libc: Add Armv8.3-A PAuth and Armv8.5-A BTI compatibility to *.S

The most notable change is in sigsetjmp/siglongjmp. The former
stores LR signed with the current SP into jmp_buf. Calling siglongjmp
reads a signed LR and the corresponding SP from jmp_buf. This way not
only the checksum provides some means of integrity protection but
Pointer Authentication too.

Test: Tested on FVP with BTI enabled.

Change-Id: I9d720239775f8d2829a677901f546c4b14b5cbe5
diff --git a/libc/arch-arm64/bionic/__bionic_clone.S b/libc/arch-arm64/bionic/__bionic_clone.S
index c3ff0e5..e9932ad 100644
--- a/libc/arch-arm64/bionic/__bionic_clone.S
+++ b/libc/arch-arm64/bionic/__bionic_clone.S
@@ -57,3 +57,5 @@
     ldp     x0, x1, [sp], #16
     b       __start_thread
 END(__bionic_clone)
+
+NOTE_GNU_PROPERTY()
diff --git a/libc/arch-arm64/bionic/_exit_with_stack_teardown.S b/libc/arch-arm64/bionic/_exit_with_stack_teardown.S
index 6a7b1e5..c53a1f4 100644
--- a/libc/arch-arm64/bionic/_exit_with_stack_teardown.S
+++ b/libc/arch-arm64/bionic/_exit_with_stack_teardown.S
@@ -39,3 +39,5 @@
   svc #0
   // The exit syscall does not return.
 END(_exit_with_stack_teardown)
+
+NOTE_GNU_PROPERTY()
diff --git a/libc/arch-arm64/bionic/setjmp.S b/libc/arch-arm64/bionic/setjmp.S
index a2b2370..07270c9 100644
--- a/libc/arch-arm64/bionic/setjmp.S
+++ b/libc/arch-arm64/bionic/setjmp.S
@@ -118,6 +118,8 @@
 // int sigsetjmp(sigjmp_buf env, int save_signal_mask);
 ENTRY(sigsetjmp)
 __BIONIC_WEAK_ASM_FOR_NATIVE_BRIDGE(sigsetjmp)
+  hint #25 // paciasp
+  .cfi_negate_ra_state
   stp x0, x30, [sp, #-16]!
   .cfi_def_cfa_offset 16
   .cfi_rel_offset x0, 0
@@ -184,6 +186,8 @@
 #endif
 
   mov w0, #0
+  hint #29 // autiasp
+  .cfi_negate_ra_state
   ret
 END(sigsetjmp)
 
@@ -250,7 +254,9 @@
 1:
   // Restore core registers.
   bic x2, x2, #1
+  // x30 was saved with PAC to jmp_buf in sigsetjmp().
   ldp x30, x10, [x0, #(_JB_X30_SP  * 8)]
+  .cfi_negate_ra_state
   ldp x28, x29, [x0, #(_JB_X28_X29 * 8)]
   ldp x26, x27, [x0, #(_JB_X26_X27 * 8)]
   ldp x24, x25, [x0, #(_JB_X24_X25 * 8)]
@@ -290,6 +296,8 @@
   // Set return value.
   cmp w1, wzr
   csinc w0, w1, wzr, ne
+  hint #29 // autiasp
+  .cfi_negate_ra_state
   ret
 END(siglongjmp)
 
@@ -297,3 +305,5 @@
 __BIONIC_WEAK_ASM_FOR_NATIVE_BRIDGE(longjmp)
 ALIAS_SYMBOL(_longjmp, siglongjmp)
 __BIONIC_WEAK_ASM_FOR_NATIVE_BRIDGE(_longjmp)
+
+NOTE_GNU_PROPERTY()
diff --git a/libc/arch-arm64/bionic/syscall.S b/libc/arch-arm64/bionic/syscall.S
index 8389f98..9e6f68a 100644
--- a/libc/arch-arm64/bionic/syscall.S
+++ b/libc/arch-arm64/bionic/syscall.S
@@ -47,3 +47,5 @@
 
     ret
 END(syscall)
+
+NOTE_GNU_PROPERTY()
diff --git a/libc/arch-arm64/bionic/vfork.S b/libc/arch-arm64/bionic/vfork.S
index 5cfb8b0..81b84a3 100644
--- a/libc/arch-arm64/bionic/vfork.S
+++ b/libc/arch-arm64/bionic/vfork.S
@@ -67,6 +67,8 @@
 
     // Clean up stack shadow in the parent process.
     // https://github.com/google/sanitizers/issues/925
+    hint #25 // paciasp
+    .cfi_negate_ra_state
     stp x0, x30, [sp, #-16]!
     .cfi_adjust_cfa_offset 16
     .cfi_rel_offset x0, 0
@@ -79,9 +81,13 @@
     .cfi_adjust_cfa_offset -16
     .cfi_restore x0
     .cfi_restore x30
+    hint #29 // autiasp
+    .cfi_negate_ra_state
 
 #endif
 
 .L_exit:
     ret
 END(vfork)
+
+NOTE_GNU_PROPERTY()
diff --git a/libc/arch-arm64/generic/bionic/__memcpy_chk.S b/libc/arch-arm64/generic/bionic/__memcpy_chk.S
index a6eeca4..a8e9e83 100644
--- a/libc/arch-arm64/generic/bionic/__memcpy_chk.S
+++ b/libc/arch-arm64/generic/bionic/__memcpy_chk.S
@@ -43,3 +43,5 @@
 
   bl __memcpy_chk_fail
 END(__memcpy_chk)
+
+NOTE_GNU_PROPERTY()
diff --git a/libc/arch-arm64/generic/bionic/memcpy.S b/libc/arch-arm64/generic/bionic/memcpy.S
index baadb92..bc1945c 100644
--- a/libc/arch-arm64/generic/bionic/memcpy.S
+++ b/libc/arch-arm64/generic/bionic/memcpy.S
@@ -33,3 +33,5 @@
 ENTRY(__memcpy)
   #include "memcpy_base.S"
 END(__memcpy)
+
+NOTE_GNU_PROPERTY()
diff --git a/libc/arch-arm64/generic/bionic/memmove.S b/libc/arch-arm64/generic/bionic/memmove.S
index 335b7d6..0f752ea 100644
--- a/libc/arch-arm64/generic/bionic/memmove.S
+++ b/libc/arch-arm64/generic/bionic/memmove.S
@@ -153,3 +153,5 @@
 
 ALIAS_SYMBOL(memcpy, memmove)
 #endif
+
+NOTE_GNU_PROPERTY()
diff --git a/libc/arch-arm64/generic/bionic/memset.S b/libc/arch-arm64/generic/bionic/memset.S
index 12fc09d..19d3510 100644
--- a/libc/arch-arm64/generic/bionic/memset.S
+++ b/libc/arch-arm64/generic/bionic/memset.S
@@ -249,3 +249,5 @@
 	b	L(tail64)
 
 END(memset)
+
+NOTE_GNU_PROPERTY()
diff --git a/libc/arch-arm64/generic/bionic/wmemmove.S b/libc/arch-arm64/generic/bionic/wmemmove.S
index e4f67f7..b130530 100644
--- a/libc/arch-arm64/generic/bionic/wmemmove.S
+++ b/libc/arch-arm64/generic/bionic/wmemmove.S
@@ -28,3 +28,5 @@
 #define WMEMMOVE
 #include "memmove.S"
 #undef WMEMMOVE
+
+NOTE_GNU_PROPERTY()
diff --git a/libc/arch-arm64/static_function_dispatch.S b/libc/arch-arm64/static_function_dispatch.S
index 65a1492..161ece8 100644
--- a/libc/arch-arm64/static_function_dispatch.S
+++ b/libc/arch-arm64/static_function_dispatch.S
@@ -42,3 +42,5 @@
 FUNCTION_DELEGATE(strlen, __strlen_aarch64_mte)
 FUNCTION_DELEGATE(strrchr, __strrchr_aarch64_mte)
 FUNCTION_DELEGATE(strncmp, __strncmp_aarch64_mte)
+
+NOTE_GNU_PROPERTY()