* return `switched to same process' only if that process was actually
already on a run queue when we entered.
* skip the switch to the idle stack if we can switch immediately
* .. and because of this, don't release the scheduler lock until after
we've fully switched to the new process's stack.
> Module Name: src
> Committed By: augustss
> Date: Sun Jan 12 23:46:12 UTC 2003
>
> Modified Files:
> src/sys/arch/pmppc/pmppc: bus_space.c
>
>Log Message:
>The bus_space_mmap() returns a physaddr, not a page, on the PPC.
>(This is broken in some (all?) of the PPC ports, it seems.)
XXX scsipi mid layer spews out a few "generic HBA error"s during device probe (no slave device on bus), I don't know how to fix this
XXX This whole thing should die now that we have wdc_amiga
after the other CPUs have already return into the PROM through prom_cpustop().
So don't do it; try to halt the other CPUs only when an actual `halt'
is requested.
My guess in this case is that the PROM does not expect its original boot
CPU to call prom_cpustop(0), or possibly treats it as the equivalent of
a prom_halt() which is then called again by some other CPU. In any case,
the result is garbage.
While the pmap functions take care of properly ordering cache and TLB flushes,
not all TLB flush requests are sent to all CPUs (due to per CPU pmap tracking)
while cache flushes are always broadcast.
XXX: need to investigate pmap tracking for cache flush operation as well.
- in tlb_flush_all(), don't skip TLB entries with the high bit on,
I was confused about which MMU register it was using. it's also fine
to use the last hardware context.
- in pmap_create(), don't allocate a hardware context for the new pmap.
it's unnecessary, and when this would cause us to recycle all the contexts,
it would result in the current process's context being set to 0
(ie. the kernel's context). the current process could then return to
userspace without going through the context-switch code (and thus without
having a hardware context reallocated). this would lead to user mappings
being entered in the kernel's context later, causing all sorts of trouble.
add some assertions to catch this kind of thing.
