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Diffstat (limited to 'arch/arm64/kernel/stacktrace.c')
-rw-r--r--arch/arm64/kernel/stacktrace.c78
1 files changed, 70 insertions, 8 deletions
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index ccb6078ed..d9751a476 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -17,9 +17,11 @@
*/
#include <linux/kernel.h>
#include <linux/export.h>
+#include <linux/ftrace.h>
#include <linux/sched.h>
#include <linux/stacktrace.h>
+#include <asm/irq.h>
#include <asm/stacktrace.h>
/*
@@ -35,25 +37,82 @@
* ldp x29, x30, [sp]
* add sp, sp, #0x10
*/
-int notrace unwind_frame(struct stackframe *frame)
+int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
{
unsigned long high, low;
unsigned long fp = frame->fp;
+ unsigned long irq_stack_ptr;
+
+ /*
+ * Switching between stacks is valid when tracing current and in
+ * non-preemptible context.
+ */
+ if (tsk == current && !preemptible())
+ irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
+ else
+ irq_stack_ptr = 0;
low = frame->sp;
- high = ALIGN(low, THREAD_SIZE);
+ /* irq stacks are not THREAD_SIZE aligned */
+ if (on_irq_stack(frame->sp, raw_smp_processor_id()))
+ high = irq_stack_ptr;
+ else
+ high = ALIGN(low, THREAD_SIZE) - 0x20;
- if (fp < low || fp > high - 0x18 || fp & 0xf)
+ if (fp < low || fp > high || fp & 0xf)
return -EINVAL;
frame->sp = fp + 0x10;
- frame->fp = *(unsigned long *)(fp);
- frame->pc = *(unsigned long *)(fp + 8);
+ frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));
+ frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8));
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ if (tsk && tsk->ret_stack &&
+ (frame->pc == (unsigned long)return_to_handler)) {
+ /*
+ * This is a case where function graph tracer has
+ * modified a return address (LR) in a stack frame
+ * to hook a function return.
+ * So replace it to an original value.
+ */
+ frame->pc = tsk->ret_stack[frame->graph--].ret;
+ }
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+ /*
+ * Check whether we are going to walk through from interrupt stack
+ * to task stack.
+ * If we reach the end of the stack - and its an interrupt stack,
+ * unpack the dummy frame to find the original elr.
+ *
+ * Check the frame->fp we read from the bottom of the irq_stack,
+ * and the original task stack pointer are both in current->stack.
+ */
+ if (frame->sp == irq_stack_ptr) {
+ struct pt_regs *irq_args;
+ unsigned long orig_sp = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);
+
+ if (object_is_on_stack((void *)orig_sp) &&
+ object_is_on_stack((void *)frame->fp)) {
+ frame->sp = orig_sp;
+
+ /* orig_sp is the saved pt_regs, find the elr */
+ irq_args = (struct pt_regs *)orig_sp;
+ frame->pc = irq_args->pc;
+ } else {
+ /*
+ * This frame has a non-standard format, and we
+ * didn't fix it, because the data looked wrong.
+ * Refuse to output this frame.
+ */
+ return -EINVAL;
+ }
+ }
return 0;
}
-void notrace walk_stackframe(struct stackframe *frame,
+void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
int (*fn)(struct stackframe *, void *), void *data)
{
while (1) {
@@ -61,7 +120,7 @@ void notrace walk_stackframe(struct stackframe *frame,
if (fn(frame, data))
break;
- ret = unwind_frame(frame);
+ ret = unwind_frame(tsk, frame);
if (ret < 0)
break;
}
@@ -112,8 +171,11 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
frame.sp = current_stack_pointer;
frame.pc = (unsigned long)save_stack_trace_tsk;
}
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ frame.graph = tsk->curr_ret_stack;
+#endif
- walk_stackframe(&frame, save_trace, &data);
+ walk_stackframe(tsk, &frame, save_trace, &data);
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}