with a more generic "devmap" structure that can also handle mappings
made with large and small pages. Add new pmap routines to enter these
mappings during bootstrap (and "remember" the devmap), and routines to
look up the static mappings once the kernel is running.
Also in the ARM32_PMAP_NEW case, reclaim the USPACE-bytes of wasted space
at the top of the user address that hasn't been needed for a very very
long time.
add rd, pc, #foo - . - 8 -> adr rd, foo
ldr rd, [pc, #foo - . - 8] -> ldr rd, foo
Also, when saving the return address for a function pointer call, use
"mov lr, pc" just before the call unless the return address is somewhere
other than just after the call site.
Finally, a few obvious little micro-optimisations like using LDR directly
rather than ADR followed by LDR, and loading directly into PC rather than
bouncing via R0.
attached to "obio") on the IQ80310 and IQ80321. It makes more sense
to do it this way for this type of system (the goal being to encapsulate
as much information about the board as possible into one file).
to do uncached memory access during VM operations (which can be
quite expensive on some CPUs).
We currently write-back PTEs as soon as they're modified; there is
some room for optimization (to write them back in larger chunks).
For PTEs in the APTE space (i.e. PTEs for pmaps that describe another
process's address space), PTEs must also be evicted from the cache
complete (PTEs in PTE space will be evicted durint a context switch).
counters. These counters do not exist on all CPUs, but where they
do exist, can be used for counting events such as dcache misses that
would otherwise be difficult or impossible to instrument by code
inspection or hardware simulation.
pmc(9) is meant to be a general interface. Initially, the Intel XScale
counters are the only ones supported.
into platform-specific initialization code, giving platform-specific
code control over which free list a given chunk of memory gets put
onto.
Changes are essentially mechanical. Test compiled for all ARM
platforms, test booted on Intel IQ80321 and Shark.
Discussed some time ago on port-arm.
thorpej