[Bug target/102952] New code-gen options for retpolines and straight line speculation

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102952

--- Comment #8 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to peterz from comment #7)
> (In reply to H.J. Lu from comment #3)
> > Created attachment 51678 [details]
> > A patch to add -mharden-sls=
> > 
> > x86: Add -mharden-sls=[none|all|return|indirect-branch]
> > 
> > Generate code to mitigate against straight line speculation.
> 
> I'm getting (a lot) spurious int3 instructions with this, for example:
> 
> 0000000000000280 <do_SYSENTER_32>:
>  280:   48 81 8f 90 00 00 00 00 02 00 00        orq    $0x200,0x90(%rdi)
>  28b:   48 8b 47 20             mov    0x20(%rdi),%rax
>  28f:   48 89 87 98 00 00 00    mov    %rax,0x98(%rdi)
>  296:   e9 75 ff ff ff          jmp    210 <do_fast_syscall_32>
>  29b:   cc                      int3
> 
> That's not an *indirect* jump there.

Please provide a testcase.