For CONFIG_INIT_STACK_ALL it's sometimes handy to disable
force-initialization for a local variable, if it is known to be initialized
later on before the first use. This can be done by using the
__do_not_initialize macro.
__do_not_initialize should be applied carefully, as future changes to
the code around the local variable may introduce paths on which the
variable remains uninitialized before the use.
Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
---
include/linux/compiler-clang.h | 10 ++++++++++
include/linux/compiler_types.h | 4 ++++
2 files changed, 14 insertions(+)
diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
index 333a6695a918c..9204334d39261 100644
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -24,6 +24,16 @@
#define __no_sanitize_address
#endif
+/*
+ * Disable initialization of a local variable when building with
+ * CONFIG_INIT_STACK_ALL.
+ */
+#ifdef CONFIG_INIT_STACK_ALL
+#define __do_not_initialize __attribute__((uninitialized))
+#else
+#define __do_not_initialize
+#endif
+
/*
* Not all versions of clang implement the the type-generic versions
* of the builtin overflow checkers. Fortunately, clang implements
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 72393a8c1a6c5..b216beb5586fc 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -180,6 +180,10 @@ struct ftrace_likely_data {
#endif /* __ASSEMBLY__ */
+#ifndef __do_not_initialize
+#define __do_not_initialize
+#endif
+
/*
* The below symbols may be defined for one or more, but not ALL, of the above
* compilers. We don't consider that to be an error, so set them to nothing.
--
2.25.0.265.gbab2e86ba0-goog
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