1 files changed, 6 insertions, 68 deletions

diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 85aea381fbf6..665c7fedc65b 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -18,11 +18,9 @@
 #include <linux/kasan.h>
 #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>
 
 /*
@@ -38,29 +36,15 @@
  *	ldp	x29, x30, [sp]
  *	add	sp, sp, #0x10
  */
-int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
+int notrace unwind_frame(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;
-	/* 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;
+	high = ALIGN(low, THREAD_SIZE);
 
-	if (fp < low || fp > high || fp & 0xf)
+	if (fp < low || fp > high - 0x18 || fp & 0xf)
 		return -EINVAL;
 
 	kasan_disable_current();
@@ -69,55 +53,12 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
 	frame->fp = *(unsigned long *)(fp);
 	frame->pc = *(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;
-		}
-	}
-
 	kasan_enable_current();
 
 	return 0;
 }
 
-void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
+void notrace walk_stackframe(struct stackframe *frame,
 		     int (*fn)(struct stackframe *, void *), void *data)
 {
 	while (1) {
@@ -125,7 +66,7 @@ void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
 
 		if (fn(frame, data))
 			break;
-		ret = unwind_frame(tsk, frame);
+		ret = unwind_frame(frame);
 		if (ret < 0)
 			break;
 	}
@@ -176,11 +117,8 @@ 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(tsk, &frame, save_trace, &data);
+	walk_stackframe(&frame, save_trace, &data);
 	if (trace->nr_entries < trace->max_entries)
 		trace->entries[trace->nr_entries++] = ULONG_MAX;
 }