Only adding cpus is supports at the moment, removal
will come next.
When new cpus are configured, the machine description is
updated. When we get the configure request we pass in a
cpu mask of to-be-added cpus to the mdesc CPU node parser
so it only fetches information for those cpus. That code
also proceeds to update the SMT/multi-core scheduling bitmaps.
cpu_up() does all the work and we return the status back
over the DS channel.
CPUs via dr-cpu need to be booted straight out of the
hypervisor, and this requires:
1) A new trampoline mechanism. CPUs are booted straight
out of the hypervisor with MMU disabled and running in
physical addresses with no mappings installed in the TLB.
The new hvtramp.S code sets up the critical cpu state,
installs the locked TLB mappings for the kernel, and
turns the MMU on. It then proceeds to follow the logic
of the existing trampoline.S SMP cpu bringup code.
2) All calls into OBP have to be disallowed when domaining
is enabled. Since cpus boot straight into the kernel from
the hypervisor, OBP has no state about that cpu and therefore
cannot handle being invoked on that cpu.
Luckily it's only a handful of interfaces which can be called
after the OBP device tree is obtained. For example, rebooting,
halting, powering-off, and setting options node variables.
CPU removal support will require some infrastructure changes
here. Namely we'll have to process the requests via a true
kernel thread instead of in a workqueue. workqueues run on
a per-cpu thread, but when unconfiguring we might need to
force the thread to execute on another cpu if the current cpu
is the one being removed. Removal of a cpu also causes the kernel
to destroy that cpu's workqueue running thread.
Another issue on removal is that we may have interrupts still
pointing to the cpu-to-be-removed. So new code will be needed
to walk the active INO list and retarget those cpus as-needed.
Signed-off-by: David S. Miller <davem@davemloft.net>
There is a special domain services capability for setting
variables in the OBP options node. Guests don't have permanent
store for the OBP variables like a normal system, so they are
instead maintained in the LDOM control node or in the SC.
Signed-off-by: David S. Miller <davem@davemloft.net>
Report 'sun4v' when appropriate in /proc/cpuinfo
Remove all the verifications of the OBP version string. Just
make sure it's there, and report it raw in the bootup logs and
via /proc/cpuinfo.
Signed-off-by: David S. Miller <davem@davemloft.net>
They were getting truncated to 32-bit and this is very bad
when your MMU fault status area is in physical memory above
4GB on SUN4V.
Signed-off-by: David S. Miller <davem@davemloft.net>
Use prom_startcpu_cpuid() on SUN4V instead of prom_startcpu().
We should really test for "SUNW,start-cpu-by-cpuid" presence
and use it if present even on SUN4U.
Signed-off-by: David S. Miller <davem@davemloft.net>
This is where the virtual address of the fault status
area belongs.
To set it up we don't make a hypervisor call, instead
we call OBP's SUNW,set-trap-table with the real address
of the fault status area as the second argument. And
right before that call we write the virtual address into
ASI_SCRATCHPAD vaddr 0x0.
Signed-off-by: David S. Miller <davem@davemloft.net>
Doing a "SUNW,stop-self" firmware call on the other cpus is not the
correct thing to do when dropping into the firmware for a halt,
reboot, or power-off.
For now, just do nothing to quiet the other cpus, as the system should
be quiescent enough. Later we may decide to implement smp_send_stop()
like the other SMP platforms do.
Based upon a report from Christopher Zimmermann.
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of all of this cpu-specific code to remap the kernel
to the correct location, use portable firmware calls to do
this instead.
What we do now is the following in position independant
assembler:
chosen_node = prom_finddevice("/chosen");
prom_mmu_ihandle_cache = prom_getint(chosen_node, "mmu");
vaddr = 4MB_ALIGN(current_text_addr());
prom_translate(vaddr, &paddr_high, &paddr_low, &mode);
prom_boot_mapping_mode = mode;
prom_boot_mapping_phys_high = paddr_high;
prom_boot_mapping_phys_low = paddr_low;
prom_map(-1, 8 * 1024 * 1024, KERNBASE, paddr_low);
and that replaces the massive amount of by-hand TLB probing and
programming we used to do here.
The new code should also handle properly the case where the kernel
is mapped at the correct address already (think: future kexec
support).
Consequently, the bulk of remap_kernel() dies as does the entirety
of arch/sparc64/prom/map.S
We try to share some strings in the PROM library with the ones used
at bootup, and while we're here mark input strings to oplib.h routines
with "const" when appropriate.
There are many more simplifications now possible. For one thing, we
can consolidate the two copies we now have of a lot of cpu setup code
sitting in head.S and trampoline.S.
This is a significant step towards CONFIG_DEBUG_PAGEALLOC support.
Signed-off-by: David S. Miller <davem@davemloft.net>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
David S. Miller