powerpc/kexec: Move kexec files into a dedicated subdir.

arch/powerpc/kernel/ contains 8 files dedicated to kexec.

Move them into a dedicated subdirectory.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Move to a/p/kexec, drop the 'machine' naming and use 'core' instead]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/afbef97ec6a978574a5cf91a4441000e0a9da42a.1572351221.git.christophe.leroy@c-s.fr

1 files changed, 417 insertions, 0 deletions

diff --git a/arch/powerpc/kexec/core_64.c b/arch/powerpc/kexec/core_64.c
new file mode 100644
index 000000000000..04a7cba58eff
--- /dev/null
+++ b/arch/powerpc/kexec/core_64.c
@@ -0,0 +1,417 @@
+// 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 */