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[209.85.220.65]) by mx.google.com with SMTPS id h82sor6113965pfd.0.2019.03.28.11.10.19 for (Google Transport Security); Thu, 28 Mar 2019 11:10:19 -0700 (PDT) Received-SPF: pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=WimfdOXD; spf=pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=andreyknvl@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=nzxjSg31IMgfFUQ8l0HID0xVlMev5O9yi4i0vq5xZ1A=; b=WimfdOXDpmaShGSBMcQLuKB53BkH6tzB8hJJY80McjiVMc24UhiE53emJHH9ruAnXP qITkYAFGoYPtrEdPvLLeHbds9C08ASJTWOwCi8Rknp1u/0cYiwDJvI+7ty2h8j8O2QAG SLpxbBGDCPNE233aCSkj5k046fv8+CH2DZQc9qlPJKgMXn0IRrUJFQQl3K1Zqaa3glct 1ZOkO8hIRPAh9zngper4MvoJ3IlW/GQr2SNDX4URyY4m5R+IwIAXgy7WbisxiLi+xUxz 36ZgPHzATOwPgngNtLBoAR5C8WJ1PCgUL23vn0K/mS5S5GTpyXavJjsC1/pJ2a10QRJz gryg== X-Google-Smtp-Source: APXvYqwVzwa7Yi2B6AwxYRYIoL9rm6INemnW30MlbEQDwJJ+Fva2F45mc9/WPibU0ilc1KkOXtX/gNq2lbuJJez5/QY= X-Received: by 2002:a62:e816:: with SMTP id c22mr13322308pfi.54.1553796618481; Thu, 28 Mar 2019 11:10:18 -0700 (PDT) MIME-Version: 1.0 References: <44ad2d0c55dbad449edac23ae46d151a04102a1d.1553093421.git.andreyknvl@google.com> <20190322114357.GC13384@arrakis.emea.arm.com> In-Reply-To: <20190322114357.GC13384@arrakis.emea.arm.com> From: Andrey Konovalov Date: Thu, 28 Mar 2019 19:10:07 +0100 Message-ID: Subject: Re: [PATCH v13 04/20] mm, arm64: untag user pointers passed to memory syscalls To: Catalin Marinas Cc: Will Deacon , Mark Rutland , Robin Murphy , Kees Cook , Kate Stewart , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Shuah Khan , Vincenzo Frascino , Eric Dumazet , "David S. Miller" , Alexei Starovoitov , Daniel Borkmann , Steven Rostedt , Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo , Alex Deucher , =?UTF-8?Q?Christian_K=C3=B6nig?= , "David (ChunMing) Zhou" , Yishai Hadas , Mauro Carvalho Chehab , Jens Wiklander , Alex Williamson , Linux ARM , Linux Memory Management List , linux-arch , netdev , bpf , amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, "open list:KERNEL SELFTEST FRAMEWORK" , LKML , Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Chintan Pandya , Luc Van Oostenryck , Dave Martin , Kevin Brodsky , Szabolcs Nagy Content-Type: text/plain; charset="UTF-8" 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 Fri, Mar 22, 2019 at 12:44 PM Catalin Marinas wrote: > > On Wed, Mar 20, 2019 at 03:51:18PM +0100, Andrey Konovalov wrote: > > This patch is a part of a series that extends arm64 kernel ABI to allow to > > pass tagged user pointers (with the top byte set to something else other > > than 0x00) as syscall arguments. > > > > This patch allows tagged pointers to be passed to the following memory > > syscalls: madvise, mbind, get_mempolicy, mincore, mlock, mlock2, brk, > > mmap_pgoff, old_mmap, munmap, remap_file_pages, mprotect, pkey_mprotect, > > mremap, msync and shmdt. > > > > This is done by untagging pointers passed to these syscalls in the > > prologues of their handlers. > > > > Signed-off-by: Andrey Konovalov > > --- > > ipc/shm.c | 2 ++ > > mm/madvise.c | 2 ++ > > mm/mempolicy.c | 5 +++++ > > mm/migrate.c | 1 + > > mm/mincore.c | 2 ++ > > mm/mlock.c | 5 +++++ > > mm/mmap.c | 7 +++++++ > > mm/mprotect.c | 1 + > > mm/mremap.c | 2 ++ > > mm/msync.c | 2 ++ > > 10 files changed, 29 insertions(+) > > I wonder whether it's better to keep these as wrappers in the arm64 > code. I don't think I understand what you propose, could you elaborate?