[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>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c417877..17fc60e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -34,6 +34,7 @@
ALSA ALSA sound support is enabled.
APIC APIC support is enabled.
APM Advanced Power Management support is enabled.
+ AVR32 AVR32 architecture is enabled.
AX25 Appropriate AX.25 support is enabled.
BLACKFIN Blackfin architecture is enabled.
DRM Direct Rendering Management support is enabled.
@@ -1123,6 +1124,10 @@
of returning the full 64-bit number.
The default is to return 64-bit inode numbers.
+ nmi_debug= [KNL,AVR32] Specify one or more actions to take
+ when a NMI is triggered.
+ Format: [state][,regs][,debounce][,die]
+
nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
diff --git a/arch/avr32/Kconfig b/arch/avr32/Kconfig
index 516015b..e34e2c9 100644
--- a/arch/avr32/Kconfig
+++ b/arch/avr32/Kconfig
@@ -170,6 +170,16 @@
enabling Nexus-compliant debuggers to keep track of the PID of the
currently executing task.
+config NMI_DEBUGGING
+ bool "NMI Debugging"
+ default n
+ help
+ Say Y here and pass the nmi_debug command-line parameter to
+ the kernel to turn on NMI debugging. Depending on the value
+ of the nmi_debug option, various pieces of information will
+ be dumped to the console when a Non-Maskable Interrupt
+ happens.
+
# FPU emulation goes here
source "kernel/Kconfig.hz"
diff --git a/arch/avr32/kernel/Makefile b/arch/avr32/kernel/Makefile
index bc224a4..e4b6d12 100644
--- a/arch/avr32/kernel/Makefile
+++ b/arch/avr32/kernel/Makefile
@@ -12,3 +12,4 @@
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 61f2de2..a8e767d 100644
--- a/arch/avr32/kernel/irq.c
+++ b/arch/avr32/kernel/irq.c
@@ -25,6 +25,17 @@
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 0000000..3414b85
--- /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 870c075..cf6f686 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 @@
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)
diff --git a/arch/avr32/mach-at32ap/at32ap700x.c b/arch/avr32/mach-at32ap/at32ap700x.c
index 9386e1f..14e61f0 100644
--- a/arch/avr32/mach-at32ap/at32ap700x.c
+++ b/arch/avr32/mach-at32ap/at32ap700x.c
@@ -13,6 +13,7 @@
#include <linux/spi/spi.h>
#include <asm/io.h>
+#include <asm/irq.h>
#include <asm/arch/at32ap700x.h>
#include <asm/arch/board.h>
diff --git a/arch/avr32/mach-at32ap/extint.c b/arch/avr32/mach-at32ap/extint.c
index f5bfd4c..e108e7b 100644
--- a/arch/avr32/mach-at32ap/extint.c
+++ b/arch/avr32/mach-at32ap/extint.c
@@ -26,16 +26,10 @@
#define EIC_MODE 0x0014
#define EIC_EDGE 0x0018
#define EIC_LEVEL 0x001c
-#define EIC_TEST 0x0020
#define EIC_NMIC 0x0024
-/* Bitfields in TEST */
-#define EIC_TESTEN_OFFSET 31
-#define EIC_TESTEN_SIZE 1
-
/* Bitfields in NMIC */
-#define EIC_EN_OFFSET 0
-#define EIC_EN_SIZE 1
+#define EIC_NMIC_ENABLE (1 << 0)
/* Bit manipulation macros */
#define EIC_BIT(name) \
@@ -63,6 +57,9 @@
unsigned int first_irq;
};
+static struct eic *nmi_eic;
+static bool nmi_enabled;
+
static void eic_ack_irq(unsigned int irq)
{
struct eic *eic = get_irq_chip_data(irq);
@@ -174,6 +171,24 @@
}
}
+int nmi_enable(void)
+{
+ nmi_enabled = true;
+
+ if (nmi_eic)
+ eic_writel(nmi_eic, NMIC, EIC_NMIC_ENABLE);
+
+ return 0;
+}
+
+void nmi_disable(void)
+{
+ if (nmi_eic)
+ eic_writel(nmi_eic, NMIC, 0);
+
+ nmi_enabled = false;
+}
+
static int __init eic_probe(struct platform_device *pdev)
{
struct eic *eic;
@@ -230,6 +245,16 @@
set_irq_chained_handler(int_irq, demux_eic_irq);
set_irq_data(int_irq, eic);
+ if (pdev->id == 0) {
+ nmi_eic = eic;
+ if (nmi_enabled)
+ /*
+ * Someone tried to enable NMI before we were
+ * ready. Do it now.
+ */
+ nmi_enable();
+ }
+
dev_info(&pdev->dev,
"External Interrupt Controller at 0x%p, IRQ %u\n",
eic->regs, int_irq);
diff --git a/include/asm-avr32/irq.h b/include/asm-avr32/irq.h
index 83e6549..9315724 100644
--- a/include/asm-avr32/irq.h
+++ b/include/asm-avr32/irq.h
@@ -11,4 +11,9 @@
#define irq_canonicalize(i) (i)
+#ifndef __ASSEMBLER__
+int nmi_enable(void);
+void nmi_disable(void);
+#endif
+
#endif /* __ASM_AVR32_IOCTLS_H */
diff --git a/include/asm-avr32/kdebug.h b/include/asm-avr32/kdebug.h
index fd7e990..ca4f954 100644
--- a/include/asm-avr32/kdebug.h
+++ b/include/asm-avr32/kdebug.h
@@ -5,6 +5,7 @@
enum die_val {
DIE_BREAKPOINT,
DIE_SSTEP,
+ DIE_NMI,
};
#endif /* __ASM_AVR32_KDEBUG_H */