1 files changed, 18 insertions, 1 deletions

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 73bc63e0a1c4..e2c7f4369eff 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -93,6 +93,10 @@
 #define __weak          __attribute__((weak))
 #define __alias(symbol) __attribute__((alias(#symbol)))
 
+#ifdef RETPOLINE
+#define __noretpoline __attribute__((indirect_branch("keep")))
+#endif
+
 /*
  * it doesn't make sense on ARM (currently the only user of __naked)
  * to trace naked functions because then mcount is called without
@@ -208,6 +212,15 @@
 #endif
 
 /*
+ * calling noreturn functions, __builtin_unreachable() and __builtin_trap()
+ * confuse the stack allocation in gcc, leading to overly large stack
+ * frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
+ *
+ * Adding an empty inline assembly before it works around the problem
+ */
+#define barrier_before_unreachable() asm volatile("")
+
+/*
  * Mark a position in code as unreachable.  This can be used to
  * suppress control flow warnings after asm blocks that transfer
  * control elsewhere.
@@ -217,7 +230,11 @@
  * unreleased.  Really, we need to have autoconf for the kernel.
  */
 #define unreachable() \
-        do { annotate_unreachable(); __builtin_unreachable(); } while (0)
+        do {                                    \
+                annotate_unreachable();         \
+                barrier_before_unreachable();   \
+                __builtin_unreachable();        \
+        } while (0)
 
 /* Mark a function definition as prohibited from being cloned. */
 #define __noclone       __attribute__((__noclone__, __optimize__("no-tracer")))