Hi Ayan,
On 03/05/2023 17:49, Ayan Kumar Halder wrote:
On 03/05/2023 08:40, Julien Grall wrote:
Hi,
Hi Julien,
Title: Did you mean "Enable spin table"?
Yes, that would be more concrete.
On 02/05/2023 11:58, Ayan Kumar Halder wrote:
On some of the Arm32 based systems (eg Cortex-R52), smpboot is
supported.
Same here.
Yes
In these systems PSCI may not always be supported. In case of
Cortex-R52, there
is no EL3 or secure mode. Thus, PSCI is not supported as it requires
EL3.
Thus, we use 'spin-table' mechanism to boot the secondary cpus. The
primary
cpu provides the startup address of the secondary cores. This address is
provided using the 'cpu-release-addr' property.
To support smpboot, we have copied the code from
xen/arch/arm/arm64/smpboot.c
I would rather prefer if we don't duplicate the code but instead move
the logic in common code.
Ack
with the following changes :-
1. 'enable-method' is an optional property. Refer to the comment in
https://www.kernel.org/doc/Documentation/devicetree/bindings/arm/cpus.yaml
" # On ARM 32-bit systems this property is optional"
Looking at this list, "spin-table" doesn't seem to be supported
for 32-bit systems.
However, looking at
https://developer.arm.com/documentation/den0013/d/Multi-core-processors/Booting-SMP-systems/SMP-boot-in-Linux , it seems "spin-table" is a valid boot mechanism for Armv7 cpus.
I am not able to find the associated code in Linux 32-bit. Do you have
any pointer?
Can you point me to the discussion/patch where this would be added?
Actually, this is the first discussion I am having with regards to
adding a "spin-table" support on Arm32.
I was asking for the discussion on the Device-Tree/Linux ML or code.
I don't really want to do a "spin-table" support if this is not even
supported in Linux.
Cheers,
--
Julien Grall
