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authorRussell King <rmk+kernel@arm.linux.org.uk>2014-05-03 16:17:16 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2014-05-22 16:33:24 +0100
commit07b403415884e961920f55e6db462dff15d9df5a (patch)
treeb29b4cc10756b984ec30b48b6f7783e91f3f6c79 /arch/arm/kernel
parent3683f44c42e991d313dc301504ee0fca1aeb8580 (diff)
downloadop-kernel-dev-07b403415884e961920f55e6db462dff15d9df5a.zip
op-kernel-dev-07b403415884e961920f55e6db462dff15d9df5a.tar.gz
ARM: stacktrace: include exception PC value in stacktrace output
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>
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r--arch/arm/kernel/stacktrace.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index 6582c4adc..5a80ddf 100644
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -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;
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