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From: Kees Cook <keescook@chromium.org>
To: linux-hardening@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
	Will Deacon <will@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 11/82] arm64: atomics: lse: Silence intentional wrapping addition
Date: Mon, 22 Jan 2024 16:26:46 -0800
Message-Id: <20240123002814.1396804-11-keescook@chromium.org>
In-Reply-To: <20240122235208.work.748-kees@kernel.org>
References: <20240122235208.work.748-kees@kernel.org>
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MIME-Version: 1.0
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Annotate atomic_add_return() and atomic_sub_return() to avoid signed
overflow instrumentation. They are expected to wrap around.

Cc: Will Deacon <will@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/arm64/include/asm/atomic_lse.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/atomic_lse.h b/arch/arm64/include/asm/atomic_lse.h
index 87f568a94e55..30572458d702 100644
--- a/arch/arm64/include/asm/atomic_lse.h
+++ b/arch/arm64/include/asm/atomic_lse.h
@@ -79,13 +79,13 @@ ATOMIC_FETCH_OP_SUB(        )
 #undef ATOMIC_FETCH_OP_SUB
 
 #define ATOMIC_OP_ADD_SUB_RETURN(name)					\
-static __always_inline int						\
+static __always_inline __signed_wrap int				\
 __lse_atomic_add_return##name(int i, atomic_t *v)			\
 {									\
 	return __lse_atomic_fetch_add##name(i, v) + i;			\
 }									\
 									\
-static __always_inline int						\
+static __always_inline __signed_wrap int				\
 __lse_atomic_sub_return##name(int i, atomic_t *v)			\
 {									\
 	return __lse_atomic_fetch_sub(i, v) - i;			\
@@ -186,13 +186,13 @@ ATOMIC64_FETCH_OP_SUB(        )
 #undef ATOMIC64_FETCH_OP_SUB
 
 #define ATOMIC64_OP_ADD_SUB_RETURN(name)				\
-static __always_inline long						\
+static __always_inline __signed_wrap long				\
 __lse_atomic64_add_return##name(s64 i, atomic64_t *v)			\
 {									\
 	return __lse_atomic64_fetch_add##name(i, v) + i;		\
 }									\
 									\
-static __always_inline long						\
+static __always_inline __signed_wrap long				\
 __lse_atomic64_sub_return##name(s64 i, atomic64_t *v)			\
 {									\
 	return __lse_atomic64_fetch_sub##name(i, v) - i;		\
-- 
2.34.1