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Date:   Thu, 23 Jun 2022 12:13:07 -0500
From:   Mike Rapoport <rppt@kernel.org>
To:     Christophe Leroy <christophe.leroy@csgroup.eu>
Cc:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        stable@vger.kernel.org
Subject: Re: [PATCH] powerpc/book3e: Fix PUD allocation size in
 map_kernel_page()
Message-ID: <YrSfIyDy3rM16NqC@kernel.org>
References: <95ddfd6176d53e6c85e13bd1c358359daa56775f.1655974558.git.christophe.leroy@csgroup.eu>
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On Thu, Jun 23, 2022 at 10:56:17AM +0200, Christophe Leroy wrote:
> Commit 2fb4706057bc ("powerpc: add support for folded p4d page tables")
> erroneously changed PUD setup to a mix of PMD and PUD. Fix it.
> 
> While at it, use PTE_TABLE_SIZE instead of PAGE_SIZE for PTE tables
> in order to avoid any confusion.
> 
> Fixes: 2fb4706057bc ("powerpc: add support for folded p4d page tables")
> Cc: stable@vger.kernel.org
> Cc: Mike Rapoport <rppt@kernel.org>
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

Acked-by: Mike Rapoport <rppt@linux.ibm.com>

> ---
>  arch/powerpc/mm/nohash/book3e_pgtable.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/mm/nohash/book3e_pgtable.c b/arch/powerpc/mm/nohash/book3e_pgtable.c
> index 7d4368d055a6..b80fc4a91a53 100644
> --- a/arch/powerpc/mm/nohash/book3e_pgtable.c
> +++ b/arch/powerpc/mm/nohash/book3e_pgtable.c
> @@ -96,8 +96,8 @@ int __ref map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot)
>  		pgdp = pgd_offset_k(ea);
>  		p4dp = p4d_offset(pgdp, ea);
>  		if (p4d_none(*p4dp)) {
> -			pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
> -			p4d_populate(&init_mm, p4dp, pmdp);
> +			pudp = early_alloc_pgtable(PUD_TABLE_SIZE);
> +			p4d_populate(&init_mm, p4dp, pudp);
>  		}
>  		pudp = pud_offset(p4dp, ea);
>  		if (pud_none(*pudp)) {
> @@ -106,7 +106,7 @@ int __ref map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot)
>  		}
>  		pmdp = pmd_offset(pudp, ea);
>  		if (!pmd_present(*pmdp)) {
> -			ptep = early_alloc_pgtable(PAGE_SIZE);
> +			ptep = early_alloc_pgtable(PTE_TABLE_SIZE);
>  			pmd_populate_kernel(&init_mm, pmdp, ptep);
>  		}
>  		ptep = pte_offset_kernel(pmdp, ea);
> -- 
> 2.36.1
> 

-- 
Sincerely yours,
Mike.