[PATCH v7 39/39] kselftest/clone3: Enable GCS in the clone3 selftests

[Mark Brown]

In order to allow testing without full userspace support for shadow stacks
the clone3() selftests open code enabling them at runtime, hook up arm64
support.

Signed-off-by: Mark Brown <broonie at kernel.org>
---
 tools/testing/selftests/clone3/clone3.c | 37 +++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selftests/clone3/clone3.c
index dbe52582573c..6114a33d6ec2 100644
--- a/tools/testing/selftests/clone3/clone3.c
+++ b/tools/testing/selftests/clone3/clone3.c
@@ -432,6 +432,43 @@ static inline void enable_shadow_stack(void)
 
 #endif
 
+#ifdef __aarc64__
+#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 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 ENABLE_SHADOW_STACK
 static void enable_shadow_stack(void)
 {

-- 
2.39.2