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authorHaavard Skinnemoen <hskinnemoen@atmel.com>2007-10-10 14:58:29 +0200
committerHaavard Skinnemoen <hskinnemoen@atmel.com>2008-01-25 08:31:43 +0100
commite7ba176b47db2ed53f258a6b4fe9d9fc6fa437a9 (patch)
treebeb9ffab7da0c24f11c04b6eb4ca29b23b1dd07b /arch/avr32/kernel
parentf6135d12db4bed3b992052020f1c50d749cd8dc6 (diff)
[AVR32] NMI debugging
Change the NMI handler to use the die notifier chain to signal anyone who cares. Add a simple "nmi debugger" which hooks into this chain and that may dump registers, task state, etc. when it happens. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Diffstat (limited to 'arch/avr32/kernel')
-rw-r--r--arch/avr32/kernel/Makefile1
-rw-r--r--arch/avr32/kernel/irq.c11
-rw-r--r--arch/avr32/kernel/nmi_debug.c82
-rw-r--r--arch/avr32/kernel/traps.c21
4 files changed, 112 insertions, 3 deletions
diff --git a/arch/avr32/kernel/Makefile b/arch/avr32/kernel/Makefile
index bc224a4e39f..e4b6d122b03 100644
--- a/arch/avr32/kernel/Makefile
+++ b/arch/avr32/kernel/Makefile
@@ -12,3 +12,4 @@ obj-y += init_task.o switch_to.o cpu.o
obj-$(CONFIG_MODULES) += module.o avr32_ksyms.o
obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
+obj-$(CONFIG_NMI_DEBUGGING) += nmi_debug.o
diff --git a/arch/avr32/kernel/irq.c b/arch/avr32/kernel/irq.c
index 61f2de266f6..a8e767d836a 100644
--- a/arch/avr32/kernel/irq.c
+++ b/arch/avr32/kernel/irq.c
@@ -25,6 +25,17 @@ void ack_bad_irq(unsigned int irq)
printk("unexpected IRQ %u\n", irq);
}
+/* May be overridden by platform code */
+int __weak nmi_enable(void)
+{
+ return -ENOSYS;
+}
+
+void __weak nmi_disable(void)
+{
+
+}
+
#ifdef CONFIG_PROC_FS
int show_interrupts(struct seq_file *p, void *v)
{
diff --git a/arch/avr32/kernel/nmi_debug.c b/arch/avr32/kernel/nmi_debug.c
new file mode 100644
index 00000000000..3414b8566c2
--- /dev/null
+++ b/arch/avr32/kernel/nmi_debug.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2007 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/delay.h>
+#include <linux/kdebug.h>
+#include <linux/notifier.h>
+#include <linux/sched.h>
+
+#include <asm/irq.h>
+
+enum nmi_action {
+ NMI_SHOW_STATE = 1 << 0,
+ NMI_SHOW_REGS = 1 << 1,
+ NMI_DIE = 1 << 2,
+ NMI_DEBOUNCE = 1 << 3,
+};
+
+static unsigned long nmi_actions;
+
+static int nmi_debug_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct die_args *args = data;
+
+ if (likely(val != DIE_NMI))
+ return NOTIFY_DONE;
+
+ if (nmi_actions & NMI_SHOW_STATE)
+ show_state();
+ if (nmi_actions & NMI_SHOW_REGS)
+ show_regs(args->regs);
+ if (nmi_actions & NMI_DEBOUNCE)
+ mdelay(10);
+ if (nmi_actions & NMI_DIE)
+ return NOTIFY_BAD;
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block nmi_debug_nb = {
+ .notifier_call = nmi_debug_notify,
+};
+
+static int __init nmi_debug_setup(char *str)
+{
+ char *p, *sep;
+
+ register_die_notifier(&nmi_debug_nb);
+ if (nmi_enable()) {
+ printk(KERN_WARNING "Unable to enable NMI.\n");
+ return 0;
+ }
+
+ if (*str != '=')
+ return 0;
+
+ for (p = str + 1; *p; p = sep + 1) {
+ sep = strchr(p, ',');
+ if (sep)
+ *sep = 0;
+ if (strcmp(p, "state") == 0)
+ nmi_actions |= NMI_SHOW_STATE;
+ else if (strcmp(p, "regs") == 0)
+ nmi_actions |= NMI_SHOW_REGS;
+ else if (strcmp(p, "debounce") == 0)
+ nmi_actions |= NMI_DEBOUNCE;
+ else if (strcmp(p, "die") == 0)
+ nmi_actions |= NMI_DIE;
+ else
+ printk(KERN_WARNING "NMI: Unrecognized action `%s'\n",
+ p);
+ if (!sep)
+ break;
+ }
+
+ return 0;
+}
+__setup("nmi_debug", nmi_debug_setup);
diff --git a/arch/avr32/kernel/traps.c b/arch/avr32/kernel/traps.c
index 870c075e631..cf6f686d9b0 100644
--- a/arch/avr32/kernel/traps.c
+++ b/arch/avr32/kernel/traps.c
@@ -9,6 +9,7 @@
#include <linux/bug.h>
#include <linux/init.h>
#include <linux/kallsyms.h>
+#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/sched.h>
@@ -107,9 +108,23 @@ void _exception(long signr, struct pt_regs *regs, int code,
asmlinkage void do_nmi(unsigned long ecr, struct pt_regs *regs)
{
- printk(KERN_ALERT "Got Non-Maskable Interrupt, dumping regs\n");
- show_regs_log_lvl(regs, KERN_ALERT);
- show_stack_log_lvl(current, regs->sp, regs, KERN_ALERT);
+ int ret;
+
+ nmi_enter();
+
+ ret = notify_die(DIE_NMI, "NMI", regs, 0, ecr, SIGINT);
+ switch (ret) {
+ case NOTIFY_OK:
+ case NOTIFY_STOP:
+ return;
+ case NOTIFY_BAD:
+ die("Fatal Non-Maskable Interrupt", regs, SIGINT);
+ default:
+ break;
+ }
+
+ printk(KERN_ALERT "Got NMI, but nobody cared. Disabling...\n");
+ nmi_disable();
}
asmlinkage void do_critical_exception(unsigned long ecr, struct pt_regs *regs)