Re: [Qemu-devel] QEMU+Linux ARMv7A current state

[Guenter Roeck <linux@roeck-us.net>]

On 10/04/2015 07:21 PM, Peter Crosthwaite wrote:
> On Sun, Oct 4, 2015 at 6:08 PM, Guenter Roeck <linux@roeck-us.net> wrote:
>> On 10/04/2015 02:38 PM, Beniamino Galvani wrote:
>>>
>>> On Sun, Oct 04, 2015 at 02:11:35PM -0700, Guenter Roeck wrote:
>>>>
>>>> What is your qemu command line ?
>>>
>>>
>>> qemu-system-arm \
>>>               -M cubieboard \
>>>               -kernel ../linux/zImage-dtb \
>>>               -serial stdio \
>>>               -append "console=ttyS0 rw root=/dev/nfs
>>> nfsroot=10.0.0.1:/nfs,v3 ip=10.0.0.22" \
>>>               -m 1024 \
>>>               -net nic,vlan=0,model=allwinner-emac \
>>>               -net tap,vlan=0,ifname=tap0,script=net-up.sh \
>>>               -s \
>>>               -d guest_errors
>>>
>>> Beniamino
>>>
>>
>> With the mainline kernel and sun4i-a10-cubieboard.dtb, this gives me lots of
>>
>> [    2.480983] Division by zero in kernel.
>> [    2.481074] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
>> 4.3.0-rc3-00055-gdd36d7393d63 #1
>> [    2.481250] Hardware name: Allwinner A1X (Device Tree)
>> [    2.481376] [<c02186a8>] (unwind_backtrace) from [<c0213d84>]
>> (show_stack+0x10/0x14)
>> [    2.481544] [<c0213d84>] (show_stack) from [<c047cff0>]
>> (dump_stack+0x78/0x94)
>> [    2.481700] [<c047cff0>] (dump_stack) from [<c047bb38>] (Ldiv0+0x8/0x10)
>> [    2.481848] [<c047bb38>] (Ldiv0) from [<c0886ab0>]
>> (sun4i_a10_get_mod0_factors+0x74/0xb8)
>> [    2.482024] [<c0886ab0>] (sun4i_a10_get_mod0_factors) from [<c08867e4>]
>> (clk_factors_determine_rate+0x68/0xfc)
>> [    2.482231] [<c08867e4>] (clk_factors_determine_rate) from [<c0871070>]
>> (clk_composite_determine_rate+0x94/0x1d0)
>> [    2.482443] [<c0871070>] (clk_composite_determine_rate) from [<c086c960>]
>> (clk_core_round_rate_nolock+0x84/0xa8)
>> [    2.482654] [<c086c960>] (clk_core_round_rate_nolock) from [<c086dcbc>]
>> (clk_round_rate+0x38/0x54)
>> [    2.482845] [<c086dcbc>] (clk_round_rate) from [<c084246c>]
>> (sunxi_mmc_set_ios+0x9c/0x314)
>> [    2.483023] [<c084246c>] (sunxi_mmc_set_ios) from [<c0814564>]
>> (mmc_power_up+0xf8/0x104)
>> [    2.483197] [<c0814564>] (mmc_power_up) from [<c08151d8>]
>> (mmc_start_host+0x44/0x6c)
>> [    2.483363] [<c08151d8>] (mmc_start_host) from [<c0816244>]
>> (mmc_add_host+0x58/0x7c)
>> [    2.483528] [<c0816244>] (mmc_add_host) from [<c0842b6c>]
>> (sunxi_mmc_probe+0x488/0x590)
>> [    2.483701] [<c0842b6c>] (sunxi_mmc_probe) from [<c06287d0>]
>> (platform_drv_probe+0x48/0xa4)
>>
>
> I think that's the expected warnings we have been ignoring. I have a
> hack to make them go away.
>

Division by zero isn't something that should be ignored.
Any idea where it is coming from ?

Also, is your hack in the kernel or in qemu ?

>> Do you have a special devicetree file ?
>>
>> It also doesn't seem to accept the qemu "initrd" argument, which is
>> unexpected.
>>
>
> Yes I noticed the same and went to the SATA solution.
>

Here is a one-line qemu fix for the initrd problem.

diff --git a/hw/arm/cubieboard.c b/hw/arm/cubieboard.c
index 1582250..db3ec40 100644
--- a/hw/arm/cubieboard.c
+++ b/hw/arm/cubieboard.c
@@ -71,6 +71,7 @@ static void cubieboard_init(MachineState *machine)
      cubieboard_binfo.ram_size = machine->ram_size;
      cubieboard_binfo.kernel_filename = machine->kernel_filename;
      cubieboard_binfo.kernel_cmdline = machine->kernel_cmdline;
+    cubieboard_binfo.initrd_filename = machine->initrd_filename;
      arm_load_kernel(&s->a10->cpu, &cubieboard_binfo);
  }

Guess that is less complex than getting sata to work ?

Thanks,
Guenter