Hi Vincent,
Can we put these page table in CAR or firmware? Or your suggestion?
Have Intel do verification on real X86 hardware with 64-bit PEI?
Thanks
Stanley
-----邮件原件-----
发件人: Zimmer, Vincent [mailto:vincent.zim...@intel.com]
发送时间: 2013年7月24日 7:38
收件人: stanley.ganyezu; 'Andrew Fish'
抄送: edk2-devel@lists.sourceforge.net
主题: RE: [edk2] 答复: switch to 64 bit mode at PEI phase in X86
Yes. You can create ROM'd page tables for a long-mode transition in SEC
prior to invoking a 64-bit PEI core. As implementation guidance, make sure
to set the access/dirty bits in the ROM'd page tables in code source code.
Vincent
-----Original Message-----
From: stanley.ganyezu [mailto:stanley.gany...@gmail.com]
Sent: Tuesday, July 23, 2013 4:11 PM
To: 'Andrew Fish'
Cc: edk2-devel@lists.sourceforge.net
Subject: [edk2] 答复: switch to 64 bit mode at PEI phase in X86
Hi Andrew,
I introduce some background. Our plan is to build a big system with
many sockets.
There are so many sockets that there is no enough MMCFG space below 4Gb. So
we have to put these register at the top of physical space(Ivy bridge
support 46 bit) We need to access these register to initialize memory. It
means we can't postpone to DXE phase.
-----邮件原件-----
发件人: Andrew Fish [mailto:af...@apple.com]
发送时间: 2013年7月24日 0:22
收件人: stanley.ganyezu
抄送: 'Brian J. Johnson'; edk2-devel@lists.sourceforge.net
主题: Re: [edk2] switch to 64 bit mode at PEI phase in X86
Stanley,
The main point of PEI is to turn on memory. Given the complexity of this on
modern PCs there has been a tendency to do "too much" work in PEI. When we
designed SEC/PEI/DXE/BDS we thought that PEI would be smaller and DXE larger
than it turns out today in many systems. So my first answer is do the work
in DXE.
After memory is available in PEI it is possible to enter long mode (this is
what the DXE IPL code does
https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2/MdeModulePkg/Core/D
xeIplPeim/X64/VirtualMemory.c), but this work is already done prior to
jumping into to DXE, so why reinvent the wheel? Just do it in DXE.
Andrew Fish
PS I thought PSE supported 36-bits of physical address, and PAE supports
52-bits. The PAE bit enables an extra level of page tables or some such.
Note 52-bits is what is possible in the page table, but the CPU may not
support that much physical address space.
On Jul 23, 2013, at 5:52 AM, "stanley.ganyezu" <stanley.gany...@gmail.com>
wrote:
> Hi Andrew,
> You're right. Itanium have 64-bit PEI. Actually, I need to access
the
> MMIOH space between 32T~64T.
> But PAE can only support up to 64GB. If only PAE enabled, it still can
> not solve my problem. Do Intel ever think about this limitation?
> Is there any Intel guys to give some help?
>
>
> -----邮件原件-----
> 发件人: Andrew Fish [mailto:af...@apple.com]
> 发送时间: 2013年7月23日 8:44
> 收件人: stanley.ganyezu
> 抄送: 'Brian J. Johnson'; edk2-devel@lists.sourceforge.net
> 主题: Re: [edk2] switch to 64 bit mode at PEI phase in X86
>
>
> On Jul 22, 2013, at 5:38 PM, "stanley.ganyezu"
> <stanley.gany...@gmail.com>
> wrote:
>
>> Thanks for Andrew and Brian. Do somebody ever succeed before?
>>
>
> It works fine in an emulator or VM, but if you run on real hardware
without
> memory (at least t he ones I tried) the processor crashes if the page
tables
> are in FLASH or CAR.
>
> For Itanium and Aarch64 it is possible to have a 64-bit PEI, so most
> of
the
> generic code is 64-bit clean.
>
> Thanks,
>
> Andrew Fish
>
>> -----邮件原件-----
>> 发件人: Andrew Fish [mailto:af...@apple.com]
>> 发送时间: 2013年7月23日 7:36
>> 收件人: Brian J. Johnson
>> 抄送: stanley.ganyezu; edk2-devel@lists.sourceforge.net
>> 主题: Re: [edk2] switch to 64 bit mode at PEI phase in X86
>>
>> Most of the X64 (x86_64) processors I know about crash and die hard
>> if
you
>> place page tables in the Cache as RAM or the FLASH. That is why you
>> see
> IA32
>> PEI and X64 DXE on this class of systems.
>>
>> It is possible to use PAE in IA32 mode to access memory above 4 GB,
>> http://en.wikipedia.org/wiki/Physical_Address_Extension
>>
>> Thanks,
>>
>> Andrew Fish
>>
>>
>> On Jul 22, 2013, at 3:16 PM, "Brian J. Johnson" <bjohn...@sgi.com> wrote:
>>
>>> On 07/22/2013 08:55 AM, stanley.ganyezu wrote:
>>>> Hi Everyone,
>>>>
>>>> I want to access address above 4Gb at PEI phase in X86. Can
>>>> we switch to 64 bit mode before MRC?
>>>
>>> I wouldn't call myself a real expert on X86 addressing modes, but
>>> here are some thoughts:
>>>
>>> AFAIK the PEI core and common modules work just fine in 64-bit mode.
>>> So
>>> that's good.
>>>
>>> If you don't have RAM available, i.e. if you're running on real
>>> hardware
>>> as opposed to a virtual machine or emulator, switching to 64-bit
>>> mode may be difficult. Running C code before RAM is initialized
>>> requires putting the CPU in cache-as-RAM mode, where it uses the CPU
>>> caches as a small amount of RAM. I'm not sure if it's possible to
>>> use cache-as-RAM in 64-bit mode... you'd need to read the CPU
>>> manufacturer's docs pretty carefully to find out. (I've never seen
>>> it done, but that doesn't necessarily mean it's impossible... SMM
>>> was never run in 64-bit mode in the past, and I was told it was
>>> impossible, but now it's done
regularly.)
>>>
>>> A big "gotcha" for 64-bit mode is that it requires writable page
>>> tables,
>>> which requires generating the required tables in your cache-as-RAM
>>> in 32-bit mode (which uses several 4k pages of space, unless you're
>>> really clever about repurposing the unused table entries for other
>>> data) or implementing a TLB miss handler. If you can map all
>>> addresses with gigabyte-sized pages, and especially if you don't
>>> need to access the entire address space before MRC, the tables
>>> shouldn't take that much space. If you try to map a 2^46 address
>>> space with 4k pages, your tables will never fit in cache-as-RAM....
>>>
>>> You may need to switch back to 32-bit mode to exit cache-as-RAM...
>>> not sure just what that dance would look like. It would probably
>>> take some experimentation.
>>>
>>> There may be other issues I haven't thought of. Good luck!
>>> --
>>>
>>> Brian J. Johnson
>>>
>>> --------------------------------------------------------------------
>>>
>>> "If you want your dreams to come true: Wake Up!"
>>> -- Jaime Roman's Radio
>>>
>>>
>>
>
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