* [PATCH] x86: Add -mharden-sls=[none|all|return|indirect-branch]
@ 2021-11-16 18:20 H.J. Lu
2021-11-17 9:05 ` Uros Bizjak
0 siblings, 1 reply; 5+ messages in thread
From: H.J. Lu @ 2021-11-16 18:20 UTC (permalink / raw)
To: gcc-patches
Add -mharden-sls= to mitigate against straight line speculation (SLS)
for function return and indirect branch by adding an INT3 instruction
after function return and indirect branch.
gcc/
PR target/102952
* config/i386/i386-opts.h (harden_sls): New enum.
* config/i386/i386.c (output_indirect_thunk): Mitigate against
SLS for function return.
(ix86_output_function_return): Likewise.
(ix86_output_jmp_thunk_or_indirect): Mitigate against indirect
branch.
(ix86_output_indirect_jmp): Likewise.
(ix86_output_call_insn): Likewise.
* config/i386/i386.opt: Add -mharden-sls=.
* doc/invoke.texi: Document -mharden-sls=.
gcc/testsuite/
PR target/102952
* gcc.target/i386/harden-sls-1.c: New test.
* gcc.target/i386/harden-sls-2.c: Likewise.
* gcc.target/i386/harden-sls-3.c: Likewise.
* gcc.target/i386/harden-sls-4.c: Likewise.
---
gcc/config/i386/i386-opts.h | 7 +++++
gcc/config/i386/i386.c | 30 ++++++++++++++++----
gcc/config/i386/i386.opt | 20 +++++++++++++
gcc/doc/invoke.texi | 10 ++++++-
gcc/testsuite/gcc.target/i386/harden-sls-1.c | 14 +++++++++
gcc/testsuite/gcc.target/i386/harden-sls-2.c | 14 +++++++++
gcc/testsuite/gcc.target/i386/harden-sls-3.c | 14 +++++++++
gcc/testsuite/gcc.target/i386/harden-sls-4.c | 14 +++++++++
8 files changed, 116 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-2.c
create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-3.c
create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-4.c
diff --git a/gcc/config/i386/i386-opts.h b/gcc/config/i386/i386-opts.h
index 04e4ad608fb..171d3106d0a 100644
--- a/gcc/config/i386/i386-opts.h
+++ b/gcc/config/i386/i386-opts.h
@@ -121,4 +121,11 @@ enum instrument_return {
instrument_return_nop5
};
+enum harden_sls {
+ harden_sls_none = 0,
+ harden_sls_return = 1 << 0,
+ harden_sls_indirect_branch = 1 << 1,
+ harden_sls_all = harden_sls_return | harden_sls_indirect_branch
+};
+
#endif
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index cc9f9322fad..0a902d66321 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -5914,6 +5914,8 @@ output_indirect_thunk (unsigned int regno)
}
fputs ("\tret\n", asm_out_file);
+ if ((ix86_harden_sls & harden_sls_return))
+ fputs ("\tint3\n", asm_out_file);
}
/* Output a funtion with a call and return thunk for indirect branch.
@@ -15987,6 +15989,8 @@ ix86_output_jmp_thunk_or_indirect (const char *thunk_name, const int regno)
fprintf (asm_out_file, "\tjmp\t");
assemble_name (asm_out_file, thunk_name);
putc ('\n', asm_out_file);
+ if ((ix86_harden_sls & harden_sls_indirect_branch))
+ fputs ("\tint3\n", asm_out_file);
}
else
output_indirect_thunk (regno);
@@ -16212,10 +16216,14 @@ ix86_output_indirect_jmp (rtx call_op)
gcc_unreachable ();
ix86_output_indirect_branch (call_op, "%0", true);
- return "";
+ if ((ix86_harden_sls & harden_sls_indirect_branch))
+ return "int3";
+ else
+ return "";
}
else
- return "%!jmp\t%A0";
+ return ((ix86_harden_sls & harden_sls_indirect_branch)
+ ? "%!jmp\t%A0\n\tint3" : "%!jmp\t%A0");
}
/* Output return instrumentation for current function if needed. */
@@ -16283,10 +16291,15 @@ ix86_output_function_return (bool long_p)
return "";
}
- if (!long_p)
- return "%!ret";
+ if ((ix86_harden_sls & harden_sls_return))
+ return "%!ret\n\tint3";
+ else
+ {
+ if (!long_p)
+ return "%!ret";
- return "rep%; ret";
+ return "rep%; ret";
+ }
}
/* Output indirect function return. RET_OP is the function return
@@ -16381,7 +16394,12 @@ ix86_output_call_insn (rtx_insn *insn, rtx call_op)
if (output_indirect_p && !direct_p)
ix86_output_indirect_branch (call_op, xasm, true);
else
- output_asm_insn (xasm, &call_op);
+ {
+ output_asm_insn (xasm, &call_op);
+ if (!direct_p
+ && (ix86_harden_sls & harden_sls_indirect_branch))
+ return "int3";
+ }
return "";
}
diff --git a/gcc/config/i386/i386.opt b/gcc/config/i386/i386.opt
index b38ac13fc91..c5452c49597 100644
--- a/gcc/config/i386/i386.opt
+++ b/gcc/config/i386/i386.opt
@@ -1121,6 +1121,26 @@ mrecord-return
Target Var(ix86_flag_record_return) Init(0)
Generate a __return_loc section pointing to all return instrumentation code.
+mharden-sls=
+Target RejectNegative Joined Enum(harden_sls) Var(ix86_harden_sls) Init(harden_sls_none)
+Generate code to mitigate against straight line speculation.
+
+Enum
+Name(harden_sls) Type(enum harden_sls)
+Known choices for mitigation against straight line speculation with -mharden-sls=:
+
+EnumValue
+Enum(harden_sls) String(none) Value(harden_sls_none)
+
+EnumValue
+Enum(harden_sls) String(all) Value(harden_sls_all)
+
+EnumValue
+Enum(harden_sls) String(return) Value(harden_sls_return)
+
+EnumValue
+Enum(harden_sls) String(indirect-branch) Value(harden_sls_indirect_branch)
+
mavx512bf16
Target Mask(ISA2_AVX512BF16) Var(ix86_isa_flags2) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2, AVX512F and
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 6070288856c..f3b4b467765 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -1425,7 +1425,7 @@ See RS/6000 and PowerPC Options.
-mstack-protector-guard-symbol=@var{symbol} @gol
-mgeneral-regs-only -mcall-ms2sysv-xlogues -mrelax-cmpxchg-loop @gol
-mindirect-branch=@var{choice} -mfunction-return=@var{choice} @gol
--mindirect-branch-register -mneeded}
+-mindirect-branch-register -mharden-sls=@var{choice} -mneeded}
@emph{x86 Windows Options}
@gccoptlist{-mconsole -mcygwin -mno-cygwin -mdll @gol
@@ -32382,6 +32382,14 @@ not be reachable in the large code model.
@opindex mindirect-branch-register
Force indirect call and jump via register.
+@item -mharden-sls=@var{choice}
+@opindex mharden-sls
+Generate code to mitigate against straight line speculation (SLS) with
+@var{choice}. The default is @samp{none} which disables all SLS
+hardening. @samp{return} enables SLS hardening for function return.
+@samp{indirect-branch} enables SLS hardening for indirect branch.
+@samp{all} enables all SLS hardening.
+
@end table
These @samp{-m} switches are supported in addition to the above
diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-1.c b/gcc/testsuite/gcc.target/i386/harden-sls-1.c
new file mode 100644
index 00000000000..6f70dc94a23
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/harden-sls-1.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mindirect-branch=thunk-extern -mharden-sls=all" } */
+/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
+
+extern void foo (void);
+
+void
+bar (void)
+{
+ foo ();
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]+_?foo" } } */
+/* { dg-final { scan-assembler-not {int3} } } */
diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-2.c b/gcc/testsuite/gcc.target/i386/harden-sls-2.c
new file mode 100644
index 00000000000..a7c59078d03
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/harden-sls-2.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mindirect-branch=thunk-extern -mharden-sls=all" } */
+/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
+
+extern void (*fptr) (void);
+
+void
+foo (void)
+{
+ fptr ();
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]+_?__x86_indirect_thunk_(r|e)ax" } } */
+/* { dg-final { scan-assembler-times "int3" 1 } } */
diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-3.c b/gcc/testsuite/gcc.target/i386/harden-sls-3.c
new file mode 100644
index 00000000000..1a6056b6d7b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/harden-sls-3.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mindirect-branch=thunk -mharden-sls=all" } */
+/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
+
+extern void (*fptr) (void);
+
+void
+foo (void)
+{
+ fptr ();
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]+_?__x86_indirect_thunk_(r|e)ax" } } */
+/* { dg-final { scan-assembler-times "int3" 2 } } */
diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-4.c b/gcc/testsuite/gcc.target/i386/harden-sls-4.c
new file mode 100644
index 00000000000..c33147f11b5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/harden-sls-4.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mindirect-branch=keep -mharden-sls=all" } */
+/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
+
+extern void (*fptr) (void);
+
+void
+foo (void)
+{
+ fptr ();
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]+\\*_?fptr" } } */
+/* { dg-final { scan-assembler-times "int3" 1 } } */
--
2.33.1
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86: Add -mharden-sls=[none|all|return|indirect-branch]
2021-11-16 18:20 [PATCH] x86: Add -mharden-sls=[none|all|return|indirect-branch] H.J. Lu
@ 2021-11-17 9:05 ` Uros Bizjak
2021-11-17 13:45 ` H.J. Lu
0 siblings, 1 reply; 5+ messages in thread
From: Uros Bizjak @ 2021-11-17 9:05 UTC (permalink / raw)
To: H.J. Lu; +Cc: gcc-patches
On Tue, Nov 16, 2021 at 7:20 PM H.J. Lu via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Add -mharden-sls= to mitigate against straight line speculation (SLS)
> for function return and indirect branch by adding an INT3 instruction
> after function return and indirect branch.
>
> gcc/
>
> PR target/102952
> * config/i386/i386-opts.h (harden_sls): New enum.
> * config/i386/i386.c (output_indirect_thunk): Mitigate against
> SLS for function return.
> (ix86_output_function_return): Likewise.
> (ix86_output_jmp_thunk_or_indirect): Mitigate against indirect
> branch.
> (ix86_output_indirect_jmp): Likewise.
> (ix86_output_call_insn): Likewise.
> * config/i386/i386.opt: Add -mharden-sls=.
> * doc/invoke.texi: Document -mharden-sls=.
>
> gcc/testsuite/
>
> PR target/102952
> * gcc.target/i386/harden-sls-1.c: New test.
> * gcc.target/i386/harden-sls-2.c: Likewise.
> * gcc.target/i386/harden-sls-3.c: Likewise.
> * gcc.target/i386/harden-sls-4.c: Likewise.
> ---
> gcc/config/i386/i386-opts.h | 7 +++++
> gcc/config/i386/i386.c | 30 ++++++++++++++++----
> gcc/config/i386/i386.opt | 20 +++++++++++++
> gcc/doc/invoke.texi | 10 ++++++-
> gcc/testsuite/gcc.target/i386/harden-sls-1.c | 14 +++++++++
> gcc/testsuite/gcc.target/i386/harden-sls-2.c | 14 +++++++++
> gcc/testsuite/gcc.target/i386/harden-sls-3.c | 14 +++++++++
> gcc/testsuite/gcc.target/i386/harden-sls-4.c | 14 +++++++++
> 8 files changed, 116 insertions(+), 7 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-1.c
> create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-2.c
> create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-3.c
> create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-4.c
>
> diff --git a/gcc/config/i386/i386-opts.h b/gcc/config/i386/i386-opts.h
> index 04e4ad608fb..171d3106d0a 100644
> --- a/gcc/config/i386/i386-opts.h
> +++ b/gcc/config/i386/i386-opts.h
> @@ -121,4 +121,11 @@ enum instrument_return {
> instrument_return_nop5
> };
>
> +enum harden_sls {
> + harden_sls_none = 0,
> + harden_sls_return = 1 << 0,
> + harden_sls_indirect_branch = 1 << 1,
> + harden_sls_all = harden_sls_return | harden_sls_indirect_branch
> +};
> +
> #endif
> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index cc9f9322fad..0a902d66321 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -5914,6 +5914,8 @@ output_indirect_thunk (unsigned int regno)
> }
>
> fputs ("\tret\n", asm_out_file);
> + if ((ix86_harden_sls & harden_sls_return))
> + fputs ("\tint3\n", asm_out_file);
> }
>
> /* Output a funtion with a call and return thunk for indirect branch.
> @@ -15987,6 +15989,8 @@ ix86_output_jmp_thunk_or_indirect (const char *thunk_name, const int regno)
> fprintf (asm_out_file, "\tjmp\t");
> assemble_name (asm_out_file, thunk_name);
> putc ('\n', asm_out_file);
> + if ((ix86_harden_sls & harden_sls_indirect_branch))
> + fputs ("\tint3\n", asm_out_file);
> }
> else
> output_indirect_thunk (regno);
> @@ -16212,10 +16216,14 @@ ix86_output_indirect_jmp (rtx call_op)
> gcc_unreachable ();
>
> ix86_output_indirect_branch (call_op, "%0", true);
> - return "";
> + if ((ix86_harden_sls & harden_sls_indirect_branch))
> + return "int3";
> + else
> + return "";
> }
> else
> - return "%!jmp\t%A0";
> + return ((ix86_harden_sls & harden_sls_indirect_branch)
> + ? "%!jmp\t%A0\n\tint3" : "%!jmp\t%A0");
> }
Just change existing returns to fputs and end function with:
return (ix86_harden_sls & harden_sls_indirect_branch) ? "int3" : "";
> /* Output return instrumentation for current function if needed. */
> @@ -16283,10 +16291,15 @@ ix86_output_function_return (bool long_p)
> return "";
> }
>
> - if (!long_p)
> - return "%!ret";
> + if ((ix86_harden_sls & harden_sls_return))
> + return "%!ret\n\tint3";
> + else
> + {
> + if (!long_p)
> + return "%!ret";
>
> - return "rep%; ret";
> + return "rep%; ret";
> + }
> }
Also here.
>
> /* Output indirect function return. RET_OP is the function return
> @@ -16381,7 +16394,12 @@ ix86_output_call_insn (rtx_insn *insn, rtx call_op)
> if (output_indirect_p && !direct_p)
> ix86_output_indirect_branch (call_op, xasm, true);
> else
> - output_asm_insn (xasm, &call_op);
> + {
> + output_asm_insn (xasm, &call_op);
> + if (!direct_p
> + && (ix86_harden_sls & harden_sls_indirect_branch))
> + return "int3";
> + }
> return "";
> }
>
> diff --git a/gcc/config/i386/i386.opt b/gcc/config/i386/i386.opt
> index b38ac13fc91..c5452c49597 100644
> --- a/gcc/config/i386/i386.opt
> +++ b/gcc/config/i386/i386.opt
> @@ -1121,6 +1121,26 @@ mrecord-return
> Target Var(ix86_flag_record_return) Init(0)
> Generate a __return_loc section pointing to all return instrumentation code.
>
> +mharden-sls=
> +Target RejectNegative Joined Enum(harden_sls) Var(ix86_harden_sls) Init(harden_sls_none)
> +Generate code to mitigate against straight line speculation.
> +
> +Enum
> +Name(harden_sls) Type(enum harden_sls)
> +Known choices for mitigation against straight line speculation with -mharden-sls=:
> +
> +EnumValue
> +Enum(harden_sls) String(none) Value(harden_sls_none)
> +
> +EnumValue
> +Enum(harden_sls) String(all) Value(harden_sls_all)
> +
> +EnumValue
> +Enum(harden_sls) String(return) Value(harden_sls_return)
> +
> +EnumValue
> +Enum(harden_sls) String(indirect-branch) Value(harden_sls_indirect_branch)
> +
> mavx512bf16
> Target Mask(ISA2_AVX512BF16) Var(ix86_isa_flags2) Save
> Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2, AVX512F and
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index 6070288856c..f3b4b467765 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -1425,7 +1425,7 @@ See RS/6000 and PowerPC Options.
> -mstack-protector-guard-symbol=@var{symbol} @gol
> -mgeneral-regs-only -mcall-ms2sysv-xlogues -mrelax-cmpxchg-loop @gol
> -mindirect-branch=@var{choice} -mfunction-return=@var{choice} @gol
> --mindirect-branch-register -mneeded}
> +-mindirect-branch-register -mharden-sls=@var{choice} -mneeded}
>
> @emph{x86 Windows Options}
> @gccoptlist{-mconsole -mcygwin -mno-cygwin -mdll @gol
> @@ -32382,6 +32382,14 @@ not be reachable in the large code model.
> @opindex mindirect-branch-register
> Force indirect call and jump via register.
>
> +@item -mharden-sls=@var{choice}
> +@opindex mharden-sls
> +Generate code to mitigate against straight line speculation (SLS) with
> +@var{choice}. The default is @samp{none} which disables all SLS
> +hardening. @samp{return} enables SLS hardening for function return.
> +@samp{indirect-branch} enables SLS hardening for indirect branch.
> +@samp{all} enables all SLS hardening.
> +
> @end table
>
> These @samp{-m} switches are supported in addition to the above
> diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-1.c b/gcc/testsuite/gcc.target/i386/harden-sls-1.c
> new file mode 100644
> index 00000000000..6f70dc94a23
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/harden-sls-1.c
> @@ -0,0 +1,14 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mindirect-branch=thunk-extern -mharden-sls=all" } */
> +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> +
> +extern void foo (void);
> +
> +void
> +bar (void)
> +{
> + foo ();
> +}
> +
> +/* { dg-final { scan-assembler "jmp\[ \t\]+_?foo" } } */
> +/* { dg-final { scan-assembler-not {int3} } } */
> diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-2.c b/gcc/testsuite/gcc.target/i386/harden-sls-2.c
> new file mode 100644
> index 00000000000..a7c59078d03
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/harden-sls-2.c
> @@ -0,0 +1,14 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mindirect-branch=thunk-extern -mharden-sls=all" } */
> +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> +
> +extern void (*fptr) (void);
> +
> +void
> +foo (void)
> +{
> + fptr ();
> +}
> +
> +/* { dg-final { scan-assembler "jmp\[ \t\]+_?__x86_indirect_thunk_(r|e)ax" } } */
> +/* { dg-final { scan-assembler-times "int3" 1 } } */
> diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-3.c b/gcc/testsuite/gcc.target/i386/harden-sls-3.c
> new file mode 100644
> index 00000000000..1a6056b6d7b
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/harden-sls-3.c
> @@ -0,0 +1,14 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mindirect-branch=thunk -mharden-sls=all" } */
> +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> +
> +extern void (*fptr) (void);
> +
> +void
> +foo (void)
> +{
> + fptr ();
> +}
> +
> +/* { dg-final { scan-assembler "jmp\[ \t\]+_?__x86_indirect_thunk_(r|e)ax" } } */
> +/* { dg-final { scan-assembler-times "int3" 2 } } */
> diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-4.c b/gcc/testsuite/gcc.target/i386/harden-sls-4.c
> new file mode 100644
> index 00000000000..c33147f11b5
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/harden-sls-4.c
> @@ -0,0 +1,14 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mindirect-branch=keep -mharden-sls=all" } */
> +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> +
> +extern void (*fptr) (void);
> +
> +void
> +foo (void)
> +{
> + fptr ();
> +}
> +
> +/* { dg-final { scan-assembler "jmp\[ \t\]+\\*_?fptr" } } */
> +/* { dg-final { scan-assembler-times "int3" 1 } } */
> --
> 2.33.1
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86: Add -mharden-sls=[none|all|return|indirect-branch]
2021-11-17 9:05 ` Uros Bizjak
@ 2021-11-17 13:45 ` H.J. Lu
2021-11-17 14:07 ` Uros Bizjak
0 siblings, 1 reply; 5+ messages in thread
From: H.J. Lu @ 2021-11-17 13:45 UTC (permalink / raw)
To: Uros Bizjak; +Cc: gcc-patches
On Wed, Nov 17, 2021 at 1:05 AM Uros Bizjak <ubizjak@gmail.com> wrote:
>
> On Tue, Nov 16, 2021 at 7:20 PM H.J. Lu via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
> >
> > Add -mharden-sls= to mitigate against straight line speculation (SLS)
> > for function return and indirect branch by adding an INT3 instruction
> > after function return and indirect branch.
> >
> > gcc/
> >
> > PR target/102952
> > * config/i386/i386-opts.h (harden_sls): New enum.
> > * config/i386/i386.c (output_indirect_thunk): Mitigate against
> > SLS for function return.
> > (ix86_output_function_return): Likewise.
> > (ix86_output_jmp_thunk_or_indirect): Mitigate against indirect
> > branch.
> > (ix86_output_indirect_jmp): Likewise.
> > (ix86_output_call_insn): Likewise.
> > * config/i386/i386.opt: Add -mharden-sls=.
> > * doc/invoke.texi: Document -mharden-sls=.
> >
> > gcc/testsuite/
> >
> > PR target/102952
> > * gcc.target/i386/harden-sls-1.c: New test.
> > * gcc.target/i386/harden-sls-2.c: Likewise.
> > * gcc.target/i386/harden-sls-3.c: Likewise.
> > * gcc.target/i386/harden-sls-4.c: Likewise.
> > ---
> > gcc/config/i386/i386-opts.h | 7 +++++
> > gcc/config/i386/i386.c | 30 ++++++++++++++++----
> > gcc/config/i386/i386.opt | 20 +++++++++++++
> > gcc/doc/invoke.texi | 10 ++++++-
> > gcc/testsuite/gcc.target/i386/harden-sls-1.c | 14 +++++++++
> > gcc/testsuite/gcc.target/i386/harden-sls-2.c | 14 +++++++++
> > gcc/testsuite/gcc.target/i386/harden-sls-3.c | 14 +++++++++
> > gcc/testsuite/gcc.target/i386/harden-sls-4.c | 14 +++++++++
> > 8 files changed, 116 insertions(+), 7 deletions(-)
> > create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-1.c
> > create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-2.c
> > create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-3.c
> > create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-4.c
> >
> > diff --git a/gcc/config/i386/i386-opts.h b/gcc/config/i386/i386-opts.h
> > index 04e4ad608fb..171d3106d0a 100644
> > --- a/gcc/config/i386/i386-opts.h
> > +++ b/gcc/config/i386/i386-opts.h
> > @@ -121,4 +121,11 @@ enum instrument_return {
> > instrument_return_nop5
> > };
> >
> > +enum harden_sls {
> > + harden_sls_none = 0,
> > + harden_sls_return = 1 << 0,
> > + harden_sls_indirect_branch = 1 << 1,
> > + harden_sls_all = harden_sls_return | harden_sls_indirect_branch
> > +};
> > +
> > #endif
> > diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> > index cc9f9322fad..0a902d66321 100644
> > --- a/gcc/config/i386/i386.c
> > +++ b/gcc/config/i386/i386.c
> > @@ -5914,6 +5914,8 @@ output_indirect_thunk (unsigned int regno)
> > }
> >
> > fputs ("\tret\n", asm_out_file);
> > + if ((ix86_harden_sls & harden_sls_return))
> > + fputs ("\tint3\n", asm_out_file);
> > }
> >
> > /* Output a funtion with a call and return thunk for indirect branch.
> > @@ -15987,6 +15989,8 @@ ix86_output_jmp_thunk_or_indirect (const char *thunk_name, const int regno)
> > fprintf (asm_out_file, "\tjmp\t");
> > assemble_name (asm_out_file, thunk_name);
> > putc ('\n', asm_out_file);
> > + if ((ix86_harden_sls & harden_sls_indirect_branch))
> > + fputs ("\tint3\n", asm_out_file);
> > }
> > else
> > output_indirect_thunk (regno);
> > @@ -16212,10 +16216,14 @@ ix86_output_indirect_jmp (rtx call_op)
> > gcc_unreachable ();
> >
> > ix86_output_indirect_branch (call_op, "%0", true);
> > - return "";
> > + if ((ix86_harden_sls & harden_sls_indirect_branch))
> > + return "int3";
> > + else
> > + return "";
> > }
> > else
> > - return "%!jmp\t%A0";
> > + return ((ix86_harden_sls & harden_sls_indirect_branch)
> > + ? "%!jmp\t%A0\n\tint3" : "%!jmp\t%A0");
> > }
>
> Just change existing returns to fputs and end function with:
>
> return (ix86_harden_sls & harden_sls_indirect_branch) ? "int3" : "";
But fputs doesn't support %A0.
> > /* Output return instrumentation for current function if needed. */
> > @@ -16283,10 +16291,15 @@ ix86_output_function_return (bool long_p)
> > return "";
> > }
> >
> > - if (!long_p)
> > - return "%!ret";
> > + if ((ix86_harden_sls & harden_sls_return))
> > + return "%!ret\n\tint3";
> > + else
> > + {
> > + if (!long_p)
> > + return "%!ret";
> >
> > - return "rep%; ret";
> > + return "rep%; ret";
> > + }
> > }
>
> Also here.
But fputs doesn't know "%!".
>
> >
> > /* Output indirect function return. RET_OP is the function return
> > @@ -16381,7 +16394,12 @@ ix86_output_call_insn (rtx_insn *insn, rtx call_op)
> > if (output_indirect_p && !direct_p)
> > ix86_output_indirect_branch (call_op, xasm, true);
> > else
> > - output_asm_insn (xasm, &call_op);
> > + {
> > + output_asm_insn (xasm, &call_op);
> > + if (!direct_p
> > + && (ix86_harden_sls & harden_sls_indirect_branch))
> > + return "int3";
> > + }
> > return "";
> > }
> >
> > diff --git a/gcc/config/i386/i386.opt b/gcc/config/i386/i386.opt
> > index b38ac13fc91..c5452c49597 100644
> > --- a/gcc/config/i386/i386.opt
> > +++ b/gcc/config/i386/i386.opt
> > @@ -1121,6 +1121,26 @@ mrecord-return
> > Target Var(ix86_flag_record_return) Init(0)
> > Generate a __return_loc section pointing to all return instrumentation code.
> >
> > +mharden-sls=
> > +Target RejectNegative Joined Enum(harden_sls) Var(ix86_harden_sls) Init(harden_sls_none)
> > +Generate code to mitigate against straight line speculation.
> > +
> > +Enum
> > +Name(harden_sls) Type(enum harden_sls)
> > +Known choices for mitigation against straight line speculation with -mharden-sls=:
> > +
> > +EnumValue
> > +Enum(harden_sls) String(none) Value(harden_sls_none)
> > +
> > +EnumValue
> > +Enum(harden_sls) String(all) Value(harden_sls_all)
> > +
> > +EnumValue
> > +Enum(harden_sls) String(return) Value(harden_sls_return)
> > +
> > +EnumValue
> > +Enum(harden_sls) String(indirect-branch) Value(harden_sls_indirect_branch)
> > +
> > mavx512bf16
> > Target Mask(ISA2_AVX512BF16) Var(ix86_isa_flags2) Save
> > Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2, AVX512F and
> > diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> > index 6070288856c..f3b4b467765 100644
> > --- a/gcc/doc/invoke.texi
> > +++ b/gcc/doc/invoke.texi
> > @@ -1425,7 +1425,7 @@ See RS/6000 and PowerPC Options.
> > -mstack-protector-guard-symbol=@var{symbol} @gol
> > -mgeneral-regs-only -mcall-ms2sysv-xlogues -mrelax-cmpxchg-loop @gol
> > -mindirect-branch=@var{choice} -mfunction-return=@var{choice} @gol
> > --mindirect-branch-register -mneeded}
> > +-mindirect-branch-register -mharden-sls=@var{choice} -mneeded}
> >
> > @emph{x86 Windows Options}
> > @gccoptlist{-mconsole -mcygwin -mno-cygwin -mdll @gol
> > @@ -32382,6 +32382,14 @@ not be reachable in the large code model.
> > @opindex mindirect-branch-register
> > Force indirect call and jump via register.
> >
> > +@item -mharden-sls=@var{choice}
> > +@opindex mharden-sls
> > +Generate code to mitigate against straight line speculation (SLS) with
> > +@var{choice}. The default is @samp{none} which disables all SLS
> > +hardening. @samp{return} enables SLS hardening for function return.
> > +@samp{indirect-branch} enables SLS hardening for indirect branch.
> > +@samp{all} enables all SLS hardening.
> > +
> > @end table
> >
> > These @samp{-m} switches are supported in addition to the above
> > diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-1.c b/gcc/testsuite/gcc.target/i386/harden-sls-1.c
> > new file mode 100644
> > index 00000000000..6f70dc94a23
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/harden-sls-1.c
> > @@ -0,0 +1,14 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -mindirect-branch=thunk-extern -mharden-sls=all" } */
> > +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> > +
> > +extern void foo (void);
> > +
> > +void
> > +bar (void)
> > +{
> > + foo ();
> > +}
> > +
> > +/* { dg-final { scan-assembler "jmp\[ \t\]+_?foo" } } */
> > +/* { dg-final { scan-assembler-not {int3} } } */
> > diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-2.c b/gcc/testsuite/gcc.target/i386/harden-sls-2.c
> > new file mode 100644
> > index 00000000000..a7c59078d03
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/harden-sls-2.c
> > @@ -0,0 +1,14 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -mindirect-branch=thunk-extern -mharden-sls=all" } */
> > +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> > +
> > +extern void (*fptr) (void);
> > +
> > +void
> > +foo (void)
> > +{
> > + fptr ();
> > +}
> > +
> > +/* { dg-final { scan-assembler "jmp\[ \t\]+_?__x86_indirect_thunk_(r|e)ax" } } */
> > +/* { dg-final { scan-assembler-times "int3" 1 } } */
> > diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-3.c b/gcc/testsuite/gcc.target/i386/harden-sls-3.c
> > new file mode 100644
> > index 00000000000..1a6056b6d7b
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/harden-sls-3.c
> > @@ -0,0 +1,14 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -mindirect-branch=thunk -mharden-sls=all" } */
> > +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> > +
> > +extern void (*fptr) (void);
> > +
> > +void
> > +foo (void)
> > +{
> > + fptr ();
> > +}
> > +
> > +/* { dg-final { scan-assembler "jmp\[ \t\]+_?__x86_indirect_thunk_(r|e)ax" } } */
> > +/* { dg-final { scan-assembler-times "int3" 2 } } */
> > diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-4.c b/gcc/testsuite/gcc.target/i386/harden-sls-4.c
> > new file mode 100644
> > index 00000000000..c33147f11b5
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/harden-sls-4.c
> > @@ -0,0 +1,14 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -mindirect-branch=keep -mharden-sls=all" } */
> > +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> > +
> > +extern void (*fptr) (void);
> > +
> > +void
> > +foo (void)
> > +{
> > + fptr ();
> > +}
> > +
> > +/* { dg-final { scan-assembler "jmp\[ \t\]+\\*_?fptr" } } */
> > +/* { dg-final { scan-assembler-times "int3" 1 } } */
> > --
> > 2.33.1
> >
--
H.J.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86: Add -mharden-sls=[none|all|return|indirect-branch]
2021-11-17 13:45 ` H.J. Lu
@ 2021-11-17 14:07 ` Uros Bizjak
2021-11-17 15:39 ` H.J. Lu
0 siblings, 1 reply; 5+ messages in thread
From: Uros Bizjak @ 2021-11-17 14:07 UTC (permalink / raw)
To: H.J. Lu; +Cc: gcc-patches
On Wed, Nov 17, 2021 at 2:46 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Wed, Nov 17, 2021 at 1:05 AM Uros Bizjak <ubizjak@gmail.com> wrote:
> >
> > On Tue, Nov 16, 2021 at 7:20 PM H.J. Lu via Gcc-patches
> > <gcc-patches@gcc.gnu.org> wrote:
> > >
> > > Add -mharden-sls= to mitigate against straight line speculation (SLS)
> > > for function return and indirect branch by adding an INT3 instruction
> > > after function return and indirect branch.
> > >
> > > gcc/
> > >
> > > PR target/102952
> > > * config/i386/i386-opts.h (harden_sls): New enum.
> > > * config/i386/i386.c (output_indirect_thunk): Mitigate against
> > > SLS for function return.
> > > (ix86_output_function_return): Likewise.
> > > (ix86_output_jmp_thunk_or_indirect): Mitigate against indirect
> > > branch.
> > > (ix86_output_indirect_jmp): Likewise.
> > > (ix86_output_call_insn): Likewise.
> > > * config/i386/i386.opt: Add -mharden-sls=.
> > > * doc/invoke.texi: Document -mharden-sls=.
> > >
> > > gcc/testsuite/
> > >
> > > PR target/102952
> > > * gcc.target/i386/harden-sls-1.c: New test.
> > > * gcc.target/i386/harden-sls-2.c: Likewise.
> > > * gcc.target/i386/harden-sls-3.c: Likewise.
> > > * gcc.target/i386/harden-sls-4.c: Likewise.
> > > ---
> > > gcc/config/i386/i386-opts.h | 7 +++++
> > > gcc/config/i386/i386.c | 30 ++++++++++++++++----
> > > gcc/config/i386/i386.opt | 20 +++++++++++++
> > > gcc/doc/invoke.texi | 10 ++++++-
> > > gcc/testsuite/gcc.target/i386/harden-sls-1.c | 14 +++++++++
> > > gcc/testsuite/gcc.target/i386/harden-sls-2.c | 14 +++++++++
> > > gcc/testsuite/gcc.target/i386/harden-sls-3.c | 14 +++++++++
> > > gcc/testsuite/gcc.target/i386/harden-sls-4.c | 14 +++++++++
> > > 8 files changed, 116 insertions(+), 7 deletions(-)
> > > create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-1.c
> > > create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-2.c
> > > create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-3.c
> > > create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-4.c
> > >
> > > diff --git a/gcc/config/i386/i386-opts.h b/gcc/config/i386/i386-opts.h
> > > index 04e4ad608fb..171d3106d0a 100644
> > > --- a/gcc/config/i386/i386-opts.h
> > > +++ b/gcc/config/i386/i386-opts.h
> > > @@ -121,4 +121,11 @@ enum instrument_return {
> > > instrument_return_nop5
> > > };
> > >
> > > +enum harden_sls {
> > > + harden_sls_none = 0,
> > > + harden_sls_return = 1 << 0,
> > > + harden_sls_indirect_branch = 1 << 1,
> > > + harden_sls_all = harden_sls_return | harden_sls_indirect_branch
> > > +};
> > > +
> > > #endif
> > > diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> > > index cc9f9322fad..0a902d66321 100644
> > > --- a/gcc/config/i386/i386.c
> > > +++ b/gcc/config/i386/i386.c
> > > @@ -5914,6 +5914,8 @@ output_indirect_thunk (unsigned int regno)
> > > }
> > >
> > > fputs ("\tret\n", asm_out_file);
> > > + if ((ix86_harden_sls & harden_sls_return))
> > > + fputs ("\tint3\n", asm_out_file);
> > > }
> > >
> > > /* Output a funtion with a call and return thunk for indirect branch.
> > > @@ -15987,6 +15989,8 @@ ix86_output_jmp_thunk_or_indirect (const char *thunk_name, const int regno)
> > > fprintf (asm_out_file, "\tjmp\t");
> > > assemble_name (asm_out_file, thunk_name);
> > > putc ('\n', asm_out_file);
> > > + if ((ix86_harden_sls & harden_sls_indirect_branch))
> > > + fputs ("\tint3\n", asm_out_file);
> > > }
> > > else
> > > output_indirect_thunk (regno);
> > > @@ -16212,10 +16216,14 @@ ix86_output_indirect_jmp (rtx call_op)
> > > gcc_unreachable ();
> > >
> > > ix86_output_indirect_branch (call_op, "%0", true);
> > > - return "";
> > > + if ((ix86_harden_sls & harden_sls_indirect_branch))
> > > + return "int3";
> > > + else
> > > + return "";
> > > }
> > > else
> > > - return "%!jmp\t%A0";
> > > + return ((ix86_harden_sls & harden_sls_indirect_branch)
> > > + ? "%!jmp\t%A0\n\tint3" : "%!jmp\t%A0");
> > > }
> >
> > Just change existing returns to fputs and end function with:
> >
> > return (ix86_harden_sls & harden_sls_indirect_branch) ? "int3" : "";
>
> But fputs doesn't support %A0.
Sorry for the thinko, output_asm_insn instead of fputs will do the trick.
Uros.
>
> > > /* Output return instrumentation for current function if needed. */
> > > @@ -16283,10 +16291,15 @@ ix86_output_function_return (bool long_p)
> > > return "";
> > > }
> > >
> > > - if (!long_p)
> > > - return "%!ret";
> > > + if ((ix86_harden_sls & harden_sls_return))
> > > + return "%!ret\n\tint3";
> > > + else
> > > + {
> > > + if (!long_p)
> > > + return "%!ret";
> > >
> > > - return "rep%; ret";
> > > + return "rep%; ret";
> > > + }
> > > }
> >
> > Also here.
>
> But fputs doesn't know "%!".
>
> >
> > >
> > > /* Output indirect function return. RET_OP is the function return
> > > @@ -16381,7 +16394,12 @@ ix86_output_call_insn (rtx_insn *insn, rtx call_op)
> > > if (output_indirect_p && !direct_p)
> > > ix86_output_indirect_branch (call_op, xasm, true);
> > > else
> > > - output_asm_insn (xasm, &call_op);
> > > + {
> > > + output_asm_insn (xasm, &call_op);
> > > + if (!direct_p
> > > + && (ix86_harden_sls & harden_sls_indirect_branch))
> > > + return "int3";
> > > + }
> > > return "";
> > > }
> > >
> > > diff --git a/gcc/config/i386/i386.opt b/gcc/config/i386/i386.opt
> > > index b38ac13fc91..c5452c49597 100644
> > > --- a/gcc/config/i386/i386.opt
> > > +++ b/gcc/config/i386/i386.opt
> > > @@ -1121,6 +1121,26 @@ mrecord-return
> > > Target Var(ix86_flag_record_return) Init(0)
> > > Generate a __return_loc section pointing to all return instrumentation code.
> > >
> > > +mharden-sls=
> > > +Target RejectNegative Joined Enum(harden_sls) Var(ix86_harden_sls) Init(harden_sls_none)
> > > +Generate code to mitigate against straight line speculation.
> > > +
> > > +Enum
> > > +Name(harden_sls) Type(enum harden_sls)
> > > +Known choices for mitigation against straight line speculation with -mharden-sls=:
> > > +
> > > +EnumValue
> > > +Enum(harden_sls) String(none) Value(harden_sls_none)
> > > +
> > > +EnumValue
> > > +Enum(harden_sls) String(all) Value(harden_sls_all)
> > > +
> > > +EnumValue
> > > +Enum(harden_sls) String(return) Value(harden_sls_return)
> > > +
> > > +EnumValue
> > > +Enum(harden_sls) String(indirect-branch) Value(harden_sls_indirect_branch)
> > > +
> > > mavx512bf16
> > > Target Mask(ISA2_AVX512BF16) Var(ix86_isa_flags2) Save
> > > Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2, AVX512F and
> > > diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> > > index 6070288856c..f3b4b467765 100644
> > > --- a/gcc/doc/invoke.texi
> > > +++ b/gcc/doc/invoke.texi
> > > @@ -1425,7 +1425,7 @@ See RS/6000 and PowerPC Options.
> > > -mstack-protector-guard-symbol=@var{symbol} @gol
> > > -mgeneral-regs-only -mcall-ms2sysv-xlogues -mrelax-cmpxchg-loop @gol
> > > -mindirect-branch=@var{choice} -mfunction-return=@var{choice} @gol
> > > --mindirect-branch-register -mneeded}
> > > +-mindirect-branch-register -mharden-sls=@var{choice} -mneeded}
> > >
> > > @emph{x86 Windows Options}
> > > @gccoptlist{-mconsole -mcygwin -mno-cygwin -mdll @gol
> > > @@ -32382,6 +32382,14 @@ not be reachable in the large code model.
> > > @opindex mindirect-branch-register
> > > Force indirect call and jump via register.
> > >
> > > +@item -mharden-sls=@var{choice}
> > > +@opindex mharden-sls
> > > +Generate code to mitigate against straight line speculation (SLS) with
> > > +@var{choice}. The default is @samp{none} which disables all SLS
> > > +hardening. @samp{return} enables SLS hardening for function return.
> > > +@samp{indirect-branch} enables SLS hardening for indirect branch.
> > > +@samp{all} enables all SLS hardening.
> > > +
> > > @end table
> > >
> > > These @samp{-m} switches are supported in addition to the above
> > > diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-1.c b/gcc/testsuite/gcc.target/i386/harden-sls-1.c
> > > new file mode 100644
> > > index 00000000000..6f70dc94a23
> > > --- /dev/null
> > > +++ b/gcc/testsuite/gcc.target/i386/harden-sls-1.c
> > > @@ -0,0 +1,14 @@
> > > +/* { dg-do compile } */
> > > +/* { dg-options "-O2 -mindirect-branch=thunk-extern -mharden-sls=all" } */
> > > +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> > > +
> > > +extern void foo (void);
> > > +
> > > +void
> > > +bar (void)
> > > +{
> > > + foo ();
> > > +}
> > > +
> > > +/* { dg-final { scan-assembler "jmp\[ \t\]+_?foo" } } */
> > > +/* { dg-final { scan-assembler-not {int3} } } */
> > > diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-2.c b/gcc/testsuite/gcc.target/i386/harden-sls-2.c
> > > new file mode 100644
> > > index 00000000000..a7c59078d03
> > > --- /dev/null
> > > +++ b/gcc/testsuite/gcc.target/i386/harden-sls-2.c
> > > @@ -0,0 +1,14 @@
> > > +/* { dg-do compile } */
> > > +/* { dg-options "-O2 -mindirect-branch=thunk-extern -mharden-sls=all" } */
> > > +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> > > +
> > > +extern void (*fptr) (void);
> > > +
> > > +void
> > > +foo (void)
> > > +{
> > > + fptr ();
> > > +}
> > > +
> > > +/* { dg-final { scan-assembler "jmp\[ \t\]+_?__x86_indirect_thunk_(r|e)ax" } } */
> > > +/* { dg-final { scan-assembler-times "int3" 1 } } */
> > > diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-3.c b/gcc/testsuite/gcc.target/i386/harden-sls-3.c
> > > new file mode 100644
> > > index 00000000000..1a6056b6d7b
> > > --- /dev/null
> > > +++ b/gcc/testsuite/gcc.target/i386/harden-sls-3.c
> > > @@ -0,0 +1,14 @@
> > > +/* { dg-do compile } */
> > > +/* { dg-options "-O2 -mindirect-branch=thunk -mharden-sls=all" } */
> > > +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> > > +
> > > +extern void (*fptr) (void);
> > > +
> > > +void
> > > +foo (void)
> > > +{
> > > + fptr ();
> > > +}
> > > +
> > > +/* { dg-final { scan-assembler "jmp\[ \t\]+_?__x86_indirect_thunk_(r|e)ax" } } */
> > > +/* { dg-final { scan-assembler-times "int3" 2 } } */
> > > diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-4.c b/gcc/testsuite/gcc.target/i386/harden-sls-4.c
> > > new file mode 100644
> > > index 00000000000..c33147f11b5
> > > --- /dev/null
> > > +++ b/gcc/testsuite/gcc.target/i386/harden-sls-4.c
> > > @@ -0,0 +1,14 @@
> > > +/* { dg-do compile } */
> > > +/* { dg-options "-O2 -mindirect-branch=keep -mharden-sls=all" } */
> > > +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> > > +
> > > +extern void (*fptr) (void);
> > > +
> > > +void
> > > +foo (void)
> > > +{
> > > + fptr ();
> > > +}
> > > +
> > > +/* { dg-final { scan-assembler "jmp\[ \t\]+\\*_?fptr" } } */
> > > +/* { dg-final { scan-assembler-times "int3" 1 } } */
> > > --
> > > 2.33.1
> > >
>
>
>
> --
> H.J.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86: Add -mharden-sls=[none|all|return|indirect-branch]
2021-11-17 14:07 ` Uros Bizjak
@ 2021-11-17 15:39 ` H.J. Lu
0 siblings, 0 replies; 5+ messages in thread
From: H.J. Lu @ 2021-11-17 15:39 UTC (permalink / raw)
To: Uros Bizjak; +Cc: gcc-patches
On Wed, Nov 17, 2021 at 6:08 AM Uros Bizjak <ubizjak@gmail.com> wrote:
>
> On Wed, Nov 17, 2021 at 2:46 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> > On Wed, Nov 17, 2021 at 1:05 AM Uros Bizjak <ubizjak@gmail.com> wrote:
> > >
> > > On Tue, Nov 16, 2021 at 7:20 PM H.J. Lu via Gcc-patches
> > > <gcc-patches@gcc.gnu.org> wrote:
> > > >
> > > > Add -mharden-sls= to mitigate against straight line speculation (SLS)
> > > > for function return and indirect branch by adding an INT3 instruction
> > > > after function return and indirect branch.
> > > >
> > > > gcc/
> > > >
> > > > PR target/102952
> > > > * config/i386/i386-opts.h (harden_sls): New enum.
> > > > * config/i386/i386.c (output_indirect_thunk): Mitigate against
> > > > SLS for function return.
> > > > (ix86_output_function_return): Likewise.
> > > > (ix86_output_jmp_thunk_or_indirect): Mitigate against indirect
> > > > branch.
> > > > (ix86_output_indirect_jmp): Likewise.
> > > > (ix86_output_call_insn): Likewise.
> > > > * config/i386/i386.opt: Add -mharden-sls=.
> > > > * doc/invoke.texi: Document -mharden-sls=.
> > > >
> > > > gcc/testsuite/
> > > >
> > > > PR target/102952
> > > > * gcc.target/i386/harden-sls-1.c: New test.
> > > > * gcc.target/i386/harden-sls-2.c: Likewise.
> > > > * gcc.target/i386/harden-sls-3.c: Likewise.
> > > > * gcc.target/i386/harden-sls-4.c: Likewise.
> > > > ---
> > > > gcc/config/i386/i386-opts.h | 7 +++++
> > > > gcc/config/i386/i386.c | 30 ++++++++++++++++----
> > > > gcc/config/i386/i386.opt | 20 +++++++++++++
> > > > gcc/doc/invoke.texi | 10 ++++++-
> > > > gcc/testsuite/gcc.target/i386/harden-sls-1.c | 14 +++++++++
> > > > gcc/testsuite/gcc.target/i386/harden-sls-2.c | 14 +++++++++
> > > > gcc/testsuite/gcc.target/i386/harden-sls-3.c | 14 +++++++++
> > > > gcc/testsuite/gcc.target/i386/harden-sls-4.c | 14 +++++++++
> > > > 8 files changed, 116 insertions(+), 7 deletions(-)
> > > > create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-1.c
> > > > create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-2.c
> > > > create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-3.c
> > > > create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-4.c
> > > >
> > > > diff --git a/gcc/config/i386/i386-opts.h b/gcc/config/i386/i386-opts.h
> > > > index 04e4ad608fb..171d3106d0a 100644
> > > > --- a/gcc/config/i386/i386-opts.h
> > > > +++ b/gcc/config/i386/i386-opts.h
> > > > @@ -121,4 +121,11 @@ enum instrument_return {
> > > > instrument_return_nop5
> > > > };
> > > >
> > > > +enum harden_sls {
> > > > + harden_sls_none = 0,
> > > > + harden_sls_return = 1 << 0,
> > > > + harden_sls_indirect_branch = 1 << 1,
> > > > + harden_sls_all = harden_sls_return | harden_sls_indirect_branch
> > > > +};
> > > > +
> > > > #endif
> > > > diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> > > > index cc9f9322fad..0a902d66321 100644
> > > > --- a/gcc/config/i386/i386.c
> > > > +++ b/gcc/config/i386/i386.c
> > > > @@ -5914,6 +5914,8 @@ output_indirect_thunk (unsigned int regno)
> > > > }
> > > >
> > > > fputs ("\tret\n", asm_out_file);
> > > > + if ((ix86_harden_sls & harden_sls_return))
> > > > + fputs ("\tint3\n", asm_out_file);
> > > > }
> > > >
> > > > /* Output a funtion with a call and return thunk for indirect branch.
> > > > @@ -15987,6 +15989,8 @@ ix86_output_jmp_thunk_or_indirect (const char *thunk_name, const int regno)
> > > > fprintf (asm_out_file, "\tjmp\t");
> > > > assemble_name (asm_out_file, thunk_name);
> > > > putc ('\n', asm_out_file);
> > > > + if ((ix86_harden_sls & harden_sls_indirect_branch))
> > > > + fputs ("\tint3\n", asm_out_file);
> > > > }
> > > > else
> > > > output_indirect_thunk (regno);
> > > > @@ -16212,10 +16216,14 @@ ix86_output_indirect_jmp (rtx call_op)
> > > > gcc_unreachable ();
> > > >
> > > > ix86_output_indirect_branch (call_op, "%0", true);
> > > > - return "";
> > > > + if ((ix86_harden_sls & harden_sls_indirect_branch))
> > > > + return "int3";
> > > > + else
> > > > + return "";
> > > > }
> > > > else
> > > > - return "%!jmp\t%A0";
> > > > + return ((ix86_harden_sls & harden_sls_indirect_branch)
> > > > + ? "%!jmp\t%A0\n\tint3" : "%!jmp\t%A0");
> > > > }
> > >
> > > Just change existing returns to fputs and end function with:
> > >
> > > return (ix86_harden_sls & harden_sls_indirect_branch) ? "int3" : "";
> >
> > But fputs doesn't support %A0.
>
> Sorry for the thinko, output_asm_insn instead of fputs will do the trick.
Fixed in the v2 patch.
Thanks.
> Uros.
>
> >
> > > > /* Output return instrumentation for current function if needed. */
> > > > @@ -16283,10 +16291,15 @@ ix86_output_function_return (bool long_p)
> > > > return "";
> > > > }
> > > >
> > > > - if (!long_p)
> > > > - return "%!ret";
> > > > + if ((ix86_harden_sls & harden_sls_return))
> > > > + return "%!ret\n\tint3";
> > > > + else
> > > > + {
> > > > + if (!long_p)
> > > > + return "%!ret";
> > > >
> > > > - return "rep%; ret";
> > > > + return "rep%; ret";
> > > > + }
> > > > }
> > >
> > > Also here.
> >
> > But fputs doesn't know "%!".
> >
> > >
> > > >
> > > > /* Output indirect function return. RET_OP is the function return
> > > > @@ -16381,7 +16394,12 @@ ix86_output_call_insn (rtx_insn *insn, rtx call_op)
> > > > if (output_indirect_p && !direct_p)
> > > > ix86_output_indirect_branch (call_op, xasm, true);
> > > > else
> > > > - output_asm_insn (xasm, &call_op);
> > > > + {
> > > > + output_asm_insn (xasm, &call_op);
> > > > + if (!direct_p
> > > > + && (ix86_harden_sls & harden_sls_indirect_branch))
> > > > + return "int3";
> > > > + }
> > > > return "";
> > > > }
> > > >
> > > > diff --git a/gcc/config/i386/i386.opt b/gcc/config/i386/i386.opt
> > > > index b38ac13fc91..c5452c49597 100644
> > > > --- a/gcc/config/i386/i386.opt
> > > > +++ b/gcc/config/i386/i386.opt
> > > > @@ -1121,6 +1121,26 @@ mrecord-return
> > > > Target Var(ix86_flag_record_return) Init(0)
> > > > Generate a __return_loc section pointing to all return instrumentation code.
> > > >
> > > > +mharden-sls=
> > > > +Target RejectNegative Joined Enum(harden_sls) Var(ix86_harden_sls) Init(harden_sls_none)
> > > > +Generate code to mitigate against straight line speculation.
> > > > +
> > > > +Enum
> > > > +Name(harden_sls) Type(enum harden_sls)
> > > > +Known choices for mitigation against straight line speculation with -mharden-sls=:
> > > > +
> > > > +EnumValue
> > > > +Enum(harden_sls) String(none) Value(harden_sls_none)
> > > > +
> > > > +EnumValue
> > > > +Enum(harden_sls) String(all) Value(harden_sls_all)
> > > > +
> > > > +EnumValue
> > > > +Enum(harden_sls) String(return) Value(harden_sls_return)
> > > > +
> > > > +EnumValue
> > > > +Enum(harden_sls) String(indirect-branch) Value(harden_sls_indirect_branch)
> > > > +
> > > > mavx512bf16
> > > > Target Mask(ISA2_AVX512BF16) Var(ix86_isa_flags2) Save
> > > > Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2, AVX512F and
> > > > diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> > > > index 6070288856c..f3b4b467765 100644
> > > > --- a/gcc/doc/invoke.texi
> > > > +++ b/gcc/doc/invoke.texi
> > > > @@ -1425,7 +1425,7 @@ See RS/6000 and PowerPC Options.
> > > > -mstack-protector-guard-symbol=@var{symbol} @gol
> > > > -mgeneral-regs-only -mcall-ms2sysv-xlogues -mrelax-cmpxchg-loop @gol
> > > > -mindirect-branch=@var{choice} -mfunction-return=@var{choice} @gol
> > > > --mindirect-branch-register -mneeded}
> > > > +-mindirect-branch-register -mharden-sls=@var{choice} -mneeded}
> > > >
> > > > @emph{x86 Windows Options}
> > > > @gccoptlist{-mconsole -mcygwin -mno-cygwin -mdll @gol
> > > > @@ -32382,6 +32382,14 @@ not be reachable in the large code model.
> > > > @opindex mindirect-branch-register
> > > > Force indirect call and jump via register.
> > > >
> > > > +@item -mharden-sls=@var{choice}
> > > > +@opindex mharden-sls
> > > > +Generate code to mitigate against straight line speculation (SLS) with
> > > > +@var{choice}. The default is @samp{none} which disables all SLS
> > > > +hardening. @samp{return} enables SLS hardening for function return.
> > > > +@samp{indirect-branch} enables SLS hardening for indirect branch.
> > > > +@samp{all} enables all SLS hardening.
> > > > +
> > > > @end table
> > > >
> > > > These @samp{-m} switches are supported in addition to the above
> > > > diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-1.c b/gcc/testsuite/gcc.target/i386/harden-sls-1.c
> > > > new file mode 100644
> > > > index 00000000000..6f70dc94a23
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/gcc.target/i386/harden-sls-1.c
> > > > @@ -0,0 +1,14 @@
> > > > +/* { dg-do compile } */
> > > > +/* { dg-options "-O2 -mindirect-branch=thunk-extern -mharden-sls=all" } */
> > > > +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> > > > +
> > > > +extern void foo (void);
> > > > +
> > > > +void
> > > > +bar (void)
> > > > +{
> > > > + foo ();
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-assembler "jmp\[ \t\]+_?foo" } } */
> > > > +/* { dg-final { scan-assembler-not {int3} } } */
> > > > diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-2.c b/gcc/testsuite/gcc.target/i386/harden-sls-2.c
> > > > new file mode 100644
> > > > index 00000000000..a7c59078d03
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/gcc.target/i386/harden-sls-2.c
> > > > @@ -0,0 +1,14 @@
> > > > +/* { dg-do compile } */
> > > > +/* { dg-options "-O2 -mindirect-branch=thunk-extern -mharden-sls=all" } */
> > > > +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> > > > +
> > > > +extern void (*fptr) (void);
> > > > +
> > > > +void
> > > > +foo (void)
> > > > +{
> > > > + fptr ();
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-assembler "jmp\[ \t\]+_?__x86_indirect_thunk_(r|e)ax" } } */
> > > > +/* { dg-final { scan-assembler-times "int3" 1 } } */
> > > > diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-3.c b/gcc/testsuite/gcc.target/i386/harden-sls-3.c
> > > > new file mode 100644
> > > > index 00000000000..1a6056b6d7b
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/gcc.target/i386/harden-sls-3.c
> > > > @@ -0,0 +1,14 @@
> > > > +/* { dg-do compile } */
> > > > +/* { dg-options "-O2 -mindirect-branch=thunk -mharden-sls=all" } */
> > > > +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> > > > +
> > > > +extern void (*fptr) (void);
> > > > +
> > > > +void
> > > > +foo (void)
> > > > +{
> > > > + fptr ();
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-assembler "jmp\[ \t\]+_?__x86_indirect_thunk_(r|e)ax" } } */
> > > > +/* { dg-final { scan-assembler-times "int3" 2 } } */
> > > > diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-4.c b/gcc/testsuite/gcc.target/i386/harden-sls-4.c
> > > > new file mode 100644
> > > > index 00000000000..c33147f11b5
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/gcc.target/i386/harden-sls-4.c
> > > > @@ -0,0 +1,14 @@
> > > > +/* { dg-do compile } */
> > > > +/* { dg-options "-O2 -mindirect-branch=keep -mharden-sls=all" } */
> > > > +/* { dg-additional-options "-fno-pic" { target { ! *-*-darwin* } } } */
> > > > +
> > > > +extern void (*fptr) (void);
> > > > +
> > > > +void
> > > > +foo (void)
> > > > +{
> > > > + fptr ();
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-assembler "jmp\[ \t\]+\\*_?fptr" } } */
> > > > +/* { dg-final { scan-assembler-times "int3" 1 } } */
> > > > --
> > > > 2.33.1
> > > >
> >
> >
> >
> > --
> > H.J.
--
H.J.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-11-17 15:40 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-11-16 18:20 [PATCH] x86: Add -mharden-sls=[none|all|return|indirect-branch] H.J. Lu
2021-11-17 9:05 ` Uros Bizjak
2021-11-17 13:45 ` H.J. Lu
2021-11-17 14:07 ` Uros Bizjak
2021-11-17 15:39 ` H.J. Lu
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