From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E74AA606A897 for ; Fri, 13 Nov 2026 10:50:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=Qdsy38aj; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=NneODPg5 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; 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Fri, 13 Nov 2026 10:50:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794567045; bh=0JXP8ijEUph+DH7eK7vAJyLP+Bw6tzlYEIbg+5Jovus=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=NneODPg5Lm7PgKusVQTTjim0GwSW5e0lbqq+NWR9bvLd97yPbNhZe9Y0LmWebgvgL CAOw1Ac+t8trQnJncFKKYqIgJl0yTBlsebndJYxBEBtu5oO/s6z+Azwf8gH7aeUgLH OikDWGvl1iYsa12pbPkUNFWo/BVTZKVL6VA0YhDbEp5pWjYPb6lKn/2+/qR+fOcvdW vYMHEdFGcGtOrsxK/QjxDvOhs8YYEUrxU4gtiJ+DfTGvlbyKCAjYd6k9gyMHsEBf1P XCHGwM3DJvppC4w3ICUq1nllm6XFK6Qbjj8dzvOi4r5KSgPFnetZ8KTT9img7cvlZM MLwoFy43sV16g== Message-ID: Date: Fri, 13 Nov 2026 11:50:39 +0100 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 4/6] mm: drop HIGHPTE support altogether To: Arnd Bergmann , Mike Rapoport , Arnd Bergmann Cc: linux-mm@kvack.org, Andrew Morton , Andreas Larsson , Christophe Leroy , Dave Hansen , Jason Gunthorpe , Linus Walleij , Lorenzo Stoakes , Matthew Wilcox , Malin Jonsson , Richard Weinberger , Russell King , linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org References: <20261112112528.1116405-1-arnd@kernel.org> <20261112112528.1116405-5-arnd@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 11/12/26 14:26, Arnd Bergmann wrote: > On Thu, Nov 12, 2026, at 12:54, Mike Rapoport wrote: >> On Thu, Nov 12, 2026 at 12:25:26PM +0100, Arnd Bergmann wrote: >>> From: Arnd Bergmann >>> >>> With both x86 and arm having dropped CONFIG_HIGHPTE support, no >>> architecture is left using it, so remove the remnants in common code. >>> >>> It is likely that further cleanups are possible in the page table >>> code but those are not obvious from the config options. >>> >>> Signed-off-by: Arnd Bergmann >>> --- >>> include/linux/hugetlb.h | 5 +---- >>> include/linux/mm.h | 1 - >>> include/linux/pgtable.h | 9 --------- >>> 3 files changed, 1 insertion(+), 14 deletions(-) >> >> With this and arm HIGHPTE patches applied there are still a few leftovers: >> >> $ git grep HIGHPTE >> arch/arm/configs/vt8500_v6_v7_defconfig:CONFIG_HIGHPTE=y > > This got dropped in patch 5/6 in v2, but I've moved that here now. > >> mm/memory.c: * Dumping the PTE would be nice, but it's tricky with >> CONFIG_HIGHPTE, > > Added the patch below for this. Untested so far. > >> mm/pgtable-generic.c: * kmapped if necessary (when CONFIG_HIGHPTE), and >> locked against concurrent > > Updated the comment and also dropped __pte_map() after I noticed that > open-coding the only caller in pte_offset_map_rw_nolock() is consistent > with that comment change: > > --- a/mm/pgtable-generic.c > +++ b/mm/pgtable-generic.c > @@ -314,7 +314,7 @@ pte_t *__pte_offset_map(pmd_t *pmd, unsigned long addr, pmd_t *pmdvalp) > pmd_clear_bad(pmd); > goto nomap; > } > - return __pte_map(&pmdval, addr); > + return pte_offset_kernel(&pmdval, addr); > nomap: > rcu_read_unlock(); > return NULL; > > >> mm/userfaultfd.c: * index ordering when CONFIG_HIGHPTE is >> enabled. We mapped dst_pte > > Dropped that comment block as it no longer applies. > >> Acked-by: Mike Rapoport (Microsoft) > > Thanks, > > Arnd > --- > Subject: [PATCH] mm: print pte in __print_bad_page_map_pgtable() > > HIGHPTE support is gone now, so it's easy enough to print the > PTE here along with the upper level entries. > > Signed-off-by: Arnd Bergmann > > diff --git a/mm/memory.c b/mm/memory.c > index ec3d9d99ccee..dabeb5568c94 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -528,9 +528,11 @@ static void __print_bad_page_map_pgtable(struct mm_struct *mm, unsigned long add > char p4d_str[PTVAL_STR_MAX]; > char pud_str[PTVAL_STR_MAX]; > char pmd_str[PTVAL_STR_MAX]; > + char pte_str[PTVAL_STR_MAX]; > p4d_t p4d, *p4dp; > pud_t pud, *pudp; > pmd_t pmd, *pmdp; > + pte_t pte, *ptep; > pgd_t *pgdp; > > /* > @@ -567,13 +569,18 @@ static void __print_bad_page_map_pgtable(struct mm_struct *mm, unsigned long add > pmd = pmdp_get(pmdp); > ptval_to_str(pmd_str, pmd_val(pmd)); > > - /* > - * Dumping the PTE would be nice, but it's tricky with CONFIG_HIGHPTE, > - * because the table should already be mapped by the caller and > - * doing another map would be bad. print_bad_page_map() should > - * already take care of printing the PTE. > - */ > - pr_alert("pgd:%s p4d:%s pud:%s pmd:%s\n", pgd_str, p4d_str, pud_str, pmd_str); > + if (!pmd_present(pmd) || pmd_leaf(pmd)) { > + pr_alert("pgd:%s p4d:%s pud:%s pmd: %s\n", > + pgd_str, p4d_str, pud_str, pmd_str); > + return; > + } > + > + ptep = pte_offset_kernel(pmdp, addr); > + pte = ptep_get(ptep); > + ptval_to_str(pte_str, pte_val(pte)); > + > + pr_alert("pgd:%s p4d:%s pud:%s pmd:%s pte:%s\n", > + pgd_str, p4d_str, pud_str, pmd_str, pte_str); > } > > /* Yeah, that LGTM. I assume you'll send out a v3. -- Cheers, David