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[23.128.96.18]) by mx.google.com with ESMTP id m26si2011657edj.174.2020.05.01.02.04.25; Fri, 01 May 2020 02:04:50 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=eP8zzJ0a; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728373AbgEAJCd (ORCPT + 99 others); Fri, 1 May 2020 05:02:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37168 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728159AbgEAJCd (ORCPT ); Fri, 1 May 2020 05:02:33 -0400 Received: from mail-pg1-x543.google.com (mail-pg1-x543.google.com [IPv6:2607:f8b0:4864:20::543]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ABDD3C035495 for ; Fri, 1 May 2020 02:02:31 -0700 (PDT) Received: by mail-pg1-x543.google.com with SMTP id l20so4308696pgb.11 for ; Fri, 01 May 2020 02:02:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=u3Ysbis/inrfbBoA8BHLbvKshdlzgqGs68fIPEsHEVg=; b=eP8zzJ0a/Hmxxv5G2MaxHN/LWkzXcKt9XG/Dkv5ekKbIOKKvJns/1BXUiUvN6wBFR1 ubq6YddXMtvjXmTLTdz2/V79yjXk6Jcz8rG/1h2spbuEE705AGdFp5QJ+sjjfJukGYup tqCILrFlD2kfAciwlWW5qH3SyEn4KpUe+4gHFU/LQwQFix0zCmFoB/0ILU4+KHaUKqSr 6ppcJC24WyNXNI0Jy6GZSjwMK2NWCWmJ06Vp/4ZGELxAfSLtCXCMHRaDuLVwHcF75KTW qhDuhgJO4bXNK61Ji7BmtVdVywwIl4sPbL1pdfgXXDxPYSeWCQyZrverPp90pUs70n/1 /WSw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=u3Ysbis/inrfbBoA8BHLbvKshdlzgqGs68fIPEsHEVg=; b=Jn2m/GimktFTSpednsDTNbokzrKB4VKXFZ3XpAtLyuEKrSgMw1BGa/hpHPY0wzrqH8 mXSc1wm0JIfFF/89OUXRKd+4R+tJ+OOMhFs7TMxlMsjP2+kZfzv6DG8oIvkT7qTXzBA/ GbhPFW4X4Tv+FeFS6Sxq9FzBuFMAUyoZMt3Nuvk9nD7ecOIcFebpDEEJt3K9wgpEzHFS whblhaSf1GUJP42FWVtE7Mf3JXGNzZcl9EltcDCI29O3G2p85vBWG/VIUijo8309MOh0 s9Yy9IP9wLjpJi4B95/G11xybsQ088HElAENBMGRD7MTc9pnUG75jaa+86oISgIT8wzM 9o1A== X-Gm-Message-State: AGi0Pubkk2+EKO3E4LjFeDipxT6AvD0uSxcpJVOaWzOOeYK01I+qeyet kRGMSbdvXuGrHUA1ZdEImGJZ1txMtAv5/uGbV5Y= X-Received: by 2002:a63:d3:: with SMTP id 202mr3124152pga.378.1588323750902; Fri, 01 May 2020 02:02:30 -0700 (PDT) MIME-Version: 1.0 References: <20200430203845.582900-1-ira.weiny@intel.com> <20200501084634.GH27858@infradead.org> In-Reply-To: <20200501084634.GH27858@infradead.org> From: Max Filippov Date: Fri, 1 May 2020 02:02:19 -0700 Message-ID: Subject: Re: xtensa question, was Re: [PATCH V1 00/10] Remove duplicated kmap code To: Christoph Hellwig Cc: ira.weiny@intel.com, LKML , "open list:TENSILICA XTENSA PORT (xtensa)" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Christoph, On Fri, May 1, 2020 at 1:46 AM Christoph Hellwig wrote: > any idea why xtensa uses PAGE_KERNEL_EXEC instead of PAGE_KERNEL > for kmap_prot? Mapping all mapped highmem as executable seems rather > dangerous. I sure do: to allow instruction cache flushing when writing to high user pages temporarily mapped with kmap. Instruction cache management opcodes that operate on virtual addresses would raise an exception if the address is not executable. -- Thanks. -- Max