Re: BUG: Kernel Panic: kernel-2.6.0-test9-bk21 for alpha in scsi context ll_rw_blk.c

[Thomas Steudten <alpha@steudten.com>]

On http://steudten.com/alpha/perf.php4 you can read:
See prefetch section:
The Alpha 21264 initiates a prefetch operation by executing one of the load 
instructions as summarized in the table below. Note that the destination 
register is R31 or F31. When used as a source register, R31 and F31 return 
integer zero and floating point zero, respectively. When used as a 
destination register as shown below, R31 and F31 denote the purpose of 
these instructions as a prefetch operation. Earlier Alpha implementations 
ignore these instructions. Some care must be taken as a prefetch with an 
invalid address must be dismissed by firmware and a prefetch can cause an 
alignment trap.

Tom


Falk Hueffner wrote:

> Thomas Steudten <alpha@steudten.com> writes:
> 
> 
>>-> 0xfffffc0000476cb8 <__make_request+152>:        lds     $f31,0(t2)
> 
> 
> The kernel is stupid, this is a prefetch, it should be totally ignored
> if it is faulty. This is already handled for userspace accesses
> IIRC... (I wonder why the PALcode doesn't already do that. Oh well.)
> 

-- 
Tom

LINUX user since kernel 0.99.x 1994.
RPM Alpha packages at http://alpha.steudten.com/packages
Want to know what S.u.S.E 1995 cdrom-set contains?