On 1/13/09, Jakub Jermar jakub@jermar.eu wrote:
Blue Swirl wrote:
On 1/12/09, Jakub Jermar jakub@jermar.eu wrote:
Hi,
when I make the following change to helper.c, get_physical_address_code:
// ctx match, vaddr match?
// ctx match, vaddr match, valid? if (env->dmmuregs[1] == (env->itlb_tag[i] & 0x1fff) &&
(address & mask) == (env->itlb_tag[i] & ~0x1fffULL)) {// valid, access ok?if ((env->itlb_tte[i] & 0x8000000000000000ULL) == 0 ||((env->itlb_tte[i] & 0x4) && is_user)) {
(address & mask) == (env->itlb_tag[i] & ~0x1fffULL) &&env->itlb_tte[i] & 0x8000000000000000ULL) {// access ok?if ((env->itlb_tte[i] & 0x4) && is_user) {HelenOS gets a little bit further than without this change and seems to panic more or less gracefully later.
In short, non-valid entries should be skipped by the loop in get_physical_address_code instead of causing TFAULT, because the ITLB can contain a valid entry for the same address. The same is true for DTLB.
Can you confirm this?
Yes, this looks correct. I'll apply a fix.
Thanks!
With this fix in place, HelenOS most of the time panics on:
Kernel panic: Cannot find property 'screen'.
I.e. it searches property 'screen' in /aliases and doesn't find any. If it is not there already, could you please add it (together with keyboard) to openbios?
Recent OpenBIOS (including the version in Qemu) should have both "screen" and "keyboard" aliases. In /chosen there is "display" (?) and "keyboard".