#include <linux/sched.h>
#include <linux/stacktrace.h>
-#include "stacktrace.h"
+#include <asm/stacktrace.h>
-int walk_stackframe(unsigned long fp, unsigned long low, unsigned long high,
- int (*fn)(struct stackframe *, void *), void *data)
+#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
+/*
+ * Unwind the current stack frame and store the new register values in the
+ * structure passed as argument. Unwinding is equivalent to a function return,
+ * hence the new PC value rather than LR should be used for backtrace.
+ *
+ * With framepointer enabled, a simple function prologue looks like this:
+ * mov ip, sp
+ * stmdb sp!, {fp, ip, lr, pc}
+ * sub fp, ip, #4
+ *
+ * A simple function epilogue looks like this:
+ * ldm sp, {fp, sp, pc}
+ *
+ * Note that with framepointer enabled, even the leaf functions have the same
+ * prologue and epilogue, therefore we can ignore the LR value in this case.
+ */
+int unwind_frame(struct stackframe *frame)
{
- struct stackframe *frame;
+ unsigned long high, low;
+ unsigned long fp = frame->fp;
- do {
- /*
- * Check current frame pointer is within bounds
- */
- if (fp < (low + 12) || fp + 4 >= high)
- break;
-
- frame = (struct stackframe *)(fp - 12);
+ /* only go to a higher address on the stack */
+ low = frame->sp;
+ high = ALIGN(low, THREAD_SIZE) + THREAD_SIZE;
- if (fn(frame, data))
- break;
+ /* check current frame pointer is within bounds */
+ if (fp < (low + 12) || fp + 4 >= high)
+ return -EINVAL;
- /*
- * Update the low bound - the next frame must always
- * be at a higher address than the current frame.
- */
- low = fp + 4;
- fp = frame->fp;
- } while (fp);
+ /* restore the registers from the stack frame */
+ frame->fp = *(unsigned long *)(fp - 12);
+ frame->sp = *(unsigned long *)(fp - 8);
+ frame->pc = *(unsigned long *)(fp - 4);
return 0;
}
+#endif
+
+void walk_stackframe(struct stackframe *frame,
+ int (*fn)(struct stackframe *, void *), void *data)
+{
+ while (1) {
+ int ret;
+
+ if (fn(frame, data))
+ break;
+ ret = unwind_frame(frame);
+ if (ret < 0)
+ break;
+ }
+}
EXPORT_SYMBOL(walk_stackframe);
#ifdef CONFIG_STACKTRACE
struct stack_trace_data {
struct stack_trace *trace;
+ unsigned int no_sched_functions;
unsigned int skip;
};
{
struct stack_trace_data *data = d;
struct stack_trace *trace = data->trace;
+ unsigned long addr = frame->pc;
+ if (data->no_sched_functions && in_sched_functions(addr))
+ return 0;
if (data->skip) {
data->skip--;
return 0;
}
- trace->entries[trace->nr_entries++] = frame->lr;
+ trace->entries[trace->nr_entries++] = addr;
return trace->nr_entries >= trace->max_entries;
}
-void save_stack_trace(struct stack_trace *trace)
+void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
struct stack_trace_data data;
- unsigned long fp, base;
+ struct stackframe frame;
data.trace = trace;
data.skip = trace->skip;
- base = (unsigned long)task_stack_page(current);
- asm("mov %0, fp" : "=r" (fp));
- walk_stackframe(fp, base, base + THREAD_SIZE, save_trace, &data);
+ if (tsk != current) {
+#ifdef CONFIG_SMP
+ /*
+ * What guarantees do we have here that 'tsk'
+ * is not running on another CPU?
+ */
+ BUG();
+#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 */
+ frame.pc = thread_saved_pc(tsk);
+#endif
+ } else {
+ register unsigned long current_sp asm ("sp");
+
+ data.no_sched_functions = 0;
+ 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;
+ }
+
+ walk_stackframe(&frame, save_trace, &data);
+ if (trace->nr_entries < trace->max_entries)
+ trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+
+void save_stack_trace(struct stack_trace *trace)
+{
+ save_stack_trace_tsk(current, trace);
}
+EXPORT_SYMBOL_GPL(save_stack_trace);
#endif