@@ -22,6 +22,19 @@
* A simple function epilogue looks like this:
* ldm sp, {fp, sp, pc}
*
+ * When compiled with clang, pc and sp are not pushed. A simple function
+ * prologue looks like this when built with clang:
+ *
+ * stmdb {..., fp, lr}
+ * add fp, sp, #x
+ * sub sp, sp, #y
+ *
+ * A simple function epilogue looks like this when built with clang:
+ *
+ * sub sp, fp, #x
+ * ldm {..., fp, 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.
*/
@@ -34,6 +47,16 @@ int notrace unwind_frame(struct stackfra
low = frame->sp;
high = ALIGN(low, THREAD_SIZE);
+#ifdef CONFIG_CC_IS_CLANG
+ /* check current frame pointer is within bounds */
+ if (fp < low + 4 || fp > high - 4)
+ return -EINVAL;
+
+ frame->sp = frame->fp;
+ frame->fp = *(unsigned long *)(fp);
+ frame->pc = frame->lr;
+ frame->lr = *(unsigned long *)(fp + 4);
+#else
/* check current frame pointer is within bounds */
if (fp < low + 12 || fp > high - 4)
return -EINVAL;
@@ -42,6 +65,7 @@ int notrace unwind_frame(struct stackfra
frame->fp = *(unsigned long *)(fp - 12);
frame->sp = *(unsigned long *)(fp - 8);
frame->pc = *(unsigned long *)(fp - 4);
+#endif
return 0;
}