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authorLinus Torvalds <torvalds@linux-foundation.org>2020-08-04 13:38:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-04 13:38:35 -0700
commit5b5d3be5d690a94be390ccf3e4db8dcb7409bf75 (patch)
tree3a5a4981e702c4a7db1f74c7c5471db248d509fc /Makefile
parent3e4a12a1bafafecaf1631f02099e82b424967718 (diff)
parentf0fe00d4972a8cd4b98cc2c29758615e4d51cdfe (diff)
Merge tag 'var-init-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull automatic variable initialization updates from Kees Cook: "This adds the "zero" init option from Clang, which is being used widely in production builds of Android and Chrome OS (though it also keeps the "pattern" init, which is better for debug builds). - Introduce CONFIG_INIT_STACK_ALL_ZERO (Alexander Potapenko)" * tag 'var-init-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: security: allow using Clang's zero initialization for stack variables
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile13
1 files changed, 11 insertions, 2 deletions
diff --git a/Makefile b/Makefile
index aef9ca61caf0..09c1bd1fcb64 100644
--- a/Makefile
+++ b/Makefile
@@ -803,11 +803,20 @@ KBUILD_CFLAGS += -fomit-frame-pointer
endif
endif
-# Initialize all stack variables with a pattern, if desired.
-ifdef CONFIG_INIT_STACK_ALL
+# Initialize all stack variables with a 0xAA pattern.
+ifdef CONFIG_INIT_STACK_ALL_PATTERN
KBUILD_CFLAGS += -ftrivial-auto-var-init=pattern
endif
+# Initialize all stack variables with a zero value.
+ifdef CONFIG_INIT_STACK_ALL_ZERO
+# Future support for zero initialization is still being debated, see
+# https://bugs.llvm.org/show_bug.cgi?id=45497. These flags are subject to being
+# renamed or dropped.
+KBUILD_CFLAGS += -ftrivial-auto-var-init=zero
+KBUILD_CFLAGS += -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang
+endif
+
DEBUG_CFLAGS := $(call cc-option, -fno-var-tracking-assignments)
ifdef CONFIG_DEBUG_INFO