[linux-2.6-block.git] / arch / powerpc / kernel / machine_kexec_64.c

/*
 * PPC64 code to handle Linux booting another kernel.
 *
 * Copyright (C) 2004-2005, IBM Corp.
 *
 * Created by: Milton D Miller II
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 */


#include <linux/kexec.h>
#include <linux/smp.h>
#include <linux/thread_info.h>
#include <linux/init_task.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/cpu.h>
#include <linux/hardirq.h>

#include <asm/page.h>
#include <asm/current.h>
#include <asm/machdep.h>
#include <asm/cacheflush.h>
#include <asm/paca.h>
#include <asm/mmu.h>
#include <asm/sections.h>	/* _end */
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/hw_breakpoint.h>

int default_machine_kexec_prepare(struct kimage *image)
{
	int i;
	unsigned long begin, end;	/* limits of segment */
	unsigned long low, high;	/* limits of blocked memory range */
	struct device_node *node;
	const unsigned long *basep;
	const unsigned int *sizep;

	if (!ppc_md.hpte_clear_all)
		return -ENOENT;

	/*
	 * Since we use the kernel fault handlers and paging code to
	 * handle the virtual mode, we must make sure no destination
	 * overlaps kernel static data or bss.
	 */
	for (i = 0; i < image->nr_segments; i++)
		if (image->segment[i].mem < __pa(_end))
			return -ETXTBSY;

	/*
	 * For non-LPAR, we absolutely can not overwrite the mmu hash
	 * table, since we are still using the bolted entries in it to
	 * do the copy.  Check that here.
	 *
	 * It is safe if the end is below the start of the blocked
	 * region (end <= low), or if the beginning is after the
	 * end of the blocked region (begin >= high).  Use the
	 * boolean identity !(a || b)  === (!a && !b).
	 */
	if (htab_address) {
		low = __pa(htab_address);
		high = low + htab_size_bytes;

		for (i = 0; i < image->nr_segments; i++) {
			begin = image->segment[i].mem;
			end = begin + image->segment[i].memsz;

			if ((begin < high) && (end > low))
				return -ETXTBSY;
		}
	}

	/* We also should not overwrite the tce tables */
	for_each_node_by_type(node, "pci") {
		basep = of_get_property(node, "linux,tce-base", NULL);
		sizep = of_get_property(node, "linux,tce-size", NULL);
		if (basep == NULL || sizep == NULL)
			continue;

		low = *basep;
		high = low + (*sizep);

		for (i = 0; i < image->nr_segments; i++) {
			begin = image->segment[i].mem;
			end = begin + image->segment[i].memsz;

			if ((begin < high) && (end > low))
				return -ETXTBSY;
		}
	}

	return 0;
}

#define IND_FLAGS (IND_DESTINATION | IND_INDIRECTION | IND_DONE | IND_SOURCE)

static void copy_segments(unsigned long ind)
{
	unsigned long entry;
	unsigned long *ptr;
	void *dest;
	void *addr;

	/*
	 * We rely on kexec_load to create a lists that properly
	 * initializes these pointers before they are used.
	 * We will still crash if the list is wrong, but at least
	 * the compiler will be quiet.
	 */
	ptr = NULL;
	dest = NULL;

	for (entry = ind; !(entry & IND_DONE); entry = *ptr++) {
		addr = __va(entry & PAGE_MASK);

		switch (entry & IND_FLAGS) {
		case IND_DESTINATION:
			dest = addr;
			break;
		case IND_INDIRECTION:
			ptr = addr;
			break;
		case IND_SOURCE:
			copy_page(dest, addr);
			dest += PAGE_SIZE;
		}
	}
}

void kexec_copy_flush(struct kimage *image)
{
	long i, nr_segments = image->nr_segments;
	struct  kexec_segment ranges[KEXEC_SEGMENT_MAX];

	/* save the ranges on the stack to efficiently flush the icache */
	memcpy(ranges, image->segment, sizeof(ranges));

	/*
	 * After this call we may not use anything allocated in dynamic
	 * memory, including *image.
	 *
	 * Only globals and the stack are allowed.
	 */
	copy_segments(image->head);

	/*
	 * we need to clear the icache for all dest pages sometime,
	 * including ones that were in place on the original copy
	 */
	for (i = 0; i < nr_segments; i++)
		flush_icache_range((unsigned long)__va(ranges[i].mem),
			(unsigned long)__va(ranges[i].mem + ranges[i].memsz));
}

#ifdef CONFIG_SMP

static int kexec_all_irq_disabled = 0;

static void kexec_smp_down(void *arg)
{
	local_irq_disable();
	hard_irq_disable();

	mb(); /* make sure our irqs are disabled before we say they are */
	get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF;
	while(kexec_all_irq_disabled == 0)
		cpu_relax();
	mb(); /* make sure all irqs are disabled before this */
	hw_breakpoint_disable();
	/*
	 * Now every CPU has IRQs off, we can clear out any pending
	 * IPIs and be sure that no more will come in after this.
	 */
	if (ppc_md.kexec_cpu_down)
		ppc_md.kexec_cpu_down(0, 1);

	kexec_smp_wait();
	/* NOTREACHED */
}

static void kexec_prepare_cpus_wait(int wait_state)
{
	int my_cpu, i, notified=-1;

	hw_breakpoint_disable();
	my_cpu = get_cpu();
	/* Make sure each CPU has at least made it to the state we need.
	 *
	 * FIXME: There is a (slim) chance of a problem if not all of the CPUs
	 * are correctly onlined.  If somehow we start a CPU on boot with RTAS
	 * start-cpu, but somehow that CPU doesn't write callin_cpu_map[] in
	 * time, the boot CPU will timeout.  If it does eventually execute
	 * stuff, the secondary will start up (paca[].cpu_start was written) and
	 * get into a peculiar state.  If the platform supports
	 * smp_ops->take_timebase(), the secondary CPU will probably be spinning
	 * in there.  If not (i.e. pseries), the secondary will continue on and
	 * try to online itself/idle/etc. If it survives that, we need to find
	 * these possible-but-not-online-but-should-be CPUs and chaperone them
	 * into kexec_smp_wait().
	 */
	for_each_online_cpu(i) {
		if (i == my_cpu)
			continue;

		while (paca[i].kexec_state < wait_state) {
			barrier();
			if (i != notified) {
				printk(KERN_INFO "kexec: waiting for cpu %d "
				       "(physical %d) to enter %i state\n",
				       i, paca[i].hw_cpu_id, wait_state);
				notified = i;
			}
		}
	}
	mb();
}

/*
 * We need to make sure each present CPU is online.  The next kernel will scan
 * the device tree and assume primary threads are online and query secondary
 * threads via RTAS to online them if required.  If we don't online primary
 * threads, they will be stuck.  However, we also online secondary threads as we
 * may be using 'cede offline'.  In this case RTAS doesn't see the secondary
 * threads as offline -- and again, these CPUs will be stuck.
 *
 * So, we online all CPUs that should be running, including secondary threads.
 */
static void wake_offline_cpus(void)
{
	int cpu = 0;

	for_each_present_cpu(cpu) {
		if (!cpu_online(cpu)) {
			printk(KERN_INFO "kexec: Waking offline cpu %d.\n",
			       cpu);
			WARN_ON(cpu_up(cpu));
		}
	}
}

static void kexec_prepare_cpus(void)
{
	wake_offline_cpus();
	smp_call_function(kexec_smp_down, NULL, /* wait */0);
	local_irq_disable();
	hard_irq_disable();

	mb(); /* make sure IRQs are disabled before we say they are */
	get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF;

	kexec_prepare_cpus_wait(KEXEC_STATE_IRQS_OFF);
	/* we are sure every CPU has IRQs off at this point */
	kexec_all_irq_disabled = 1;

	/* after we tell the others to go down */
	if (ppc_md.kexec_cpu_down)
		ppc_md.kexec_cpu_down(0, 0);

	/*
	 * Before removing MMU mappings make sure all CPUs have entered real
	 * mode:
	 */
	kexec_prepare_cpus_wait(KEXEC_STATE_REAL_MODE);

	put_cpu();
}

#else /* ! SMP */

static void kexec_prepare_cpus(void)
{
	/*
	 * move the secondarys to us so that we can copy
	 * the new kernel 0-0x100 safely
	 *
	 * do this if kexec in setup.c ?
	 *
	 * We need to release the cpus if we are ever going from an
	 * UP to an SMP kernel.
	 */
	smp_release_cpus();
	if (ppc_md.kexec_cpu_down)
		ppc_md.kexec_cpu_down(0, 0);
	local_irq_disable();
	hard_irq_disable();
}

#endif /* SMP */

/*
 * kexec thread structure and stack.
 *
 * We need to make sure that this is 16384-byte aligned due to the
 * way process stacks are handled.  It also must be statically allocated
 * or allocated as part of the kimage, because everything else may be
 * overwritten when we copy the kexec image.  We piggyback on the
 * "init_task" linker section here to statically allocate a stack.
 *
 * We could use a smaller stack if we don't care about anything using
 * current, but that audit has not been performed.
 */
static union thread_union kexec_stack __init_task_data =
	{ };

/*
 * For similar reasons to the stack above, the kexecing CPU needs to be on a
 * static PACA; we switch to kexec_paca.
 */
struct paca_struct kexec_paca;

/* Our assembly helper, in misc_64.S */
extern void kexec_sequence(void *newstack, unsigned long start,
			   void *image, void *control,
			   void (*clear_all)(void)) __noreturn;

/* too late to fail here */
void default_machine_kexec(struct kimage *image)
{
	/* prepare control code if any */

	/*
        * If the kexec boot is the normal one, need to shutdown other cpus
        * into our wait loop and quiesce interrupts.
        * Otherwise, in the case of crashed mode (crashing_cpu >= 0),
        * stopping other CPUs and collecting their pt_regs is done before
        * using debugger IPI.
        */

	if (!kdump_in_progress())
		kexec_prepare_cpus();

	pr_debug("kexec: Starting switchover sequence.\n");

	/* switch to a staticly allocated stack.  Based on irq stack code.
	 * We setup preempt_count to avoid using VMX in memcpy.
	 * XXX: the task struct will likely be invalid once we do the copy!
	 */
	kexec_stack.thread_info.task = current_thread_info()->task;
	kexec_stack.thread_info.flags = 0;
	kexec_stack.thread_info.preempt_count = HARDIRQ_OFFSET;
	kexec_stack.thread_info.cpu = current_thread_info()->cpu;

	/* We need a static PACA, too; copy this CPU's PACA over and switch to
	 * it.  Also poison per_cpu_offset to catch anyone using non-static
	 * data.
	 */
	memcpy(&kexec_paca, get_paca(), sizeof(struct paca_struct));
	kexec_paca.data_offset = 0xedeaddeadeeeeeeeUL;
	paca = (struct paca_struct *)RELOC_HIDE(&kexec_paca, 0) -
		kexec_paca.paca_index;
	setup_paca(&kexec_paca);

	/* XXX: If anyone does 'dynamic lppacas' this will also need to be
	 * switched to a static version!
	 */

	/* Some things are best done in assembly.  Finding globals with
	 * a toc is easier in C, so pass in what we can.
	 */
	kexec_sequence(&kexec_stack, image->start, image,
			page_address(image->control_code_page),
			ppc_md.hpte_clear_all);
	/* NOTREACHED */
}

/* Values we need to export to the second kernel via the device tree. */
static unsigned long htab_base;
static unsigned long htab_size;

static struct property htab_base_prop = {
	.name = "linux,htab-base",
	.length = sizeof(unsigned long),
	.value = &htab_base,
};

static struct property htab_size_prop = {
	.name = "linux,htab-size",
	.length = sizeof(unsigned long),
	.value = &htab_size,
};

static int __init export_htab_values(void)
{
	struct device_node *node;
	struct property *prop;

	/* On machines with no htab htab_address is NULL */
	if (!htab_address)
		return -ENODEV;

	node = of_find_node_by_path("/chosen");
	if (!node)
		return -ENODEV;

	/* remove any stale propertys so ours can be found */
	prop = of_find_property(node, htab_base_prop.name, NULL);
	if (prop)
		of_remove_property(node, prop);
	prop = of_find_property(node, htab_size_prop.name, NULL);
	if (prop)
		of_remove_property(node, prop);

	htab_base = cpu_to_be64(__pa(htab_address));
	of_add_property(node, &htab_base_prop);
	htab_size = cpu_to_be64(htab_size_bytes);
	of_add_property(node, &htab_size_prop);

	of_node_put(node);
	return 0;
}
late_initcall(export_htab_values);
Commit	Line	Data
fce0d574	1	/*
3d1229d6	2	* PPC64 code to handle Linux booting another kernel.
fce0d574 S	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
fce0d574 S	13	#include <linux/kexec.h>
	14	#include <linux/smp.h>
	15	#include <linux/thread_info.h>
d200c922	16	#include <linux/init_task.h>
fce0d574	17	#include <linux/errno.h>
e2f7f737	18	#include <linux/kernel.h>
e8e5c215	19	#include <linux/cpu.h>
79c66ce8	20	#include <linux/hardirq.h>
fce0d574 S	21
	22	#include <asm/page.h>
	23	#include <asm/current.h>
	24	#include <asm/machdep.h>
	25	#include <asm/cacheflush.h>
	26	#include <asm/paca.h>
	27	#include <asm/mmu.h>
	28	#include <asm/sections.h> /* _end */
	29	#include <asm/prom.h>
2249ca9d	30	#include <asm/smp.h>
5aae8a53	31	#include <asm/hw_breakpoint.h>
fce0d574	32
3d1229d6	33	int default_machine_kexec_prepare(struct kimage *image)
fce0d574 S	34	{
	35	int i;
	36	unsigned long begin, end; /* limits of segment */
	37	unsigned long low, high; /* limits of blocked memory range */
	38	struct device_node *node;
a7f67bdf JK	39	const unsigned long *basep;
a7f67bdf JK	40	const unsigned int *sizep;
fce0d574 S	41
	42	if (!ppc_md.hpte_clear_all)
	43	return -ENOENT;
	44
	45	/*
	46	* Since we use the kernel fault handlers and paging code to
	47	* handle the virtual mode, we must make sure no destination
	48	* overlaps kernel static data or bss.
	49	*/
72414d3f	50	for (i = 0; i < image->nr_segments; i++)
fce0d574 S	51	if (image->segment[i].mem < __pa(_end))
	52	return -ETXTBSY;
	53
	54	/*
	55	* For non-LPAR, we absolutely can not overwrite the mmu hash
	56	* table, since we are still using the bolted entries in it to
	57	* do the copy. Check that here.
	58	*
	59	* It is safe if the end is below the start of the blocked
	60	* region (end <= low), or if the beginning is after the
	61	* end of the blocked region (begin >= high). Use the
	62	* boolean identity !(a \|\| b) === (!a && !b).
	63	*/
	64	if (htab_address) {
	65	low = __pa(htab_address);
337a7128	66	high = low + htab_size_bytes;
fce0d574	67
72414d3f	68	for (i = 0; i < image->nr_segments; i++) {
fce0d574 S	69	begin = image->segment[i].mem;
	70	end = begin + image->segment[i].memsz;
	71
	72	if ((begin < high) && (end > low))
	73	return -ETXTBSY;
	74	}
	75	}
	76
	77	/* We also should not overwrite the tce tables */
94db7c5e	78	for_each_node_by_type(node, "pci") {
e2eb6392 SR	79	basep = of_get_property(node, "linux,tce-base", NULL);
e2eb6392 SR	80	sizep = of_get_property(node, "linux,tce-size", NULL);
fce0d574 S	81	if (basep == NULL \|\| sizep == NULL)
	82	continue;
	83
	84	low = *basep;
	85	high = low + (*sizep);
	86
72414d3f	87	for (i = 0; i < image->nr_segments; i++) {
fce0d574 S	88	begin = image->segment[i].mem;
	89	end = begin + image->segment[i].memsz;
	90
	91	if ((begin < high) && (end > low))
	92	return -ETXTBSY;
	93	}
	94	}
	95
	96	return 0;
	97	}
	98
fce0d574 S	99	#define IND_FLAGS (IND_DESTINATION \| IND_INDIRECTION \| IND_DONE \| IND_SOURCE)
	100
	101	static void copy_segments(unsigned long ind)
	102	{
	103	unsigned long entry;
	104	unsigned long *ptr;
	105	void *dest;
	106	void *addr;
	107
	108	/*
	109	* We rely on kexec_load to create a lists that properly
	110	* initializes these pointers before they are used.
	111	* We will still crash if the list is wrong, but at least
	112	* the compiler will be quiet.
	113	*/
	114	ptr = NULL;
	115	dest = NULL;
	116
	117	for (entry = ind; !(entry & IND_DONE); entry = *ptr++) {
	118	addr = __va(entry & PAGE_MASK);
	119
	120	switch (entry & IND_FLAGS) {
	121	case IND_DESTINATION:
	122	dest = addr;
	123	break;
	124	case IND_INDIRECTION:
	125	ptr = addr;
	126	break;
	127	case IND_SOURCE:
	128	copy_page(dest, addr);
	129	dest += PAGE_SIZE;
	130	}
	131	}
	132	}
	133
	134	void kexec_copy_flush(struct kimage *image)
	135	{
	136	long i, nr_segments = image->nr_segments;
	137	struct kexec_segment ranges[KEXEC_SEGMENT_MAX];
	138
	139	/* save the ranges on the stack to efficiently flush the icache */
	140	memcpy(ranges, image->segment, sizeof(ranges));
	141
	142	/*
	143	* After this call we may not use anything allocated in dynamic
	144	* memory, including *image.
	145	*
	146	* Only globals and the stack are allowed.
	147	*/
	148	copy_segments(image->head);
	149
	150	/*
	151	* we need to clear the icache for all dest pages sometime,
	152	* including ones that were in place on the original copy
	153	*/
	154	for (i = 0; i < nr_segments; i++)
b5666f70 ME	155	flush_icache_range((unsigned long)__va(ranges[i].mem),
b5666f70 ME	156	(unsigned long)__va(ranges[i].mem + ranges[i].memsz));
fce0d574 S	157	}
	158
	159	#ifdef CONFIG_SMP
	160
1fc711f7 MN	161	static int kexec_all_irq_disabled = 0;
1fc711f7 MN	162
1c21a293	163	static void kexec_smp_down(void *arg)
fce0d574	164	{
1fc711f7	165	local_irq_disable();
8520e443 PF	166	hard_irq_disable();
8520e443 PF	167
1fc711f7 MN	168	mb(); /* make sure our irqs are disabled before we say they are */
	169	get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF;
	170	while(kexec_all_irq_disabled == 0)
	171	cpu_relax();
	172	mb(); /* make sure all irqs are disabled before this */
5aae8a53	173	hw_breakpoint_disable();
1fc711f7 MN	174	/*
	175	* Now every CPU has IRQs off, we can clear out any pending
	176	* IPIs and be sure that no more will come in after this.
	177	*/
c5e24354 ME	178	if (ppc_md.kexec_cpu_down)
c5e24354 ME	179	ppc_md.kexec_cpu_down(0, 1);
fce0d574	180
fce0d574 S	181	kexec_smp_wait();
	182	/* NOTREACHED */
	183	}
	184
1fc711f7	185	static void kexec_prepare_cpus_wait(int wait_state)
fce0d574 S	186	{
	187	int my_cpu, i, notified=-1;
	188
5aae8a53	189	hw_breakpoint_disable();
fce0d574	190	my_cpu = get_cpu();
e2f7f737 ME	191	/* Make sure each CPU has at least made it to the state we need.
	192	*
	193	* FIXME: There is a (slim) chance of a problem if not all of the CPUs
	194	* are correctly onlined. If somehow we start a CPU on boot with RTAS
	195	* start-cpu, but somehow that CPU doesn't write callin_cpu_map[] in
	196	* time, the boot CPU will timeout. If it does eventually execute
	197	* stuff, the secondary will start up (paca[].cpu_start was written) and
	198	* get into a peculiar state. If the platform supports
	199	* smp_ops->take_timebase(), the secondary CPU will probably be spinning
	200	* in there. If not (i.e. pseries), the secondary will continue on and
	201	* try to online itself/idle/etc. If it survives that, we need to find
	202	* these possible-but-not-online-but-should-be CPUs and chaperone them
	203	* into kexec_smp_wait().
	204	*/
b636f137	205	for_each_online_cpu(i) {
fce0d574 S	206	if (i == my_cpu)
	207	continue;
	208
1fc711f7	209	while (paca[i].kexec_state < wait_state) {
b3ca8093	210	barrier();
fce0d574	211	if (i != notified) {
e2f7f737 ME	212	printk(KERN_INFO "kexec: waiting for cpu %d "
	213	"(physical %d) to enter %i state\n",
	214	i, paca[i].hw_cpu_id, wait_state);
fce0d574 S	215	notified = i;
	216	}
	217	}
	218	}
1fc711f7 MN	219	mb();
	220	}
	221
e8e5c215 ME	222	/*
	223	* We need to make sure each present CPU is online. The next kernel will scan
	224	* the device tree and assume primary threads are online and query secondary
	225	* threads via RTAS to online them if required. If we don't online primary
	226	* threads, they will be stuck. However, we also online secondary threads as we
	227	* may be using 'cede offline'. In this case RTAS doesn't see the secondary
	228	* threads as offline -- and again, these CPUs will be stuck.
	229	*
	230	* So, we online all CPUs that should be running, including secondary threads.
	231	*/
	232	static void wake_offline_cpus(void)
1fc711f7	233	{
e8e5c215 ME	234	int cpu = 0;
	235
	236	for_each_present_cpu(cpu) {
	237	if (!cpu_online(cpu)) {
	238	printk(KERN_INFO "kexec: Waking offline cpu %d.\n",
	239	cpu);
011e4b02	240	WARN_ON(cpu_up(cpu));
e8e5c215 ME	241	}
	242	}
	243	}
1fc711f7	244
e8e5c215 ME	245	static void kexec_prepare_cpus(void)
	246	{
	247	wake_offline_cpus();
1fc711f7 MN	248	smp_call_function(kexec_smp_down, NULL, /* wait */0);
1fc711f7 MN	249	local_irq_disable();
8520e443 PF	250	hard_irq_disable();
8520e443 PF	251
1fc711f7 MN	252	mb(); /* make sure IRQs are disabled before we say they are */
	253	get_paca()->kexec_state = KEXEC_STATE_IRQS_OFF;
	254
	255	kexec_prepare_cpus_wait(KEXEC_STATE_IRQS_OFF);
	256	/* we are sure every CPU has IRQs off at this point */
	257	kexec_all_irq_disabled = 1;
fce0d574 S	258
fce0d574 S	259	/* after we tell the others to go down */
c5e24354 ME	260	if (ppc_md.kexec_cpu_down)
c5e24354 ME	261	ppc_md.kexec_cpu_down(0, 0);
fce0d574	262
e2f7f737 ME	263	/*
	264	* Before removing MMU mappings make sure all CPUs have entered real
	265	* mode:
	266	*/
1fc711f7	267	kexec_prepare_cpus_wait(KEXEC_STATE_REAL_MODE);
fce0d574	268
1fc711f7	269	put_cpu();
fce0d574 S	270	}
	271
	272	#else /* ! SMP */
	273
	274	static void kexec_prepare_cpus(void)
	275	{
	276	/*
	277	* move the secondarys to us so that we can copy
	278	* the new kernel 0-0x100 safely
	279	*
	280	* do this if kexec in setup.c ?
75eedfed OJ	281	*
	282	* We need to release the cpus if we are ever going from an
	283	* UP to an SMP kernel.
fce0d574	284	*/
75eedfed	285	smp_release_cpus();
c5e24354 ME	286	if (ppc_md.kexec_cpu_down)
c5e24354 ME	287	ppc_md.kexec_cpu_down(0, 0);
fce0d574	288	local_irq_disable();
8520e443	289	hard_irq_disable();
fce0d574 S	290	}
	291
	292	#endif /* SMP */
	293
	294	/*
	295	* kexec thread structure and stack.
	296	*
	297	* We need to make sure that this is 16384-byte aligned due to the
	298	* way process stacks are handled. It also must be statically allocated
	299	* or allocated as part of the kimage, because everything else may be
	300	* overwritten when we copy the kexec image. We piggyback on the
	301	* "init_task" linker section here to statically allocate a stack.
	302	*
	303	* We could use a smaller stack if we don't care about anything using
	304	* current, but that audit has not been performed.
	305	*/
d200c922 JP	306	static union thread_union kexec_stack __init_task_data =
d200c922 JP	307	{ };
fce0d574	308
fc53b420 ME	309	/*
	310	* For similar reasons to the stack above, the kexecing CPU needs to be on a
	311	* static PACA; we switch to kexec_paca.
	312	*/
	313	struct paca_struct kexec_paca;
	314
07fb41a7	315	/* Our assembly helper, in misc_64.S */
9402c95f JP	316	extern void kexec_sequence(void *newstack, unsigned long start,
9402c95f JP	317	void image, void control,
ff2d8b19	318	void (*clear_all)(void)) __noreturn;
fce0d574 S	319
fce0d574 S	320	/* too late to fail here */
3d1229d6	321	void default_machine_kexec(struct kimage *image)
fce0d574	322	{
fce0d574 S	323	/* prepare control code if any */
fce0d574 S	324
cc532915 ME	325	/*
	326	* If the kexec boot is the normal one, need to shutdown other cpus
	327	* into our wait loop and quiesce interrupts.
	328	* Otherwise, in the case of crashed mode (crashing_cpu >= 0),
	329	* stopping other CPUs and collecting their pt_regs is done before
	330	* using debugger IPI.
	331	*/
	332
c1caae3d	333	if (!kdump_in_progress())
54622f10	334	kexec_prepare_cpus();
fce0d574	335
e2f7f737 ME	336	pr_debug("kexec: Starting switchover sequence.\n");
e2f7f737 ME	337
fce0d574	338	/* switch to a staticly allocated stack. Based on irq stack code.
79c66ce8	339	* We setup preempt_count to avoid using VMX in memcpy.
fce0d574 S	340	* XXX: the task struct will likely be invalid once we do the copy!
	341	*/
	342	kexec_stack.thread_info.task = current_thread_info()->task;
	343	kexec_stack.thread_info.flags = 0;
79c66ce8 AB	344	kexec_stack.thread_info.preempt_count = HARDIRQ_OFFSET;
79c66ce8 AB	345	kexec_stack.thread_info.cpu = current_thread_info()->cpu;
fce0d574	346
fc53b420 ME	347	/* We need a static PACA, too; copy this CPU's PACA over and switch to
	348	* it. Also poison per_cpu_offset to catch anyone using non-static
	349	* data.
	350	*/
	351	memcpy(&kexec_paca, get_paca(), sizeof(struct paca_struct));
	352	kexec_paca.data_offset = 0xedeaddeadeeeeeeeUL;
	353	paca = (struct paca_struct *)RELOC_HIDE(&kexec_paca, 0) -
	354	kexec_paca.paca_index;
	355	setup_paca(&kexec_paca);
	356
	357	/* XXX: If anyone does 'dynamic lppacas' this will also need to be
	358	* switched to a static version!
	359	*/
	360
fce0d574 S	361	/* Some things are best done in assembly. Finding globals with
	362	* a toc is easier in C, so pass in what we can.
	363	*/
	364	kexec_sequence(&kexec_stack, image->start, image,
	365	page_address(image->control_code_page),
1767c8f3	366	ppc_md.hpte_clear_all);
fce0d574 S	367	/* NOTREACHED */
fce0d574 S	368	}
593e537b ME	369
593e537b ME	370	/* Values we need to export to the second kernel via the device tree. */
2e8e4f5b	371	static unsigned long htab_base;
ea961a82	372	static unsigned long htab_size;
593e537b ME	373
	374	static struct property htab_base_prop = {
	375	.name = "linux,htab-base",
	376	.length = sizeof(unsigned long),
1a38147e	377	.value = &htab_base,
593e537b ME	378	};
	379
	380	static struct property htab_size_prop = {
	381	.name = "linux,htab-size",
	382	.length = sizeof(unsigned long),
ea961a82	383	.value = &htab_size,
593e537b ME	384	};
593e537b ME	385
6f29c329	386	static int __init export_htab_values(void)
593e537b ME	387	{
593e537b ME	388	struct device_node *node;
ed7b2144	389	struct property *prop;
593e537b	390
2e8e4f5b DF	391	/* On machines with no htab htab_address is NULL */
2e8e4f5b DF	392	if (!htab_address)
6f29c329	393	return -ENODEV;
2e8e4f5b	394
593e537b ME	395	node = of_find_node_by_path("/chosen");
593e537b ME	396	if (!node)
6f29c329	397	return -ENODEV;
593e537b	398
ed7b2144	399	/* remove any stale propertys so ours can be found */
ed7b2144 MM	400	prop = of_find_property(node, htab_base_prop.name, NULL);
ed7b2144 MM	401	if (prop)
79d1c712	402	of_remove_property(node, prop);
ed7b2144 MM	403	prop = of_find_property(node, htab_size_prop.name, NULL);
ed7b2144 MM	404	if (prop)
79d1c712	405	of_remove_property(node, prop);
ed7b2144	406
ea961a82	407	htab_base = cpu_to_be64(__pa(htab_address));
79d1c712	408	of_add_property(node, &htab_base_prop);
ea961a82	409	htab_size = cpu_to_be64(htab_size_bytes);
79d1c712	410	of_add_property(node, &htab_size_prop);
593e537b	411
593e537b	412	of_node_put(node);
aa98c50d	413	return 0;
35dd5432	414	}
6f29c329	415	late_initcall(export_htab_values);