From 1243ffe734046745fc677f4f62d63b28b4677466 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Mon, 3 Aug 2009 09:31:54 +0200
Subject: [PATCH] --- yaml --- r: 158035 b: refs/heads/master c:
 47cab6a722d44c71c4f8224017ef548522243cf4 h: refs/heads/master i:   158033:
 74c90a1096921e10b7c754fe1f5f8df34e48ac30   158031:
 27d3111ca074a366cb8c5eaf3a564df0ed3581e8 v: v3

---
 [refs]                                |  2 +-
 trunk/arch/sparc/include/asm/irq_64.h |  4 ++--
 trunk/arch/sparc/kernel/process_64.c  |  4 ++--
 trunk/arch/x86/include/asm/nmi.h      |  4 ++--
 trunk/arch/x86/kernel/apic/nmi.c      |  2 +-
 trunk/drivers/char/sysrq.c            | 15 ++++++++++++++-
 trunk/include/linux/nmi.h             | 19 +++++++++++++++++--
 7 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/[refs] b/[refs]
index f2f9b100aed4..551ccd5da2b3 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c1dc0b9c0c8979ce4d411caadff5c0d79dee58bc
+refs/heads/master: 47cab6a722d44c71c4f8224017ef548522243cf4
diff --git a/trunk/arch/sparc/include/asm/irq_64.h b/trunk/arch/sparc/include/asm/irq_64.h
index 1934f2cbf513..a0b443cb3c1f 100644
--- a/trunk/arch/sparc/include/asm/irq_64.h
+++ b/trunk/arch/sparc/include/asm/irq_64.h
@@ -89,8 +89,8 @@ static inline unsigned long get_softint(void)
 	return retval;
 }
 
-void __trigger_all_cpu_backtrace(void);
-#define trigger_all_cpu_backtrace() __trigger_all_cpu_backtrace()
+void arch_trigger_all_cpu_backtrace(void);
+#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
 
 extern void *hardirq_stack[NR_CPUS];
 extern void *softirq_stack[NR_CPUS];
diff --git a/trunk/arch/sparc/kernel/process_64.c b/trunk/arch/sparc/kernel/process_64.c
index 4041f94e7724..18d67854a1b8 100644
--- a/trunk/arch/sparc/kernel/process_64.c
+++ b/trunk/arch/sparc/kernel/process_64.c
@@ -251,7 +251,7 @@ static void __global_reg_poll(struct global_reg_snapshot *gp)
 	}
 }
 
-void __trigger_all_cpu_backtrace(void)
+void arch_trigger_all_cpu_backtrace(void)
 {
 	struct thread_info *tp = current_thread_info();
 	struct pt_regs *regs = get_irq_regs();
@@ -304,7 +304,7 @@ void __trigger_all_cpu_backtrace(void)
 
 static void sysrq_handle_globreg(int key, struct tty_struct *tty)
 {
-	__trigger_all_cpu_backtrace();
+	arch_trigger_all_cpu_backtrace();
 }
 
 static struct sysrq_key_op sparc_globalreg_op = {
diff --git a/trunk/arch/x86/include/asm/nmi.h b/trunk/arch/x86/include/asm/nmi.h
index c86e5ed4af51..e63cf7d441e1 100644
--- a/trunk/arch/x86/include/asm/nmi.h
+++ b/trunk/arch/x86/include/asm/nmi.h
@@ -45,8 +45,8 @@ extern int proc_nmi_enabled(struct ctl_table *, int , struct file *,
 			void __user *, size_t *, loff_t *);
 extern int unknown_nmi_panic;
 
-void __trigger_all_cpu_backtrace(void);
-#define trigger_all_cpu_backtrace() __trigger_all_cpu_backtrace()
+void arch_trigger_all_cpu_backtrace(void);
+#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
 
 static inline void localise_nmi_watchdog(void)
 {
diff --git a/trunk/arch/x86/kernel/apic/nmi.c b/trunk/arch/x86/kernel/apic/nmi.c
index 1bb1ac20e9ec..db7220220d09 100644
--- a/trunk/arch/x86/kernel/apic/nmi.c
+++ b/trunk/arch/x86/kernel/apic/nmi.c
@@ -554,7 +554,7 @@ int do_nmi_callback(struct pt_regs *regs, int cpu)
 	return 0;
 }
 
-void __trigger_all_cpu_backtrace(void)
+void arch_trigger_all_cpu_backtrace(void)
 {
 	int i;
 
diff --git a/trunk/drivers/char/sysrq.c b/trunk/drivers/char/sysrq.c
index 165f307f30e8..50eecfe1d724 100644
--- a/trunk/drivers/char/sysrq.c
+++ b/trunk/drivers/char/sysrq.c
@@ -223,7 +223,20 @@ static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus);
 
 static void sysrq_handle_showallcpus(int key, struct tty_struct *tty)
 {
-	trigger_all_cpu_backtrace();
+	/*
+	 * Fall back to the workqueue based printing if the
+	 * backtrace printing did not succeed or the
+	 * architecture has no support for it:
+	 */
+	if (!trigger_all_cpu_backtrace()) {
+		struct pt_regs *regs = get_irq_regs();
+
+		if (regs) {
+			printk(KERN_INFO "CPU%d:\n", smp_processor_id());
+			show_regs(regs);
+		}
+		schedule_work(&sysrq_showallcpus);
+	}
 }
 
 static struct sysrq_key_op sysrq_showallcpus_op = {
diff --git a/trunk/include/linux/nmi.h b/trunk/include/linux/nmi.h
index 29af2d5df097..b752e807adde 100644
--- a/trunk/include/linux/nmi.h
+++ b/trunk/include/linux/nmi.h
@@ -28,8 +28,23 @@ static inline void acpi_nmi_disable(void) { }
 static inline void acpi_nmi_enable(void) { }
 #endif
 
-#ifndef trigger_all_cpu_backtrace
-#define trigger_all_cpu_backtrace() do { } while (0)
+/*
+ * Create trigger_all_cpu_backtrace() out of the arch-provided
+ * base function. Return whether such support was available,
+ * to allow calling code to fall back to some other mechanism:
+ */
+#ifdef arch_trigger_all_cpu_backtrace
+static inline bool trigger_all_cpu_backtrace(void)
+{
+	arch_trigger_all_cpu_backtrace();
+
+	return true;
+}
+#else
+static inline bool trigger_all_cpu_backtrace(void)
+{
+	return false;
+}
 #endif
 
 #endif