Linux Kernel Selftest development
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From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Shuah Khan <shuah@kernel.org>
Cc: linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	"H . Peter Anvin" <hpa@zytor.com>, Paul Turner <pjt@google.com>,
	linux-api@vger.kernel.org, linux-kselftest@vger.kernel.org,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>
Subject: [PATCH 3/4] selftests/rseq: Fix arm64 buggy load-acquire/store-release macros
Date: Tue, 27 Jun 2023 11:29:22 -0400	[thread overview]
Message-ID: <20230627152923.133238-4-mathieu.desnoyers@efficios.com> (raw)
In-Reply-To: <20230627152923.133238-1-mathieu.desnoyers@efficios.com>

The arm64 load-acquire/store-release macros from the Linux kernel rseq
selftests are buggy. Remplace them by a working implementation.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 tools/testing/selftests/rseq/rseq-arm64.h | 58 ++++++++++++-----------
 1 file changed, 30 insertions(+), 28 deletions(-)

diff --git a/tools/testing/selftests/rseq/rseq-arm64.h b/tools/testing/selftests/rseq/rseq-arm64.h
index 85b90977e7e6..21e1626a7235 100644
--- a/tools/testing/selftests/rseq/rseq-arm64.h
+++ b/tools/testing/selftests/rseq/rseq-arm64.h
@@ -27,59 +27,61 @@
 
 #define rseq_smp_load_acquire(p)						\
 __extension__ ({								\
-	__typeof(*p) ____p1;							\
-	switch (sizeof(*p)) {							\
+	union { rseq_unqual_scalar_typeof(*(p)) __val; char __c[sizeof(*(p))]; } __u; \
+	switch (sizeof(*(p))) {							\
 	case 1:									\
-		asm volatile ("ldarb %w0, %1"					\
-			: "=r" (*(__u8 *)p)					\
-			: "Q" (*p) : "memory");					\
+		__asm__ __volatile__ ("ldarb %w0, %1"				\
+			: "=r" (*(__u8 *)__u.__c)				\
+			: "Q" (*(p)) : "memory");				\
 		break;								\
 	case 2:									\
-		asm volatile ("ldarh %w0, %1"					\
-			: "=r" (*(__u16 *)p)					\
-			: "Q" (*p) : "memory");					\
+		__asm__ __volatile__ ("ldarh %w0, %1"				\
+			: "=r" (*(__u16 *)__u.__c)				\
+			: "Q" (*(p)) : "memory");				\
 		break;								\
 	case 4:									\
-		asm volatile ("ldar %w0, %1"					\
-			: "=r" (*(__u32 *)p)					\
-			: "Q" (*p) : "memory");					\
+		__asm__ __volatile__ ("ldar %w0, %1"				\
+			: "=r" (*(__u32 *)__u.__c)				\
+			: "Q" (*(p)) : "memory");				\
 		break;								\
 	case 8:									\
-		asm volatile ("ldar %0, %1"					\
-			: "=r" (*(__u64 *)p)					\
-			: "Q" (*p) : "memory");					\
+		__asm__ __volatile__ ("ldar %0, %1"				\
+			: "=r" (*(__u64 *)__u.__c)				\
+			: "Q" (*(p)) : "memory");				\
 		break;								\
 	}									\
-	____p1;									\
+	(rseq_unqual_scalar_typeof(*(p)))__u.__val;				\
 })
 
 #define rseq_smp_acquire__after_ctrl_dep()	rseq_smp_rmb()
 
 #define rseq_smp_store_release(p, v)						\
 do {										\
-	switch (sizeof(*p)) {							\
+	union { rseq_unqual_scalar_typeof(*(p)) __val; char __c[sizeof(*(p))]; } __u = \
+		{ .__val = (rseq_unqual_scalar_typeof(*(p))) (v) };		\
+	switch (sizeof(*(p))) {							\
 	case 1:									\
-		asm volatile ("stlrb %w1, %0"					\
-				: "=Q" (*p)					\
-				: "r" ((__u8)v)					\
+		__asm__ __volatile__ ("stlrb %w1, %0"				\
+				: "=Q" (*(p))					\
+				: "r" (*(__u8 *)__u.__c)			\
 				: "memory");					\
 		break;								\
 	case 2:									\
-		asm volatile ("stlrh %w1, %0"					\
-				: "=Q" (*p)					\
-				: "r" ((__u16)v)				\
+		__asm__ __volatile__ ("stlrh %w1, %0"				\
+				: "=Q" (*(p))					\
+				: "r" (*(__u16 *)__u.__c)			\
 				: "memory");					\
 		break;								\
 	case 4:									\
-		asm volatile ("stlr %w1, %0"					\
-				: "=Q" (*p)					\
-				: "r" ((__u32)v)				\
+		__asm__ __volatile__ ("stlr %w1, %0"				\
+				: "=Q" (*(p))					\
+				: "r" (*(__u32 *)__u.__c)			\
 				: "memory");					\
 		break;								\
 	case 8:									\
-		asm volatile ("stlr %1, %0"					\
-				: "=Q" (*p)					\
-				: "r" ((__u64)v)				\
+		__asm__ __volatile__ ("stlr %1, %0"				\
+				: "=Q" (*(p))					\
+				: "r" (*(__u64 *)__u.__c)			\
 				: "memory");					\
 		break;								\
 	}									\
-- 
2.25.1


  parent reply	other threads:[~2023-06-27 15:29 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-27 15:29 [PATCH 0/4] rseq selftests updates Mathieu Desnoyers
2023-06-27 15:29 ` [PATCH 1/4] selftests/rseq: Fix CID_ID typo in Makefile Mathieu Desnoyers
2023-06-27 15:29 ` [PATCH 2/4] selftests/rseq: Implement rseq_unqual_scalar_typeof Mathieu Desnoyers
2023-06-27 15:29 ` Mathieu Desnoyers [this message]
2023-06-27 15:29 ` [PATCH 4/4] selftests/rseq: Use rseq_unqual_scalar_typeof in macros Mathieu Desnoyers
  -- strict thread matches above, loose matches on Subject: below --
2023-05-15 13:57 [PATCH 0/4] RSEQ selftests updates Mathieu Desnoyers
2023-05-15 13:58 ` [PATCH 3/4] selftests/rseq: Fix arm64 buggy load-acquire/store-release macros Mathieu Desnoyers

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