[RFC,V2,AARCH64] : Re: [RFC] [PATCH, AARCH64] Machine descriptions to support stack smashing protection

Index: gcc/configure.ac
===================================================================
--- gcc/configure.ac	(revision 205378)
+++ gcc/configure.ac	(working copy)
@@ -4896,6 +4896,24 @@ 
 	    [Define if your target C library provides stack protector support])
 fi
 
+# Test for tls based stack protector support in target C library.
+AC_CACHE_CHECK(TLS stack guard support in target C library,
+   gcc_cv_libc_provides_tls_ssp,
+   [gcc_cv_libc_provides_tls_ssp=no
+   case "$target" in
+      aarch64-*-linux* | aarch64-*-kfreebsd*-gnu | aarch64-*-knetbsd*-gnu)
+     # glibc 2.19 and later provides TLS access to stack guard canary
+     # currently set for Aarch64.
+     GCC_GLIBC_VERSION_GTE_IFELSE([2], [19], [gcc_cv_libc_provides_tls_ssp=yes])
+	;;
+   *) gcc_cv_libc_provides_tls_ssp=no ;;
+   esac])
+
+if test x$gcc_cv_libc_provides_tls_ssp = xyes; then
+  AC_DEFINE(TARGET_LIBC_PROVIDES_TLS_SSP, 1,
+	    [Define if your target C library provides TLS stack protector support.])
+fi
+
 # Test for <sys/sdt.h> on the target.
 GCC_TARGET_TEMPLATE([HAVE_SYS_SDT_H])
 AC_MSG_CHECKING(sys/sdt.h in the target C library)
Index: gcc/configure
===================================================================
--- gcc/configure	(revision 205378)
+++ gcc/configure	(working copy)
@@ -27127,6 +27127,35 @@ 
 
 fi
 
+# Test for tls based stack protector support in target C library.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking TLS stack guard support in target C library" >&5
+$as_echo_n "checking TLS stack guard support in target C library... " >&6; }
+if test "${gcc_cv_libc_provides_tls_ssp+set}" = set; then :
+  $as_echo_n "(cached) " >&6
+else
+  gcc_cv_libc_provides_tls_ssp=no
+   case "$target" in
+      aarch64-*-linux* | aarch64-*-kfreebsd*-gnu | aarch64-*-knetbsd*-gnu)
+     # glibc 2.19 and later provides TLS access to stack guard canary
+     # currently set for Aarch64.
+
+if test $glibc_version_major -gt 2 \
+  || ( test $glibc_version_major -eq 2 && test $glibc_version_minor -ge 19 ); then :
+  gcc_cv_libc_provides_tls_ssp=yes
+fi
+	;;
+   *) gcc_cv_libc_provides_tls_ssp=no ;;
+   esac
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_libc_provides_tls_ssp" >&5
+$as_echo "$gcc_cv_libc_provides_tls_ssp" >&6; }
+
+if test x$gcc_cv_libc_provides_tls_ssp = xyes; then
+
+$as_echo "#define TARGET_LIBC_PROVIDES_TLS_SSP 1" >>confdefs.h
+
+fi
+
 # Test for <sys/sdt.h> on the target.
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking sys/sdt.h in the target C library" >&5
Index: gcc/testsuite/lib/target-supports.exp
===================================================================
--- gcc/testsuite/lib/target-supports.exp	(revision 205378)
+++ gcc/testsuite/lib/target-supports.exp	(working copy)
@@ -808,6 +808,17 @@ 
     } "-fstack-protector"]
 }
 
+# Return 1 the target supports stack protection.
+proc check_effective_target_stack_protection { } {
+    if { [istarget i?86-*-*]
+         || [istarget x86_64-*-*]
+         || [istarget aarch64-*-*]
+         || [istarget s390x-*-*] } {
+        return 1;
+    }
+    return 0
+}
+
 # Return 1 if compilation with -freorder-blocks-and-partition is error-free
 # for trivial code, 0 otherwise.
 
Index: gcc/testsuite/gcc.dg/fstack-protector-strong.c
===================================================================
--- gcc/testsuite/gcc.dg/fstack-protector-strong.c	(revision 205378)
+++ gcc/testsuite/gcc.dg/fstack-protector-strong.c	(working copy)
@@ -1,6 +1,6 @@ 
 /* Test that stack protection is done on chosen functions. */
 
-/* { dg-do compile { target i?86-*-* x86_64-*-* rs6000-*-* s390x-*-* } } */
+/* { dg-do compile { target stack_protection } } */
 /* { dg-options "-O2 -fstack-protector-strong" } */
 
 #include<string.h>
Index: gcc/testsuite/g++.dg/fstack-protector-strong.C
===================================================================
--- gcc/testsuite/g++.dg/fstack-protector-strong.C	(revision 205378)
+++ gcc/testsuite/g++.dg/fstack-protector-strong.C	(working copy)
@@ -1,6 +1,6 @@ 
 /* Test that stack protection is done on chosen functions. */
 
-/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-do compile { target stack_protection } } */
 /* { dg-options "-O2 -fstack-protector-strong" } */
 
 class A
Index: gcc/config.in
===================================================================
--- gcc/config.in	(revision 205378)
+++ gcc/config.in	(working copy)
@@ -1828,6 +1828,12 @@ 
 #endif
 
 
+/* Define if your target C library provides TLS stack protector support. */
+#ifndef USED_FOR_TARGET
+#undef TARGET_LIBC_PROVIDES_TLS_SSP
+#endif
+
+
 /* Define to 1 if you can safely include both <sys/time.h> and <time.h>. */
 #ifndef USED_FOR_TARGET
 #undef TIME_WITH_SYS_TIME
Index: gcc/config/aarch64/aarch64-linux.h
===================================================================
--- gcc/config/aarch64/aarch64-linux.h	(revision 205378)
+++ gcc/config/aarch64/aarch64-linux.h	(working copy)
@@ -43,4 +43,9 @@ 
     }						\
   while (0)
 
+#ifdef TARGET_LIBC_PROVIDES_TLS_SSP
+/* Aarch64 glibc provides __stack_chk_guard in [tp - 0x8].  */
+#define TARGET_THREAD_SSP_OFFSET (-1 * GET_MODE_SIZE (ptr_mode))
+#endif
+
 #endif  /* GCC_AARCH64_LINUX_H */
Index: gcc/config/aarch64/aarch64.md
===================================================================
--- gcc/config/aarch64/aarch64.md	(revision 205378)
+++ gcc/config/aarch64/aarch64.md	(working copy)
@@ -99,6 +99,10 @@ 
     UNSPEC_TLSDESC
     UNSPEC_USHL_2S
     UNSPEC_VSTRUCTDUMMY
+    UNSPEC_SP_SET
+    UNSPEC_SP_TEST
+    UNSPEC_SP_TLS_SET
+    UNSPEC_SP_TLS_TEST
 ])
 
 (define_c_enum "unspecv" [
@@ -3625,6 +3629,80 @@ 
   DONE;
 })
 
+
+;; Named patterns for stack smashing protection.
+(define_expand "stack_protect_set"
+  [(match_operand 0 "memory_operand")
+   (match_operand 1 "memory_operand")]
+  ""
+{
+  enum machine_mode mode = GET_MODE (operands[0]);
+
+#ifdef TARGET_THREAD_SSP_OFFSET
+  rtx tlsreg = gen_reg_rtx (Pmode);
+  emit_insn (gen_aarch64_load_tp_hard (tlsreg));
+  rtx addr = gen_rtx_PLUS (Pmode, tlsreg, GEN_INT (TARGET_THREAD_SSP_OFFSET));
+  operands[1] = gen_rtx_MEM (Pmode, addr);
+#endif
+
+  emit_insn ((mode == DImode
+	      ? gen_stack_protect_set_di
+	      : gen_stack_protect_set_si) (operands[0], operands[1]));
+  DONE;
+})
+
+(define_insn "stack_protect_set_<mode>"
+  [(set (match_operand:PTR 0 "memory_operand" "=m")
+	(unspec:PTR [(match_operand:PTR 1 "memory_operand" "m")]
+	 UNSPEC_SP_SET))
+   (set (match_scratch:PTR 2 "=&r") (const_int 0))]
+  ""
+  "ldr\\t%x2, %1\;str\\t%x2, %0\;mov\t%x2,0"
+  [(set_attr "length" "12")])
+
+(define_expand "stack_protect_test"
+  [(match_operand 0 "memory_operand")
+   (match_operand 1 "memory_operand")
+   (match_operand 2)]
+  ""
+{
+
+#ifdef TARGET_THREAD_SSP_OFFSET
+  rtx tlsreg = gen_reg_rtx (Pmode);
+  emit_insn (gen_aarch64_load_tp_hard (tlsreg));
+  rtx addr = gen_rtx_PLUS (Pmode, tlsreg, GEN_INT (TARGET_THREAD_SSP_OFFSET));
+  operands[1] = gen_rtx_MEM (Pmode, addr);
+#endif
+
+  rtx result = gen_reg_rtx (Pmode);
+
+  enum machine_mode mode = GET_MODE (operands[0]);
+
+  emit_insn ((mode == DImode
+	      ? gen_stack_protect_test_di
+	      : gen_stack_protect_test_si) (result,
+					    operands[0],
+ 					    operands[1]));
+
+  if (mode == DImode)
+    emit_jump_insn (gen_cbranchdi4 (gen_rtx_EQ (VOIDmode, result, const0_rtx),
+				    result, const0_rtx, operands[2]));
+  else
+    emit_jump_insn (gen_cbranchsi4 (gen_rtx_EQ (VOIDmode, result, const0_rtx),
+				    result, const0_rtx, operands[2]));
+  DONE;
+})
+
+(define_insn "stack_protect_test_<mode>"
+  [(set (match_operand:PTR 0 "register_operand")
+	(unspec:PTR [(match_operand:PTR 1 "memory_operand" "m")
+		     (match_operand:PTR 2 "memory_operand" "m")]
+	 UNSPEC_SP_TEST))
+   (clobber (match_scratch:PTR 3 "=&r"))]
+  ""
+  "ldr\t%x3, %x1\;ldr\t%x0, %x2\;eor\t%x0, %x3, %x0"
+  [(set_attr "length" "12")])
+
 ;; AdvSIMD Stuff
 (include "aarch64-simd.md")