From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Sun, 8 Dec 2013 04:02:41 +0100 Subject: [PATCH] ARM: clean-up common multi-platform kconfig options In-Reply-To: References: <1386262722-26016-1-git-send-email-robherring2@gmail.com> Message-ID: <201312080402.42101.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Sunday 08 December 2013, Nicolas Pitre wrote: > The right fix is probably to leave it as is and optimize your user space > for ARMv6k instead, meaning that this operation would then be > implemented inline rather than relying on the kernel helper. That would not make the program run on ARMv6 though. The bug we're trying to fix is for running a kernel with ARMv6k support built-in on an OMAP2 with ARMv6. The kuser helper already supports cmpxchg for pure v6 builds, but that code doesn't get built (and isn't SMP safe) with CONFIG_CPU_V6K or CONFIG_CPU_V7 enabled. > Otherwise if you really want to optimize the kernel helper at runtime > for ARMv6k when ARMv6 is also configured in, then you could do some > instruction patching in kuser_init() as we already do for getting the > TLS value. This does sound like the cleanest solution. Arnd