Patchwork [i386] Add -mstack-protector-guard= for i386

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Submitter Andrew Hsieh
Date April 15, 2013, 6:30 a.m.
Message ID <CABySjRs+9oLLxiC+fmoJVRxciz_1=PQMddyE9LiFuE1Z0P-yrA@mail.gmail.com>
Download mbox | patch
Permalink /patch/236498/
State New
Headers show

Comments

Andrew Hsieh - April 15, 2013, 6:30 a.m.
Sure.  Put back Init(SSP_TLS) and rebase to r197955.
If no further feedback, please merge.

2013-04-15  Andrew Hsieh  <andrewhsieh.google.com>

        * config/i386/i386.opt: New option mstack-protector-guard=.
        * config/i386/i386-opts.h: Add enum stack_protector_guard.
        * config/i386/i386.h: Introduce TARGET_SSP_GLOBAL_GUARD and
        TARGET_SSP_TLS_GUARD.
        * config/i386/i386.c (ix86_option_override_internal): Default
        to SSP_TLS unless it's bionic
        * config/i386/i386.md: define_expand/insn "stack_protect_set/test..."
        if TARGET_SSP_TLS_GUARD
        * doc/invoke.texi (i386 Option): Document.


On Fri, Apr 12, 2013 at 7:10 PM, Uros Bizjak <ubizjak@gmail.com> wrote:
> On Fri, Apr 12, 2013 at 12:28 PM, Andrew Hsieh <andrewhsieh@google.com> wrote:
>> One question: If I drop Init(SSP_TLS), I got the following error
>> during compilation:
>>    options.c:1122:1: error: invalid conversion from 'int' to
>> 'stack_protector_guard' [-fpermissive]
>> It's because w/o Init(SSP_TLS), '0' is placed in global_options_init
>> where enum stack_protector_guard is expected.
>> Used to be okay with C but no good in 4.8+ since C++ becomes
>> implementation language.
>>
>> What is the best way to deal with it?
>
> Just leave Init(SSP_TLS) for now, I have CC'd Joseph for the problem
> with option system.
>
> Uros.
Uros Bizjak - April 15, 2013, 10:05 a.m.
On Mon, Apr 15, 2013 at 8:30 AM, Andrew Hsieh <andrewhsieh@google.com> wrote:
> Sure.  Put back Init(SSP_TLS) and rebase to r197955.
> If no further feedback, please merge.

Committed with slightly changed ChangeLog entry:

2013-04-15  Andrew Hsieh  <andrewhsieh.google.com>

    * config/i386/i386.opt: New option mstack-protector-guard=.
    * config/i386/i386-opts.h: Add enum stack_protector_guard.
    * config/i386/i386.h: Define TARGET_SSP_GLOBAL_GUARD and
    TARGET_SSP_TLS_GUARD.
    * config/i386/i386.c (ix86_option_override_internal): Set
    ix86_stack_protector_guard.
    * config/i386/i386.md (stack_protect_set): Enable for
    TARGET_SSP_TLS_GUARD only.
    (stack_protect_set_<mode>): Ditto.
    (stack_protect_test): Ditto.
    (stack_protect_test_<mode>): Ditto.
    * doc/invoke.texi (i386 Option): Document.

Thanks,
Uros.

Patch

Index: gcc/config/i386/i386.opt
===================================================================
--- gcc/config/i386/i386.opt (revision 197955)
+++ gcc/config/i386/i386.opt (working copy)
@@ -626,3 +626,17 @@ 
 mrtm
 Target Report Mask(ISA_RTM) Var(ix86_isa_flags) Save
 Support RTM built-in functions and code generation
+
+mstack-protector-guard=
+Target RejectNegative Joined Enum(stack_protector_guard)
Var(ix86_stack_protector_guard) Init(SSP_TLS)
+Use given stack-protector guard
+
+Enum
+Name(stack_protector_guard) Type(enum stack_protector_guard)
+Known stack protector guard (for use with the -mstack-protector-guard= option):
+
+EnumValue
+Enum(stack_protector_guard) String(tls) Value(SSP_TLS)
+
+EnumValue
+Enum(stack_protector_guard) String(global) Value(SSP_GLOBAL)
Index: gcc/config/i386/i386.md
===================================================================
--- gcc/config/i386/i386.md (revision 197955)
+++ gcc/config/i386/i386.md (working copy)
@@ -17058,7 +17058,7 @@ 
 (define_expand "stack_protect_set"
   [(match_operand 0 "memory_operand")
    (match_operand 1 "memory_operand")]
-  "!TARGET_HAS_BIONIC"
+  "TARGET_SSP_TLS_GUARD"
 {
   rtx (*insn)(rtx, rtx);

@@ -17083,7 +17083,7 @@ 
     UNSPEC_SP_SET))
    (set (match_scratch:PTR 2 "=&r") (const_int 0))
    (clobber (reg:CC FLAGS_REG))]
-  "!TARGET_HAS_BIONIC"
+  "TARGET_SSP_TLS_GUARD"
   "mov{<imodesuffix>}\t{%1, %2|%2, %1}\;mov{<imodesuffix>}\t{%2,
%0|%0, %2}\;xor{l}\t%k2, %k2"
   [(set_attr "type" "multi")])

@@ -17101,7 +17101,7 @@ 
   [(match_operand 0 "memory_operand")
    (match_operand 1 "memory_operand")
    (match_operand 2)]
-  "!TARGET_HAS_BIONIC"
+  "TARGET_SSP_TLS_GUARD"
 {
   rtx flags = gen_rtx_REG (CCZmode, FLAGS_REG);

@@ -17131,7 +17131,7 @@ 
      (match_operand:PTR 2 "memory_operand" "m")]
     UNSPEC_SP_TEST))
    (clobber (match_scratch:PTR 3 "=&r"))]
-  "!TARGET_HAS_BIONIC"
+  "TARGET_SSP_TLS_GUARD"
   "mov{<imodesuffix>}\t{%1, %3|%3, %1}\;xor{<imodesuffix>}\t{%2, %3|%3, %2}"
   [(set_attr "type" "multi")])

Index: gcc/config/i386/i386-opts.h
===================================================================
--- gcc/config/i386/i386-opts.h (revision 197955)
+++ gcc/config/i386/i386-opts.h (working copy)
@@ -85,4 +85,9 @@ 
   ix86_veclibabi_type_acml
 };

+enum stack_protector_guard {
+  SSP_TLS,      /* per-thread canary in TLS block */
+  SSP_GLOBAL    /* global canary */
+};
+
 #endif
Index: gcc/config/i386/i386.c
===================================================================
--- gcc/config/i386/i386.c (revision 197955)
+++ gcc/config/i386/i386.c (working copy)
@@ -3922,6 +3922,10 @@ 
   if (main_args_p)
     target_option_default_node = target_option_current_node
       = build_target_option_node ();
+
+  /* Handle stack protector */
+  if (!global_options_set.x_ix86_stack_protector_guard)
+    ix86_stack_protector_guard = TARGET_HAS_BIONIC ? SSP_GLOBAL : SSP_TLS;
 }

 /* Implement the TARGET_OPTION_OVERRIDE hook.  */
Index: gcc/config/i386/i386.h
===================================================================
--- gcc/config/i386/i386.h (revision 197955)
+++ gcc/config/i386/i386.h (working copy)
@@ -486,6 +486,9 @@ 
 #define TARGET_TLS_DIRECT_SEG_REFS_DEFAULT 0
 #endif

+#define TARGET_SSP_GLOBAL_GUARD (ix86_stack_protector_guard == SSP_GLOBAL)
+#define TARGET_SSP_TLS_GUARD    (ix86_stack_protector_guard == SSP_TLS)
+
 /* Fence to use after loop using storent.  */

 extern tree x86_mfence;
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi (revision 197955)
+++ gcc/doc/invoke.texi (working copy)
@@ -657,7 +657,8 @@ 
 -mcmodel=@var{code-model} -mabi=@var{name} -maddress-mode=@var{mode} @gol
 -m32 -m64 -mx32 -mlarge-data-threshold=@var{num} @gol
 -msse2avx -mfentry -m8bit-idiv @gol
--mavx256-split-unaligned-load -mavx256-split-unaligned-store}
+-mavx256-split-unaligned-load -mavx256-split-unaligned-store @gol
+-mstack-protector-guard=@var{guard}}

 @emph{i386 and x86-64 Windows Options}
 @gccoptlist{-mconsole -mcygwin -mno-cygwin -mdll @gol
@@ -14592,6 +14593,13 @@ 
 @opindex avx256-split-unaligned-store
 Split 32-byte AVX unaligned load and store.

+@item -mstack-protector-guard=@var{guard}
+@opindex mstack-protector-guard=@var{guard}
+Generate stack protection code using canary at @var{guard}.  Supported
+locations are @samp{global} or @samp{tls} per thread at %gs:20 (the default).
+This option has effect only when @option{-fstack-protector}
+or @option{-fstack-protector-all} is also specified.
+
 @end table

 These @samp{-m} switches are supported in addition to the above