Hi Steve, When you set a breakpoint with the ice and step through, for each step the ICE set's a breakpoint on the next instruction: e.g.: - modifies next instruction in memory (via CPU !!!) with a breakpoint instruction, - and update the cache so that the breakpoint instruction is really in memory and that i-cache is invalid. (or something like that) So indead you have a cache problem which is explanable solved/disapeared by steppig through with the ICE. Maybe a stupid question from me but why flushing an icache ?: r4k_flush_icache_range regards, Niels > Well I'm hoping it isn't so strange to some of you folks and you'll be > able > to tell what's going on :) > > Here's my problem: > > Using MontaVista Linux 3.1 on a Toshiba RBTx4938 board. Using YAMON, when > I > download the kernel via the debug ethernet port it runs fine. If I > download > the kernel via the Tx4938 inbuilt ethernet controller, it crashes! > > Memory checksumming and a quick manual memory dump inspection reveals that > the kernel download went perfectly ok, and the image is completely and > correctly downloaded to RAM. > > The crash is occuring inside the function r4k_flush_icache_range(). > > I tried 'flush -i' and 'flush -d' on YAMON after the download but before > the > 'go', but that didn't help. I also tried completely disabling caches and > loading/running uncached, but it gave the same error. > > Now, the final twist! Using an ICE, I set a breakpoint at the > r4k_flush_icache_range function. Then I loaded the kernel as usual, ran it > with the ICE, stepped through a few instructions inside the > r4k_flush_icache_range function and then did a 'cont'. The kernel now > booted > fine! > > If I don't set the breakpoint inside that function though, and just try to > run with the ICE the same > error (Inst fetch/Load error) occurs. > > I'm at a loss trying to figure out what's going on. I suspect it has > something to do with caches perhaps (duh!), but have no clue what! > Anybody > out there face a similar kind of a situation before? > > Thanks in advance for any help offered. > > Regards, > -Steve > > _________________________________________________________________ > MSN 9 Dial-up Internet Access helps fight spam and pop-ups ? now 2 months > FREE! http://join.msn.click-url.com/go/onm00200361ave/direct/01/ > > >
