Currently we do a spin on secondary cpus when waiting to boot. This
theoretically causes issues with power consumption and does cause issues
with qemu cycle burning (it starves cpu 0 from actually being able to
boot.)
This change puts each secondary cpu to sleep if they have a power
management unit, then signals them to wake via IPI when its time to boot.
If the cpus have no power management unit they will loop as before.
Note: The wakeup IPI requires a special interrupt handler as on secondary
cpu's the interrupt infrastructure is not yet established. This
interrupt handler is set and reset by updating SPR_EVBAR.
Signed-off-by: Stafford Horne <shorne@gmail.com>
This patch introduces the SMP support for the OpenRISC architecture.
The SMP architecture requires cores which have multi-core features which
have been introduced a few years back including:
- New SPRS SPR_COREID SPR_NUMCORES
- Shadow SPRs
- Atomic Instructions
- Cache Coherency
- A wired in IPI controller
This patch adds all of the SMP specific changes to core infrastructure,
it looks big but it needs to go all together as its hard to split this
one up.
Boot loader spinning of second cpu is not supported yet, it's assumed
that Linux is booted straight after cpu reset.
The bulk of these changes are trivial changes to refactor to use per cpu
data structures throughout. The addition of the smp.c and changes in
time.c are the changes. Some specific notes:
MM changes
----------
The reason why this is created as an array, and not with DEFINE_PER_CPU
is that doing it this way, we'll save a load in the tlb-miss handler
(the load from __per_cpu_offset).
TLB Flush
---------
The SMP implementation of flush_tlb_* works by sending out a
function-call IPI to all the non-local cpus by using the generic
on_each_cpu() function.
Currently, all flush_tlb_* functions will result in a flush_tlb_all(),
which has always been the behaviour in the UP case.
CPU INFO
--------
This creates a per cpu cpuinfo struct and fills it out accordingly for
each activated cpu. show_cpuinfo is also updated to reflect new version
information in later versions of the spec.
SMP API
-------
This imitates the arm64 implementation by having a smp_cross_call
callback that can be set by set_smp_cross_call to initiate an IPI and a
handle_IPI function that is expected to be called from an IPI irqchip
driver.
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
[shorne@gmail.com: added cpu stop, checkpatch fixes, wrote commit message]
Signed-off-by: Stafford Horne <shorne@gmail.com>
Previously, the area between 0x0-0x100 have been used as a "scratch"
memory area to temporarily store regs during exception entry. In a
multi-core environment, this will not work.
This change is to use shadow registers for nested context.
Currently only the "critical" temp load/stores are covered, the
EMERGENCY_PRINT ones are left as is (when they are used, it's game over
anyway), they need to be handled as well in the future.
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Signed-off-by: Stafford Horne <shorne@gmail.com>
Fix typos and add the following to the scripts/spelling.txt:
aligment||alignment
I did not touch the "N_BYTE_ALIGMENT" macro in
drivers/net/wireless/realtek/rtlwifi/wifi.h to avoid unpredictable
impact.
I fixed "_aligment_handler" in arch/openrisc/kernel/entry.S because
it is surrounded by #if 0 ... #endif. It is surely safe and I
confirmed "_alignment_handler" is correct.
I also fixed the "controler" I found in the same hunk in
arch/openrisc/kernel/head.S.
Link: http://lkml.kernel.org/r/1481573103-11329-8-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Originally openrisc spec 0 specified that r0 would be wired to ground.
This is no longer the case. r0 is not guaranteed to be 0 at init, so we
need to initialize it to 0 before using it.
Also, if we are clearing r0 we cant use r0 to clear itself. Change the
the CLEAR_GPR macro to use movhi for clearing.
Reported-by: Jakob Viketoft <jakob.viketoft@aacmicrotec.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>
These string definitions are no longer used removed them. Noticed this
while working on a CONFIG_DEBUG_INFO build issue.
Signed-off-by: Stafford Horne <shorne@gmail.com>
The strings used during the head/init phase of openrisc bootup were
stored in the executable section of the binary.
This causes compilation to fail when using CONFIG_DEBUG_INFO with
error:
Error: unaligned opcodes detected in executable segment
Signed-off-by: Stafford Horne <shorne@gmail.com>
This brings it inline with the other setup oprations done like the cache
enables _ic_enable and _dc_enable. Also, this is going to make it
easier to initialize additional cpu's when smp is introduced.
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
[shorne@gmail.com: Added commit body]
Signed-off-by: Stafford Horne <shorne@gmail.com>
The stack size was hard coded to 0x2000, use the standard THREAD_SIZE
definition loaded from thread_info.h.
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
[shorne@gmail.com: Added body to the commit message]
Signed-off-by: Stafford Horne <shorne@gmail.com>
By slightly reorganizing the code, the number of registers
used in the tlb miss handlers can be reduced by two,
thus removing the need to save them to memory.
Also, some dead and commented out code is removed.
No functional change.
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Stafford Horne <shorne@gmail.com>
Prevents build issue with updated toolchain
Reported-by: Jack Thomasson <jkt@moonlitsw.com>
Tested-by: Christian Svensson <blue@cmd.nu>
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Signed-off-by: Jonas Bonn <jonas@southpole.se>
vmalloc'ed pages are faulted into a process' page tables on demand. In
order to facilitate this, do_page_fault needs to know whether it was
called via a page fault exception or a TLB-miss exception.
This patch adds a wrapper around the _x_page_fault_handler entry points
that the TLB-miss exceptions can call into in order to have the relevant
parameter set to satisfy do_page_fault.
This fixes a bug and is "good enough" for now. That said, this whole
handling of vmalloc needs to be audited for correctness at some point.
Signed-off-by: Jonas Bonn <jonas@southpole.se>
The kernel might be invoked through the reset vector, so to
preserve parameters passed to it, temp regs that are not
in the function parameter range needs to be used.
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Signed-off-by: Jonas Bonn <jonas@southpole.se>
This patch enables passing a fdt pointer to the kernel.
This makes for the kernel parameter API:
void kernel(unsigned int fdt);
which, in accordance with the OpenRISC ABI results in:
r3 = pointer to fdt
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Architecture code and early setup routines for booting Linux.
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Stafford Horne