x86, modpost: Replace last remnants of RETPOLINE with CONFIG_RETPOLINE

[GitHub/LineageOS/android_kernel_motorola_exynos9610.git] / include / linux / compiler-gcc.h

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index bb78e5bdff26334376eb54a4b142845bbbaf8c46..00b06d7efb830ea453dbe35a62fb8c71c98bc4fc 100644 (file)
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __LINUX_COMPILER_H
+#ifndef __LINUX_COMPILER_TYPES_H
 #error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
 #endif
 
@@ -65,6 +65,18 @@
 #define __must_be_array(a)     BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
 #endif
 
+/*
+ * Feature detection for gnu_inline (gnu89 extern inline semantics). Either
+ * __GNUC_STDC_INLINE__ is defined (not using gnu89 extern inline semantics,
+ * and we opt in to the gnu89 semantics), or __GNUC_STDC_INLINE__ is not
+ * defined so the gnu89 semantics are the default.
+ */
+#ifdef __GNUC_STDC_INLINE__
+# define __gnu_inline  __attribute__((gnu_inline))
+#else
+# define __gnu_inline
+#endif
+
 /*
  * Force always-inline if the user requests it so via the .config,
  * or if gcc is too old.
@@ -72,19 +84,22 @@
  * -Wunused-function.  This turns out to avoid the need for complex #ifdef
  * directives.  Suppress the warning in clang as well by using "unused"
  * function attribute, which is redundant but not harmful for gcc.
+ * Prefer gnu_inline, so that extern inline functions do not emit an
+ * externally visible function. This makes extern inline behave as per gnu89
+ * semantics rather than c99. This prevents multiple symbol definition errors
+ * of extern inline functions at link time.
+ * A lot of inline functions can cause havoc with function tracing.
  */
 #if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) ||               \
     !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
-#define inline inline          __attribute__((always_inline,unused)) notrace
-#define __inline__ __inline__  __attribute__((always_inline,unused)) notrace
-#define __inline __inline      __attribute__((always_inline,unused)) notrace
+#define inline \
+       inline __attribute__((always_inline, unused)) notrace __gnu_inline
 #else
-/* A lot of inline functions can cause havoc with function tracing */
-#define inline inline          __attribute__((unused)) notrace
-#define __inline__ __inline__  __attribute__((unused)) notrace
-#define __inline __inline      __attribute__((unused)) notrace
+#define inline inline          __attribute__((unused)) notrace __gnu_inline
 #endif
 
+#define __inline__ inline
+#define __inline inline
 #define __always_inline        inline __attribute__((always_inline))
 #define  noinline      __attribute__((noinline))
 
@@ -93,6 +108,10 @@
 #define __weak         __attribute__((weak))
 #define __alias(symbol)        __attribute__((alias(#symbol)))
 
+#ifdef CONFIG_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
@@ -167,8 +186,6 @@
 
 #if GCC_VERSION >= 40100
 # define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
-
-#define __nostackprotector     __attribute__((__optimize__("no-stack-protector")))
 #endif
 
 #if GCC_VERSION >= 40300
@@ -196,6 +213,11 @@
 #endif /* __CHECKER__ */
 #endif /* GCC_VERSION >= 40300 */
 
+#if GCC_VERSION >= 40400
+#define __optimize(level)      __attribute__((__optimize__(level)))
+#define __nostackprotector     __optimize("no-stack-protector")
+#endif /* GCC_VERSION >= 40400 */
+
 #if GCC_VERSION >= 40500
 
 #ifndef __CHECKER__
@@ -204,6 +226,15 @@
 #endif
 #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
@@ -214,7 +245,11 @@
  * 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")))
@@ -222,6 +257,9 @@
 #ifdef RANDSTRUCT_PLUGIN
 #define __randomize_layout __attribute__((randomize_layout))
 #define __no_randomize_layout __attribute__((no_randomize_layout))
+/* This anon struct can add padding, so only enable it under randstruct. */
+#define randomized_struct_fields_start struct {
+#define randomized_struct_fields_end   } __randomize_layout;
 #endif
 
 #endif /* GCC_VERSION >= 40500 */
@@ -236,15 +274,6 @@
  */
 #define __visible      __attribute__((externally_visible))
 
-/*
- * RANDSTRUCT_PLUGIN wants to use an anonymous struct, but it is only
- * possible since GCC 4.6. To provide as much build testing coverage
- * as possible, this is used for all GCC 4.6+ builds, and not just on
- * RANDSTRUCT_PLUGIN builds.
- */
-#define randomized_struct_fields_start struct {
-#define randomized_struct_fields_end   } __randomize_layout;
-
 #endif /* GCC_VERSION >= 40600 */