[PATCH 3/3][GCC][AARCH64] Add support for pointer authentication B key

gcc/
2019-05-29  Sam Tebbs  <sam.tebbs@arm.com>

	* config/aarch64/aarch64-builtins.c (aarch64_builtins): Add
	AARCH64_PAUTH_BUILTIN_AUTIB1716 and AARCH64_PAUTH_BUILTIN_PACIB1716.
	* config/aarch64/aarch64-builtins.c (aarch64_init_pauth_hint_builtins):
	Add autib1716 and pacib1716 initialisation.
	* config/aarch64/aarch64-builtins.c (aarch64_expand_builtin): Add checks
	for autib1716 and pacib1716.
	* config/aarch64/aarch64-protos.h (aarch64_key_type,
	aarch64_post_cfi_startproc): Define.
	* config/aarch64/aarch64-protos.h (aarch64_ra_sign_key): Define extern.
	* config/aarch64/aarch64.c (aarch64_handle_standard_branch_protection,
	aarch64_handle_pac_ret_protection): Set default sign key to A.
	* config/aarch64/aarch64.c (aarch64_expand_epilogue,
	aarch64_expand_prologue): Add check for b-key.
	* config/aarch64/aarch64.c (aarch64_ra_sign_key,
	aarch64_post_cfi_startproc, aarch64_handle_pac_ret_b_key): Define.
	* config/aarch64/aarch64.h (TARGET_ASM_POST_CFI_STARTPROC): Define.
	* config/aarch64/aarch64.c (aarch64_pac_ret_subtypes): Add "b-key".
	* config/aarch64/aarch64.md (unspec): Add UNSPEC_AUTIA1716,
	UNSPEC_AUTIB1716, UNSPEC_AUTIASP, UNSPEC_AUTIBSP, UNSPEC_PACIA1716,
	UNSPEC_PACIB1716, UNSPEC_PACIASP, UNSPEC_PACIBSP.
	* config/aarch64/aarch64.md (do_return): Add check for b-key.
	* config/aarch64/aarch64.md (<pauth_mnem_prefix>sp): Replace
	pauth_hint_num_a with pauth_hint_num.
	* config/aarch64/aarch64.md (<pauth_mnem_prefix>1716): Replace
	pauth_hint_num_a with pauth_hint_num.
	* config/aarch64/aarch64.opt (msign-return-address=): Deprecate.
	* config/aarch64/iterators.md (PAUTH_LR_SP): Add UNSPEC_AUTIASP,
	UNSPEC_AUTIBSP, UNSPEC_PACIASP, UNSPEC_PACIBSP.
	* config/aarch64/iterators.md (PAUTH_17_16): Add UNSPEC_AUTIA1716,
	UNSPEC_AUTIB1716, UNSPEC_PACIA1716, UNSPEC_PACIB1716.
	* config/aarch64/iterators.md (pauth_mnem_prefix): Add UNSPEC_AUTIA1716,
	UNSPEC_AUTIB1716, UNSPEC_PACIA1716, UNSPEC_PACIB1716, UNSPEC_AUTIASP,
	UNSPEC_AUTIBSP, UNSPEC_PACIASP, UNSPEC_PACIBSP.
	* config/aarch64/iterators.md (pauth_hint_num_a): Replace
	UNSPEC_PACI1716 and UNSPEC_AUTI1716 with UNSPEC_PACIA1716 and
	UNSPEC_AUTIA1716 respectively.
	* config/aarch64/iterators.md (pauth_hint_num_a): Rename to pauth_hint_num
	and add UNSPEC_PACIBSP, UNSPEC_AUTIBSP, UNSPEC_PACIB1716, UNSPEC_AUTIB1716.
	* doc/invoke.texi (-mbranch-protection): Add b-key type.
	* config/aarch64/aarch64-bti-insert.c (aarch64_pac_insn_p): Rename
	UNSPEC_PACISP to UNSPEC_PACIASP and UNSPEC_PACIBSP.

gcc/testsuite
2019-05-29  Sam Tebbs  <sam.tebbs@arm.com>

	* gcc.target/aarch64/return_address_sign_b_1.c: New file.
	* gcc.target/aarch64/return_address_sign_b_2.c: New file.
	* gcc.target/aarch64/return_address_sign_b_3.c: New file.
	* gcc.target/aarch64/return_address_sign_b_exception.c: New file.
	* gcc.target/aarch64/return_address_sign_ab_exception.c: New file.
	* gcc.target/aarch64/return_address_sign_builtin.c: New file

libgcc/
2019-05-29  Sam Tebbs  <sam.tebbs@arm.com>

	* config/aarch64/aarch64-unwind.h (aarch64_cie_signed_with_b_key): New
	function.
	* config/aarch64/aarch64-unwind.h (aarch64_post_extract_frame_addr,
	aarch64_post_frob_eh_handler_addr): Add	check for b-key.
	* config/aarch64/aarch64-unwind-h (aarch64_post_extract_frame_addr,
	aarch64_post_frob_eh_handler_addr, aarch64_post_frob_update_context):
	Rename RA_A_SIGNED_BIT to RA_SIGNED_BIT.
	* unwind-dw2-fde.c (get_cie_encoding): Add check for 'B' in augmentation
	string.
	* unwind-dw2.c (extract_cie_info): Add check for 'B' in augmentation
	string.
	(RA_A_SIGNED_BIT): Rename to RA_SIGNED_BIT.

From-SVN: r271735

4 files changed, 54 insertions, 6 deletions

diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index 316c203..c86decf 100644
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,3 +1,18 @@
+2019-05-29  Sam Tebbs  <sam.tebbs@arm.com>
+
+	* config/aarch64/aarch64-unwind.h (aarch64_cie_signed_with_b_key): New
+	function.
+	* config/aarch64/aarch64-unwind.h (aarch64_post_extract_frame_addr,
+	aarch64_post_frob_eh_handler_addr): Add	check for b-key.
+	* config/aarch64/aarch64-unwind-h (aarch64_post_extract_frame_addr,
+	aarch64_post_frob_eh_handler_addr, aarch64_post_frob_update_context):
+	Rename RA_A_SIGNED_BIT to RA_SIGNED_BIT.
+	* unwind-dw2-fde.c (get_cie_encoding): Add check for 'B' in augmentation
+	string.
+	* unwind-dw2.c (extract_cie_info): Add check for 'B' in augmentation
+	string.
+	(RA_A_SIGNED_BIT): Rename to RA_SIGNED_BIT.
+
 2019-05-28  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
 	* config/sparc/sol2-unwind.h [__arch64__] (sparc64_is_sighandler):
diff --git a/libgcc/config/aarch64/aarch64-unwind.h b/libgcc/config/aarch64/aarch64-unwind.h
index 223ac91..13e6e4a 100644
--- a/libgcc/config/aarch64/aarch64-unwind.h
+++ b/libgcc/config/aarch64/aarch64-unwind.h
@@ -35,6 +35,23 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define MD_FROB_UPDATE_CONTEXT(context, fs) \
   aarch64_frob_update_context (context, fs)
 
+static inline int
+aarch64_cie_signed_with_b_key (struct _Unwind_Context *context)
+{
+  const struct dwarf_fde *fde = _Unwind_Find_FDE (context->bases.func,
+						  &context->bases);
+  if (fde != NULL)
+    {
+      const struct dwarf_cie *cie = get_cie (fde);
+      if (cie != NULL)
+	{
+	  char *aug_str = cie->augmentation;
+	  return strchr (aug_str, 'B') == NULL ? 0 : 1;
+	}
+    }
+  return 0;
+}
+
 /* 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.  */
@@ -43,9 +60,11 @@ 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)
+  if (context->flags & RA_SIGNED_BIT)
     {
       _Unwind_Word salt = (_Unwind_Word) context->cfa;
+      if (aarch64_cie_signed_with_b_key (context) != 0)
+	return __builtin_aarch64_autib1716 (addr, salt);
       return __builtin_aarch64_autia1716 (addr, salt);
     }
   else
@@ -62,9 +81,14 @@ aarch64_post_frob_eh_handler_addr (struct _Unwind_Context *current,
 				   ATTRIBUTE_UNUSED,
 				   void *handler_addr)
 {
-  if (current->flags & RA_A_SIGNED_BIT)
-    return __builtin_aarch64_pacia1716 (handler_addr,
+  if (current->flags & RA_SIGNED_BIT)
+    {
+      if (aarch64_cie_signed_with_b_key (current))
+	return __builtin_aarch64_pacib1716 (handler_addr,
+					    (_Unwind_Word) current->cfa);
+      return __builtin_aarch64_pacia1716 (handler_addr,
 					(_Unwind_Word) current->cfa);
+    }
   else
     return handler_addr;
 }
@@ -79,7 +103,7 @@ aarch64_frob_update_context (struct _Unwind_Context *context,
 {
   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;
+    context->flags |= RA_SIGNED_BIT;
 
   return;
 }
diff --git a/libgcc/unwind-dw2-fde.c b/libgcc/unwind-dw2-fde.c
index 24b4ece..40ebf85 100644
--- a/libgcc/unwind-dw2-fde.c
+++ b/libgcc/unwind-dw2-fde.c
@@ -334,6 +334,9 @@ get_cie_encoding (const struct dwarf_cie *cie)
       /* LSDA encoding.  */
       else if (*aug == 'L')
 	p++;
+      /* aarch64 b-key pointer authentication.  */
+      else if (*aug == 'B')
+	p++;
       /* Otherwise end of string, or unknown augmentation.  */
       else
 	return DW_EH_PE_absptr;
diff --git a/libgcc/unwind-dw2.c b/libgcc/unwind-dw2.c
index e6130af..e76a1cb 100644
--- a/libgcc/unwind-dw2.c
+++ b/libgcc/unwind-dw2.c
@@ -136,8 +136,9 @@ 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)
+  /* Bit reserved on AArch64, return address has been signed with A or B
+     key.  */
+#define RA_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.  */
@@ -502,6 +503,11 @@ extract_cie_info (const struct dwarf_cie *cie, struct _Unwind_Context *context,
 	  fs->signal_frame = 1;
 	  aug += 1;
 	}
+      /* aarch64 B-key pointer authentication.  */
+      else if (aug[0] == 'B')
+	{
+	  aug += 1;
+      }
 
       /* Otherwise we have an unknown augmentation string.
 	 Bail unless we saw a 'z' prefix.  */