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

[Chris Packham]

On Mon, 2019-08-05 at 14:06 +1200, Chris Packham wrote:
> 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.

I've bisected this to the following commit

commit ed1cd6deb013a11959d17a94e35ce159197632da
Author: Christophe Leroy <christophe.leroy at c-s.fr>
Date:   Thu Jan 31 10:08:58 2019 +0000

    powerpc: Activate CONFIG_THREAD_INFO_IN_TASK
    
    This patch activates CONFIG_THREAD_INFO_IN_TASK which
    moves the thread_info into task_struct.

I'll be the first to admit this is well beyond my area of knowledge so
I'm unsure what about this patch is problematic but I can be fairly
sure that a build immediately before this patch works while a build
with this patch hangs.

> 
> 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 ...