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+/*
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+ * machine_kexec.c - handle transition of Linux booting another kernel
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+ *
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+ * Copyright (C) 2004-2005, IBM Corp.
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+ *
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+ * Created by: Milton D Miller II
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+ *
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+ * This source code is licensed under the GNU General Public License,
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+ * Version 2. See the file COPYING for more details.
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+ */
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+
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+
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+#include <linux/cpumask.h>
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+#include <linux/kexec.h>
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+#include <linux/smp.h>
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+#include <linux/thread_info.h>
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+#include <linux/errno.h>
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+
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+#include <asm/page.h>
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+#include <asm/current.h>
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+#include <asm/machdep.h>
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+#include <asm/cacheflush.h>
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+#include <asm/paca.h>
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+#include <asm/mmu.h>
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+#include <asm/sections.h> /* _end */
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+#include <asm/prom.h>
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+
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+#define HASH_GROUP_SIZE 0x80 /* size of each hash group, asm/mmu.h */
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+
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+/* Have this around till we move it into crash specific file */
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+note_buf_t crash_notes[NR_CPUS];
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+
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+/* Dummy for now. Not sure if we need to have a crash shutdown in here
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+ * and if what it will achieve. Letting it be now to compile the code
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+ * in generic kexec environment
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+ */
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+void machine_crash_shutdown(void)
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+{
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+ /* do nothing right now */
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+ /* smp_relase_cpus() if we want smp on panic kernel */
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+ /* cpu_irq_down to isolate us until we are ready */
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+}
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+
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+int machine_kexec_prepare(struct kimage *image)
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+{
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+ int i;
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+ unsigned long begin, end; /* limits of segment */
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+ unsigned long low, high; /* limits of blocked memory range */
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+ struct device_node *node;
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+ unsigned long *basep;
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+ unsigned int *sizep;
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+
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+ if (!ppc_md.hpte_clear_all)
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+ return -ENOENT;
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+
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+ /*
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+ * Since we use the kernel fault handlers and paging code to
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+ * handle the virtual mode, we must make sure no destination
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+ * overlaps kernel static data or bss.
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+ */
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+ for(i = 0; i < image->nr_segments; i++)
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+ if (image->segment[i].mem < __pa(_end))
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+ return -ETXTBSY;
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+
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+ /*
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+ * For non-LPAR, we absolutely can not overwrite the mmu hash
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+ * table, since we are still using the bolted entries in it to
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+ * do the copy. Check that here.
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+ *
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+ * It is safe if the end is below the start of the blocked
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+ * region (end <= low), or if the beginning is after the
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+ * end of the blocked region (begin >= high). Use the
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+ * boolean identity !(a || b) === (!a && !b).
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+ */
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+ if (htab_address) {
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+ low = __pa(htab_address);
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+ high = low + (htab_hash_mask + 1) * HASH_GROUP_SIZE;
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+
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+ for(i = 0; i < image->nr_segments; i++) {
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+ begin = image->segment[i].mem;
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+ end = begin + image->segment[i].memsz;
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+
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+ if ((begin < high) && (end > low))
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+ return -ETXTBSY;
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+ }
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+ }
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+
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+ /* We also should not overwrite the tce tables */
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+ for (node = of_find_node_by_type(NULL, "pci"); node != NULL;
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+ node = of_find_node_by_type(node, "pci")) {
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+ basep = (unsigned long *)get_property(node, "linux,tce-base",
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+ NULL);
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+ sizep = (unsigned int *)get_property(node, "linux,tce-size",
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+ NULL);
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+ if (basep == NULL || sizep == NULL)
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+ continue;
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+
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+ low = *basep;
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+ high = low + (*sizep);
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+
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+ for(i = 0; i < image->nr_segments; i++) {
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+ begin = image->segment[i].mem;
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+ end = begin + image->segment[i].memsz;
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+
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+ if ((begin < high) && (end > low))
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+ return -ETXTBSY;
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+ }
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+ }
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+
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+ return 0;
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+}
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+
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+void machine_kexec_cleanup(struct kimage *image)
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+{
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+ /* we do nothing in prepare that needs to be undone */
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+}
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+
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+#define IND_FLAGS (IND_DESTINATION | IND_INDIRECTION | IND_DONE | IND_SOURCE)
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+
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+static void copy_segments(unsigned long ind)
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+{
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+ unsigned long entry;
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+ unsigned long *ptr;
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+ void *dest;
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+ void *addr;
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+
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+ /*
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+ * We rely on kexec_load to create a lists that properly
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+ * initializes these pointers before they are used.
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+ * We will still crash if the list is wrong, but at least
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+ * the compiler will be quiet.
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+ */
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+ ptr = NULL;
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+ dest = NULL;
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+
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+ for (entry = ind; !(entry & IND_DONE); entry = *ptr++) {
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+ addr = __va(entry & PAGE_MASK);
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+
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+ switch (entry & IND_FLAGS) {
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+ case IND_DESTINATION:
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+ dest = addr;
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+ break;
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+ case IND_INDIRECTION:
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+ ptr = addr;
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+ break;
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+ case IND_SOURCE:
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+ copy_page(dest, addr);
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+ dest += PAGE_SIZE;
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+ }
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+ }
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+}
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+
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+void kexec_copy_flush(struct kimage *image)
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+{
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+ long i, nr_segments = image->nr_segments;
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+ struct kexec_segment ranges[KEXEC_SEGMENT_MAX];
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+
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+ /* save the ranges on the stack to efficiently flush the icache */
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+ memcpy(ranges, image->segment, sizeof(ranges));
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+
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+ /*
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+ * After this call we may not use anything allocated in dynamic
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+ * memory, including *image.
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+ *
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+ * Only globals and the stack are allowed.
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+ */
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+ copy_segments(image->head);
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+
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+ /*
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+ * we need to clear the icache for all dest pages sometime,
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+ * including ones that were in place on the original copy
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+ */
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+ for (i = 0; i < nr_segments; i++)
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+ flush_icache_range(ranges[i].mem + KERNELBASE,
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+ ranges[i].mem + KERNELBASE +
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+ ranges[i].memsz);
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+}
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+
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+#ifdef CONFIG_SMP
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+
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+/* FIXME: we should schedule this function to be called on all cpus based
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+ * on calling the interrupts, but we would like to call it off irq level
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+ * so that the interrupt controller is clean.
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+ */
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+void kexec_smp_down(void *arg)
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+{
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+ if (ppc_md.cpu_irq_down)
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+ ppc_md.cpu_irq_down();
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+
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+ local_irq_disable();
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+ kexec_smp_wait();
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+ /* NOTREACHED */
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+}
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+
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+static void kexec_prepare_cpus(void)
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+{
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+ int my_cpu, i, notified=-1;
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+
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+ smp_call_function(kexec_smp_down, NULL, 0, /* wait */0);
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+ my_cpu = get_cpu();
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+
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+ /* check the others cpus are now down (via paca hw cpu id == -1) */
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+ for (i=0; i < NR_CPUS; i++) {
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+ if (i == my_cpu)
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+ continue;
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+
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+ while (paca[i].hw_cpu_id != -1) {
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+ if (!cpu_possible(i)) {
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+ printk("kexec: cpu %d hw_cpu_id %d is not"
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+ " possible, ignoring\n",
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+ i, paca[i].hw_cpu_id);
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+ break;
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+ }
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+ if (!cpu_online(i)) {
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+ /* Fixme: this can be spinning in
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+ * pSeries_secondary_wait with a paca
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+ * waiting for it to go online.
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+ */
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+ printk("kexec: cpu %d hw_cpu_id %d is not"
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+ " online, ignoring\n",
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+ i, paca[i].hw_cpu_id);
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+ break;
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+ }
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+ if (i != notified) {
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+ printk( "kexec: waiting for cpu %d (physical"
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+ " %d) to go down\n",
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+ i, paca[i].hw_cpu_id);
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+ notified = i;
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+ }
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+ }
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+ }
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+
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+ /* after we tell the others to go down */
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+ if (ppc_md.cpu_irq_down)
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+ ppc_md.cpu_irq_down();
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+
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+ put_cpu();
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+
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+ local_irq_disable();
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+}
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+
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+#else /* ! SMP */
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+
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+static void kexec_prepare_cpus(void)
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+{
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+ /*
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+ * move the secondarys to us so that we can copy
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+ * the new kernel 0-0x100 safely
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+ *
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+ * do this if kexec in setup.c ?
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+ */
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+ smp_relase_cpus();
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+ if (ppc_md.cpu_irq_down)
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+ ppc_md.cpu_irq_down();
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+ local_irq_disable();
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+}
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+
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+#endif /* SMP */
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+
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+/*
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+ * kexec thread structure and stack.
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+ *
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+ * We need to make sure that this is 16384-byte aligned due to the
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+ * way process stacks are handled. It also must be statically allocated
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+ * or allocated as part of the kimage, because everything else may be
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+ * overwritten when we copy the kexec image. We piggyback on the
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+ * "init_task" linker section here to statically allocate a stack.
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+ *
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+ * We could use a smaller stack if we don't care about anything using
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+ * current, but that audit has not been performed.
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+ */
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+union thread_union kexec_stack
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+ __attribute__((__section__(".data.init_task"))) = { };
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+
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+/* Our assembly helper, in kexec_stub.S */
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+extern NORET_TYPE void kexec_sequence(void *newstack, unsigned long start,
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+ void *image, void *control, void (*clear_all)(void)) ATTRIB_NORET;
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+
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+/* too late to fail here */
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+void machine_kexec(struct kimage *image)
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+{
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+
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+ /* prepare control code if any */
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+
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+ /* shutdown other cpus into our wait loop and quiesce interrupts */
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+ kexec_prepare_cpus();
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+
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+ /* switch to a staticly allocated stack. Based on irq stack code.
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+ * XXX: the task struct will likely be invalid once we do the copy!
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+ */
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+ kexec_stack.thread_info.task = current_thread_info()->task;
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+ kexec_stack.thread_info.flags = 0;
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+
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+ /* Some things are best done in assembly. Finding globals with
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+ * a toc is easier in C, so pass in what we can.
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+ */
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+ kexec_sequence(&kexec_stack, image->start, image,
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+ page_address(image->control_code_page),
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+ ppc_md.hpte_clear_all);
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+ /* NOTREACHED */
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+}
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R Sharada