enabled as well (but then we have bolted TLB entries).
346 #ifdef CONFIG_PPC_BOOK3E
347 copy_with_mmu_off
= false;
349 copy_with_mmu_off
= radix_enabled() ||
350 !(firmware_has_feature(FW_FEATURE_LPAR
) ||
351 firmware_has_feature(FW_FEATURE_PS3_LV1
));
354 /* Some things are best done in assembly. Finding globals with
355 * a toc is easier in C, so pass in what we can.
357 kexec_sequence(&kexec_stack
, image
->start
, image
,
358 page_address(image
->control_code_page
),
359 mmu_cleanup_all
, copy_with_mmu_off
);
363 #ifdef CONFIG_PPC_STD_MMU_64
364 /* Values we need to export to the second kernel via the device tree. */
365 static unsigned long htab_base
;
366 static unsigned long htab_size
;
368 static struct property htab_base_prop
= {
369 .name
= "linux,htab-base",
370 .length
= sizeof(unsigned long),
374 static struct property htab_size_prop
= {
375 .name
= "linux,htab-size",
376 .length
= sizeof(unsigned long),
380 static int __init
export_htab_values(void)
382 struct device_node
*node
;
384 /* On machines with no htab htab_address is NULL */
388 node
= of_find_node_by_path("/chosen");
392 /* remove any stale propertys so ours can be found */
393 of_remove_property(node
, of_find_property(node
, htab_base_prop
.name
, NULL
));
394 of_remove_property(node
, of_find_property(node
, htab_size_prop
.name
, NULL
));
396 htab_base
= cpu_to_be64(__pa(htab_address
));
397 of_add_property(node
, &htab_base_prop
);
398 htab_size
= cpu_to_be64(htab_size_bytes
);
399 of_add_property(node
, &htab_size_prop
);
404 late_initcall(export_htab_values
);
405 #endif /* CONFIG_PPC_STD_MMU_64 */