From: Bill Schmidt <wschmidt@linux.ibm.com>
Date: Fri, 14 May 2021 19:15:55 +0000 (-0500)
Subject: rs6000: Add -mrop-protect and -mprivileged flags
X-Git-Tag: releases/gcc-11.2.0~364
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4ffe506d025e953a0ab3ef0392867d1a46bb9ff5;p=thirdparty%2Fgcc.git

rs6000: Add -mrop-protect and -mprivileged flags

2021-05-14  Bill Schmidt  <wschmidt@linux.ibm.com>

gcc/
	* config/rs6000/rs6000.c (rs6000_option_override_internal):
	Disable shrink wrap when inserting ROP-protect instructions.
	* config/rs6000/rs6000.opt (mrop-protect): New option.
	(mprivileged): Likewise.
	* doc/invoke.texi: Document mrop-protect and mprivileged.
---

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 844fee88cf3c..83ef1be6afef 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -4036,6 +4036,10 @@ rs6000_option_override_internal (bool global_init_p)
       && ((rs6000_isa_flags_explicit & OPTION_MASK_QUAD_MEMORY_ATOMIC) == 0))
     rs6000_isa_flags |= OPTION_MASK_QUAD_MEMORY_ATOMIC;
 
+  /* If we are inserting ROP-protect instructions, disable shrink wrap.  */
+  if (rs6000_rop_protect)
+    flag_shrink_wrap = 0;
+
   /* If we can shrink-wrap the TOC register save separately, then use
      -msave-toc-indirect unless explicitly disabled.  */
   if ((rs6000_isa_flags_explicit & OPTION_MASK_SAVE_TOC_INDIRECT) == 0
diff --git a/gcc/config/rs6000/rs6000.opt b/gcc/config/rs6000/rs6000.opt
index 0dbdf7536735..2685fa715176 100644
--- a/gcc/config/rs6000/rs6000.opt
+++ b/gcc/config/rs6000/rs6000.opt
@@ -619,3 +619,11 @@ Generate (do not generate) MMA instructions.
 
 mrelative-jumptables
 Target Undocumented Var(rs6000_relative_jumptables) Init(1) Save
+
+mrop-protect
+Target Var(rs6000_rop_protect) Init(0)
+Enable instructions that guard against return-oriented programming attacks.
+
+mprivileged
+Target Var(rs6000_privileged) Init(0)
+Generate code that will run in privileged state.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 4a87b9ef8e8c..7f13ffb79e10 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -1238,7 +1238,8 @@ See RS/6000 and PowerPC Options.
 -mgnu-attribute  -mno-gnu-attribute @gol
 -mstack-protector-guard=@var{guard} -mstack-protector-guard-reg=@var{reg} @gol
 -mstack-protector-guard-offset=@var{offset} -mprefixed -mno-prefixed @gol
--mpcrel -mno-pcrel -mmma -mno-mmma}
+-mpcrel -mno-pcrel -mmma -mno-mmma -mrop-protect -mno-rop-protect @gol
+-mprivileged -mno-privileged}
 
 @emph{RX Options}
 @gccoptlist{-m64bit-doubles  -m32bit-doubles  -fpu  -nofpu@gol
@@ -27019,7 +27020,8 @@ following options:
 -mmulhw  -mdlmzb  -mmfpgpr  -mvsx @gol
 -mcrypto  -mhtm  -mpower8-fusion  -mpower8-vector @gol
 -mquad-memory  -mquad-memory-atomic  -mfloat128 @gol
--mfloat128-hardware -mprefixed -mpcrel -mmma}
+-mfloat128-hardware -mprefixed -mpcrel -mmma @gol
+-mrop-protect}
 
 The particular options set for any particular CPU varies between
 compiler versions, depending on what setting seems to produce optimal
@@ -28024,6 +28026,20 @@ store instructions when the option @option{-mcpu=future} is used.
 Generate (do not generate) the MMA instructions when the option
 @option{-mcpu=future} is used.
 
+@item -mrop-protect
+@itemx -mno-rop-protect
+@opindex mrop-protect
+@opindex mno-rop-protect
+Generate (do not generate) ROP protection instructions when the target
+processor supports them.  Currently this option disables the shrink-wrap
+optimization (@option{-fshrink-wrap}).
+
+@item -mprivileged
+@itemx -mno-privileged
+@opindex mprivileged
+@opindex mno-privileged
+Generate (do not generate) code that will run in privileged state.
+
 @item -mblock-ops-unaligned-vsx
 @itemx -mno-block-ops-unaligned-vsx
 @opindex block-ops-unaligned-vsx