2017-01-19  Jiong Wang  <jiong.wang@arm.com>

	* config/aarch64/aarch64-unwind.h: New file.

	(DWARF_REGNUM_AARCH64_RA_STATE): Define.

	(MD_POST_EXTRACT_ROOT_ADDR): New target marcro and define it on AArch64.

	(MD_POST_EXTRACT_FRAME_ADDR): Likewise.

	(MD_POST_FROB_EH_HANDLER_ADDR): Likewise.

	(MD_FROB_UPDATE_CONTEXT): Define it on AArch64.

	(aarch64_post_extract_frame_addr): New function.

	(aarch64_post_frob_eh_handler_addr): New function.

	(aarch64_frob_update_context): New function.

	* config/aarch64/linux-unwind.h: Include aarch64-unwind.h

	* config.host (aarch64*-*-elf, aarch64*-*-rtems*,

	aarch64*-*-freebsd*):

	Initialize md_unwind_header to include aarch64-unwind.h.

	* unwind-dw2.c (struct _Unwind_Context): Define "RA_A_SIGNED_BIT".

	(execute_cfa_program): Multiplex DW_CFA_GNU_window_save for

	__aarch64__.

	(uw_update_context): Honor MD_POST_EXTRACT_FRAME_ADDR.

	(uw_init_context_1): Honor MD_POST_EXTRACT_ROOT_ADDR.

	(uw_frob_return_addr): New function.

	(uw_install_context): Use uw_frob_return_addr.

--- libgcc/config.host	(revision 244672)

+++ libgcc/config.host	(revision 244674)

@@ -284,6 +284,7 @@

 	extra_parts="$extra_parts crtbegin.o crtend.o crti.o crtn.o"

 	tmake_file="${tmake_file} ${cpu_type}/t-aarch64"

 	tmake_file="${tmake_file} ${cpu_type}/t-softfp t-softfp"

+	md_unwind_header=aarch64/aarch64-unwind.h

 	;;

 aarch64*-*-linux*)

 	md_unwind_header=aarch64/linux-unwind.h

--- libgcc/config/aarch64/aarch64-unwind.h	(nonexistent)

+++ libgcc/config/aarch64/aarch64-unwind.h	(revision 244674)

@@ -0,0 +1,89 @@

+/* Copyright (C) 2017 Free Software Foundation, Inc.

+   Contributed by ARM Ltd.

+

+This file is part of GCC.

+

+GCC is free software; you can redistribute it and/or modify it under

+the terms of the GNU General Public License as published by the Free

+Software Foundation; either version 3, or (at your option) any later

+version.

+

+GCC 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

+for more details.

+

+Under Section 7 of GPL version 3, you are granted additional

+permissions described in the GCC Runtime Library Exception, version

+3.1, as published by the Free Software Foundation.

+

+You should have received a copy of the GNU General Public License and

+a copy of the GCC Runtime Library Exception along with this program;

+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

+<http://www.gnu.org/licenses/>.  */

+

+#ifndef AARCH64_UNWIND_H

+#define AARCH64_UNWIND_H

+

+#define DWARF_REGNUM_AARCH64_RA_STATE 34

+

+#define MD_POST_EXTRACT_ROOT_ADDR(addr) \

+  ({ void *__addr; asm ("mov x30, %0; hint 7; mov %0, x30" \

+			: "=r" (__addr) : "0" (addr) : "x30", "cc"); __addr; })

+#define MD_POST_EXTRACT_FRAME_ADDR(context, fs, addr) \

+  aarch64_post_extract_frame_addr (context, fs, addr)

+#define MD_POST_FROB_EH_HANDLER_ADDR(current, target, addr) \

+  aarch64_post_frob_eh_handler_addr (current, target, addr)

+#define MD_FROB_UPDATE_CONTEXT(context, fs) \

+  aarch64_frob_update_context (context, fs)

+

+/* Do AArch64 private extraction on ADDR based on context info CONTEXT and

+   unwind frame info FS.  If ADDR is signed, we do address authentication on it

+   using CFA of current frame.  */

+

+static inline void *

+aarch64_post_extract_frame_addr (struct _Unwind_Context *context,

+				 _Unwind_FrameState *fs, void *addr)

+{

+  if (fs->regs.reg[DWARF_REGNUM_AARCH64_RA_STATE].loc.offset & 0x1)

+    {

+      _Unwind_Word salt = (_Unwind_Word) context->cfa;

+      asm ("mov x17, %0; mov x16, %1; hint 12; mov %0, x17"

+	   : "+r" (addr) : "r" (salt) : "x16", "x17", "cc");

+    }

+  return addr;

+}

+

+/* Do AArch64 private frob on exception handler's address HANDLER_ADDR before

+   installing it into current context CURRENT.  TARGET is currently not used.

+   We need to sign exception handler's address if CURRENT itself is signed.  */

+

+static inline void *

+aarch64_post_frob_eh_handler_addr (struct _Unwind_Context *current,

+				   struct _Unwind_Context *target

+				   ATTRIBUTE_UNUSED,

+				   void *handler_addr)

+{

+  if (current->flags & RA_A_SIGNED_BIT)

+    asm ("mov x17, %0; mov x16, %1; hint 8; mov %0, x17"

+	  : "+r" (handler_addr) : "r" ((_Unwind_Word) current->cfa)

+	  : "x16", "x17", "cc");

+  return handler_addr;

+}

+

+/* Do AArch64 private initialization on CONTEXT based on frame info FS.  Mark

+   CONTEXT as return address signed if bit 0 of DWARF_REGNUM_AARCH64_RA_STATE is

+   set.  */

+

+static inline void

+aarch64_frob_update_context (struct _Unwind_Context *context,

+			     _Unwind_FrameState *fs)

+{

+  if (fs->regs.reg[DWARF_REGNUM_AARCH64_RA_STATE].loc.offset & 0x1)

+    /* The flag is used for re-authenticating EH handler's address.  */

+    context->flags |= RA_A_SIGNED_BIT;

+

+  return;

+}

+

+#endif /* defined AARCH64_UNWIND_H */

--- libgcc/config/aarch64/linux-unwind.h	(revision 244672)

+++ libgcc/config/aarch64/linux-unwind.h	(revision 244674)

@@ -24,6 +24,7 @@

 #include <signal.h>

 #include <sys/ucontext.h>

+#include "config/aarch64/aarch64-unwind.h"

 #define MD_FALLBACK_FRAME_STATE_FOR aarch64_fallback_frame_state

--- libgcc/unwind-dw2.c	(revision 244672)

+++ libgcc/unwind-dw2.c	(revision 244674)

@@ -136,6 +136,8 @@ struct _Unwind_Context

 #define SIGNAL_FRAME_BIT ((~(_Unwind_Word) 0 >> 1) + 1)

   /* Context which has version/args_size/by_value fields.  */

 #define EXTENDED_CONTEXT_BIT ((~(_Unwind_Word) 0 >> 2) + 1)

+  /* Bit reserved on AArch64, return address has been signed with A key.  */

+#define RA_A_SIGNED_BIT ((~(_Unwind_Word) 0 >> 3) + 1)

   _Unwind_Word flags;

   /* 0 for now, can be increased when further fields are added to

      struct _Unwind_Context.  */

@@ -1189,6 +1191,11 @@ execute_cfa_program (const unsigned char

 	  break;

 	case DW_CFA_GNU_window_save:

+#ifdef __aarch64__

+	  /* This CFA is multiplexed with Sparc.  On AArch64 it's used to toggle

+	     return address signing status.  */

+	  fs->regs.reg[DWARF_REGNUM_AARCH64_RA_STATE].loc.offset ^= 1;

+#else

 	  /* ??? Hardcoded for SPARC register window configuration.  */

 	  if (DWARF_FRAME_REGISTERS >= 32)

 	    for (reg = 16; reg < 32; ++reg)

@@ -1192,6 +1199,7 @@ execute_cfa_program (const unsigned char

 		fs->regs.reg[reg].how = REG_SAVED_OFFSET;

 		fs->regs.reg[reg].loc.offset = (reg - 16) * sizeof (void *);

 	      }

+#endif

 	  break;

 	case DW_CFA_GNU_args_size:

@@ -1513,10 +1521,15 @@ uw_update_context (struct _Unwind_Contex

        stack frame.  */

     context->ra = 0;

   else

-    /* Compute the return address now, since the return address column

-       can change from frame to frame.  */

-    context->ra = __builtin_extract_return_addr

-      (_Unwind_GetPtr (context, fs->retaddr_column));

+    {

+      /* Compute the return address now, since the return address column

+	 can change from frame to frame.  */

+      context->ra = __builtin_extract_return_addr

+	(_Unwind_GetPtr (context, fs->retaddr_column));

+#ifdef MD_POST_EXTRACT_FRAME_ADDR

+      context->ra = MD_POST_EXTRACT_FRAME_ADDR (context, fs, context->ra);

+#endif

+    }

 }

 static void

@@ -1550,6 +1563,9 @@ uw_init_context_1 (struct _Unwind_Contex

 		   void *outer_cfa, void *outer_ra)

 {

   void *ra = __builtin_extract_return_addr (__builtin_return_address (0));

+#ifdef MD_POST_EXTRACT_ROOT_ADDR

+  ra = MD_POST_EXTRACT_ROOT_ADDR (ra);

+#endif

   _Unwind_FrameState fs;

   _Unwind_SpTmp sp_slot;

   _Unwind_Reason_Code code;

@@ -1586,6 +1602,9 @@ uw_init_context_1 (struct _Unwind_Contex

      initialization context, then we can't see it in the given

      call frame data.  So have the initialization context tell us.  */

   context->ra = __builtin_extract_return_addr (outer_ra);

+#ifdef MD_POST_EXTRACT_ROOT_ADDR

+  context->ra = MD_POST_EXTRACT_ROOT_ADDR (context->ra);

+#endif

 }

 static void _Unwind_DebugHook (void *, void *)

@@ -1608,6 +1627,10 @@ _Unwind_DebugHook (void *cfa __attribute

 #endif

 }

+#ifndef MD_POST_FROB_EH_HANDLER_ADDR

+#define MD_POST_FROB_EH_HANDLER_ADDR(c, t, r) r

+#endif 

+

 /* Install TARGET into CURRENT so that we can return to it.  This is a

    macro because __builtin_eh_return must be invoked in the context of

    our caller.  */

@@ -1621,6 +1644,8 @@ _Unwind_DebugHook (void *cfa __attribute

     {									\

       long offset = uw_install_context_1 ((CURRENT), (TARGET));		\

       void *handler = __builtin_frob_return_addr ((TARGET)->ra);	\

+      handler = (MD_POST_FROB_EH_HANDLER_ADDR ((CURRENT), (TARGET),	\

+		  handler));						\

       _Unwind_DebugHook ((TARGET)->cfa, handler);			\

       __builtin_eh_return (offset, handler);				\

     }									\