Messages in this thread | | | Subject | Re: [PATCH] x86/speculation: Use AMD specific retpoline for inline asm on AMD | From | Zhenzhong Duan <> | Date | Tue, 18 Sep 2018 22:41:10 +0800 |
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On 2018/9/18 21:00, Peter Zijlstra wrote: > 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. >
Clear, thanks for your explanation.
Zhenzhong
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