答复: 答复: 答复: Cache On and ECC clear

[YhLu]

Eric,

After change the FALLBACK_SIZE from 96k to 128k. it works. And 64k as
XIP_ROM_SIZE it works.

Regards

YH

-----邮件原件-----
发件人: [e-mail] [mailto:[e-mail]] 
发送时间: 2004年3月29日 22:50
收件人: YhLu
抄送: ron minnich; Li-Ta Lo; LinuxBIOS
主题: Re: 答复: 答复: Cache On and ECC clear

YhLu  writes:
> Eric,
>
> It seems it's all right in mtrr setting. Except 0x201 and 0x203 setting in
> earlymtrr.inc should set 0xff for msr.hi intead of 0xf
>
> Before mtrr processing for clearing

Hmm.  Assuming 0000 == 0x200, 0001 == 0x201 etc.  So
you have to base and mask pairs.
> Normal mode
> 0000=0x0000000000000006
> 0001=0x000000fffff00800
> 0002=0x00000000fffe8006

This is a base address 4GB - 96K
> 0003=0x000000fffffe8800

This is a size and it tries to be 96K.
  It is actually something like 32K.
> Fallback mode
> 0000=0x0000000000000006
> 0001=0x000000fffff00800
> 0002=0x00000000fffd0006

This is a base address 4GB - 160K
> 0003=0x000000fffffe8800

This is a size aand it tries to be 96K.
  It is actually something like 32K.

So somehow you got at non power of 2 size into XIP_ROM_SIZE.  So much less
of your code is cached than you would expect.  So instruction fetches take
a very long time.  And loops are slow.

The comments from my HDAMA Config.lb 
## XIP_ROM_SIZE must be a power of 2.
## XIP_ROM_BASE must be a multiple of XIP_ROM_SIZE

It looks like these needs to be enforced, somehow so build time mistakes
don't happen. Perhaps:
#if ((XIP_ROM_BASE % XIP_ROM_SIZE) != 0) || ((XIP_ROM_SIZE & (XIP_ROM_SIZE -
1)) != 0)
#error XIP_ROM_SIZE must be a power of 2 and XIP_ROM_BASE must be a multiple
of it
#endif

Eric