SMP lockup at boot on Freescale/NXP T2080 (powerpc 64)

[Chris Packham]

Hi All,

I have a custom board that uses the Freescale/NXP T2080 SoC.

The board boots fine using v4.19.60 but when I use v5.1.21 it locks up
waiting for the other CPUs to come online (earlyprintk output below).
If I set maxcpus=0 then the system boots all the way through to
userland. The same thing happens with 5.3-rc2.

The defconfig I'm using is https://gist.github.com/cpackham/f24d0b426f3
de0eaaba17b82c3528a9d it was updated from the working v4.19.60
defconfig using make olddefconfig.

Does this ring any bells for anyone?

I haven't dug into the differences between the working an non-working
versions yet. I'll start looking now.

Booting...
MMU: Supported page sizes
         4 KB as direct
      2048 KB as direct & indirect
      4096 KB as direct
     16384 KB as direct
     65536 KB as direct
    262144 KB as direct
   1048576 KB as direct
MMU: Book3E HW tablewalk enabled
Linux version 5.1.21-at1+ (@chrisp-dl) (gcc version 4.9.3 (crosstool-NG 
crosstool-ng-1.22.0)) #24 SMP PREEMPT Mon Aug 5 01:42:00 UTC 2019
Found initrd at 0xc00000002f045000:0xc000000030000000
Using CoreNet Generic machine description
Found legacy serial port 0 for /soc at ffe000000/serial at 11c500
  mem=ffe11c500, taddr=ffe11c500, irq=0, clk=300000000, speed=0
Found legacy serial port 1 for /soc at ffe000000/serial at 11c600
  mem=ffe11c600, taddr=ffe11c600, irq=0, clk=300000000, speed=0
Found legacy serial port 2 for /soc at ffe000000/serial at 11d500
  mem=ffe11d500, taddr=ffe11d500, irq=0, clk=300000000, speed=0
Found legacy serial port 3 for /soc at ffe000000/serial at 11d600
  mem=ffe11d600, taddr=ffe11d600, irq=0, clk=300000000, speed=0
printk: bootconsole [udbg0] enabled
CPU maps initialized for 2 threads per core
 (thread shift is 1)
Allocated 1856 bytes for 8 pacas
-----------------------------------------------------
phys_mem_size     = 0x100000000
dcache_bsize      = 0x40
icache_bsize      = 0x40
cpu_features      = 0x00000003009003b6
  possible        = 0x00000003009003b6
  always          = 0x00000003008003b4
cpu_user_features = 0xdc008000 0x08000000
mmu_features      = 0x000a0010
firmware_features = 0x0000000000000000
-----------------------------------------------------
CoreNet Generic board
barrier-nospec: using isync; sync as speculation barrier
barrier-nospec: patched 412 locations
Top of RAM: 0x100000000, Total RAM: 0x100000000
Memory hole size: 0MB
Zone ranges:
  DMA      [mem 0x0000000000000000-0x000000007fffefff]
  Normal   [mem 0x000000007ffff000-0x00000000ffffffff]
Movable zone start for each node
Early memory node ranges
  node   0: [mem 0x0000000000000000-0x00000000ffffffff]
Initmem setup node 0 [mem 0x0000000000000000-0x00000000ffffffff]
On node 0 totalpages: 1048576
  DMA zone: 7168 pages used for memmap
  DMA zone: 0 pages reserved
  DMA zone: 524287 pages, LIFO batch:63
  Normal zone: 7169 pages used for memmap
  Normal zone: 524289 pages, LIFO batch:63
MMU: Allocated 2112 bytes of context maps for 255 contexts
percpu: Embedded 22 pages/cpu s49304 r0 d40808 u131072
pcpu-alloc: s49304 r0 d40808 u131072 alloc=1*1048576
pcpu-alloc: [0] 0 1 2 3 4 5 6 7 
Built 1 zonelists, mobility grouping on.  Total pages: 1034239
Kernel command line: console=ttyS0,115200 root=/dev/ram0
releasefile=linuxbox_ppc64_e6500mc-tb233.rel bootversion=6.2.7
loglevel=8 mtdoops.mtddev=errlog
mtdparts=fff800000.flash:4088M(user),8M(errlog)
earlyprintk=ttyS0,115200 real_init=
/bin/sh securitylevel=1 reladdr=0x1000000,1522523
printk: log_buf_len individual max cpu contribution: 4096 bytes
printk: log_buf_len total cpu_extra contributions: 28672 bytes
printk: log_buf_len min size: 16384 bytes
printk: log_buf_len: 65536 bytes
printk: early log buf free: 12412(75%)
Dentry cache hash table entries: 524288 (order: 10, 4194304 bytes)
Inode-cache hash table entries: 262144 (order: 9, 2097152 bytes)
Memory: 3979284K/4194304K available (8704K kernel code, 1584K rwdata,
2496K rodata, 472K init, 299K bss, 215020K reserved, 0K cma-reserved)
SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=8, Nodes=1
rcu: Preemptible hierarchical RCU implementation.
rcu:    RCU event tracing is enabled.
        Tasks RCU enabled.
rcu: RCU calculated value of scheduler-enlistment delay is 25 jiffies.
NR_IRQS: 512, nr_irqs: 512, preallocated irqs: 16
mpic: Setting up MPIC " OpenPIC  " version 1.2 at ffe040000, max 8 CPUs
mpic: ISU size: 512, shift: 9, mask: 1ff
mpic: Initializing for 512 sources
time_init: decrementer frequency = 37.500000 MHz
time_init: processor frequency   = 1500.000000 MHz
clocksource: timebase: mask: 0xffffffffffffffff max_cycles:
0x8a60dd6a9, max_idle_ns: 440795204056 ns
clocksource: timebase mult[1aaaaaab] shift[24] registered
clockevent: decrementer mult[999999a] shift[32] cpu[0]
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 8192 (order: 4, 65536 bytes)
Mountpoint-cache hash table entries: 8192 (order: 4, 65536 bytes)
e6500 family performance monitor hardware support registered
rcu: Hierarchical SRCU implementation.
smp: Bringing up secondary CPUs ...