rs6000: ROP - Emit hashst and hashchk insns on Power8 and later [PR114759]

We currently only emit the ROP-protect hash* insns for Power10, where the
insns were added to the architecture.  We want to emit them for earlier
cpus (where they operate as NOPs), so that if those older binaries are
ever executed on a Power10, then they'll be protected from ROP attacks.
Binutils accepts hashst and hashchk back to Power8, so change GCC to emit
them for Power8 and later.  This matches clang's behavior.

2024-06-19  Peter Bergner  <bergner@linux.ibm.com>

gcc/
	PR target/114759
	* config/rs6000/rs6000-logue.cc (rs6000_stack_info): Use TARGET_POWER8.
	(rs6000_emit_prologue): Likewise.
	* config/rs6000/rs6000.md (hashchk): Likewise.
	(hashst): Likewise.
	Fix whitespace.

gcc/testsuite/
	PR target/114759
	* gcc.target/powerpc/pr114759-2.c: New test.
	* lib/target-supports.exp (rop_ok): Use
	check_effective_target_has_arch_pwr8.

diff --git a/gcc/config/rs6000/rs6000-logue.cc b/gcc/config/rs6000/rs6000-logue.cc
index 193e2122c0f9b380a7cd823b2571adca65755878..48f406330714f01e6d96f2037af7d015c8b68597 100644 (file)
--- a/gcc/config/rs6000/rs6000-logue.cc
+++ b/gcc/config/rs6000/rs6000-logue.cc
@@ -716,7 +716,7 @@ rs6000_stack_info (void)
   info->calls_p = (!crtl->is_leaf || cfun->machine->ra_needs_full_frame);
   info->rop_hash_size = 0;
 
-  if (TARGET_POWER10
+  if (TARGET_POWER8
       && info->calls_p
       && DEFAULT_ABI == ABI_ELFv2
       && rs6000_rop_protect)
@@ -3272,7 +3272,7 @@ rs6000_emit_prologue (void)
   /* NOTE: The hashst isn't needed if we're going to do a sibcall,
      but there's no way to know that here.  Harmless except for
      performance, of course.  */
-  if (TARGET_POWER10 && rs6000_rop_protect && info->rop_hash_size != 0)
+  if (TARGET_POWER8 && rs6000_rop_protect && info->rop_hash_size != 0)
     {
       gcc_assert (DEFAULT_ABI == ABI_ELFv2);
       rtx stack_ptr = gen_rtx_REG (Pmode, STACK_POINTER_REGNUM);
@@ -5051,7 +5051,7 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type)
 
   /* The ROP hash check must occur after the stack pointer is restored
      (since the hash involves r1), and is not performed for a sibcall.  */
-  if (TARGET_POWER10
+  if (TARGET_POWER8
       && rs6000_rop_protect
       && info->rop_hash_size != 0
       && epilogue_type != EPILOGUE_TYPE_SIBCALL)

diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 276a5c9cf2d36067733333bb1e2ba4eed0f017d2..679aac5a10d573f338681b4bfaa00e7b31a77b19 100644 (file)
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -15808,9 +15808,9 @@
 
 (define_insn "hashst"
   [(set (match_operand:DI 0 "simple_offsettable_mem_operand" "=m")
-        (unspec_volatile:DI [(match_operand:DI 1 "int_reg_operand" "r")]
+       (unspec_volatile:DI [(match_operand:DI 1 "int_reg_operand" "r")]
                            UNSPEC_HASHST))]
-  "TARGET_POWER10 && rs6000_rop_protect"
+  "TARGET_POWER8 && rs6000_rop_protect"
 {
   static char templ[32];
   const char *p = rs6000_privileged ? "p" : "";
@@ -15823,7 +15823,7 @@
   [(unspec_volatile [(match_operand:DI 0 "int_reg_operand" "r")
                     (match_operand:DI 1 "simple_offsettable_mem_operand" "m")]
                    UNSPEC_HASHCHK)]
-  "TARGET_POWER10 && rs6000_rop_protect"
+  "TARGET_POWER8 && rs6000_rop_protect"
 {
   static char templ[32];
   const char *p = rs6000_privileged ? "p" : "";

diff --git a/gcc/testsuite/gcc.target/powerpc/pr114759-2.c b/gcc/testsuite/gcc.target/powerpc/pr114759-2.c
new file mode 100644 (file)
index 0000000..3881ebd
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr114759-2.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mdejagnu-cpu=power8 -mrop-protect" } */
+/* { dg-require-effective-target rop_ok } Only enable on supported ABIs.  */
+
+/* Verify we generate ROP-protect hash insns when compiling for Power8.  */
+
+extern void foo (void);
+
+int
+bar (void)
+{
+  foo ();
+  return 5;
+}
+
+/* { dg-final { scan-assembler-times {\mhashst\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mhashchk\M} 1 } } */

diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index f001c28072f6943c00eb9cf548a3e1da67e15336..daa0c75d2bc3790491cf16f236a2a87af81f2f62 100644 (file)
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -7452,7 +7452,7 @@ proc check_effective_target_powerpc_elfv2 { } {
 # Return 1 if this is a PowerPC target supporting -mrop-protect
 
 proc check_effective_target_rop_ok { } {
-    return [check_effective_target_power10_ok] && [check_effective_target_powerpc_elfv2]
+    return [check_effective_target_has_arch_pwr8] && [check_effective_target_powerpc_elfv2]
 }
 
 # The VxWorks SPARC simulator accepts only EM_SPARC executables and