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Date: Wed, 10 Jul 2019 19:27:53 +0800 From: Xi Ruoyao <xry111@...gyan1223.wang> To: Kees Cook <keescook@...omium.org>, Thomas Gleixner <tglx@...utronix.de> Cc: Linus Torvalds <torvalds@...ux-foundation.org>, Ingo Molnar <mingo@...nel.org>, Linux List Kernel Mailing <linux-kernel@...r.kernel.org>, Borislav Petkov <bp@...en8.de>, Len Brown <lenb@...nel.org>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, Andrew Morton <akpm@...ux-foundation.org>, "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>, Tony Luck <tony.luck@...el.com>, Jiri Kosina <jkosina@...e.cz>, Bob Moore <robert.moore@...el.com>, Erik Schmauss <erik.schmauss@...el.com>, xry111@...gyan1223.wang Subject: Re: [GIT PULL] x86/topology changes for v5.3 On 2019-07-09 17:31 -0700, Kees Cook wrote: > On Wed, Jul 10, 2019 at 01:17:11AM +0200, Thomas Gleixner wrote: > > On Wed, 10 Jul 2019, Thomas Gleixner wrote: > > > That still does not explain the cr4/0 issue you have. Can you send me your > > > .config please? > > > > Does your machine have UMIP support? None of my test boxes has. So that'd > > be the difference of bits enforced in CR4. Should not matter because it's > > User mode instruction prevention, but who knows. > > Ew. Yeah, I don't have i9 nor i7 for testing this. I did try everything > else I had (and hibernation). Is only Linus able to reproduce this so far? I can, too. > To rule out (in?) UMIP, this would remove UMIP from the pinning: > > diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c > index 309b6b9b49d4..f3beedb6da8a 100644 > --- a/arch/x86/kernel/cpu/common.c > +++ b/arch/x86/kernel/cpu/common.c > @@ -380,7 +380,7 @@ static void __init setup_cr_pinning(void) > { > unsigned long mask; > > - mask = (X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_UMIP); > + mask = (X86_CR4_SMEP | X86_CR4_SMAP); > cr4_pinned_bits = this_cpu_read(cpu_tlbstate.cr4) & mask; > static_key_enable(&cr_pinning.key); > } I'll try it. -- Xi Ruoyao <xry111@...gyan1223.wang> School of Aerospace Science and Technology, Xidian University
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