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Message-ID: <e90289af-f557-58f2-f4c8-f79feab4f185@ghiti.fr>
Date:   Fri, 25 Nov 2022 14:47:46 +0100
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Subject: Re: [PATCH] riscv: increase boot command line size to 1K
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To:     Andrea Righi <andrea.righi@canonical.com>
Cc:     Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Emil Renner Berthing <emil.renner.berthing@canonical.com>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20221125133713.314796-1-andrea.righi@canonical.com>
 <6fee29f8-8150-e6ec-e2ec-210610a7e27d@ghiti.fr>
 <Y4DGxWLIVx9p9TS+@righiandr-XPS-13-7390>
From:   Alexandre Ghiti <alex@ghiti.fr>
In-Reply-To: <Y4DGxWLIVx9p9TS+@righiandr-XPS-13-7390>
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On 11/25/22 14:44, Andrea Righi wrote:
> On Fri, Nov 25, 2022 at 02:41:11PM +0100, Alexandre Ghiti wrote:
>> Hi Andrea,
>>
>> On 11/25/22 14:37, Andrea Righi wrote:
>>> Kernel parameters string is limited to 512 characters on riscv (using
>>> the default from include/uapi/asm-generic/setup.h).
>>>
>>> In some testing environments (e.g., qemu with long kernel parameters
>>> string) we may exceed this limit, triggering errors like the following:
>>>
>>> [    3.331893] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000000
>>> [    3.332625] CPU: 2 PID: 1 Comm: sh Not tainted 6.1.0-rc6-kc #1
>>> [    3.333233] Hardware name: riscv-virtio,qemu (DT)
>>> [    3.333550] Call Trace:
>>> [    3.333736] [<ffffffff800062b6>] dump_backtrace+0x1c/0x24
>>> [    3.334053] [<ffffffff806e8f54>] show_stack+0x2c/0x38
>>> [    3.334260] [<ffffffff806f2d06>] dump_stack_lvl+0x5a/0x7c
>>> [    3.334483] [<ffffffff806f2d3c>] dump_stack+0x14/0x1c
>>> [    3.334687] [<ffffffff806e92fa>] panic+0x116/0x2d0
>>> [    3.334878] [<ffffffff8001b0aa>] do_exit+0x80a/0x810
>>> [    3.335079] [<ffffffff8001b1d0>] do_group_exit+0x24/0x70
>>> [    3.335287] [<ffffffff8001b234>] __wake_up_parent+0x0/0x20
>>> [    3.335502] [<ffffffff80003cee>] ret_from_syscall+0x0/0x2
>>> [    3.335857] SMP: stopping secondary CPUs
>>> [    3.337561] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000000 ]---
>>>
>>> It seems reasonable enough to increase the default command line size to
>>> 1024, like arm, to prevent issues like the one reported above.
>>>
>>> Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
>>> ---
>>>    arch/riscv/include/asm/setup.h      | 7 +++++++
>>>    arch/riscv/include/uapi/asm/setup.h | 7 +++++++
>>>    2 files changed, 14 insertions(+)
>>>    create mode 100644 arch/riscv/include/asm/setup.h
>>>    create mode 100644 arch/riscv/include/uapi/asm/setup.h
>>>
>>> diff --git a/arch/riscv/include/asm/setup.h b/arch/riscv/include/asm/setup.h
>>> new file mode 100644
>>> index 000000000000..f4fe549aab40
>>> --- /dev/null
>>> +++ b/arch/riscv/include/asm/setup.h
>>> @@ -0,0 +1,7 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>> +#ifndef __ASMRISCV_SETUP_H
>>> +#define __ASMRISCV_SETUP_H
>>> +
>>> +#include <uapi/asm/setup.h>
>>> +
>>> +#endif /* __ASMRISCV_SETUP_H */
>>> diff --git a/arch/riscv/include/uapi/asm/setup.h b/arch/riscv/include/uapi/asm/setup.h
>>> new file mode 100644
>>> index 000000000000..5738f93ae437
>>> --- /dev/null
>>> +++ b/arch/riscv/include/uapi/asm/setup.h
>>> @@ -0,0 +1,7 @@
>>> +/* SPDX-License-Identifier: GPL-2.0 */
>>> +#ifndef _UAPI__ASMRISCV_SETUP_H
>>> +#define _UAPI__ASMRISCV_SETUP_H
>>> +
>>> +#define COMMAND_LINE_SIZE 1024
>>> +
>>> +#endif /* _UAPI__ASMRISCV_SETUP_H */
>>
>> Just for reference to previous discussions regarding this: https://lore.kernel.org/lkml/CACT4Y+YYAfTafFk7DE0B=qQFgkPXS7492AhBdY_CP1WdB8CGfA@mail.gmail.com/T/
>>
>> Thanks,
>>
>> Alex
> Ah! It has been address/discussed already, great! Thanks for pointing
> that out and sorry for the unnecessary patch. :)


Not unnecessary at all, that will hopefully trigger a new discussion 
because no progress was made so far :)


> -Andrea
>
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