On Thu, Jan 6, 2022 at 7:58 PM H.J. Lu <hjl.to...@gmail.com> wrote:
>
> Generate INT3 after indirect jmp in exception return for -fcf-protection
> with -mharden-sls=indirect-jmp.
>
> gcc/
>
> PR target/103925
> * config/i386/i386.c (ix86_output_indirect_function_return):
> Generate INT3 after indirect jmp for -mharden-sls=indirect-jmp.
>
> gcc/testsuite/
>
> PR target/103925
> * gcc.target/i386/harden-sls-6.c: New test.
OK.
Thanks,
Uros.
> ---
> gcc/config/i386/i386.c | 9 ++++++---
> gcc/testsuite/gcc.target/i386/harden-sls-6.c | 18 ++++++++++++++++++
> 2 files changed, 24 insertions(+), 3 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/i386/harden-sls-6.c
>
> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index 835ec2cafcb..35fb5adf2ef 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -16367,11 +16367,14 @@ ix86_output_indirect_function_return (rtx ret_op)
> }
> else
> output_indirect_thunk (regno);
> -
> - return "";
> }
> else
> - return "%!jmp\t%A0";
> + {
> + output_asm_insn ("%!jmp\t%A0", &ret_op);
> + if (ix86_harden_sls & harden_sls_indirect_jmp)
> + fputs ("\tint3\n", asm_out_file);
> + }
> + return "";
> }
>
> /* Output the assembly for a call instruction. */
> diff --git a/gcc/testsuite/gcc.target/i386/harden-sls-6.c
> b/gcc/testsuite/gcc.target/i386/harden-sls-6.c
> new file mode 100644
> index 00000000000..9068eb64008
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/harden-sls-6.c
> @@ -0,0 +1,18 @@
> +/* { dg-do compile { target { ! ia32 } } } */
> +/* { dg-options "-O2 -fcf-protection -mharden-sls=indirect-jmp" } */
> +
> +struct _Unwind_Context _Unwind_Resume_or_Rethrow_this_context;
> +
> +void offset (int);
> +
> +struct _Unwind_Context {
> + void *reg[7];
> +} _Unwind_Resume_or_Rethrow() {
> + struct _Unwind_Context cur_contextcur_context =
> + _Unwind_Resume_or_Rethrow_this_context;
> + offset(0);
> + __builtin_eh_return ((long) offset, 0);
> +}
> +
> +/* { dg-final { scan-assembler "jmp\[ \t\]+\\*%rcx" } } */
> +/* { dg-final { scan-assembler-times "int3" 1 } } */
> --
> 2.33.1
>
