Re: Deprecate the ppc405 boards in QEMU?

["Cédric Le Goater" <clg@kaod.org>]

On 10/19/21 18:12, Christophe Leroy wrote:
> 
> 
> Le 19/10/2021 à 16:56, BALATON Zoltan a écrit :
>> On Tue, 19 Oct 2021, Christophe Leroy wrote:
>>> Le 19/10/2021 à 15:44, Christophe Leroy a écrit :
>>>> There is something:
>>>>
>>>> => bootm 0
>>>> Wrong Image Format for bootm command
>>>> ERROR: can't get kernel image!
>>>>
>>>> => md 0
>>>> 00000000: 00000000 b497aae1 616e9207 003227a4    '..V....an...2'.
>>>> 00000010: 00000000 00000000 ee36255f 05070201    .........6%_....
>>>> 00000020: 4c696e75 782d352e 31352e30 2d726335    Linux-5.15.0-rc5
>>>> 00000030: 2d303232 32342d67 61336330 30376164    -02224-ga3c007ad
>>>> 00000040: 1f8b0800 00000000 0203ec5c 0f7013e7    ...........\.p..
>>>>
>>>> => mw.l 0 0x27051956
>>>>
>>>> => bootm 0
>>>> ## Booting kernel from Legacy Image at 00000000 ...
>>>>     Image Name:   Linux-5.15.0-rc5-02224-ga3c007ad
>>>>     Image Type:   PowerPC Linux Kernel Image (gzip compressed)
>>>>     Data Size:    3286948 Bytes = 3.1 MiB
>>>>     Load Address: 00000000
>>>>     Entry Point:  00000000
>>>>     Verifying Checksum ... Bad Data CRC
>>>> ERROR: can't get kernel image!
>>>>
>>>>
>>>> So we have something but it seems it gets overwritten by stuff.
>>>>
>>>> Anyway loading a uImage at 0 is just bad because it is a gzipped image that should get gunzipped at address 0.
>>>>
>>>> Or should we just copy the raw kernel at 0 and jump to the entry point ? But then we also need a device tree somewhere.
>>>>
>>>
>>> If I change KERNEL_LOAD_ADDR to 0x1000000, I can bootm at that address, and it seems it properly decompress the kernel:
>>>
>>> => bootm 0x1000000
>>> ## Booting kernel from Legacy Image at 01000000 ...
>>>   Image Name:   Linux-5.15.0-rc5-02224-ga3c007ad
>>>   Image Type:   PowerPC Linux Kernel Image (gzip compressed)
>>>   Data Size:    3296789 Bytes = 3.1 MiB
>>>   Load Address: 00000000
>>>   Entry Point:  00000000
>>>   Verifying Checksum ... OK
>>>   Uncompressing Kernel Image ... OK
>>>
>>>
>>> And it initialises the MMU properly.
>>>
>>> Then it gets stuck because there is no devicetree.
>>>
>>> (gdb) bt
>>> #0  0xc00094cc in udelay ()
>>> #1  0xc0025d34 in panic ()
>>> #2  0xc06415a0 in early_init_devtree ()
>>> #3  0xc0641da8 in machine_init ()
>>> #4  0xc0002200 in start_here ()
>>
>> Maybe you need to embed a dtb in your kernel if that's possible somehow? Or QEMU has a -dtb option that sets machine->dtb but you need board code to do something with it. See how it's done in other boards like virtex_ml507 and sam460ex. But maybe you'd be better off not using -kernel option as it seems to not really working for these 405 boards but load and start the kernel from u-boot. Not sure what device does u-boot support but QEMU can emulate usb-storage, network, different disks so something might work with u-boot if this board has any peripherals. If it doesn't emulate any peripherals what do you expect to do with the kernel once it boots?
>>
> 
> I should be able to build a multi-FIT image that embeds the kernel and the device tree.
> 
> I don't know about the peripherals, what I need it a kernel that is able to boot and run some user exe. I'm working on low level functionnalities like VMAP_STACK, STRICT_KERNEL_RWX, Userspace protection, etc ... I want to be able to check that after some modifications the kernel can still boot on every CPU sub-family, and I need to run LKDTM tests.
> 
> For this a kernel + initrd is enough.

hotfoot.dts is the only DT with a CPU model "PowerPC,405EP".

With cuImage.hotfoot,

U-Boot 2015.10-00236-g677f970bc6-dirty (Oct 06 2021 - 08:59:53 +0200)

CPU:   AMCC PowerPC 405EP Rev. B at 770 MHz (PLB=256 OPB=128 EBC=128)
        I2C boot EEPROM disabled
        Internal PCI arbiter enabled
        16 KiB I-Cache 16 KiB D-Cache
Board: Taihu - AMCC PPC405EP Evaluation Board
I2C:   ready
DRAM:  128 MiB
Flash: ## Unknown FLASH on Bank 0 - Size = 0x00000000 = 0 MB
## Unknown FLASH on Bank 1 - Size = 0x00000000 = 0 MB
0 Bytes
*** Warning - bad CRC, using default environment

PCI:   Bus Dev VenId DevId Class Int
PCI:
Net:   No ethernet found.

Type run flash_nfs to mount root filesystem over NFS

Hit any key to stop autoboot:  0
=> bootm 01000000
## Booting kernel from Legacy Image at 01000000 ...
    Image Name:   Linux-5.15.0-rc6-dirty
    Image Type:   PowerPC Linux Kernel Image (gzip compressed)
    Data Size:    3326878 Bytes = 3.2 MiB
    Load Address: 00700000
    Entry Point:  00701aa8
    Verifying Checksum ... OK
    Uncompressing Kernel Image ... OK
Memory <- <0x0 0x8000000> (128MB)
CPU clock-frequency <- 0x0 (0MHz)
CPU timebase-frequency <- 0x0 (0MHz)
/plb: clock-frequency <- 0 (0MHz)
/plb/opb: clock-frequency <- 0 (0MHz)
/plb/ebc: clock-frequency <- 0 (0MHz)
/plb/opb/serial@ef600300: clock-frequency <- 0 (0MHz)
/plb/opb/serial@ef600400: clock-frequency <- 0 (0MHz)
ethernet0: local-mac-address <- 00:00:00:00:00:00
ethernet1: local-mac-address <- 00:00:2d:e5:44:80
Fixing devtree for 4M Flash

zImage starting: loaded at 0x00700000 (sp: 0x07eaabb0)
Decompression error: 'Not a gzip file'
No valid compressed data found, assume uncompressed data
Allocating 0x6c128c bytes for kernel...
0x69e1ec bytes of uncompressed data copied

Linux/PowerPC load:
Finalizing device tree... flat tree at 0xdc5960
Linux version 5.15.0-rc6-dirty (legoater@yukon) (powerpc64-linux-gnu-gcc (GCC) 11.2.1 20210728 (Red Hat Cross 11.2.1-1), GNU ld version 2.35.2-1.fc34) #1 Tue Oct 19 15:15:21 CEST 2021
Using PowerPC 40x Platform machine description
printk: bootconsole [udbg0] enabled
-----------------------------------------------------
phys_mem_size     = 0x8000000
dcache_bsize      = 0x20
icache_bsize      = 0x20
cpu_features      = 0x0000000000000100
   possible        = 0x0000000000000100
   always          = 0x0000000000000100
cpu_user_features = 0x86000000 0x00000000
mmu_features      = 0x00000004
-----------------------------------------------------
Zone ranges:
   Normal   [mem 0x0000000000000000-0x0000000007ffffff]
Movable zone start for each node
Early memory node ranges
   node   0: [mem 0x0000000000000000-0x0000000007ffffff]
Initmem setup node 0 [mem 0x0000000000000000-0x0000000007ffffff]
MMU: Allocated 1088 bytes of context maps for 255 contexts
Built 1 zonelists, mobility grouping on.  Total pages: 32512
Kernel command line:
Dentry cache hash table entries: 16384 (order: 4, 65536 bytes, linear)
Inode-cache hash table entries: 8192 (order: 3, 32768 bytes, linear)
mem auto-init: stack:off, heap alloc:off, heap free:off
Kernel virtual memory layout:
   * 0xffbdf000..0xfffff000  : fixmap
   * 0xc9000000..0xffbdf000  : vmalloc & ioremap
Memory: 122948K/131072K available (5040K kernel code, 220K rwdata, 1320K rodata, 200K init, 136K bss, 8124K reserved, 0K cma-reserved)
SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
NR_IRQS: 512, nr_irqs: 512, preallocated irqs: 16
UIC0 (32 IRQ sources) at DCR 0xc0
random: get_random_u32 called from start_kernel+0x498/0x5f8 with crng_init=0