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Date: Mon, 25 Dec 2023 14:02:36 +0000
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Subject: Re: [PATCH] LoongArch: Let cores_io_master cover the largest NR_CPUS
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To: Huacai Chen <chenhuacai@kernel.org>, maobibo <maobibo@loongson.cn>
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>
 <3db5c086-db9b-cb3a-5521-44f18cb55c4a@loongson.cn>
 <CAAhV-H5Rs4BGKHZrA5bxSh0=4uhPx7vbVwBXtdtfU4hemN2QjA@mail.gmail.com>
From: Jiaxun Yang <jiaxun.yang@flygoat.com>
In-Reply-To: <CAAhV-H5Rs4BGKHZrA5bxSh0=4uhPx7vbVwBXtdtfU4hemN2QjA@mail.gmail.com>
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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;
```

Thanks
- Jiaxun
[...]

> 
> Huacai