On Tue, Sep 18, 2018 at 08:04:44PM +0800, Zhenzhong Duan wrote: > On 2018/9/18 18:59, Peter Zijlstra wrote: > > On Tue, Sep 18, 2018 at 06:31:07PM +0800, Zhenzhong Duan wrote: > > > On 2018/9/18 17:50, Peter Zijlstra wrote: > > > > On Mon, Sep 17, 2018 at 10:17:30PM -0700, Zhenzhong Duan wrote: > > > > > -#elif defined(CONFIG_X86_32) && defined(CONFIG_RETPOLINE) > > > > > +#elif defined(CONFIG_RETPOLINE) > > > > > > > > This doesn't make any sense.. > > > This change is used for x86_64 to have minimal Retpoline support when > > > CONFIG_RETPOLINE is defined but RETPOLINE isn't defined, or I missed > > > something? > > > > No it doesn't. > > > > #if defined(X86_64) && defined(RETPOLINE) > > > > /* x86_64 retpoline goes here */ > > > > #elif defined(RETPOLINE) > > > > /* !x86_64 retpoline goes here */ > > > > #else > > > > /* !retpoline goes here > > > > #endif > > Sorry, but I am confused. > So where is 'if defined(x86_64) && !defined(RETPOLINE) && > defined(CONFIG_RETPOLINE)' go?
Argh, CONFIG_RETPOLINE vs RETPOLINE :/ The thing is, the one you modify has a comment on that explains why it is i386 only. CET and retpolines don't like one another much. And the x86_64 version uses %V which requires new GCC. So I'm all for fixing the RETPOLINE_AMD thing, but at this point nobody should use the minimal stuff, that's just delusional. > In original code, it will go to "call *%[thunk_target]\n" while > we have set SPECTRE_V2_RETPOLINE_MINIMAL or > SPECTRE_V2_RETPOLINE_MINIMAL_AMD. Is this expected? Yes, that is exactly right -- it does that with or without your change though.
