[PATCH v5 04/38] kmsan: introduce __no_sanitize_memory and __SANITIZE_MEMORY__

From: glider@google.com
To: Vegard Nossum <vegard.nossum@oracle.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	 Marco Elver <elver@google.com>,
	Andrey Konovalov <andreyknvl@google.com>,
	linux-mm@kvack.org
Cc: glider@google.com, viro@zeniv.linux.org.uk,
	adilger.kernel@dilger.ca,  akpm@linux-foundation.org,
	aryabinin@virtuozzo.com, luto@kernel.org,
	 ard.biesheuvel@linaro.org, arnd@arndb.de, hch@infradead.org,
	hch@lst.de,  darrick.wong@oracle.com, davem@davemloft.net,
	dmitry.torokhov@gmail.com,  ebiggers@google.com,
	edumazet@google.com, ericvh@gmail.com,
	 gregkh@linuxfoundation.org, harry.wentland@amd.com,
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	rdunlap@infradead.org, robin.murphy@arm.com,
	 sergey.senozhatsky@gmail.com, rostedt@goodmis.org,
	tiwai@suse.com,  tytso@mit.edu, tglx@linutronix.de,
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Subject: [PATCH v5 04/38] kmsan: introduce __no_sanitize_memory and __SANITIZE_MEMORY__
Date: Wed, 25 Mar 2020 17:12:15 +0100	[thread overview]
Message-ID: <20200325161249.55095-5-glider@google.com> (raw)
In-Reply-To: <20200325161249.55095-1-glider@google.com>

__no_sanitize_memory is a function attribute that makes KMSAN
ignore the uninitialized values coming from the function's
inputs, and initialize the function's outputs.

Functions marked with this attribute can't be inlined into functions
not marked with it, and vice versa.

__SANITIZE_MEMORY__ is a macro that's defined iff the file is
instrumented with KMSAN. This is not the same as CONFIG_KMSAN, which is
defined for every file.

Signed-off-by: Alexander Potapenko <glider@google.com>
To: Alexander Potapenko <glider@google.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: linux-mm@kvack.org
Acked-by: Marco Elver <elver@google.com>

---

v4:
 - dropped an unnecessary comment as requested by Marco Elver

Change-Id: I1f1672652c8392f15f7ca8ac26cd4e71f9cc1e4b
---
 include/linux/compiler-clang.h | 7 +++++++
 include/linux/compiler-gcc.h   | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
index 2cb42d8bdedc6..d4f929b4a6705 100644
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -33,6 +33,13 @@
 #define __no_sanitize_thread
 #endif
 
+#if __has_feature(memory_sanitizer)
+# define __SANITIZE_MEMORY__
+# define __no_sanitize_memory __attribute__((no_sanitize("kernel-memory")))
+#else
+# define __no_sanitize_memory
+#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-gcc.h b/include/linux/compiler-gcc.h
index cf294faec2f87..1121557252f88 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -151,6 +151,11 @@
 #define __no_sanitize_thread
 #endif
 
+/*
+ * GCC doesn't support KMSAN.
+ */
+#define __no_sanitize_memory
+
 #if GCC_VERSION >= 50100
 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
 #endif
-- 
2.25.1.696.g5e7596f4ac-goog


