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Subject: Re: [PATCH] powerpc/64s/radix: Define arch_ioremap_p4d_supported()
To:     Anshuman Khandual <anshuman.khandual@arm.com>, linux-mm@kvack.org
Cc:     Stephen Rothwell <sfr@canb.auug.org.au>,
        linux-kernel@vger.kernel.org, Nicholas Piggin <npiggin@gmail.com>,
        linux-next@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linuxppc-dev@lists.ozlabs.org
References: <1561555260-17335-1-git-send-email-anshuman.khandual@arm.com>
From:   Christophe Leroy <christophe.leroy@c-s.fr>
Message-ID: <f32fbb6c-0600-991a-6d1a-72670c27c8de@c-s.fr>
Date:   Thu, 27 Jun 2019 04:38:50 +0000
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On 06/26/2019 01:21 PM, Anshuman Khandual wrote:
> Recent core ioremap changes require HAVE_ARCH_HUGE_VMAP subscribing archs
> provide arch_ioremap_p4d_supported() failing which will result in a build
> failure like the following.
> 
> ld: lib/ioremap.o: in function `.ioremap_huge_init':
> ioremap.c:(.init.text+0x3c): undefined reference to
> `.arch_ioremap_p4d_supported'
> 
> This defines a stub implementation for arch_ioremap_p4d_supported() keeping
> it disabled for now to fix the build problem.
> 
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-next@vger.kernel.org
> 
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>

Add a Fixes: tag ? For instance:

Fixes: d909f9109c30 ("powerpc/64s/radix: Enable HAVE_ARCH_HUGE_VMAP")

Christophe

> ---
> This has been just build tested and fixes the problem reported earlier.
> 
>   arch/powerpc/mm/book3s64/radix_pgtable.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
> index 8904aa1..c81da88 100644
> --- a/arch/powerpc/mm/book3s64/radix_pgtable.c
> +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
> @@ -1124,6 +1124,11 @@ void radix__ptep_modify_prot_commit(struct vm_area_struct *vma,
>   	set_pte_at(mm, addr, ptep, pte);
>   }
>   
> +int __init arch_ioremap_p4d_supported(void)
> +{
> +	return 0;
> +}
> +
>   int __init arch_ioremap_pud_supported(void)
>   {
>   	/* HPT does not cope with large pages in the vmalloc area */
>