save EFLAGS, and GPA1 auxiliary registers during context switch,
since they may be changed by the new task in kernel mode, while using atomic
ops e.g. cmpxchg.
Signed-off-by: Noam Camus <noamc@ezchip.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
HW bug description: in case of HW thread context switch
the dpc configuration of the exiting thread is dragged
one cycle into the next thread.
In order to avoid the consequences of this bug, the DPC register
is set to an initial value, and not changed afterwards.
Signed-off-by: Elad Kanfi <eladkan@mellanox.com>
Signed-off-by: Noam Camus <noamca@mellanox.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit add new configuration that enables us to distinguish
between building the kernel for platforms that have a different set
of auxiliary registers for each cpu and platforms that have a shared
set of auxiliary registers across every thread in each core.
On platforms that implement a different set of auxiliary registers
disabling this configuration insures that we initialize registers on
every cpu and not just for the first thread of the core.
Example for non shared registers is working with EZsim (non silicon)
Signed-off-by: Liav Rehana <liavr@mellanox.com>
Signed-off-by: Noam Camus <noamca@mellanox.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
We add ability for all cores at NPS SoC to control the number of cycles
HW thread can execute before it is replace with another eligible
HW thread within the same core. The replacement is done by the
HW scheduler.
Signed-off-by: Noam Camus <noamca@mellanox.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
[vgupta: simplified handlign of out of range argument value]
On ARC700 (and nSIM), user mode memory error triggers an L2 interrupt
which is handled gracefully by kernel (or it tries to despite this being
imprecise, and error could get charged to kernel itself). The offending
task is killed and kernel moves on.
NPS hardware however raises a Machine Check exception for same error
which is NOT recoverable by kernel.
This patch aligns kernel handling for nSIM case, to same as hardware by
overriding the default user space bus error handler.
Signed-off-by: Noam Camus <noamca@mellanox.com>
Signed-off-by: Elad Kanfi <eladkan@mellanox.com>
[vgupta: rewrote changelog]
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
When HW threads are active we want CPU to enter idle state only
for the calling HW thread and not to put on sleep all HW threads
sharing this core. For this need the NPS400 got dedicated instruction
so only calling thread is entring sleep and all other are still awake
and can execute instructions.
Signed-off-by: Noam Camus <noamca@mellanox.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
[vgupta: reworked patch to not use inline ifdef but a new function itself]
This counter represents threshold for consecutive stall which
would trigger HW threads scheduling. However when enabled, low
threshhold values cause performance degradation and in the
worst case even livelock.
So disable it by resorting to HW reset value
Signed-off-by: Noam Camus <noamca@mellanox.com>
Reviewed-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
[vgupta: fixed changelog]
A typical SMP system expects cache coherency. Initial NPS platform
support was slated to be SMP w/o cache coherency.
However it seems the platform now selects that option, so there is no
point in keeping it around.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This new header file is for NPS400 SoC (part of ARC architecture).
The header file includes macros for save/restore of HW scheduling.
The control of HW scheduling is achieved by writing core registers.
This code was moved from arc/plat-eznps so it can be used
from drivers/clocksource/, available only for CONFIG_EZNPS_MTM_EXT.
Signed-off-by: Noam Camus <noamca@mellanox.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Today we register to plat_smp_ops.clear() method which actually
is acking the IPI.
However this is already taking care by our irqchip driver specifically
by the irq_chip.irq_eoi() method.
This is perfect timing where it should be done and no special handling
is needed at plat_smp_ops.clear().
Signed-off-by: Noam Camus <noamca@mellanox.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
With generic "identity" num of CPUs is limited to 256 (8 bit).
We use our alternative AUX register GLOBAL_ID (12 bit).
Now we can support up to 4096 CPUs.
Signed-off-by: Noam Camus <noamc@ezchip.com>
