1 files changed, 80 insertions, 0 deletions
diff --git a/tests/tcg/aarch64/gcs.h b/tests/tcg/aarch64/gcs.h
new file mode 100644
index 0000000..6f013d0
--- /dev/null
+++ b/tests/tcg/aarch64/gcs.h
@@ -0,0 +1,80 @@
+/*
+ * Linux kernel fallback API definitions for GCS and test helpers.
+ *
+ * Copyright (c) 2025 Linaro Ltd
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <assert.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <errno.h>
+#include <signal.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+#include <sys/syscall.h>
+
+#ifndef PR_GET_SHADOW_STACK_STATUS
+#define PR_GET_SHADOW_STACK_STATUS      74
+#endif
+#ifndef PR_SET_SHADOW_STACK_STATUS
+#define PR_SET_SHADOW_STACK_STATUS      75
+#endif
+#ifndef PR_LOCK_SHADOW_STACK_STATUS
+#define PR_LOCK_SHADOW_STACK_STATUS     76
+#endif
+#ifndef PR_SHADOW_STACK_ENABLE
+# define PR_SHADOW_STACK_ENABLE         (1 << 0)
+# define PR_SHADOW_STACK_WRITE          (1 << 1)
+# define PR_SHADOW_STACK_PUSH           (1 << 2)
+#endif
+#ifndef SHADOW_STACK_SET_TOKEN
+#define SHADOW_STACK_SET_TOKEN          (1 << 0)
+#endif
+#ifndef SHADOW_STACK_SET_MARKER
+#define SHADOW_STACK_SET_MARKER         (1 << 1)
+#endif
+#ifndef SEGV_CPERR
+#define SEGV_CPERR  10
+#endif
+#ifndef __NR_map_shadow_stack
+#define __NR_map_shadow_stack  453
+#endif
+
+/*
+ * Macros, and implement the syscall inline, lest we fail
+ * the checked return from any function call.
+ */
+#define enable_gcs(flags) \
+    do {                                                                     \
+        register long num  __asm__ ("x8") = __NR_prctl;                      \
+        register long arg1 __asm__ ("x0") = PR_SET_SHADOW_STACK_STATUS;      \
+        register long arg2 __asm__ ("x1") = PR_SHADOW_STACK_ENABLE | flags;  \
+        register long arg3 __asm__ ("x2") = 0;                               \
+        register long arg4 __asm__ ("x3") = 0;                               \
+        register long arg5 __asm__ ("x4") = 0;                               \
+        asm volatile("svc #0"                                                \
+                     : "+r"(arg1)                                            \
+                     : "r"(arg2), "r"(arg3), "r"(arg4), "r"(arg5), "r"(num)  \
+                     : "memory", "cc");                                      \
+        if (arg1) {                                                          \
+            errno = -arg1;                                                   \
+            perror("PR_SET_SHADOW_STACK_STATUS");                            \
+            exit(2);                                                         \
+        }                                                                    \
+    } while (0)
+
+#define gcspr() \
+    ({ uint64_t *r; asm volatile("mrs %0, s3_3_c2_c5_1" : "=r"(r)); r; })
+
+#define gcsss1(val) \
+    do {                                                                     \
+        asm volatile("sys #3, c7, c7, #2, %0" : : "r"(val) : "memory");      \
+    } while (0)
+
+#define gcsss2() \
+    ({ uint64_t *r;                                                          \
+       asm volatile("sysl %0, #3, c7, c7, #3" : "=r"(r) : : "memory"); r; })