From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-in6.apple.com (mail-out6.apple.com [17.151.62.28]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id D4A931A1F32 for ; Thu, 22 Sep 2016 08:34:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; d=apple.com; s=mailout2048s; c=relaxed/simple; q=dns/txt; i=@apple.com; t=1474558446; x=2338472046; h=From:Sender:Reply-To:Subject:Date:Message-id:To:Cc:MIME-version:Content-type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-reply-to:References:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=YH0tEWoeMa8uYjqFkwm/NXImy9/NJkeuAo/vSeDy9a8=; b=d3NNOgh7O9CyzkXuEt6AHKM5JqTIdrRW15oB7bJ69l3l4ycKlQUO5LOTx2oOMgIB nSa8ZU3oRwpr3wHwD/ZATko4vc0vaiSchV3ACGsPK20oUd9FQS7HtyXBXhgseeOV v/Y+AMhtSwR508o/9CjeEPI4d2k6FXuDBkXpiMTk7A/ZiWutDiRUDV+paV/7SXql QgTMy+JWIqrQH8j+OCLbKyTys5f2hS8ihPBXOs3Gl0z9jgMZG6KfxcOzgIZrAXlg cpf06MKXtxcimIEAzXs1W1PSqLa6bRPABecRNdruowZ0i0mTxv+C2VF1YtVxPMZS JZiQQfmwGs72O6RR7r3Gnw==; Received: from relay6.apple.com (relay6.apple.com [17.128.113.90]) by mail-in6.apple.com (Apple Secure Mail Relay) with SMTP id 77.D7.07752.EE9F3E75; Thu, 22 Sep 2016 08:34:06 -0700 (PDT) X-AuditID: 11973e15-f798f6d000001e48-91-57e3f9eec671 Received: from chive.apple.com (chive.apple.com [17.128.115.15]) by relay6.apple.com (Apple SCV relay) with SMTP id C4.A6.23613.EE9F3E75; Thu, 22 Sep 2016 08:34:06 -0700 (PDT) MIME-version: 1.0 Received: from [17.153.85.100] by chive.apple.com (Oracle Communications Messaging Server 8.0.1.1.0 64bit (built May 17 2016)) with ESMTPSA id <0ODW00CXXWKSUY60@chive.apple.com>; Thu, 22 Sep 2016 08:34:06 -0700 (PDT) Sender: afish@apple.com From: Andrew Fish Message-id: <5A6D70A5-3A7C-417E-87D0-58F9E478ED21@apple.com> Date: Thu, 22 Sep 2016 08:34:05 -0700 In-reply-to: Cc: valerij zaporogeci , edk2-devel To: Ard Biesheuvel References: X-Mailer: Apple Mail (2.3226) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrGLMWRmVeSWpSXmKPExsUi2FAYpfvu5+NwgwvrxS3+f9jNaLHn0FFm i8f/2pkdmD12zrrL7nHn2h42j+7Z/1gCmKO4bFJSczLLUov07RK4MjrmP2Qr2BNbsf3AB5YG xtuBXYycHBICJhJzT09igrDFJC7cW8/WxcjFISSwl1Hi3q7FLDBF/9s6oBIbGSWe757EBpLg FRCU+DH5HlgRs0CYxM7/rcwQRfcYJU7snguWEBYQl3h3ZhMziM0moCyxYv4HdohmG4k3j7oZ uxg5gGqsJSZPVgUxWQRUJa5tyAExOQWCJZauiYOYHiKx8NgudpCwiICeREuXGcSimYwS6zdM BYtLCMhKzP7lBRKXELjNJvHqQyf7BEbhWUgOnYXkUAhbS+L7o1agOAeQLS9x8LwsRFhT4tm9 T+wQtrbEk3cXWBcwsq1iFMpNzMzRzcwz00ssKMhJ1UvOz93ECIqY6XaiOxjPrLI6xCjAwajE w/vg8eNwIdbEsuLK3EOM0hwsSuK8ud+AQgLpiSWp2ampBalF8UWlOanFhxiZODilGhhvbl66 6Re7tomLiOscnq/ij5MjatZlHA/+9C9NrvZNsOqt4Ng1SpfFjCdqS1ut4Hsv19u/mqeSM/f1 xp4yBuUXalMljXw8HmuJ1DG/W5Jau/nFLM69YTEsk0OXMPhc/HdE+sgT0+31H7Qjrf5Wr90r JB7NFffl75eMm5dfSas4a7NVHXe+cVuJpTgj0VCLuag4EQB9/mISeQIAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrAIsWRmVeSWpSXmKPExsUi2FDMr/vu5+Nwg+7zwhb/P+xmtNhz6Ciz xeN/7cwOzB47Z91l97hzbQ+bR/fsfywBzFFcNimpOZllqUX6dglcGR3zH7IV7Imt2H7gA0sD 4+3ALkZODgkBE4n/bR1sELaYxIV764FsLg4hgY2MEs93TwJL8AoISvyYfI8FxGYWCJPY+b+V GaLoHqPEid1zwRLCAuIS785sYgax2QSUJVbM/8AO0Wwj8eZRN2MXIwdQjbXE5MmqICaLgKrE tQ05ICanQLDE0jVxENNDJBYe28UOEhYR0JNo6TKDWDSTUWL9hqlgcQkBWYnZv7wmMArMQnLb LCS3QdhaEt8ftQLFOYBseYmD52UhwpoSz+59YoewtSWevLvAuoCRbRWjQFFqTmKlmV5iQUFO ql5yfu4mRnCAF0btYGxYbnWIUYCDUYmH98Hjx+FCrIllxZW5hxglOJiVRHhXfgMK8aYkVlal FuXHF5XmpBYfYpzICPThRGYp0eR8YPzllcQbmpgYmBgbmxkbm5uY01JYSZx3He+DcCGB9MSS 1OzU1ILUIpijmDg4pRoYp969OFUgXfp2+VH2gOqp91OmvHr8qDP/1Oae4vYrvUcetUy9897e tEX7+jqR3ZbHTTclMb7MS1jtf8lhyY+wPZMO8NaeW1YdUWspVf398oQoQxul0HeT/y5JXlnG 5eXjuVowa4ndwvqpfuZqR5cdjk6P/d/Ypd+zXKYr83fPtHLegoUdXHt1lFiKMxINtZiLihMB HpbZ/OMCAAA= X-Content-Filtered-By: Mailman/MimeDel 2.1.21 Subject: Re: flat mapping vs identity mapping on ARM X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 22 Sep 2016 15:34:07 -0000 Content-Type: text/plain; CHARSET=US-ASCII Content-Transfer-Encoding: 7BIT > On Sep 22, 2016, at 8:03 AM, Ard Biesheuvel wrote: > > On 22 September 2016 at 15:30, valerij zaporogeci > wrote: >> In the ARM architecture, there is such a thing - "flat mapping", where >> MMU stage 1 is disabled and the mapping done is 1:1 and attributes set >> to the predefined values. > > What do you mean by 'attributes set to the predefined values' ? > >> Did I understand right, that this is NOT what UEFI means by "identity >> mapping" with MMU enabled? Identity mapping means the virtual address is the same as the physical address. For x86 IA64 (x86_64) you have to have paging enabled to enter long (64-bit) mode (the processor comes out of reset in 16-bit mode). For ARM you need the MMU to control cacheability. For IA32 (i386) paging is not enabled and MTRR registers are used to control cacheability. For Itainium Processors paging is not enabled and bit 63 is used to disable cacheability. Thanks, Andrew Fish >> And in the latter case there is need to >> create all those page tables and stuff, setting 1:1 mapping between VA >> and PA? If so, why to do that? Why "flat mapping" isn't what UEFI >> would love to see as its mapping regime? > > On ARM, you need to enable the MMU in order to enable the Dcache. > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel