[PATCH v8 38/38] kselftest: Provide shadow stack enable helpers for arm64

From: Mark Brown <broonie@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>,
	 Will Deacon <will@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
	 Andrew Morton <akpm@linux-foundation.org>,
	Marc Zyngier <maz@kernel.org>,
	 Oliver Upton <oliver.upton@linux.dev>,
	James Morse <james.morse@arm.com>,
	 Suzuki K Poulose <suzuki.poulose@arm.com>,
	Arnd Bergmann <arnd@arndb.de>,  Oleg Nesterov <oleg@redhat.com>,
	Eric Biederman <ebiederm@xmission.com>,
	 Kees Cook <keescook@chromium.org>, Shuah Khan <shuah@kernel.org>,
	 "Rick P. Edgecombe" <rick.p.edgecombe@intel.com>,
	 Deepak Gupta <debug@rivosinc.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	 Szabolcs Nagy <Szabolcs.Nagy@arm.com>
Cc: "H.J. Lu" <hjl.tools@gmail.com>,
	 Paul Walmsley <paul.walmsley@sifive.com>,
	 Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	 Florian Weimer <fweimer@redhat.com>,
	Christian Brauner <brauner@kernel.org>,
	 Thiago Jung Bauermann <thiago.bauermann@linaro.org>,
	 linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
	 kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org,
	 linux-arch@vger.kernel.org, linux-mm@kvack.org,
	 linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
	 linux-riscv@lists.infradead.org, Mark Brown <broonie@kernel.org>
Subject: [PATCH v8 38/38] kselftest: Provide shadow stack enable helpers for arm64
Date: Sat, 03 Feb 2024 12:26:04 +0000	[thread overview]
Message-ID: <20240203-arm64-gcs-v8-38-c9fec77673ef@kernel.org> (raw)
In-Reply-To: <20240203-arm64-gcs-v8-0-c9fec77673ef@kernel.org>

Allow test programs to use the shadow stack helpers on arm64.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/ksft_shstk.h | 37 ++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/tools/testing/selftests/ksft_shstk.h b/tools/testing/selftests/ksft_shstk.h
index 85d0747c1802..223e24b4eb80 100644
--- a/tools/testing/selftests/ksft_shstk.h
+++ b/tools/testing/selftests/ksft_shstk.h
@@ -50,6 +50,43 @@ static inline __attribute__((always_inline)) void enable_shadow_stack(void)
 
 #endif
 
+#ifdef __aarch64__
+#define PR_SET_SHADOW_STACK_STATUS      72
+# define PR_SHADOW_STACK_ENABLE         (1UL << 0)
+
+#define my_syscall2(num, arg1, arg2)                                          \
+({                                                                            \
+	register long _num  __asm__ ("x8") = (num);                           \
+	register long _arg1 __asm__ ("x0") = (long)(arg1);                    \
+	register long _arg2 __asm__ ("x1") = (long)(arg2);                    \
+	register long _arg3 __asm__ ("x2") = 0;                               \
+	register long _arg4 __asm__ ("x3") = 0;                               \
+	register long _arg5 __asm__ ("x4") = 0;                               \
+	                                                                      \
+	__asm__  volatile (                                                   \
+		"svc #0\n"                                                    \
+		: "=r"(_arg1)                                                 \
+		: "r"(_arg1), "r"(_arg2),                                     \
+		  "r"(_arg3), "r"(_arg4),                                     \
+		  "r"(_arg5), "r"(_num)					      \
+		: "memory", "cc"                                              \
+	);                                                                    \
+	_arg1;                                                                \
+})
+
+#define ENABLE_SHADOW_STACK
+static inline __attribute__((always_inline))  void enable_shadow_stack(void)
+{
+	int ret;
+
+	ret = my_syscall2(__NR_prctl, PR_SET_SHADOW_STACK_STATUS,
+			  PR_SHADOW_STACK_ENABLE);
+	if (ret == 0)
+		shadow_stack_enabled = true;
+}
+
+#endif
+
 #ifndef __NR_map_shadow_stack
 #define __NR_map_shadow_stack 453
 #endif

-- 
2.30.2


