So far only a per thread canary in the TLS block is supported. This
patch adds support for a global canary, too. For this the new option
-mstack-protector-guard={global,tls} is added which defaults to tls.
The global canary is expected at symbol __stack_chk_guard which means
for a function prologue instructions larl/l(g)fr + mvc are emitted and
for an epilogue larl/l(g)fr + clc.
Furthermore, option -mstack-protector-guard-record is added which is
inspired by -mrecord-mcount and generates section __stack_protector_loc
containing pointers to all instructions which load the address of the
global guard. Thus, this option has only an effect in conjunction with
-mstack-protector-guard=global. The intended use is for the Linux
kernel in order to support run-time patching. In each task_struct of
the kernel a canary is held which will be copied into the lowcore.
Since the kernel supports migration of the lowcore, addresses are not
necessarily constant. Therefore, the kernel expects that all
instructions loading the address of the canary to be of format RIL or
more precisely are either larl or lgrl and that the instructions
addresses are recorded in section __stack_protector_loc. The kernel is
then required to patch those instructions e.g. to llilf, prior first
execution or whenever the lowcore moves.
In total this means -mstack-protector-guard=global emits code suitable
for user and kernel space.
gcc/ChangeLog:
* config/s390/s390-opts.h (enum stack_protector_guard): Define
SP_TLS and SP_GLOBAL.
* config/s390/s390.h (TARGET_SP_GLOBAL_GUARD): Define predicate.
(TARGET_SP_TLS_GUARD): Define predicate.
* config/s390/s390.md (stack_protect_global_guard_addr<mode>):
New insn.
(stack_protect_set): Also deal with a global guard.
(stack_protect_test): Also deal with a global guard.
* config/s390/s390.opt (-mstack-protector-guard={global,tls}):
New option.
(-mstack-protector-guard-record) New option.
gcc/testsuite/ChangeLog:
* gcc.target/s390/stack-protector-guard-global-1.c: New test.
* gcc.target/s390/stack-protector-guard-global-2.c: New test.
* gcc.target/s390/stack-protector-guard-global-3.c: New test.
* gcc.target/s390/stack-protector-guard-global-4.c: New test.
---
gcc/config/s390/s390-opts.h | 8 ++
gcc/config/s390/s390.h | 3 +
gcc/config/s390/s390.md | 87 +++++++++++++++----
gcc/config/s390/s390.opt | 18 ++++
.../s390/stack-protector-guard-global-1.c | 27 ++++++
.../s390/stack-protector-guard-global-2.c | 5 ++
.../s390/stack-protector-guard-global-3.c | 6 ++
.../s390/stack-protector-guard-global-4.c | 6 ++
8 files changed, 144 insertions(+), 16 deletions(-)
create mode 100644
gcc/testsuite/gcc.target/s390/stack-protector-guard-global-1.c
create mode 100644
gcc/testsuite/gcc.target/s390/stack-protector-guard-global-2.c
create mode 100644
gcc/testsuite/gcc.target/s390/stack-protector-guard-global-3.c
create mode 100644
gcc/testsuite/gcc.target/s390/stack-protector-guard-global-4.c
diff --git a/gcc/config/s390/s390-opts.h b/gcc/config/s390/s390-opts.h
index 9cacb2c29d1..29dd4a5f77f 100644
--- a/gcc/config/s390/s390-opts.h
+++ b/gcc/config/s390/s390-opts.h
@@ -53,4 +53,12 @@ enum indirect_branch {
indirect_branch_thunk_inline,
indirect_branch_thunk_extern
};
+
+
+/* Where to get the canary for the stack protector. */
+enum stack_protector_guard
+{
+ SP_TLS, /* per-thread canary in TLS block */
+ SP_GLOBAL /* global canary */
+};
#endif
diff --git a/gcc/config/s390/s390.h b/gcc/config/s390/s390.h
index 8b04bc9a755..2631788df4c 100644
--- a/gcc/config/s390/s390.h
+++ b/gcc/config/s390/s390.h
@@ -251,6 +251,9 @@ enum processor_flags
&& (s390_tune < PROCESSOR_2964_Z13 || (VAL) != const0_rtx) \
&& (!CONST_INT_P (LEN) || INTVAL ((LEN)) > TARGET_SETMEM_PREFETCH_DISTANCE))
+#define TARGET_SP_GLOBAL_GUARD (s390_stack_protector_guard == SP_GLOBAL)
+#define TARGET_SP_TLS_GUARD (s390_stack_protector_guard == SP_TLS)
+
/* Run-time target specification. */
/* Defaults for option flags defined only on some subtargets. */
diff --git a/gcc/config/s390/s390.md b/gcc/config/s390/s390.md
index 02bc149b0fb..2d3027e1574 100644
--- a/gcc/config/s390/s390.md
+++ b/gcc/config/s390/s390.md
@@ -311,6 +311,7 @@
; Stack Protector
UNSPECV_SP_GET_TP
+ UNSPECV_SP_GLOBAL_GUARD_ADDR
])
;;
@@ -11930,6 +11931,36 @@
; Stack Protector Patterns
;
+(define_insn "stack_protect_global_guard_addr<mode>"
+ [(set (match_operand:P 0 "register_operand" "=d")
+ (unspec_volatile:P [(const_int 0)] UNSPECV_SP_GLOBAL_GUARD_ADDR))]
+ ""
+{
+ if (flag_s390_stack_protector_guard_record)
+ fprintf (asm_out_file, "1:\n");
+ if (flag_pic)
+ {
+ if (TARGET_Z10)
+ output_asm_insn ("l<g>rl\t%0,__stack_chk_guard@GOTENT", operands);
+ else
+ {
+ output_asm_insn ("larl\t%0,__stack_chk_guard@GOTENT", operands);
+ output_asm_insn ("l<g>\t%0,0(%0)", operands);
+ }
+ }
+ else
+ output_asm_insn ("larl\t%0,__stack_chk_guard", operands);
+ if (flag_s390_stack_protector_guard_record)
+ fprintf (asm_out_file, "\t.section
__stack_protector_loc,\\"a\\",@progbits\n"
+ "\t.%s 1b\n"
+ "\t.previous\n", TARGET_64BIT ? "quad" : "long");
+ return "";
+}
+ [(set (attr "mnemonic")
+ (cond [(match_test "flag_pic && TARGET_Z10") (const_string "l<g>rl")
+ (match_test "flag_pic && !TARGET_Z10") (const_string "*")]
+ (const_string "larl")))])
+
; Insns stack_protect_get_tp{si,di} are similar to *get_tp_{31,64} but still
; distinct in the sense that they force recomputation of the thread pointer
; instead of potentially reloading it from stack.
@@ -11958,16 +11989,28 @@
(match_operand 1 "memory_operand" ""))]
""
{
-#ifdef TARGET_THREAD_SSP_OFFSET
- rtx tp = gen_reg_rtx (Pmode);
- if (TARGET_64BIT)
- emit_insn (gen_stack_protect_get_tpdi (tp));
+ if (TARGET_SP_GLOBAL_GUARD)
+ {
+ rtx addr = gen_reg_rtx (Pmode);
+ if (TARGET_64BIT)
+ emit_insn (gen_stack_protect_global_guard_addrdi (addr));
+ else
+ emit_insn (gen_stack_protect_global_guard_addrsi (addr));
+ operands[1] = gen_rtx_MEM (Pmode, addr);
+ }
else
- emit_insn (gen_stack_protect_get_tpsi (tp));
- operands[1]
- = gen_rtx_MEM (Pmode, gen_rtx_PLUS (Pmode, tp,
- GEN_INT (TARGET_THREAD_SSP_OFFSET)));
+ {
+#ifdef TARGET_THREAD_SSP_OFFSET
+ rtx tp = gen_reg_rtx (Pmode);
+ if (TARGET_64BIT)
+ emit_insn (gen_stack_protect_get_tpdi (tp));
+ else
+ emit_insn (gen_stack_protect_get_tpsi (tp));
+ operands[1]
+ = gen_rtx_MEM (Pmode, gen_rtx_PLUS (Pmode, tp,
+ GEN_INT
(TARGET_THREAD_SSP_OFFSET)));
#endif
+ }
if (TARGET_64BIT)
emit_insn (gen_stack_protect_setdi (operands[0], operands[1]));
else
@@ -11991,16 +12034,28 @@
""
{
rtx cc_reg, test;
-#ifdef TARGET_THREAD_SSP_OFFSET
- rtx tp = gen_reg_rtx (Pmode);
- if (TARGET_64BIT)
- emit_insn (gen_stack_protect_get_tpdi (tp));
+ if (TARGET_SP_GLOBAL_GUARD)
+ {
+ rtx addr = gen_reg_rtx (Pmode);
+ if (TARGET_64BIT)
+ emit_insn (gen_stack_protect_global_guard_addrdi (addr));
+ else
+ emit_insn (gen_stack_protect_global_guard_addrsi (addr));
+ operands[1] = gen_rtx_MEM (Pmode, addr);
+ }
else
- emit_insn (gen_stack_protect_get_tpsi (tp));
- operands[1]
- = gen_rtx_MEM (Pmode, gen_rtx_PLUS (Pmode, tp,
- GEN_INT (TARGET_THREAD_SSP_OFFSET)));
+ {
+#ifdef TARGET_THREAD_SSP_OFFSET
+ rtx tp = gen_reg_rtx (Pmode);
+ if (TARGET_64BIT)
+ emit_insn (gen_stack_protect_get_tpdi (tp));
+ else
+ emit_insn (gen_stack_protect_get_tpsi (tp));
+ operands[1]
+ = gen_rtx_MEM (Pmode, gen_rtx_PLUS (Pmode, tp,
+ GEN_INT
(TARGET_THREAD_SSP_OFFSET)));
#endif
+ }
if (TARGET_64BIT)
emit_insn (gen_stack_protect_testdi (operands[0], operands[1]));
else
diff --git a/gcc/config/s390/s390.opt b/gcc/config/s390/s390.opt
index 6753a9326be..a82992ef7ef 100644
--- a/gcc/config/s390/s390.opt
+++ b/gcc/config/s390/s390.opt
@@ -196,6 +196,24 @@ mno-stack-guard
Target RejectNegative Alias(mstack-guard=,0) Negative(mstack-guard=)
Switches off the -mstack-guard= option.
+mstack-protector-guard=
+Target RejectNegative Joined Enum(stack_protector_guard)
Var(s390_stack_protector_guard) Init(SP_TLS)
+Use given stack-protector guard.
+
+Enum
+Name(stack_protector_guard) Type(enum stack_protector_guard)
+Valid arguments to -mstack-protector-guard=:
+
+EnumValue
+Enum(stack_protector_guard) String(tls) Value(SP_TLS)
+
+EnumValue
+Enum(stack_protector_guard) String(global) Value(SP_GLOBAL)
+
+mstack-protector-guard-record
+Target Var(flag_s390_stack_protector_guard_record)
+Generate section __stack_protector_loc containing pointers to all instructions
which load the address of the global guard.
+
mstack-size=
Target RejectNegative Joined UInteger Var(s390_stack_size) Save
Emit extra code in the function prologue in order to trap if the stack size
exceeds the given limit.
diff --git a/gcc/testsuite/gcc.target/s390/stack-protector-guard-global-1.c
b/gcc/testsuite/gcc.target/s390/stack-protector-guard-global-1.c
new file mode 100644
index 00000000000..f276645adcb
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/stack-protector-guard-global-1.c
@@ -0,0 +1,27 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fstack-protector-all -mstack-protector-guard=global
-mstack-protector-guard-record" } */
+/* { dg-final { scan-assembler-times
{\n1:\n\tlarl\t%r[0-9]+,__stack_chk_guard\n} 4 } } */
+
+void test_0 (void) { }
+
+void test_1 (void)
+{
+ __asm__ __volatile ("" :::
+ "r0",
+ "r1",
+ "r2",
+ "r3",
+ "r4",
+ "r5",
+ "r6",
+ "r7",
+ "r8",
+ "r9",
+ "r10",
+ "r11",
+#ifndef __PIC__
+ "r12",
+#endif
+ "r13",
+ "r14");
+}
diff --git a/gcc/testsuite/gcc.target/s390/stack-protector-guard-global-2.c
b/gcc/testsuite/gcc.target/s390/stack-protector-guard-global-2.c
new file mode 100644
index 00000000000..7441a87adf7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/stack-protector-guard-global-2.c
@@ -0,0 +1,5 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fstack-protector-all -mstack-protector-guard=global
-mstack-protector-guard-record -fPIC" } */
+/* { dg-final { scan-assembler-times
{\n1:\n\t(larl|lg?rl)\t%r[0-9]+,__stack_chk_guard@GOTENT\n} 4 } } */
+
+#include "stack-protector-guard-global-1.c"
diff --git a/gcc/testsuite/gcc.target/s390/stack-protector-guard-global-3.c
b/gcc/testsuite/gcc.target/s390/stack-protector-guard-global-3.c
new file mode 100644
index 00000000000..4ef379aa8f7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/stack-protector-guard-global-3.c
@@ -0,0 +1,6 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fstack-protector-all -mstack-protector-guard=global" } */
+/* { dg-final { scan-assembler-times {\tlarl\t%r[0-9]+,__stack_chk_guard\n} 4
} } */
+/* { dg-final { scan-assembler-not {\n1:\n} } } */
+
+#include "stack-protector-guard-global-1.c"
diff --git a/gcc/testsuite/gcc.target/s390/stack-protector-guard-global-4.c
b/gcc/testsuite/gcc.target/s390/stack-protector-guard-global-4.c
new file mode 100644
index 00000000000..d57fc79bd83
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/stack-protector-guard-global-4.c
@@ -0,0 +1,6 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fstack-protector-all -mstack-protector-guard=global
-fPIC" } */
+/* { dg-final { scan-assembler-times
{\t(larl|lg?rl)\t%r[0-9]+,__stack_chk_guard@GOTENT\n} 4 } } */
+/* { dg-final { scan-assembler-not {\n1:\n} } } */
+
+#include "stack-protector-guard-global-1.c"
--
2.49.0
