{"id":2219754,"url":"http://patchwork.ozlabs.org/api/1.1/covers/2219754/?format=json","web_url":"http://patchwork.ozlabs.org/project/sparclinux/cover/20260404071720.3577290-1-songmuchun@bytedance.com/","project":{"id":10,"url":"http://patchwork.ozlabs.org/api/1.1/projects/10/?format=json","name":"Linux SPARC Development ","link_name":"sparclinux","list_id":"sparclinux.vger.kernel.org","list_email":"sparclinux@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null},"msgid":"<20260404071720.3577290-1-songmuchun@bytedance.com>","date":"2026-04-04T07:17:04","name":"[0/5] mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd()","submitter":{"id":78930,"url":"http://patchwork.ozlabs.org/api/1.1/people/78930/?format=json","name":"Muchun Song","email":"songmuchun@bytedance.com"},"mbox":"http://patchwork.ozlabs.org/project/sparclinux/cover/20260404071720.3577290-1-songmuchun@bytedance.com/mbox/","series":[{"id":498702,"url":"http://patchwork.ozlabs.org/api/1.1/series/498702/?format=json","web_url":"http://patchwork.ozlabs.org/project/sparclinux/list/?series=498702","date":"2026-04-04T07:17:04","name":"mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd()","version":1,"mbox":"http://patchwork.ozlabs.org/series/498702/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/covers/2219754/comments/","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","sparclinux@vger.kernel.org"],"Delivered-To":["patchwork-incoming@legolas.ozlabs.org","patchwork-incoming@ozlabs.org"],"Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=bytedance.com header.i=@bytedance.com\n header.a=rsa-sha256 header.s=google header.b=bb8eb65R;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=2404:9400:2221:ea00::3; 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Miller\" ,\n\tAndreas Larsson ,\n\tAndrew Morton ,\n\tDavid Hildenbrand ","Cc":"Muchun Song ,\n\tMuchun Song ,\n\tWANG Xuerui ,\n\tAlexandre Ghiti ,\n\tLorenzo Stoakes ,\n\t\"Liam R. Howlett\" ,\n\tVlastimil Babka ,\n\tMike Rapoport ,\n\tSuren Baghdasaryan ,\n\tMichal Hocko ,\n\tRyan Roberts ,\n\tKevin Brodsky ,\n\tDev Jain ,\n\tAnshuman Khandual ,\n\tYang Shi ,\n\tChaitanya S Prakash ,\n\tYuquan Wang ,\n\tPetr Tesarik ,\n\tAustin Kim ,\n\t\"Vishal Moola (Oracle)\" ,\n\tJunhui Liu ,\n\t\"Matthew Wilcox (Oracle)\" ,\n\tAlex Shi ,\n\tChengkaitao ,\n\tlinux-arm-kernel@lists.infradead.org,\n\tlinux-kernel@vger.kernel.org,\n\tloongarch@lists.linux.dev,\n\tlinux-riscv@lists.infradead.org,\n\tsparclinux@vger.kernel.org,\n\tlinux-mm@kvack.org","Subject":"[PATCH 0/5] mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and\n vmemmap_check_pmd()","Date":"Sat, 4 Apr 2026 15:17:04 +0800","Message-Id":"<20260404071720.3577290-1-songmuchun@bytedance.com>","X-Mailer":"git-send-email 2.20.1","Precedence":"bulk","X-Mailing-List":"sparclinux@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","X-Spam-Status":"No, score=-1.2 required=5.0 tests=ARC_SIGNED,ARC_VALID,\n\tDKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DMARC_PASS,\n\tHEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,\n\tSPF_PASS autolearn=disabled version=4.0.1","X-Spam-Checker-Version":"SpamAssassin 4.0.1 (2024-03-25) on gandalf.ozlabs.org"},"content":"The two weak functions vmemmap_set_pmd() and vmemmap_check_pmd() are\ncurrently no-ops on every architecture, forcing each platform that needs\nthem to duplicate the same handful of lines. Provide a generic implementation:\n\n- vmemmap_set_pmd() simply sets a huge PMD with PAGE_KERNEL protection.\n\n- vmemmap_check_pmd() verifies that the PMD is present and leaf,\n then calls the existing vmemmap_verify() helper.\n\nArchitectures that need special handling can continue to override the\nweak symbols; everyone else gets the standard version for free.\n\nThis series drops the custom implementations in arm64, riscv, loongarch,\nand sparc, replacing them with the generic implementation introduced\nin the first patch.\n\nMuchun Song (5):\n mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and\n vmemmap_check_pmd()\n arm64/mm: drop vmemmap_pmd helpers and use generic code\n riscv/mm: drop vmemmap_pmd helpers and use generic code\n loongarch/mm: drop vmemmap_check_pmd helper and use generic code\n sparc/mm: drop vmemmap_check_pmd helper and use generic code\n\n arch/arm64/mm/mmu.c | 14 --------------\n arch/loongarch/mm/init.c | 11 -----------\n arch/riscv/mm/init.c | 13 -------------\n arch/sparc/mm/init_64.c | 11 -----------\n mm/sparse-vmemmap.c | 7 ++++++-\n 5 files changed, 6 insertions(+), 50 deletions(-)"}