microblaze: Add stack unwinder
Implement intelligent backtracing by searching for stack frame creation,
and emitting only return addresses. Use print_hex_dump() to display the
entire binary kernel stack.
Limitation: MMU kernels are not currently able to trace beyond a system trap
(interrupt, syscall, etc.). It is the intent of this patch to provide
infrastructure that can be extended to add this capability later.
Changes from V1:
* Removed checks in find_frame_creation() that prevented location of the frame
creation instruction in heavily optimized code
* Various formatting/commenting/file location tweaks per review comments
* Dropped Kconfig option to enable STACKTRACE as something logically separate
Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
diff --git a/arch/microblaze/kernel/stacktrace.c b/arch/microblaze/kernel/stacktrace.c
index 123692f..84bc668 100644
--- a/arch/microblaze/kernel/stacktrace.c
+++ b/arch/microblaze/kernel/stacktrace.c
@@ -14,52 +14,18 @@
#include <linux/thread_info.h>
#include <linux/ptrace.h>
#include <linux/module.h>
+#include <asm/unwind.h>
-/* FIXME initial support */
void save_stack_trace(struct stack_trace *trace)
{
- unsigned long *sp;
- unsigned long addr;
- asm("addik %0, r1, 0" : "=r" (sp));
-
- while (!kstack_end(sp)) {
- addr = *sp++;
- if (__kernel_text_address(addr)) {
- if (trace->skip > 0)
- trace->skip--;
- else
- trace->entries[trace->nr_entries++] = addr;
-
- if (trace->nr_entries >= trace->max_entries)
- break;
- }
- }
+ /* Exclude our helper functions from the trace*/
+ trace->skip += 2;
+ microblaze_unwind(NULL, trace);
}
EXPORT_SYMBOL_GPL(save_stack_trace);
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
- unsigned int *sp;
- unsigned long addr;
-
- struct thread_info *ti = task_thread_info(tsk);
-
- if (tsk == current)
- asm("addik %0, r1, 0" : "=r" (sp));
- else
- sp = (unsigned int *)ti->cpu_context.r1;
-
- while (!kstack_end(sp)) {
- addr = *sp++;
- if (__kernel_text_address(addr)) {
- if (trace->skip > 0)
- trace->skip--;
- else
- trace->entries[trace->nr_entries++] = addr;
-
- if (trace->nr_entries >= trace->max_entries)
- break;
- }
- }
+ microblaze_unwind(tsk, trace);
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);