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From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Shuah Khan <shuah@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Dave Watson <davejwatson@fb.com>, Paul Turner <pjt@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Russell King <linux@arm.linux.org.uk>,
	Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
	Andi Kleen <andi@firstfloor.org>, Chris Lameter <cl@linux.com>,
	Ben Maurer <bmaurer@fb.com>, Steven Rostedt <rostedt@goodmis.org>,
	Josh Triplett <josh@joshtriplett.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Michael Kerrisk <mtk.manpages@gmail.com>,
	Joel Fernandes <joelaf@google.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	linux-kselftest@vger.kernel.org
Subject: [PATCH for 5.2 09/12] rseq/selftests: aarch64 code signature: handle big-endian environment
Date: Mon, 29 Apr 2019 11:28:00 -0400	[thread overview]
Message-ID: <20190429152803.7719-10-mathieu.desnoyers@efficios.com> (raw)
In-Reply-To: <20190429152803.7719-1-mathieu.desnoyers@efficios.com>

Handle compiling with -mbig-endian on aarch64, which generates binaries
with mixed code vs data endianness (little endian code, big endian
data).

Else mismatch between code endianness for the generated signatures and
data endianness for the RSEQ_SIG parameter passed to the rseq
registration will trigger application segmentation faults when the
kernel try to abort rseq critical sections.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Will Deacon <will.deacon@arm.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Joel Fernandes <joelaf@google.com>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Dave Watson <davejwatson@fb.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Shuah Khan <shuah@kernel.org>
CC: Andi Kleen <andi@firstfloor.org>
CC: linux-kselftest@vger.kernel.org
CC: "H . Peter Anvin" <hpa@zytor.com>
CC: Chris Lameter <cl@linux.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Michael Kerrisk <mtk.manpages@gmail.com>
CC: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
CC: Paul Turner <pjt@google.com>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Ben Maurer <bmaurer@fb.com>
CC: linux-api@vger.kernel.org
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
---
 tools/testing/selftests/rseq/rseq-arm64.h | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/rseq/rseq-arm64.h b/tools/testing/selftests/rseq/rseq-arm64.h
index b41a2a48e965..200dae9e4208 100644
--- a/tools/testing/selftests/rseq/rseq-arm64.h
+++ b/tools/testing/selftests/rseq/rseq-arm64.h
@@ -6,7 +6,20 @@
  * (C) Copyright 2018 - Will Deacon <will.deacon@arm.com>
  */
 
-#define RSEQ_SIG	0xd428bc00	/* BRK #0x45E0 */
+/*
+ * aarch64 -mbig-endian generates mixed endianness code vs data:
+ * little-endian code and big-endian data. Ensure the RSEQ_SIG signature
+ * matches code endianness.
+ */
+#define RSEQ_SIG_CODE	0xd428bc00	/* BRK #0x45E0.  */
+
+#ifdef __AARCH64EB__
+#define RSEQ_SIG_DATA	0x00bc28d4	/* BRK #0x45E0.  */
+#else
+#define RSEQ_SIG_DATA	RSEQ_SIG_CODE
+#endif
+
+#define RSEQ_SIG	RSEQ_SIG_DATA
 
 #define rseq_smp_mb()	__asm__ __volatile__ ("dmb ish" ::: "memory")
 #define rseq_smp_rmb()	__asm__ __volatile__ ("dmb ishld" ::: "memory")
@@ -121,7 +134,7 @@ do {										\
 
 #define RSEQ_ASM_DEFINE_ABORT(label, abort_label)				\
 	"	b	222f\n"							\
-	"	.inst 	"	__rseq_str(RSEQ_SIG) "\n"			\
+	"	.inst 	"	__rseq_str(RSEQ_SIG_CODE) "\n"			\
 	__rseq_str(label) ":\n"							\
 	"	b	%l[" __rseq_str(abort_label) "]\n"			\
 	"222:\n"
-- 
2.11.0


  parent reply	other threads:[~2019-04-29 15:30 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-29 15:27 [PATCH for 5.2 00/12] Restartable Sequences selftests updates Mathieu Desnoyers
2019-04-29 15:27 ` [PATCH for 5.2 01/12] rseq/selftests: x86: Work-around bogus gcc-8 optimisation Mathieu Desnoyers
2019-04-29 15:27 ` [PATCH for 5.2 02/12] rseq/selftests: Add __rseq_exit_point_array section for debuggers Mathieu Desnoyers
2019-04-29 15:27 ` [PATCH for 5.2 03/12] rseq/selftests: Introduce __rseq_cs_ptr_array, rename __rseq_table to __rseq_cs Mathieu Desnoyers
2019-04-29 15:27 ` [PATCH for 5.2 04/12] rseq/selftests: Use __rseq_handled symbol to coexist with glibc Mathieu Desnoyers
2019-04-29 15:27 ` [PATCH for 5.2 05/12] rseq/selftests: s390: use jg instruction for jumps outside of the asm Mathieu Desnoyers
2019-04-29 15:27 ` [PATCH for 5.2 06/12] rseq/selftests: x86: use ud1 instruction as RSEQ_SIG opcode Mathieu Desnoyers
2019-04-29 15:27 ` [PATCH for 5.2 07/12] rseq/selftests: s390: use trap4 for RSEQ_SIG Mathieu Desnoyers
2019-05-16 20:39   ` shuah
2019-05-16 20:49     ` Mathieu Desnoyers
2019-04-29 15:27 ` [PATCH for 5.2 08/12] rseq/selftests: arm: use udf instruction " Mathieu Desnoyers
2019-05-03 19:38   ` [PATCH v2 " Mathieu Desnoyers
2019-06-06 18:02     ` Mathieu Desnoyers
2019-06-08 15:52       ` Mathieu Desnoyers
2019-04-29 15:28 ` Mathieu Desnoyers [this message]
2019-04-29 15:28 ` [PATCH for 5.2 10/12] rseq/selftests: powerpc code signature: generate valid instructions Mathieu Desnoyers
2019-04-29 15:28 ` [PATCH for 5.2 11/12] rseq/selftests: mips: use break instruction for RSEQ_SIG Mathieu Desnoyers
2019-04-29 15:28 ` [PATCH for 5.2 12/12] rseq/selftests: add -no-integrated-as for clang Mathieu Desnoyers
2019-04-29 17:03   ` Nick Desaulniers
2019-04-29 20:28     ` Mathieu Desnoyers
2019-04-29 20:30       ` Nick Desaulniers
2019-05-03 18:36 ` [PATCH for 5.2 00/12] Restartable Sequences selftests updates Mathieu Desnoyers
2019-05-03 18:53   ` shuah
2019-05-03 19:22     ` Mathieu Desnoyers
2019-05-03 21:46       ` Joe Perches
2019-05-03 22:59       ` shuah

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