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Message-ID: <d6012fe0-9d06-f5ac-857c-c38034bf0758@redhat.com>
Date:   Wed, 6 Sep 2023 09:42:06 +0200
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Subject: Re: [PATCH] LoongArch: add p?d_leaf() definitions
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To:     Hongchen Zhang <zhanghongchen@loongson.cn>,
        Huacai Chen <chenhuacai@kernel.org>,
        WANG Xuerui <kernel@xen0n.name>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Mike Rapoport IBM)" <rppt@kernel.org>,
        Feiyang Chen <chenfeiyang@loongson.cn>,
        Qi Zheng <zhengqi.arch@bytedance.com>,
        "Matthew Wilcox Oracle)" <willy@infradead.org>,
        Kefeng Wang <wangkefeng.wang@huawei.com>
Cc:     loongarch@lists.linux.dev, linux-kernel@vger.kernel.org,
        loongson-kernel@lists.loongnix.cn
References: <20230905064955.16316-1-zhanghongchen@loongson.cn>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
In-Reply-To: <20230905064955.16316-1-zhanghongchen@loongson.cn>
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On 05.09.23 08:49, Hongchen Zhang wrote:
> When I do LTP test, LTP test case ksm06 caused panic at
> 	break_ksm_pmd_entry
> 	  -> pmd_leaf (Huge page table but False)
> 	  -> pte_present (panic)
> 

Probably there are other problematic bits without that can trigger that? 
I suspect walk_page_range*() callers might be affected,

> The reason is pmd_leaf is not defined, So like
> commit 501b81046701 ("mips: mm: add p?d_leaf() definitions")
> add p?d_leaf() definition for LoongArch.
> 

We most certainly want to cc stable, no?

Can we come up with a Fixes: tag? Probably when we added THP support to 
loongarch.

> Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn>
> ---
>   arch/loongarch/include/asm/pgtable.h | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
> index 370c6568ceb8..ea54653b7aab 100644
> --- a/arch/loongarch/include/asm/pgtable.h
> +++ b/arch/loongarch/include/asm/pgtable.h
> @@ -243,6 +243,9 @@ static inline void pmd_clear(pmd_t *pmdp)
>   
>   #define pmd_phys(pmd)		PHYSADDR(pmd_val(pmd))
>   
> +#define pmd_leaf(pmd)		((pmd_val(pmd) & _PAGE_HUGE) != 0)
> +#define pud_leaf(pud)		((pud_val(pud) & _PAGE_HUGE) != 0)
> +
>   #ifndef CONFIG_TRANSPARENT_HUGEPAGE
>   #define pmd_page(pmd)		(pfn_to_page(pmd_phys(pmd) >> PAGE_SHIFT))
>   #endif /* CONFIG_TRANSPARENT_HUGEPAGE  */

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb