From mboxrd@z Thu Jan 1 00:00:00 1970 From: hacklu Date: Wed, 22 Jun 2011 15:02:33 +0800 Subject: [U-Boot] how to understand "uboot is 32bit program even it isin the 64bit mips" References: <201106221006548156815@gmail.com> Message-ID: <201106221502272672042@gmail.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de thanks for you answer. I have got too much. On 2011-06-22 13:25:34, Aaron Williams wrote: >We have dealt with this in our release of U-Boot since we only support >64-bit Linux. We use the n32 ABI with U-Boot and set it up to use a TLB >entry to map U-Boot into a 32-bit addressable area. in the U-boot _shell_. I use md command. I found md 0x100000 and mx0x800100000 are the same. is that says:the virtual address 0x0 - 0xfffffff(256M, can I called this _kusg_ segment ?) are mapped to the _physical_ memory address 0x0 - 0xfffffff(256M) with the _TLB_. and the virtual address 0x80000000 - 0x8fffffff(like that, _kseg0_ ?) is mapped to the _physical_ memory address 0x0 - 0xfffffff(256M) according to the mips arch feature. do I understand correctly? >We have some special memcpy type routines that can handle the 64-bit >addressing. >All of our I/O registers require 64-bit addressing so we use assembly >wrappers to do the actual read/writes to those addresses. >-Aaron Williams >On 06/21/2011 07:07 PM, hacklu wrote: >> I have a 64bit cnMips borad.In the mail list archives,it says "uboot is 32bit,even in the 64bit cpu." >> but how to understand that? >> I have a guess,is the 64bit cpu support a 32bit-mode,then when does it switch to 64bit-mode to load 64-bit linux? >> >> btw,I have an other question,according to ,linux run in the _xkseg_ segment. so the first two bit >>virtual address in kernel space must be 11, >> like 11xx xxxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx (64bit). >> but when I printf a variable' address in a foo driver,is say 0xa80000041c2ea180. not start of _11_. >> the memory mapping mode has feazed me for _long_ _long_time. I hope you can answer this question for me. I really really want to know this. thans for your attention. >> Dear Wolfgang(or someone else who can anwser me),thanks >> >>-------------- >> hacklu >>2011-06-22 >> _______________________________________________ U-Boot mailing list U-Boot at lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot ------------------ hacklu 2011-06-22