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ARM: stacktrace: include exception PC value in stacktrace output

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When we unwind through an exception stack, include the saved PC value
into the stack trace: this fills in an otherwise missed functions from
the trace (as indicated below):

 [<c03f4424>] fec_enet_interrupt+0xa0/0xe8
 [<c0066c0c>] handle_irq_event_percpu+0x68/0x228
 [<c0066e18>] handle_irq_event+0x4c/0x6c
 [<c006a024>] handle_fasteoi_irq+0xac/0x198
 [<c00664b0>] generic_handle_irq+0x4c/0x60
 [<c000f014>] handle_IRQ+0x40/0x98
 [<c0008554>] gic_handle_irq+0x30/0x64
 [<c0012900>] __irq_svc+0x40/0x50
 [<c0029030>] __do_softirq+0xe0/0x2fc		<====
 [<c0029500>] irq_exit+0xb0/0x100
 [<c000f018>] handle_IRQ+0x44/0x98
 [<c0008554>] gic_handle_irq+0x30/0x64
 [<c0012900>] __irq_svc+0x40/0x50
 [<c000f34c>] arch_cpu_idle+0x30/0x38		<====
 [<c005e1e4>] cpu_startup_entry+0xac/0x214
 [<c066297c>] rest_init+0x68/0x80
 [<c08ccb10>] start_kernel+0x2fc/0x358

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2014-05-03 16:17:16 +01:00
parent 3683f44c42
commit 07b4034158
1 changed files with 23 additions and 0 deletions
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23
arch/arm/kernel/stacktrace.c
View file

@ -3,6 +3,7 @@
#include <linux/stacktrace.h>
#include <asm/stacktrace.h>
#include <asm/traps.h>
#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
/*
@ -61,6 +62,7 @@ EXPORT_SYMBOL(walk_stackframe);
#ifdef CONFIG_STACKTRACE
struct stack_trace_data {
struct stack_trace *trace;
unsigned long last_pc;
unsigned int no_sched_functions;
unsigned int skip;
};
@ -69,6 +71,7 @@ static int save_trace(struct stackframe *frame, void *d)
{
struct stack_trace_data *data = d;
struct stack_trace *trace = data->trace;
struct pt_regs *regs;
unsigned long addr = frame->pc;
if (data->no_sched_functions && in_sched_functions(addr))
@ -80,6 +83,25 @@ static int save_trace(struct stackframe *frame, void *d)
trace->entries[trace->nr_entries++] = addr;
if (trace->nr_entries >= trace->max_entries)
return 1;
/*
* in_exception_text() is designed to test if the PC is one of
* the functions which has an exception stack above it, but
* unfortunately what is in frame->pc is the return LR value,
* not the saved PC value. So, we need to track the previous
* frame PC value when doing this.
*/
addr = data->last_pc;
data->last_pc = frame->pc;
if (!in_exception_text(addr))
return 0;
regs = (struct pt_regs *)frame->sp;
trace->entries[trace->nr_entries++] = regs->ARM_pc;
return trace->nr_entries >= trace->max_entries;
}
@ -91,6 +113,7 @@ static noinline void __save_stack_trace(struct task_struct *tsk,
struct stackframe frame;
data.trace = trace;
data.last_pc = ULONG_MAX;
data.skip = trace->skip;
data.no_sched_functions = nosched;