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-rw-r--r--arch/arm/kernel/stacktrace.c60
1 files changed, 55 insertions, 5 deletions
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index af4e8c8a5422..f065eb05d254 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))
@@ -80,16 +83,39 @@ 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;
}
-void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+/* This must be noinline to so that our skip calculation works correctly */
+static noinline void __save_stack_trace(struct task_struct *tsk,
+ struct stack_trace *trace, unsigned int nosched)
{
struct stack_trace_data data;
struct stackframe frame;
data.trace = trace;
+ data.last_pc = ULONG_MAX;
data.skip = trace->skip;
+ data.no_sched_functions = nosched;
if (tsk != current) {
#ifdef CONFIG_SMP
@@ -102,7 +128,6 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
trace->entries[trace->nr_entries++] = ULONG_MAX;
return;
#else
- data.no_sched_functions = 1;
frame.fp = thread_saved_fp(tsk);
frame.sp = thread_saved_sp(tsk);
frame.lr = 0; /* recovered from the stack */
@@ -111,11 +136,12 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
} else {
register unsigned long current_sp asm ("sp");
- data.no_sched_functions = 0;
+ /* We don't want this function nor the caller */
+ data.skip += 2;
frame.fp = (unsigned long)__builtin_frame_address(0);
frame.sp = current_sp;
frame.lr = (unsigned long)__builtin_return_address(0);
- frame.pc = (unsigned long)save_stack_trace_tsk;
+ frame.pc = (unsigned long)__save_stack_trace;
}
walk_stackframe(&frame, save_trace, &data);
@@ -123,9 +149,33 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
+void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
+{
+ struct stack_trace_data data;
+ struct stackframe frame;
+
+ data.trace = trace;
+ data.skip = trace->skip;
+ data.no_sched_functions = 0;
+
+ frame.fp = regs->ARM_fp;
+ frame.sp = regs->ARM_sp;
+ frame.lr = regs->ARM_lr;
+ frame.pc = regs->ARM_pc;
+
+ walk_stackframe(&frame, save_trace, &data);
+ if (trace->nr_entries < trace->max_entries)
+ trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+
+void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+{
+ __save_stack_trace(tsk, trace, 1);
+}
+
void save_stack_trace(struct stack_trace *trace)
{
- save_stack_trace_tsk(current, trace);
+ __save_stack_trace(current, trace, 0);
}
EXPORT_SYMBOL_GPL(save_stack_trace);
#endif