[U-Boot] [sunxi/sun7i] ARMv7 SVC mode: PSCI not loaded and only 1st CPU core gets activated

[U.Mutlu]

Hi,

when building u-boot for ARMv7 with these settings
for SVC mode (ie. "Secure Mode"), instead of HYPervisor mode:

      ARM architecture  --->
  ...
  [*] Enable support for booting in non-secure mode
  [*]   Boot in secure mode by default
  [ ]   Enable support for hardware virtualization
  [*]   Enable PSCI support
  (2)   Maximum supported CPUs for PSCI
  [ ] Use LPAE page table format
  ...

then only the first CPU core gets activated.

How to bring the other core(s) online?


I tried this from https://www.kernel.org/doc/html/v5.0/core-api/cpu_hotplug.html :

# echo 1 > /sys/devices/system/cpu/cpu1/online
bash: /sys/devices/system/cpu/cpu1/online: Permission denied

(actually there is no "online" entry under cpu1, but also not under cpu0.
Attached is the tree under /sys/devices/system/cpu/ )


#
# Automatically generated file; DO NOT EDIT.
# U-Boot 2019.04-rc4 Configuration
...
CONFIG_SYS_ARCH="arm"
CONFIG_SYS_CPU="armv7"
CONFIG_SYS_SOC="sunxi"
CONFIG_SYS_BOARD="sunxi"
CONFIG_SYS_CONFIG_NAME="sun7i"
...
CONFIG_DEFAULT_DEVICE_TREE="sun7i-a20-lamobo-r1"
...


# uname -a
Linux r1-3 5.0.5 #1 SMP Sat Mar 30 05:34:40 CET 2019 armv7l GNU/Linux

kernel conf has CONFIG_HOTPLUG_CPU=y


# dmesg | grep -i "smp\|psci\|started in"
[    0.000000] Linux version 5.0.5 (u-ps at c22-local) (gcc version 9.0.1 
20190326 (experimental) [trunk revision 269955] (GCC)) #1 SMP Sat Mar 30 
05:34:40 CET 2019
[    0.004154] smp: Bringing up secondary CPUs ...
[    0.004753] smp: Brought up 1 node, 1 CPU
[    0.004766] SMP: Total of 1 processors activated (48.00 BogoMIPS).
[    0.004772] CPU: All CPU(s) started in SVC mode.

(ie. this means that PSCI is not loaded b/c otherwise there would be some 
"psci" lines in the log)


# lscpu
Architecture:          armv7l
Byte Order:            Little Endian
CPU(s):                2
On-line CPU(s) list:   0
Off-line CPU(s) list:  1
Thread(s) per core:    1
Core(s) per socket:    1
Socket(s):             1
Model name:            ARMv7 Processor rev 4 (v7l)
CPU max MHz:           960.0000
CPU min MHz:           144.0000


See also:
---------
http://linux-sunxi.org/PSCI
https://www.kernel.org/doc/Documentation/devicetree/bindings/arm/psci.txt

According to this page 
https://falstaff.agner.ch/2016/07/03/u-bootlinux-and-hyp-mode-on-armv7/
it seems in older u-boot versions it did activate all CPUs in SVC mode:
"
Brought up 2 CPUs
SMP: Total of 2 processors activated (96.00 BogoMIPS).
CPU: All CPU(s) started in SVC mode.
"

-------------- next part --------------
/sys/devices/system/cpu/
├── cpu0
│   ├── cpu_capacity
│   ├── cpufreq -> ../cpufreq/policy0
│   ├── hotplug
│   │   ├── fail
│   │   ├── state
│   │   └── target
│   ├── of_node -> ../../../../firmware/devicetree/base/cpus/cpu at 0
│   ├── power
│   │   ├── autosuspend_delay_ms
│   │   ├── control
│   │   ├── pm_qos_resume_latency_us
│   │   ├── runtime_active_time
│   │   ├── runtime_status
│   │   └── runtime_suspended_time
│   ├── subsystem -> ../../../../bus/cpu
│   ├── topology
│   │   ├── core_id
│   │   ├── core_siblings
│   │   ├── core_siblings_list
│   │   ├── physical_package_id
│   │   ├── thread_siblings
│   │   └── thread_siblings_list
│   └── uevent
├── cpu1
│   ├── cpu_capacity
│   ├── cpufreq -> ../cpufreq/policy0
│   ├── hotplug
│   │   ├── fail
│   │   ├── state
│   │   └── target
│   ├── of_node -> ../../../../firmware/devicetree/base/cpus/cpu at 1
│   ├── power
│   │   ├── autosuspend_delay_ms
│   │   ├── control
│   │   ├── pm_qos_resume_latency_us
│   │   ├── runtime_active_time
│   │   ├── runtime_status
│   │   └── runtime_suspended_time
│   ├── subsystem -> ../../../../bus/cpu
│   └── uevent
├── cpufreq
│   ├── policy0
│   │   ├── affected_cpus
│   │   ├── cpuinfo_cur_freq
│   │   ├── cpuinfo_max_freq
│   │   ├── cpuinfo_min_freq
│   │   ├── cpuinfo_transition_latency
│   │   ├── related_cpus
│   │   ├── scaling_available_frequencies
│   │   ├── scaling_available_governors
│   │   ├── scaling_cur_freq
│   │   ├── scaling_driver
│   │   ├── scaling_governor
│   │   ├── scaling_max_freq
│   │   ├── scaling_min_freq
│   │   ├── scaling_setspeed
│   │   └── stats
│   │       ├── reset
│   │       ├── time_in_state
│   │       ├── total_trans
│   │       └── trans_table
│   └── schedutil
│       └── rate_limit_us
├── cpuidle
│   ├── current_driver
│   └── current_governor_ro
├── hotplug
│   └── states
├── isolated
├── kernel_max
├── modalias
├── offline
├── online
├── possible
├── power
│   ├── autosuspend_delay_ms
│   ├── control
│   ├── runtime_active_time
│   ├── runtime_status
│   └── runtime_suspended_time
├── present
└── uevent

20 directories, 63 files