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[217.140.101.70]) by mx.google.com with ESMTP id gv4si88050ejb.226.2019.02.15.09.03.28 for ; Fri, 15 Feb 2019 09:03:29 -0800 (PST) Received-SPF: pass (google.com: domain of steven.price@arm.com designates 217.140.101.70 as permitted sender) client-ip=217.140.101.70; Authentication-Results: mx.google.com; spf=pass (google.com: domain of steven.price@arm.com designates 217.140.101.70 as permitted sender) smtp.mailfrom=steven.price@arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4A4EC1596; Fri, 15 Feb 2019 09:03:28 -0800 (PST) Received: from e112269-lin.arm.com (e112269-lin.cambridge.arm.com [10.1.196.69]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 568A13F557; Fri, 15 Feb 2019 09:03:25 -0800 (PST) From: Steven Price To: linux-mm@kvack.org Cc: Steven Price , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Dave Hansen , Ingo Molnar , James Morse , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Peter Zijlstra , Thomas Gleixner , Will Deacon , x86@kernel.org, "H. Peter Anvin" , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 07/13] mm: pagewalk: Add test_p?d callbacks Date: Fri, 15 Feb 2019 17:02:28 +0000 Message-Id: <20190215170235.23360-8-steven.price@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190215170235.23360-1-steven.price@arm.com> References: <20190215170235.23360-1-steven.price@arm.com> MIME-Version: 1.0 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: X-Virus-Scanned: ClamAV using ClamSMTP It is useful to be able to skip parts of the page table tree even when walking without VMAs. Add test_p?d callbacks similar to test_walk but which are called just before a table at that level is walked. If the callback returns non-zero then the entire table is skipped. Signed-off-by: Steven Price --- include/linux/mm.h | 11 +++++++++++ mm/pagewalk.c | 24 ++++++++++++++++++++++++ 2 files changed, 35 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 0418a018d7b3..0e4c9b6b554d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1428,6 +1428,11 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma, * value means "do page table walk over the current vma," * and a negative one means "abort current page table walk * right now." 1 means "skip the current vma." + * @test_pmd: similar to test_walk(), but called for every pmd. + * @test_pud: similar to test_walk(), but called for every pud. + * @test_p4d: similar to test_walk(), but called for every p4d. + * Returning 0 means walk this part of the page tables, + * returning 1 means to skip this range. * @mm: mm_struct representing the target process of page table walk * @vma: vma currently walked (NULL if walking outside vmas) * @private: private data for callbacks' usage @@ -1452,6 +1457,12 @@ struct mm_walk { struct mm_walk *walk); int (*test_walk)(unsigned long addr, unsigned long next, struct mm_walk *walk); + int (*test_pmd)(unsigned long addr, unsigned long next, + pmd_t *pmd_start, struct mm_walk *walk); + int (*test_pud)(unsigned long addr, unsigned long next, + pud_t *pud_start, struct mm_walk *walk); + int (*test_p4d)(unsigned long addr, unsigned long next, + p4d_t *p4d_start, struct mm_walk *walk); struct mm_struct *mm; struct vm_area_struct *vma; void *private; diff --git a/mm/pagewalk.c b/mm/pagewalk.c index b8038f852f06..bce7571c6563 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -32,6 +32,14 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, unsigned long next; int err = 0; + if (walk->test_pmd) { + err = walk->test_pmd(addr, end, pmd_offset(pud, 0), walk); + if (err < 0) + return err; + if (err > 0) + return 0; + } + pmd = pmd_offset(pud, addr); do { again: @@ -82,6 +90,14 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, unsigned long next; int err = 0; + if (walk->test_pud) { + err = walk->test_pud(addr, end, pud_offset(p4d, 0), walk); + if (err < 0) + return err; + if (err > 0) + return 0; + } + pud = pud_offset(p4d, addr); do { again: @@ -128,6 +144,14 @@ static int walk_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end, */ int depth = (PTRS_PER_P4D == 1)?0:1; + if (walk->test_p4d) { + err = walk->test_p4d(addr, end, p4d_offset(pgd, 0), walk); + if (err < 0) + return err; + if (err > 0) + return 0; + } + p4d = p4d_offset(pgd, addr); do { next = p4d_addr_end(addr, end);