Known problems with dcache?

[Andrew Cagney]

Hello,

In a recent discussion there was mention made of dcache.  How, when 
enabled, it could make things?  Are there any more details.

The only problem I know with dcache is with the way it turns a single 
byte read into a 32 byte read.  I think it should instead behave like a 
register fetch:

- request exactly the specified amount

- allow the target to supply additional data

ex: ask for a byte, get back a page.

I even think that, with that fix, the dcache could be enabled by default 
- it couldn't accidently do things like read beyond the end of memory 
and in the process trash something for instance.

Andrew

PS: Thinking about it, given ptrace's 4 byte straw, 32 bytes ~= 8 ptrace 
calls and that could be enough to make a difference?