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Subject: Re: [PATCH] LoongArch: Let cores_io_master cover the largest NR_CPUS
To: Jiaxun Yang <jiaxun.yang@flygoat.com>, Huacai Chen <chenhuacai@kernel.org>
Cc: loongson-kernel@lists.loongnix.cn, loongarch@lists.linux.dev,
 Xuefeng Li <lixuefeng@loongson.cn>, Guo Ren <guoren@kernel.org>,
 Xuerui Wang <kernel@xen0n.name>, linux-kernel@vger.kernel.org,
 Huacai Chen <chenhuacai@loongson.cn>
References: <20231225070002.1350705-1-chenhuacai@loongson.cn>
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 <b239bfee-73a7-495d-b094-bdfa31c1500e@flygoat.com>
From: maobibo <maobibo@loongson.cn>
Message-ID: <dc93675e-62a2-9648-dfbc-846e3afdf5b4@loongson.cn>
Date: Wed, 27 Dec 2023 09:09:57 +0800
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On 2023/12/25 下午10:02, Jiaxun Yang wrote:
> 
> 
> 在 2023/12/25 09:19, Huacai Chen 写道:
>> On Mon, Dec 25, 2023 at 5:13 PM maobibo <maobibo@loongson.cn> wrote:
>>>
>>>
>>>
>>> On 2023/12/25 下午3:00, Huacai Chen wrote:
>>>> Now loongson_system_configuration::cores_io_master only covers 64 cpus,
>>>> if NR_CPUS > 64 there will be memory corruption. So let cores_io_master
>>>> cover the largest NR_CPUS (256).
>>>>
>>>> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
>>>> ---
>>>>    arch/loongarch/include/asm/bootinfo.h | 4 ++--
>>>>    arch/loongarch/kernel/acpi.c          | 2 +-
>>>>    arch/loongarch/kernel/smp.c           | 2 +-
>>>>    3 files changed, 4 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/arch/loongarch/include/asm/bootinfo.h 
>>>> b/arch/loongarch/include/asm/bootinfo.h
>>>> index c60796869b2b..32fd0319594a 100644
>>>> --- a/arch/loongarch/include/asm/bootinfo.h
>>>> +++ b/arch/loongarch/include/asm/bootinfo.h
>>>> @@ -30,7 +30,7 @@ struct loongson_system_configuration {
>>>>        int boot_cpu_id;
>>>>        int cores_per_node;
>>>>        int cores_per_package;
>>>> -     unsigned long cores_io_master;
>>>> +     unsigned long cores_io_master[4];
>>> Can the hardcoded 4 be defined something like this?
>>>      DIV_ROUND_UP(CONFIG_NR_CPUS, sizeof(long))
>> Can this be used to define arrays?
> 
> I think DECLARE_BITMAP should work.
> 
> See how are we dealing with cpumask_t:
> ```
> typedef struct cpumask { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t;
> ```
Yeap, that will be better.

Regards
Bibo Mao
> 
> Thanks
> - Jiaxun
> [...]
> 
>>
>> Huacai