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Diffstat (limited to 'arch/powerpc/kexec/core_64.c')
-rw-r--r--arch/powerpc/kexec/core_64.c417
1 files changed, 417 insertions, 0 deletions
diff --git a/arch/powerpc/kexec/core_64.c b/arch/powerpc/kexec/core_64.c
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+++ b/arch/powerpc/kexec/core_64.c
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+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * PPC64 code to handle Linux booting another kernel.
+ *
+ * Copyright (C) 2004-2005, IBM Corp.
+ *
+ * Created by: Milton D Miller II
+ */
+
+
+#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/firmware.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>
+#include <asm/asm-prototypes.h>
+#include <asm/svm.h>
+#include <asm/ultravisor.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;
+
+ /*
+ * 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;
+
+ /* 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;
+}
+
+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_ptrs[]->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_ptrs[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_ptrs[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;
+
+ /*
+ * Before removing MMU mappings make sure all CPUs have entered real
+ * mode:
+ */
+ kexec_prepare_cpus_wait(KEXEC_STATE_REAL_MODE);
+
+ /* after we tell the others to go down */
+ if (ppc_md.kexec_cpu_down)
+ ppc_md.kexec_cpu_down(0, 0);
+
+ 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),
+ bool copy_with_mmu_off) __noreturn;
+
+/* too late to fail here */
+void default_machine_kexec(struct kimage *image)
+{
+ bool copy_with_mmu_off;
+
+ /* 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();
+
+ printk("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!
+ */
+ current_thread_info()->flags = 0;
+ current_thread_info()->preempt_count = HARDIRQ_OFFSET;
+
+ /* We need a static PACA, too; copy this CPU's PACA over and switch to
+ * it. Also poison per_cpu_offset and NULL lppaca to catch anyone using
+ * non-static data.
+ */
+ memcpy(&kexec_paca, get_paca(), sizeof(struct paca_struct));
+ kexec_paca.data_offset = 0xedeaddeadeeeeeeeUL;
+#ifdef CONFIG_PPC_PSERIES
+ kexec_paca.lppaca_ptr = NULL;
+#endif
+
+ if (is_secure_guest() && !(image->preserve_context ||
+ image->type == KEXEC_TYPE_CRASH)) {
+ uv_unshare_all_pages();
+ printk("kexec: Unshared all shared pages.\n");
+ }
+
+ paca_ptrs[kexec_paca.paca_index] = &kexec_paca;
+
+ setup_paca(&kexec_paca);
+
+ /*
+ * The lppaca should be unregistered at this point so the HV won't
+ * touch it. In the case of a crash, none of the lppacas are
+ * unregistered so there is not much we can do about it here.
+ */
+
+ /*
+ * On Book3S, the copy must happen with the MMU off if we are either
+ * using Radix page tables or we are not in an LPAR since we can
+ * overwrite the page tables while copying.
+ *
+ * In an LPAR, we keep the MMU on otherwise we can't access beyond
+ * the RMA. On BookE there is no real MMU off mode, so we have to
+ * keep it enabled as well (but then we have bolted TLB entries).
+ */
+#ifdef CONFIG_PPC_BOOK3E
+ copy_with_mmu_off = false;
+#else
+ copy_with_mmu_off = radix_enabled() ||
+ !(firmware_has_feature(FW_FEATURE_LPAR) ||
+ firmware_has_feature(FW_FEATURE_PS3_LV1));
+#endif
+
+ /* 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),
+ mmu_cleanup_all, copy_with_mmu_off);
+ /* NOTREACHED */
+}
+
+#ifdef CONFIG_PPC_BOOK3S_64
+/* 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;
+
+ /* 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 */
+ of_remove_property(node, of_find_property(node, htab_base_prop.name, NULL));
+ of_remove_property(node, of_find_property(node, htab_size_prop.name, NULL));
+
+ 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);
+#endif /* CONFIG_PPC_BOOK3S_64 */