Support backward cfi ability for asm file

 Issue: #I6U3D6
 Test: cfi demo pass
Signed-off-by: Narvinzzz <zhaotianyu9@huawei.com>
Change-Id: Ia9dbfdf18952b614cfed4a97e6366ee9cb8dedce

musl_src.gni

@@ -1883,6 +1883,7 @@ musl_inc_sys_files = [
   "include/sys/signal.h",
   "include/sys/socket.h",
   "include/sys/soundcard.h",
+  "include/sys/sspret.h",
   "include/sys/statfs.h",
   "include/sys/stat.h",
   "include/sys/statvfs.h",
@@ -2045,6 +2046,7 @@ musl_src_porting_file = [
   "include/stdlib.h",
   "include/string.h",
   "include/sys/stat.h",
+  "include/sys/sspret.h",
   "include/fortify/fcntl.h",
   "include/fortify/fortify.h",
   "include/fortify/poll.h",

porting/linux/user/include/sys/sspret.h

+#ifndef _SSPRET_H
+#define _SSPRET_H
+
+#if defined(__SSP_RET_STRONG__) || defined(__SSP_RET_ALL__)
+#if defined(__aarch64__)
+# define SSPRET_CALC_RETCOOKIE(reg) \
+    eor     reg, reg, x30
+
+# define SSPRET_LOAD_COOKIE(x, reg) \
+    mov     reg, x29
+
+# define SSPRET_SETUP(x, reg) \
+    SSPRET_LOAD_COOKIE(x, reg); \
+    SSPRET_CALC_RETCOOKIE(reg)
+
+# define SSPRET_CHECK(x, reg) \
+    SSPRET_LOAD_COOKIE(x, x9); \
+    SSPRET_CALC_RETCOOKIE(x9); \
+    subs    reg, reg, x9; \
+    cbz     reg, 6788f; \
+    brk     #0x1; \
+6788:
+
+# define SSPRET_PUSH(reg) \
+    str     reg, [sp, #-16]!
+
+# define SSPRET_POP(reg) \
+    ldr     reg, [sp, #16]!
+
+#endif /* __aarch64__ */
+#else
+# define SSPRET_CALC_RETCOOKIE(reg)
+# define SSPRET_LOAD_COOKIE(x, reg)
+# define SSPRET_SETUP(x, reg)
+# define SSPRET_CHECK(x, reg)
+# define SSPRET_PUSH(reg)
+# define SSPRET_POP(reg)
+#endif /* __SSP_RET_STRONG__ || __SSP_RET_ALL__ */
+
+#endif /* _SSPRET_H */