From e7ba176b47db2ed53f258a6b4fe9d9fc6fa437a9 Mon Sep 17 00:00:00 2001 From: Haavard Skinnemoen Date: Wed, 10 Oct 2007 14:58:29 +0200 Subject: [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 --- arch/avr32/kernel/Makefile | 1 + arch/avr32/kernel/irq.c | 11 ++++++ arch/avr32/kernel/nmi_debug.c | 82 +++++++++++++++++++++++++++++++++++++++++++ arch/avr32/kernel/traps.c | 21 +++++++++-- 4 files changed, 112 insertions(+), 3 deletions(-) create mode 100644 arch/avr32/kernel/nmi_debug.c (limited to 'arch/avr32/kernel') diff --git a/arch/avr32/kernel/Makefile b/arch/avr32/kernel/Makefile index bc224a4e39fe..e4b6d122b033 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 61f2de266f62..a8e767d836aa 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 000000000000..3414b8566c29 --- /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 +#include +#include +#include + +#include + +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 870c075e6314..cf6f686d9b0b 100644 --- a/arch/avr32/kernel/traps.c +++ b/arch/avr32/kernel/traps.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -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) -- cgit v1.2.3