1 files changed, 140 insertions, 108 deletions

diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index 704375bda73..879b3aacac3 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -13,7 +13,11 @@
 #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>
@@ -24,6 +28,7 @@
 #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)
 {
@@ -70,8 +75,7 @@ int default_machine_kexec_prepare(struct kimage *image)
 	}
 
 	/* 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")) {
+	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)
@@ -154,66 +158,115 @@ void kexec_copy_flush(struct kimage *image)
 
 #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)
+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);
 
-	local_irq_disable();
 	kexec_smp_wait();
 	/* NOTREACHED */
 }
 
-static void kexec_prepare_cpus(void)
+static void kexec_prepare_cpus_wait(int wait_state)
 {
 	int my_cpu, i, notified=-1;
 
-	smp_call_function(kexec_smp_down, NULL, 0, /* wait */0);
+	hw_breakpoint_disable();
 	my_cpu = get_cpu();
-
-	/* check the others cpus are now down (via paca hw cpu id == -1) */
-	for (i=0; i < NR_CPUS; i++) {
+	/* 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].hw_cpu_id != -1) {
+		while (paca[i].kexec_state < wait_state) {
 			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);
+				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);
 
-	put_cpu();
+	/*
+	 * Before removing MMU mappings make sure all CPUs have entered real
+	 * mode:
+	 */
+	kexec_prepare_cpus_wait(KEXEC_STATE_REAL_MODE);
 
-	local_irq_disable();
+	put_cpu();
 }
 
 #else /* ! SMP */
@@ -233,6 +286,7 @@ static void kexec_prepare_cpus(void)
 	if (ppc_md.kexec_cpu_down)
 		ppc_md.kexec_cpu_down(0, 0);
 	local_irq_disable();
+	hard_irq_disable();
 }
 
 #endif /* SMP */
@@ -249,13 +303,19 @@ static void kexec_prepare_cpus(void)
  * 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"))) = { };
+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 kexec_stub.S */
-extern NORET_TYPE void kexec_sequence(void *newstack, unsigned long start,
-					void *image, void *control,
-					void (*clear_all)(void)) ATTRIB_NORET;
+/* 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)
@@ -270,14 +330,33 @@ void default_machine_kexec(struct kimage *image)
         * using debugger IPI.
         */
 
-       if (crashing_cpu == -1)
-               kexec_prepare_cpus();
+	if (crashing_cpu == -1)
+		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.
@@ -289,7 +368,8 @@ void default_machine_kexec(struct kimage *image)
 }
 
 /* Values we need to export to the second kernel via the device tree. */
-static unsigned long htab_base, kernel_end;
+static unsigned long htab_base;
+static unsigned long htab_size;
 
 static struct property htab_base_prop = {
 	.name = "linux,htab-base",
@@ -300,84 +380,36 @@ static struct property htab_base_prop = {
 static struct property htab_size_prop = {
 	.name = "linux,htab-size",
 	.length = sizeof(unsigned long),
-	.value = &htab_size_bytes,
-};
-
-static struct property kernel_end_prop = {
-	.name = "linux,kernel-end",
-	.length = sizeof(unsigned long),
-	.value = &kernel_end,
+	.value = &htab_size,
 };
 
-static void __init export_htab_values(void)
+static int __init export_htab_values(void)
 {
 	struct device_node *node;
-
-	node = of_find_node_by_path("/chosen");
-	if (!node)
-		return;
-
-	kernel_end = __pa(_end);
-	prom_add_property(node, &kernel_end_prop);
+	struct property *prop;
 
 	/* On machines with no htab htab_address is NULL */
-	if (NULL == htab_address)
-		goto out;
-
-	htab_base = __pa(htab_address);
-	prom_add_property(node, &htab_base_prop);
-	prom_add_property(node, &htab_size_prop);
-
- out:
-	of_node_put(node);
-}
-
-static struct property crashk_base_prop = {
-	.name = "linux,crashkernel-base",
-	.length = sizeof(unsigned long),
-	.value = &crashk_res.start,
-};
-
-static unsigned long crashk_size;
-
-static struct property crashk_size_prop = {
-	.name = "linux,crashkernel-size",
-	.length = sizeof(unsigned long),
-	.value = &crashk_size,
-};
-
-static void __init export_crashk_values(void)
-{
-	struct device_node *node;
-	struct property *prop;
+	if (!htab_address)
+		return -ENODEV;
 
 	node = of_find_node_by_path("/chosen");
 	if (!node)
-		return;
+		return -ENODEV;
 
-	/* There might be existing crash kernel properties, but we can't
-	 * be sure what's in them, so remove them. */
-	prop = of_find_property(node, "linux,crashkernel-base", NULL);
+	/* remove any stale propertys so ours can be found */
+	prop = of_find_property(node, htab_base_prop.name, NULL);
 	if (prop)
-		prom_remove_property(node, prop);
-
-	prop = of_find_property(node, "linux,crashkernel-size", NULL);
+		of_remove_property(node, prop);
+	prop = of_find_property(node, htab_size_prop.name, NULL);
 	if (prop)
-		prom_remove_property(node, prop);
+		of_remove_property(node, prop);
 
-	if (crashk_res.start != 0) {
-		prom_add_property(node, &crashk_base_prop);
-		crashk_size = crashk_res.end - crashk_res.start + 1;
-		prom_add_property(node, &crashk_size_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);
-}
-
-static int __init kexec_setup(void)
-{
-	export_htab_values();
-	export_crashk_values();
 	return 0;
 }
-__initcall(kexec_setup);
+late_initcall(export_htab_values);