Re: [PATCH V2] mm: Define default value for FIRST_USER_ADDRESS

From: Anshuman Khandual <anshuman.khandual@arm.com>
To: linux-mm@kvack.org, akpm@linux-foundation.org
Cc: Richard Henderson <rth@twiddle.net>,
	Vineet Gupta <vgupta@synopsys.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Guo Ren <guoren@kernel.org>,
	Brian Cain <bcain@codeaurora.org>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Michal Simek <monstr@monstr.eu>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Ley Foon Tan <ley.foon.tan@intel.com>,
	Jonas Bonn <jonas@southpole.se>,
	Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>,
	Stafford Horne <shorne@gmail.com>,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Yoshinori Sato <ysato@users.sourceforge.jp>,
	"David S. Miller" <davem@davemloft.net>,
	Jeff Dike <jdike@addtoit.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Chris Zankel <chris@zankel.net>,
	linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2] mm: Define default value for FIRST_USER_ADDRESS
Date: Mon, 26 Apr 2021 05:36:46 +0530	[thread overview]
Message-ID: <830eec08-fc78-c0f4-5d7a-6cad0c0ec978@arm.com> (raw)
In-Reply-To: <1618550254-14511-1-git-send-email-anshuman.khandual@arm.com>

On 4/16/21 10:47 AM, Anshuman Khandual wrote:
> Currently most platforms define FIRST_USER_ADDRESS as 0UL duplication the
> same code all over. Instead just define a generic default value (i.e 0UL)
> for FIRST_USER_ADDRESS and let the platforms override when required. This
> makes it much cleaner with reduced code.
> 
> The default FIRST_USER_ADDRESS here would be skipped in <linux/pgtable.h>
> when the given platform overrides its value via <asm/pgtable.h>.
> 
> Cc: Richard Henderson <rth@twiddle.net>
> Cc: Vineet Gupta <vgupta@synopsys.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Guo Ren <guoren@kernel.org>
> Cc: Brian Cain <bcain@codeaurora.org>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: Michal Simek <monstr@monstr.eu>
> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> Cc: Ley Foon Tan <ley.foon.tan@intel.com>
> Cc: Jonas Bonn <jonas@southpole.se>
> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
> Cc: Stafford Horne <shorne@gmail.com>
> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
> Cc: Paul Walmsley <paul.walmsley@sifive.com>
> Cc: Palmer Dabbelt <palmer@dabbelt.com>
> Cc: Heiko Carstens <hca@linux.ibm.com>
> Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Jeff Dike <jdike@addtoit.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Chris Zankel <chris@zankel.net>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: linux-arch@vger.kernel.org
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> This applies on v5.12-rc7 and has been boot tested on arm64 platform.
> But has been cross compiled on multiple other platforms.
> 
> Changes in V2:
> 
> - Dropped ARCH_HAS_FIRST_USER_ADDRESS construct

Gentle ping. Any updates on this ?

- Anshuman