linux-kernel - Re: [patch V2 1/6] ARM: uaccess: Implement missing __get_user_asm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aMnV-hAwRnLJflC7@shell.armlinux.org.uk>
Date: Tue, 16 Sep 2025 22:26:18 +0100
From: "Russell King (Oracle)" <linux@...linux.org.uk>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Peter Zijlstra <peterz@...radead.org>,
	kernel test robot <lkp@...el.com>,
	linux-arm-kernel@...ts.infradead.org,
	Nathan Chancellor <nathan@...nel.org>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	Darren Hart <dvhart@...radead.org>,
	Davidlohr Bueso <dave@...olabs.net>,
	André Almeida <andrealmeid@...lia.com>,
	x86@...nel.org, Alexander Viro <viro@...iv.linux.org.uk>,
	Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
	linux-fsdevel@...r.kernel.org
Subject: Re: [patch V2 1/6] ARM: uaccess: Implement missing
 __get_user_asm_dword()

On Tue, Sep 16, 2025 at 06:33:09PM +0200, Thomas Gleixner wrote:
> When CONFIG_CPU_SPECTRE=n then get_user() is missing the 8 byte ASM variant
> for no real good reason. This prevents using get_user(u64) in generic code.

I'm sure you will eventually discover the reason when you start getting
all the kernel build bot warnings that will result from a cast from a
u64 to a pointer.

You're not the first to try implementing this.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!