From fd188b183270ebc0a8bc1d9fd2e7a1713a6fcccb Mon Sep 17 00:00:00 2001
From: "awilliam@xenbuild2.aw" <awilliam@xenbuild2.aw>
Date: Tue, 23 Jan 2007 11:48:29 -0700
Subject: [PATCH] [IA64] Fix broken switch stack

unw_init_running() needs to be called later in the OS INIT handler
to prevent the switch stack from being broken by calls to other
functions.

Signed-off-by: Akio Takebe <takebe_akio@jp.fujitsu.com>
---
 xen/arch/ia64/linux-xen/mca.c | 60 ++++++++++++++++++++++++-----------
 1 file changed, 41 insertions(+), 19 deletions(-)

diff --git a/xen/arch/ia64/linux-xen/mca.c b/xen/arch/ia64/linux-xen/mca.c
index 8715ef1d5e..faa73e6672 100644
--- a/xen/arch/ia64/linux-xen/mca.c
+++ b/xen/arch/ia64/linux-xen/mca.c
@@ -684,16 +684,7 @@ fetch_min_state (pal_min_state_area_t *ms, struct pt_regs *pt, struct switch_sta
 #ifdef XEN
 static spinlock_t init_dump_lock = SPIN_LOCK_UNLOCKED;
 static spinlock_t show_stack_lock = SPIN_LOCK_UNLOCKED;
-
-static void
-save_ksp (struct unw_frame_info *info, void *arg)
-{
-	current->arch._thread.ksp = (__u64)(info->sw) - 16;
-	wmb();
-}
-
-/* FIXME */
-int try_crashdump(struct pt_regs *a) { return 0; }
+static atomic_t num_stopped_cpus = ATOMIC_INIT(0);
 
 #define CPU_FLUSH_RETRY_MAX 5
 static void
@@ -716,6 +707,35 @@ init_cache_flush (void)
 	}
 	printk("\nPAL cache flush failed. status=%ld\n",rval);
 }
+
+static void inline
+save_ksp (struct unw_frame_info *info)
+{
+	current->arch._thread.ksp = (__u64)(info->sw) - 16;
+	wmb();
+	init_cache_flush();
+}	
+
+static void
+freeze_cpu_osinit (struct unw_frame_info *info, void *arg)
+{
+	save_ksp(info);
+	atomic_inc(&num_stopped_cpus);
+	printk("%s: CPU%d init handler done\n",
+	       __FUNCTION__, smp_processor_id());
+	for (;;)
+		local_irq_disable();
+}
+
+/* FIXME */
+static void
+try_crashdump(struct unw_frame_info *info, void *arg)
+{ 
+	save_ksp(info);
+	printk("\nINIT dump complete.  Please reboot now.\n");
+	for (;;)
+		local_irq_disable();
+}
 #endif /* XEN */
 
 static void
@@ -741,7 +761,8 @@ init_handler_platform (pal_min_state_area_t *ms,
 	show_min_state(ms);
 
 #ifdef XEN
-	printk("Backtrace of current vcpu (vcpu_id %d)\n", current->vcpu_id);
+	printk("Backtrace of current vcpu (vcpu_id %d of domid %d)\n",
+	       current->vcpu_id, current->domain->domain_id);
 #else
 	printk("Backtrace of current task (pid %d, %s)\n", current->pid, current->comm);
 	fetch_min_state(ms, pt, sw);
@@ -749,20 +770,21 @@ init_handler_platform (pal_min_state_area_t *ms,
 	unw_init_from_interruption(&info, current, pt, sw);
 	ia64_do_show_stack(&info, NULL);
 #ifdef XEN
-	unw_init_running(save_ksp, NULL);
 	spin_unlock(&show_stack_lock);
-	wmb();
-	init_cache_flush();
 
 	if (spin_trylock(&init_dump_lock)) {
 #ifdef CONFIG_SMP
-		udelay(5*1000000);
+		int other_cpus = num_online_cpus() - 1;
+		int wait = 1000 * other_cpus;
+
+		while ((atomic_read(&num_stopped_cpus) != other_cpus) && wait--)
+			udelay(1000);
+		if (other_cpus && wait < 0)
+			printk("timeout %d\n", atomic_read(&num_stopped_cpus));
 #endif
-		if (try_crashdump(pt) == 0)
-			printk("\nINIT dump complete.  Please reboot now.\n");
+		unw_init_running(try_crashdump, pt);
 	}
-	printk("%s: CPU%d init handler done\n",
-	       __FUNCTION__, smp_processor_id());
+	unw_init_running(freeze_cpu_osinit, NULL);
 #else /* XEN */
 #ifdef CONFIG_SMP
 	/* read_trylock() would be handy... */
-- 
2.30.2