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Re: [PATCH] i386: Add save_stack_nonlocal and restore_stack_nonlocal
On Thu, Apr 19, 2018 at 8:51 AM, Tsimbalist, Igor V
<igor.v.tsimbalist@intel.com> wrote:
>> -----Original Message-----
>> From: Lu, Hongjiu
>> Sent: Sunday, April 15, 2018 12:58 PM
>> To: gcc-patches@gcc.gnu.org
>> Cc: Uros Bizjak <ubizjak@gmail.com>; Tsimbalist, Igor V
>> <igor.v.tsimbalist@intel.com>
>> Subject: [PATCH] i386: Add save_stack_nonlocal and restore_stack_nonlocal
>>
>> Define STACK_SAVEAREA_MODE to hold both shadow stack and stack
>> pointers.
>> Replace builtin_setjmp_setup and builtin_longjmp with save_stack_nonlocal
>> and restore_stack_nonlocal to support both builtin setjmp/longjmp as well
>> as non-local goto in nested functions.
>>
>> OK for trunk?
>
> OK.
>
This is what I checked in. TARGET_SHSTK is no longer checked for
-fcf-protection.
--
H.J.
From 035c752ee0f464aeec6c8dd95f125145fa0a8f22 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Sat, 14 Apr 2018 04:11:28 -0700
Subject: [PATCH] i386: Add save_stack_nonlocal and restore_stack_nonlocal
Define STACK_SAVEAREA_MODE to hold both shadow stack and stack pointers.
Replace builtin_setjmp_setup and builtin_longjmp with save_stack_nonlocal
and restore_stack_nonlocal to support both builtin setjmp/longjmp as well
as non-local goto in nested functions.
gcc/
PR target/85397
* config/i386/i386.h (STACK_SAVEAREA_MODE): New.
* config/i386/i386.md (builtin_setjmp_setup): Removed.
(builtin_longjmp): Likewise.
(save_stack_nonlocal): New pattern.
(restore_stack_nonlocal): Likewise.
gcc/testsuite/
PR target/85397
* gcc.dg/torture/pr85397-1.c: New test.
* gcc.target/i386/cet-sjlj-6a.c: Adjusted.
* gcc.target/i386/cet-sjlj-6b.c: Likewise.
---
gcc/config/i386/i386.h | 11 +++
gcc/config/i386/i386.md | 107 +++++++++++++---------------
gcc/testsuite/gcc.dg/torture/pr85397-1.c | 29 ++++++++
gcc/testsuite/gcc.target/i386/cet-sjlj-6a.c | 4 +-
gcc/testsuite/gcc.target/i386/cet-sjlj-6b.c | 4 +-
5 files changed, 92 insertions(+), 63 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr85397-1.c
diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index 0b0f0d21942..3734ba1bc12 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -1948,6 +1948,17 @@ do { \
between pointers and any other objects of this machine mode. */
#define Pmode (ix86_pmode == PMODE_DI ? DImode : SImode)
+/* Supply a definition of STACK_SAVEAREA_MODE for emit_stack_save.
+ NONLOCAL needs space to save both shadow stack and stack pointers.
+
+ FIXME: We only need to save and restore stack pointer in ptr_mode.
+ But expand_builtin_setjmp_setup and expand_builtin_longjmp use Pmode
+ to save and restore stack pointer. See
+ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84150
+ */
+#define STACK_SAVEAREA_MODE(LEVEL) \
+ ((LEVEL) == SAVE_NONLOCAL ? (TARGET_64BIT ? TImode : DImode) : Pmode)
+
/* Specify the machine mode that bounds have. */
#define BNDmode (ix86_pmode == PMODE_DI ? BND64mode : BND32mode)
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index ae1fea1ed77..33e8060fa56 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -18487,29 +18487,6 @@
"* return output_probe_stack_range (operands[0], operands[2]);"
[(set_attr "type" "multi")])
-/* Additional processing for builtin_setjmp. Store the shadow stack pointer
- as a forth element in jmpbuf. */
-(define_expand "builtin_setjmp_setup"
- [(match_operand 0 "address_operand")]
- "TARGET_SHSTK"
-{
- if (flag_cf_protection & CF_RETURN)
- {
- rtx mem, reg_ssp;
-
- mem = gen_rtx_MEM (word_mode,
- plus_constant (Pmode, operands[0],
- 3 * GET_MODE_SIZE (ptr_mode)));
- reg_ssp = gen_reg_rtx (word_mode);
- emit_insn (gen_rtx_SET (reg_ssp, const0_rtx));
- emit_insn ((word_mode == SImode)
- ? gen_rdsspsi (reg_ssp)
- : gen_rdsspdi (reg_ssp));
- emit_move_insn (mem, reg_ssp);
- }
- DONE;
-})
-
(define_expand "builtin_setjmp_receiver"
[(label_ref (match_operand 0))]
"!TARGET_64BIT && flag_pic"
@@ -18530,19 +18507,46 @@
DONE;
})
-(define_expand "builtin_longjmp"
- [(match_operand 0 "address_operand")]
- "TARGET_SHSTK"
+(define_expand "save_stack_nonlocal"
+ [(set (match_operand 0 "memory_operand")
+ (match_operand 1 "register_operand"))]
+ ""
{
- rtx fp, lab, stack;
- rtx flags, jump, noadj_label, inc_label, loop_label;
- rtx reg_adj, reg_ssp, mem_buf, tmp, clob;
- machine_mode sa_mode = STACK_SAVEAREA_MODE (SAVE_NONLOCAL);
+ rtx stack_slot;
+ if ((flag_cf_protection & CF_RETURN))
+ {
+ /* Copy shadow stack pointer to the first slot and stack ppointer
+ to the second slot. */
+ rtx ssp_slot = adjust_address (operands[0], word_mode, 0);
+ stack_slot = adjust_address (operands[0], Pmode, UNITS_PER_WORD);
+ rtx ssp = gen_reg_rtx (word_mode);
+ emit_insn ((word_mode == SImode)
+ ? gen_rdsspsi (ssp)
+ : gen_rdsspdi (ssp));
+ emit_move_insn (ssp_slot, ssp);
+ }
+ else
+ stack_slot = adjust_address (operands[0], Pmode, 0);
+ emit_move_insn (stack_slot, operands[1]);
+ DONE;
+})
- /* Adjust the shadow stack pointer (ssp) to the value saved in the
- jmp_buf. The saving was done in the builtin_setjmp_setup. */
- if (flag_cf_protection & CF_RETURN)
+(define_expand "restore_stack_nonlocal"
+ [(set (match_operand 0 "register_operand" "")
+ (match_operand 1 "memory_operand" ""))]
+ ""
+{
+ rtx stack_slot;
+ if ((flag_cf_protection & CF_RETURN))
{
+ /* Restore shadow stack pointer from the first slot and stack
+ pointer from the second slot. */
+ rtx ssp_slot = adjust_address (operands[1], word_mode, 0);
+ stack_slot = adjust_address (operands[1], Pmode, UNITS_PER_WORD);
+
+ rtx flags, jump, noadj_label, inc_label, loop_label;
+ rtx reg_adj, reg_ssp, tmp, clob;
+
/* Get the current shadow stack pointer. The code below will check if
SHSTK feature is enabled. If it is not enabled the RDSSP instruction
is a NOP. */
@@ -18551,13 +18555,11 @@
emit_insn ((word_mode == SImode)
? gen_rdsspsi (reg_ssp)
: gen_rdsspdi (reg_ssp));
- mem_buf = gen_rtx_MEM (word_mode,
- plus_constant (Pmode, operands[0],
- 3 * GET_MODE_SIZE (ptr_mode)));
/* Compare through substraction the saved and the current ssp to decide
if ssp has to be adjusted. */
- tmp = gen_rtx_SET (reg_ssp, gen_rtx_MINUS (word_mode, reg_ssp, mem_buf));
+ tmp = gen_rtx_SET (reg_ssp, gen_rtx_MINUS (word_mode, reg_ssp,
+ ssp_slot));
clob = gen_rtx_CLOBBER (VOIDmode, gen_rtx_REG (CCmode, FLAGS_REG));
tmp = gen_rtx_PARALLEL (VOIDmode, gen_rtvec (2, tmp, clob));
emit_insn (tmp);
@@ -18597,14 +18599,17 @@
jump = emit_jump_insn (gen_rtx_SET (pc_rtx, tmp));
JUMP_LABEL (jump) = inc_label;
+ rtx reg_255 = gen_reg_rtx (word_mode);
+ emit_move_insn (reg_255, GEN_INT (255));
+
/* Adjust the ssp in a loop. */
loop_label = gen_label_rtx ();
emit_label (loop_label);
LABEL_NUSES (loop_label) = 1;
emit_insn ((word_mode == SImode)
- ? gen_incsspsi (reg_ssp)
- : gen_incsspdi (reg_ssp));
+ ? gen_incsspsi (reg_255)
+ : gen_incsspdi (reg_255));
tmp = gen_rtx_SET (reg_adj, gen_rtx_MINUS (ptr_mode,
reg_adj,
GEN_INT (255)));
@@ -18633,26 +18638,10 @@
emit_label (noadj_label);
LABEL_NUSES (noadj_label) = 1;
}
-
- /* This code is the same as in expand_buildin_longjmp. */
- fp = gen_rtx_MEM (ptr_mode, operands[0]);
- lab = gen_rtx_MEM (ptr_mode, plus_constant (Pmode, operands[0],
- GET_MODE_SIZE (ptr_mode)));
- stack = gen_rtx_MEM (sa_mode, plus_constant (Pmode, operands[0],
- 2 * GET_MODE_SIZE (ptr_mode)));
- lab = copy_to_reg (lab);
-
- emit_clobber (gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode)));
- emit_clobber (gen_rtx_MEM (BLKmode, hard_frame_pointer_rtx));
-
- if (GET_MODE (fp) != Pmode)
- fp = convert_to_mode (Pmode, fp, 1);
- emit_move_insn (hard_frame_pointer_rtx, fp);
- emit_stack_restore (SAVE_NONLOCAL, stack);
-
- emit_use (hard_frame_pointer_rtx);
- emit_use (stack_pointer_rtx);
- emit_indirect_jump (lab);
+ else
+ stack_slot = adjust_address (operands[1], Pmode, 0);
+ emit_move_insn (operands[0], stack_slot);
+ DONE;
})
diff --git a/gcc/testsuite/gcc.dg/torture/pr85397-1.c b/gcc/testsuite/gcc.dg/torture/pr85397-1.c
new file mode 100644
index 00000000000..65085240266
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr85397-1.c
@@ -0,0 +1,29 @@
+/* { dg-do run { target i?86-*-* x86_64-*-* } } */
+/* { dg-require-effective-target cet } */
+/* { dg-additional-options "-fcf-protection -mcet" } */
+
+#define DEPTH 1000
+
+int
+x(int a)
+{
+ __label__ xlab;
+ void y(int a)
+ {
+ if (a==0)
+ goto xlab;
+ y (a-1);
+ }
+ y (a);
+ xlab:;
+ return a;
+}
+
+int
+main ()
+{
+ if (x (DEPTH) != DEPTH)
+ __builtin_abort ();
+
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.target/i386/cet-sjlj-6a.c b/gcc/testsuite/gcc.target/i386/cet-sjlj-6a.c
index 8410ff99b47..87fe2e6dc67 100644
--- a/gcc/testsuite/gcc.target/i386/cet-sjlj-6a.c
+++ b/gcc/testsuite/gcc.target/i386/cet-sjlj-6a.c
@@ -2,8 +2,8 @@
/* { dg-require-effective-target maybe_x32 } */
/* { dg-options "-O -maddress-mode=short -fcf-protection -mcet -mx32" } */
/* { dg-final { scan-assembler-times "endbr64" 2 } } */
-/* { dg-final { scan-assembler-times "movq\t.*buf\\+12" 1 } } */
-/* { dg-final { scan-assembler-times "subq\tbuf\\+12" 1 } } */
+/* { dg-final { scan-assembler-times "movq\t.*buf\\+8" 1 } } */
+/* { dg-final { scan-assembler-times "subq\tbuf\\+8" 1 } } */
/* { dg-final { scan-assembler-times "shrl\t\\\$3," 1 } } */
/* { dg-final { scan-assembler-times "rdsspq" 2 } } */
/* { dg-final { scan-assembler-times "incsspq" 2 } } */
diff --git a/gcc/testsuite/gcc.target/i386/cet-sjlj-6b.c b/gcc/testsuite/gcc.target/i386/cet-sjlj-6b.c
index ce111631ac1..b3866d52946 100644
--- a/gcc/testsuite/gcc.target/i386/cet-sjlj-6b.c
+++ b/gcc/testsuite/gcc.target/i386/cet-sjlj-6b.c
@@ -1,8 +1,8 @@
/* { dg-do compile { target { ! ia32 } } } */
/* { dg-options "-O -maddress-mode=long -fcf-protection -mcet -mx32" } */
/* { dg-final { scan-assembler-times "endbr64" 2 } } */
-/* { dg-final { scan-assembler-times "movq\t.*buf\\+12" 1 } } */
-/* { dg-final { scan-assembler-times "subq\tbuf\\+12" 1 } } */
+/* { dg-final { scan-assembler-times "movq\t.*buf\\+16" 1 } } */
+/* { dg-final { scan-assembler-times "subq\tbuf\\+16" 1 } } */
/* { dg-final { scan-assembler-times "shrl\t\\\$3," 1 } } */
/* { dg-final { scan-assembler-times "rdsspq" 2 } } */
/* { dg-final { scan-assembler-times "incsspq" 2 } } */
--
2.14.3