From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mike Rapoport <rppt@kernel.org>
Date: Mon, 13 Feb 2023 07:54:17 +0000
Subject: Re: [PATCH v2 4/4] mm, arch: add generic implementation of pfn_valid() for FLATMEM
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To: Guenter Roeck <linux@roeck-us.net>
Cc: Andrew Morton <akpm@linux-foundation.org>, Arnd Bergmann <arnd@arndb.de>, Brian Cain <bcain@quicinc.com>, "David S. Miller" <davem@davemloft.net>, Dinh Nguyen <dinguyen@kernel.org>, Geert Uytterhoeven <geert@linux-m68k.org>, Greg Ungerer <gerg@linux-m68k.org>, Guo Ren <guoren@kernel.org>, Helge Deller <deller@gmx.de>, Huacai Chen <chenhuacai@kernel.org>, Matt Turner <mattst88@gmail.com>, Max Filippov <jcmvbkbc@gmail.com>, Michael Ellerman <mpe@ellerman.id.au>, Michal Simek <monstr@monstr.eu>, Palmer Dabbelt <palmer@dabbelt.com>, Rich Felker <dalias@libc.org>, Richard Weinberger <richard@nod.at>, Russell King <linux@armlinux.org.uk>, Stafford Horne <shorne@gmail.com>, Thomas Bogendoerfer <tsbogend@alpha.franken.de>, Vineet Gupta <vgupta@kernel.org>, WANG Xuerui <kernel@xen0n.name>, Yoshinori Sato <ysato@users.sourceforge.jp>, linux-alpha@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, linuxppc-dev@lists.ozlabs.org, loongarch@lists.linux.dev, openrisc@lists.librecores.org, sparclinux@vger.kernel.org, x86@kernel.org, Huacai Chen <chenhuacai@loongson.cn>

Andrew, 

On Sun, Feb 12, 2023 at 10:37:15PM -0800, Guenter Roeck wrote:
> On 2/12/23 17:26, Mike Rapoport wrote:
> > On Sun, Feb 12, 2023 at 08:13:20AM -0800, Guenter Roeck wrote:
> > > On Sun, Jan 29, 2023 at 02:42:35PM +0200, Mike Rapoport wrote:
> > > > From: "Mike Rapoport (IBM)" <rppt@kernel.org>
> > > > 
> > > > Every architecture that supports FLATMEM memory model defines its own
> > > > version of pfn_valid() that essentially compares a pfn to max_mapnr.
> > > > 
> > > > Use mips/powerpc version implemented as static inline as a generic
> > > > implementation of pfn_valid() and drop its per-architecture definitions.
> > > > 
> > > 
> > > With this patch in the tree, sh4 and sh4eb qemu emulations no longer boot.
> > > Reverting this patch fixes the problem.
> > 
> > This should be a better fix than a revert:
> > 
> > diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
> > index 506784702430..bf1b54055316 100644
> > --- a/arch/sh/mm/init.c
> > +++ b/arch/sh/mm/init.c
> > @@ -301,6 +301,7 @@ void __init paging_init(void)
> >   	 */
> >   	max_low_pfn = max_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
> >   	min_low_pfn = __MEMORY_START >> PAGE_SHIFT;
> > +	set_max_mapnr(max_low_pfn - min_low_pfn);
> >   	nodes_clear(node_online_map);
> 
> Confirmed, this fixes the problem for me.
 
What is your preference for this and m68k fix? Fixups on top of mm-stable
or v3 of the entire series? 

> Thanks,
> Guenter

-- 
Sincerely yours,
Mike.