Hello,

I figured out that the problem is in the OF source code of the commit: 
Merge tag devicetree-for-4.20. [1]

I reverted the following OF files and SMP works!

drivers/of/base.c
drivers/of/device.c
drivers/of/of_mdio.c
drivers/of/of_numa.c
drivers/of/of_private.h
drivers/of/overlay.c
drivers/of/platform.c
drivers/of/unittest-data/overlay_15.dts
drivers/of/unittest-data/tests-overlay.dtsi
drivers/of/unittest.c
include/linux/of.h

Cheers,
Christian

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b27186abb37b7bd19e0ca434f4f425c807dbd708


On 29 October 2018 at 10:56AM, Christian Zigotzky wrote:

Hello,

I have figured out that the commit 'devicetree-for-4.20' [1] is 
responsible for the SMP problem. I was able to revert this commit with 
'git revert b27186abb37b7bd19e0ca434f4f425c807dbd708 -m 1' today.

[master ec81438] Revert "Merge tag 'devicetree-for-4.20' of 
git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux"
138 files changed, 931 insertions(+), 1538 deletions(-)
rename Documentation/devicetree/bindings/arm/{atmel-sysregs.txt => 
atmel-at91.txt} (67%)
delete mode 100644 
Documentation/devicetree/bindings/arm/freescale/fsl,layerscape-dcfg.txt
delete mode 100644 
Documentation/devicetree/bindings/arm/freescale/fsl,layerscape-scfg.txt
rename Documentation/devicetree/bindings/arm/{zte,sysctrl.txt => 
zte.txt} (62%)
delete mode 100644 Documentation/devicetree/bindings/misc/lwn-bk4.txt
create mode 100644 arch/c6x/boot/dts/linked_dtb.S
delete mode 100644 arch/nios2/boot/dts/Makefile
create mode 100644 arch/nios2/boot/linked_dtb.S
delete mode 100644 arch/powerpc/boot/dts/Makefile
delete mode 100644 arch/powerpc/boot/dts/fsl/Makefile
delete mode 100644 scripts/dtc/yamltree.c

It solves the SMP problem! SMP works again on my P5020 board and on 
virtual e5500 QEMU machines.

QEMU command: ./qemu-system-ppc64 -M ppce500 -cpu e5500 -m 2048 
-kernel /home/christian/Downloads/uImage-4.20-alpha5 -drive 
format=raw,file=/home/christian/Dokumente/ubuntu_MATE_16.04.3_LTS_PowerPC_QEMU/ubuntu_MATE_16.04_PowerPC.img,index=0,if=virtio 
-nic user,model=e1000 -append "rw root=/dev/vda3" -device virtio-vga 
-device virtio-mouse-pci -device virtio-keyboard-pci -soundhw es1370 
-smp 4

Screenshot: 
https://plus.google.com/u/0/photos/photo/115515624056477014971/6617705776207990082

Do we need a new dtb file or is it a bug?

Thanks,
Christian

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b27186abb37b7bd19e0ca434f4f425c807dbd708


On 28 October 2018 at 5:35PM, Christian Zigotzky wrote:

quoted

Hello,

SMP doesn't work anymore with the latest Git kernel (28/10/18 11:12AM 
GMT) on my P5020 board and on virtual e5500 QEMU machines.

Board with P5020 dual core CPU:

[    0.000000] -----------------------------------------------------
[    0.000000] phys_mem_size     = 0x200000000
[    0.000000] dcache_bsize      = 0x40
[    0.000000] icache_bsize      = 0x40
[    0.000000] cpu_features      = 0x00000003008003b4
[    0.000000]   possible        = 0x00000003009003b4
[    0.000000]   always          = 0x00000003008003b4
[    0.000000] cpu_user_features = 0xcc008000 0x08000000
[    0.000000] mmu_features      = 0x000a0010
[    0.000000] firmware_features = 0x0000000000000000
[    0.000000] -----------------------------------------------------
[    0.000000] CoreNet Generic board

    ...

[    0.002161] smp: Bringing up secondary CPUs ...
[    0.002339] No cpu-release-addr for cpu 1
[    0.002347] smp: failed starting cpu 1 (rc -2)
[    0.002401] smp: Brought up 1 node, 1 CPU

Virtual e5500 quad core QEMU machine:

[    0.026394] smp: Bringing up secondary CPUs ...
[    0.027831] No cpu-release-addr for cpu 1
[    0.027989] smp: failed starting cpu 1 (rc -2)
[    0.030143] No cpu-release-addr for cpu 2
[    0.030304] smp: failed starting cpu 2 (rc -2)
[    0.032400] No cpu-release-addr for cpu 3
[    0.032533] smp: failed starting cpu 3 (rc -2)
[    0.033117] smp: Brought up 1 node, 1 CPU

QEMU command: ./qemu-system-ppc64 -M ppce500 -cpu e5500 -m 2048 
-kernel 
/home/christian/Downloads/vmlinux-4.20-alpha4-AmigaOne_X1000_X5000/X5000_and_QEMU_e5500/uImage-4.20 
-drive 
format=raw,file=/home/christian/Downloads/MATE_PowerPC_Remix_2017_0.9.img,index=0,if=virtio 
-nic user,model=e1000 -append "rw root=/dev/vda" -device virtio-vga 
-device virtio-mouse-pci -device virtio-keyboard-pci -usb -soundhw 
es1370 -smp 4

.config:

...
CONFIG_SMP=y
CONFIG_NR_CPUS=4
...

Please test the latest Git kernel on your NXP P50XX boards.

Thanks,
Christian