From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8C887C52D6F for ; Wed, 7 Aug 2024 22:38:06 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=2guZOYZ9; dkim=fail reason="signature verification failed" header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=IB5N8gDs; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4WfQ711NRXz3cVf for ; Thu, 8 Aug 2024 08:38:05 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=2guZOYZ9; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=IB5N8gDs; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linutronix.de (client-ip=2a0a:51c0:0:12e:550::1; helo=galois.linutronix.de; envelope-from=tglx@linutronix.de; receiver=lists.ozlabs.org) Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4WfQ6D6W4Pz2xjM for ; Thu, 8 Aug 2024 08:37:24 +1000 (AEST) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1723070242; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ijzboojuY5XpUno0lk+35UbNznLU2ucd6kpR6qcMWxg=; b=2guZOYZ99eyTcewCEP8xSZxwsHPHCJoQsL15+KAEcO68JB85EE+Hd6SCbExGA8OqLINdLh mX32IGFpl1TmhRwBqJ+dF0jiQHcEBoZBV+AltYSVcbizerrFhRVdNW9OkKsHUlLl/RpVL9 iyJoFp1hsL/2Izml40cfR4Bgi2fluswxwsvarN4ZmHFECUAurABZ5b6xRyopii7S45bIcd FEtgLFzszmtb4INfqVZrUIR9w6gSju9DqSiPuZF37VxavgThej1oJKme+a1nQ2rLwmKD82 RoYUBkCzU/T/WzNZWB+ndNEBkuWHKIi+tMWb5a+GNDneBs2LwmGEj77sWmPIfQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1723070242; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ijzboojuY5XpUno0lk+35UbNznLU2ucd6kpR6qcMWxg=; b=IB5N8gDs6FBpyO8gAD9i3Vzt37QlGsQG8iqeySMgtnjM8GKUrJWBMjTtXMeWMZFSrrqVIv yXjA4dOnrV6rqPBg== To: Peter Xu , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v4 6/7] mm/x86: Add missing pud helpers In-Reply-To: <20240807194812.819412-7-peterx@redhat.com> References: <20240807194812.819412-1-peterx@redhat.com> <20240807194812.819412-7-peterx@redhat.com> Date: Thu, 08 Aug 2024 00:37:21 +0200 Message-ID: <875xsc0xjy.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: James Houghton , David Hildenbrand , Dave Hansen , peterx@redhat.com, Christophe Leroy , Dave Jiang , "Aneesh Kumar K . V" , x86@kernel.org, Hugh Dickins , Matthew Wilcox , Ingo Molnar , Huang Ying , Rik van Riel , Nicholas Piggin , Borislav Petkov , "Kirill A . Shutemov" , Dan Williams , Vlastimil Babka , Oscar Salvador , linuxppc-dev@lists.ozlabs.org, Andrew Morton , Rick P Edgecombe , Mel Gorman Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, Aug 07 2024 at 15:48, Peter Xu wrote: > These new helpers will be needed for pud entry updates soon. Introduce > these helpers by referencing the pmd ones. Namely: > > - pudp_invalidate() > - pud_modify() Zero content about what these helpers do and why they are needed. That's not how it works, really. > +static inline pud_t pud_mkinvalid(pud_t pud) > +{ > + return pfn_pud(pud_pfn(pud), > + __pgprot(pud_flags(pud) & ~(_PAGE_PRESENT|_PAGE_PROTNONE))); 100 characters... > +} > + > static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask); > > static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) > @@ -834,14 +840,8 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) > pmd_result = __pmd(val); > > /* > - * To avoid creating Write=0,Dirty=1 PMDs, pte_modify() needs to avoid: > - * 1. Marking Write=0 PMDs Dirty=1 > - * 2. Marking Dirty=1 PMDs Write=0 > - * > - * The first case cannot happen because the _PAGE_CHG_MASK will filter > - * out any Dirty bit passed in newprot. Handle the second case by > - * going through the mksaveddirty exercise. Only do this if the old > - * value was Write=1 to avoid doing this on Shadow Stack PTEs. > + * Avoid creating shadow stack PMD by accident. See comment in > + * pte_modify(). The changelog is utterly silent about this comment update. > */ > if (oldval & _PAGE_RW) > pmd_result = pmd_mksaveddirty(pmd_result); > @@ -851,6 +851,29 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) > return pmd_result; > } > > +static inline pud_t pud_modify(pud_t pud, pgprot_t newprot) > +{ > + pudval_t val = pud_val(pud), oldval = val; > + pud_t pud_result; > + > + val &= _HPAGE_CHG_MASK; > + val |= check_pgprot(newprot) & ~_HPAGE_CHG_MASK; > + val = flip_protnone_guard(oldval, val, PHYSICAL_PUD_PAGE_MASK); > + > + pud_result = __pud(val); > + > + /* > + * Avoid creating shadow stack PUD by accident. See comment in > + * pte_modify(). > + */ > + if (oldval & _PAGE_RW) > + pud_result = pud_mksaveddirty(pud_result); > + else > + pud_result = pud_clear_saveddirty(pud_result); > + > + return pud_result; > +} > + > /* > * mprotect needs to preserve PAT and encryption bits when updating > * vm_page_prot > @@ -1389,10 +1412,26 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma, > } > #endif > > +static inline pud_t pudp_establish(struct vm_area_struct *vma, > + unsigned long address, pud_t *pudp, pud_t pud) Random line break alignment.... See documentation. > +{ > + page_table_check_pud_set(vma->vm_mm, pudp, pud); > + if (IS_ENABLED(CONFIG_SMP)) { > + return xchg(pudp, pud); > + } else { > + pud_t old = *pudp; > + WRITE_ONCE(*pudp, pud); Lacks a newline between variable declaration and code. But seriously, why optimizing for !SMP? That's a pointless exercise and a guarantee for bitrot. > + return old; > + } > +} > + > #define __HAVE_ARCH_PMDP_INVALIDATE_AD > extern pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, > unsigned long address, pmd_t *pmdp); > > +pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address, > + pud_t *pudp); While 'extern' is not required, please keep the file style consistent and use the 100 characters... > --- a/arch/x86/mm/pgtable.c > +++ b/arch/x86/mm/pgtable.c > @@ -641,6 +641,18 @@ pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address, > } > #endif > > +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ > + defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) > +pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address, > + pud_t *pudp) > +{ > + VM_WARN_ON_ONCE(!pud_present(*pudp)); > + pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp)); > + flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE); > + return old; Your keyboard clearly lacks a newline key ... Thanks, tglx