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Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu , Haitao Huang , Rick P Edgecombe , "Kirill A . Shutemov" Subject: Re: [PATCH v28 16/32] x86/mm: Update maybe_mkwrite() for shadow stack Message-ID: References: <20210722205219.7934-1-yu-cheng.yu@intel.com> <20210722205219.7934-17-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210722205219.7934-17-yu-cheng.yu@intel.com> Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=alien8.de header.s=dkim header.b=NUhUMN3z; dmarc=pass (policy=none) header.from=alien8.de; spf=pass (imf22.hostedemail.com: domain of bp@alien8.de designates 5.9.137.197 as permitted sender) smtp.mailfrom=bp@alien8.de X-Stat-Signature: hb1hoc38r9wzqq59zzurhwinsyr3wc8c X-Rspamd-Queue-Id: 63C12C3E7 X-Rspamd-Server: rspam05 X-HE-Tag: 1629133400-636186 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Jul 22, 2021 at 01:52:03PM -0700, Yu-cheng Yu wrote: > diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c > index 3364fe62b903..ba449d12ec32 100644 > --- a/arch/x86/mm/pgtable.c > +++ b/arch/x86/mm/pgtable.c > @@ -610,6 +610,26 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma, > } > #endif > > +pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) > +{ > + if (likely(vma->vm_flags & VM_WRITE)) > + pte = pte_mkwrite(pte); > + else if (likely(vma->vm_flags & VM_SHADOW_STACK)) > + pte = pte_mkwrite_shstk(pte); > + return pte; > +} > + > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > +pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) > +{ > + if (likely(vma->vm_flags & VM_WRITE)) > + pmd = pmd_mkwrite(pmd); > + else if (likely(vma->vm_flags & VM_SHADOW_STACK)) > + pmd = pmd_mkwrite_shstk(pmd); What are all those likely()ies here for? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette