/*
* machine_kexec.c - handle transition of 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/cpumask.h>
#include <linux/kexec.h>
#include <linux/smp.h>
#include <linux/thread_info.h>
#include <linux/errno.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>
#define HASH_GROUP_SIZE 0x80 /* size of each hash group, asm/mmu.h */
/* Have this around till we move it into crash specific file */
note_buf_t crash_notes[NR_CPUS];
/* Dummy for now. Not sure if we need to have a crash shutdown in here
* and if what it will achieve. Letting it be now to compile the code
* in generic kexec environment
*/
void machine_crash_shutdown(struct pt_regs *regs)
{
/* do nothing right now */
/* smp_relase_cpus() if we want smp on panic kernel */
/* cpu_irq_down to isolate us until we are ready */
}
int 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;
unsigned long *basep;
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_hash_mask + 1) * HASH_GROUP_SIZE;
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 (node = of_find_node_by_type(NULL, "pci"); node != NULL;
node = of_find_node_by_type(node, "pci")) {
basep = (unsigned long *)get_property(node, "linux,tce-base",
NULL);
sizep = (unsigned int *)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;
}
void machine_kexec_cleanup(struct kimage *image)
{
/* we do nothing in prepare that needs to be undone */
}
#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(ranges[i].mem + KERNELBASE,
ranges[i].mem + KERNELBASE +
ranges[i].memsz);
}
#ifdef CONFIG_SMP
/* FIXME: we should schedule this function to be called on all cpus based
* on calling the interrupts, but we would like to call it off irq level
* so that the interrupt controller is clean.
*/
void kexec_smp_down(void *arg)
{
if (ppc_md.cpu_irq_down)
ppc_md.cpu_irq_down(1);
local_irq_disable();
kexec_smp_wait();
/* NOTREACHED */
}
static void kexec_prepare_cpus(void)
{
int my_cpu, i, notified=-1;
smp_call_function(kexec_smp_down, NULL, 0, /* wait */0);
my_cpu = get_cpu();
/* check the others cpus are now down (via paca hw cpu id == -1) */
for (i=0; i < NR_CPUS; i++) {
if (i == my_cpu)
continue;
while (paca[i].hw_cpu_id != -1) {
barrier();
if (!cpu_possible(i)) {
printk("kexec: cpu %d hw_cpu_id %d is not"
" possible, ignoring\n",
i, paca[i].hw_cpu_id);
break;
}
if (!cpu_online(i)) {
/* Fixme: this can be spinning in
* pSeries_secondary_wait with a paca
* waiting for it to go online.
*/
printk("kexec: cpu %d hw_cpu_id %d is not"
" online, ignoring\n",
i, paca[i].hw_cpu_id);
break;
}
if (i != notified) {
printk( "kexec: waiting for cpu %d (physical"
" %d) to go down\n",
i, paca[i].hw_cpu_id);
notified = i;
}
}
}
/* after we tell the others to go down */
if (ppc_md.cpu_irq_down)
ppc_md.cpu_irq_down(0);
put_cpu();
local_irq_disable();
}
#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.cpu_irq_down)
ppc_md.cpu_irq_down(0);
local_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.
*/
union thread_union kexec_stack
__attribute__((__section__(".data.init_task"))) = { };
/* Our assembly helper, in kexec_stub.S */
extern NORET_TYPE void kexec_sequence(void *newstack, unsigned long start,
void *image, void *control,
void (*clear_all)(void)) ATTRIB_NORET;
/* too late to fail here */
void machine_kexec(struct kimage *image)
{
/* prepare control code if any */
/* shutdown other cpus into our wait loop and quiesce interrupts */
kexec_prepare_cpus();
/* switch to a staticly allocated stack. Based on irq stack code.
* 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;
/* 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 */
}
