8266749: AArch64: Backtracing broken on PAC enabled systems

Reviewed-by: gziemski, aph

src/hotspot/cpu/aarch64/frame_aarch64.cpp

@@ -272,6 +272,9 @@ void frame::patch_pc(Thread* thread, address pc) {
     tty->print_cr("patch_pc at address " INTPTR_FORMAT " [" INTPTR_FORMAT " -> " INTPTR_FORMAT "]",
                   p2i(pc_addr), p2i(*pc_addr), p2i(pc));
   }
+
+  // Only generated code frames should be patched, therefore the return address will not be signed.
+  assert(pauth_ptr_is_raw(*pc_addr), "cannot be signed");
   // Either the return address is the original one or we are going to
   // patch in the same address that's already there.
   assert(_pc == *pc_addr || pc == *pc_addr, "must be");
@@ -446,7 +449,9 @@ frame frame::sender_for_interpreter_frame(RegisterMap* map) const {
   }
 #endif // COMPILER2_OR_JVMCI
 
-  return frame(sender_sp, unextended_sp, link(), sender_pc());
+  // Use the raw version of pc - the interpreter should not have signed it.
+
+  return frame(sender_sp, unextended_sp, link(), sender_pc_maybe_signed());
 }
 
 
@@ -509,6 +514,7 @@ frame frame::sender_raw(RegisterMap* map) const {
 
   // Must be native-compiled frame, i.e. the marshaling code for native
   // methods that exists in the core system.
+
   return frame(sender_sp(), link(), sender_pc());
 }
 

src/hotspot/cpu/aarch64/frame_aarch64.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2014, Red Hat Inc. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -149,6 +149,7 @@
   intptr_t*   fp() const { return _fp; }
 
   inline address* sender_pc_addr() const;
+  inline address  sender_pc_maybe_signed() const;
 
   // expression stack tos if we are nested in a java call
   intptr_t* interpreter_frame_last_sp() const;

src/hotspot/cpu/aarch64/frame_aarch64.inline.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2014, Red Hat Inc. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -28,6 +28,7 @@
 
 #include "code/codeCache.hpp"
 #include "code/vmreg.inline.hpp"
+#include "pauth_aarch64.hpp"
 
 // Inline functions for AArch64 frames:
 
@@ -45,6 +46,7 @@ inline frame::frame() {
 static int spin;
 
 inline void frame::init(intptr_t* sp, intptr_t* fp, address pc) {
+  assert(pauth_ptr_is_raw(pc), "cannot be signed");
   intptr_t a = intptr_t(sp);
   intptr_t b = intptr_t(fp);
   _sp = sp;
@@ -69,6 +71,7 @@ inline frame::frame(intptr_t* sp, intptr_t* fp, address pc) {
 }
 
 inline frame::frame(intptr_t* sp, intptr_t* unextended_sp, intptr_t* fp, address pc) {
+  assert(pauth_ptr_is_raw(pc), "cannot be signed");
   intptr_t a = intptr_t(sp);
   intptr_t b = intptr_t(fp);
   _sp = sp;
@@ -150,8 +153,9 @@ inline intptr_t* frame::unextended_sp() const     { return _unextended_sp; }
 
 // Return address:
 
-inline address* frame::sender_pc_addr()      const { return (address*) addr_at( return_addr_offset); }
-inline address  frame::sender_pc()           const { return *sender_pc_addr(); }
+inline address* frame::sender_pc_addr()         const { return (address*) addr_at( return_addr_offset); }
+inline address  frame::sender_pc_maybe_signed() const { return *sender_pc_addr(); }
+inline address  frame::sender_pc()              const { return pauth_strip_pointer(sender_pc_maybe_signed()); }
 
 inline intptr_t*    frame::sender_sp()        const { return            addr_at(   sender_sp_offset); }
 

src/hotspot/cpu/aarch64/pauth_aarch64.hpp

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef CPU_AARCH64_PAUTH_AARCH64_INLINE_HPP
+#define CPU_AARCH64_PAUTH_AARCH64_INLINE_HPP
+
+#include OS_CPU_HEADER_INLINE(pauth)
+
+inline bool pauth_ptr_is_raw(address ptr) {
+  // Confirm none of the high bits are set in the pointer.
+  return ptr == pauth_strip_pointer(ptr);
+}
+
+#endif // CPU_AARCH64_PAUTH_AARCH64_INLINE_HPP

src/hotspot/os_cpu/bsd_aarch64/pauth_bsd_aarch64.inline.hpp

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef OS_CPU_LINUX_AARCH64_PAUTH_BSD_AARCH64_INLINE_HPP
+#define OS_CPU_LINUX_AARCH64_PAUTH_BSD_AARCH64_INLINE_HPP
+
+#ifdef __APPLE__
+#include <ptrauth.h>
+#endif
+
+// Only the PAC instructions in the NOP space can be used. This ensures the
+// binaries work on systems without PAC. Write these instructions using their
+// alternate "hint" instructions to ensure older compilers can still be used.
+// For Apple, use the provided interface as this may provide additional
+// optimization.
+
+#define XPACLRI "hint #0x7;"
+
+inline address pauth_strip_pointer(address ptr) {
+#ifdef __APPLE__
+  return ptrauth_strip(ptr, ptrauth_key_asib);
+#else
+  register address result __asm__("x30") = ptr;
+  asm (XPACLRI : "+r"(result));
+  return result;
+#endif
+}
+
+#undef XPACLRI
+
+#endif // OS_CPU_LINUX_AARCH64_PAUTH_BSD_AARCH64_INLINE_HPP
+

src/hotspot/os_cpu/linux_aarch64/pauth_linux_aarch64.inline.hpp

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef OS_CPU_LINUX_AARCH64_PAUTH_LINUX_AARCH64_INLINE_HPP
+#define OS_CPU_LINUX_AARCH64_PAUTH_LINUX_AARCH64_INLINE_HPP
+
+// Only the PAC instructions in the NOP space can be used. This ensures the
+// binaries work on systems without PAC. Write these instructions using their
+// alternate "hint" instructions to ensure older compilers can still be used.
+
+#define XPACLRI "hint #0x7;"
+
+inline address pauth_strip_pointer(address ptr) {
+  register address result __asm__("x30") = ptr;
+  asm (XPACLRI : "+r"(result));
+  return result;
+}
+
+#undef XPACLRI
+
+#endif // OS_CPU_LINUX_AARCH64_PAUTH_LINUX_AARCH64_INLINE_HPP

src/hotspot/os_cpu/windows_aarch64/pauth_windows_aarch64.inline.hpp

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef OS_CPU_LINUX_AARCH64_PAUTH_WINDOWS_AARCH64_INLINE_HPP
+#define OS_CPU_LINUX_AARCH64_PAUTH_WINDOWS_AARCH64_INLINE_HPP
+
+inline address pauth_strip_pointer(address ptr) {
+  // No PAC support in windows as of yet.
+  return ptr;
+}
+
+#endif // OS_CPU_LINUX_AARCH64_PAUTH_WINDOWS_AARCH64_INLINE_HPP
+