[ARM] Add ability to dump exception stacks to kernel backtraces

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 20 insertions, 3 deletions

diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c
index e101846ab7dd..a72b82e727f1 100644
--- a/arch/arm/kernel/irq.c
+++ b/arch/arm/kernel/irq.c
@@ -109,7 +109,7 @@ static struct irq_desc bad_irq_desc = {
  * come via this function.  Instead, they should provide their
  * own 'handler'
  */
-asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
+asmlinkage void __exception asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 {
         struct pt_regs *old_regs = set_irq_regs(regs);
         struct irq_desc *desc = irq_desc + irq;
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 24095601359b..ba1c1884e68e 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -45,7 +45,18 @@ static int __init user_debug_setup(char *str)
 __setup("user_debug=", user_debug_setup);
 #endif
 
-void dump_backtrace_entry(unsigned long where, unsigned long from)
+static void dump_mem(const char *str, unsigned long bottom, unsigned long top);
+
+static inline int in_exception_text(unsigned long ptr)
+{
+        extern char __exception_text_start[];
+        extern char __exception_text_end[];
+
+        return ptr >= (unsigned long)&__exception_text_start &&
+               ptr < (unsigned long)&__exception_text_end;
+}
+
+void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
 {
 #ifdef CONFIG_KALLSYMS
         printk("[<%08lx>] ", where);
@@ -55,6 +66,9 @@ void dump_backtrace_entry(unsigned long where, unsigned long from)
 #else
         printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
 #endif
+
+        if (in_exception_text(where))
+                dump_mem("Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
 }
 
 /*
@@ -266,7 +280,7 @@ void unregister_undef_hook(struct undef_hook *hook)
         spin_unlock_irqrestore(&undef_lock, flags);
 }
 
-asmlinkage void do_undefinstr(struct pt_regs *regs)
+asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 {
         unsigned int correction = thumb_mode(regs) ? 2 : 4;
         unsigned int instr;
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index ddbdad48f5b2..b295f6a85cf1 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -83,6 +83,9 @@ SECTIONS
 
         .text : {                       /* Real text segment            */
                 _text = .;              /* Text and read-only data      */
+                        __exception_text_start = .;
+                        *(.exception.text)
+                        __exception_text_end = .;
                         *(.text)
                         SCHED_TEXT
                         LOCK_TEXT