From mboxrd@z Thu Jan 1 00:00:00 1970 From: nicolas.pitre@linaro.org (Nicolas Pitre) Date: Mon, 6 Aug 2012 14:02:19 -0400 (EDT) Subject: [PATCH 01/22] ARM: add mechanism for late code patching In-Reply-To: <20120806132642.GC18957@n2100.arm.linux.org.uk> References: <1343775898-28345-1-git-send-email-cyril@ti.com> <1343775898-28345-2-git-send-email-cyril@ti.com> <20120806111224.GA18957@n2100.arm.linux.org.uk> <501FC44E.1040806@ti.com> <20120806132642.GC18957@n2100.arm.linux.org.uk> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, 6 Aug 2012, Russell King - ARM Linux wrote: > On Mon, Aug 06, 2012 at 09:19:10AM -0400, Cyril Chemparathy wrote: > > With a flush_cache_all(), we could avoid having to operate a cacheline > > at a time, but that clobbers way more than necessary. > > You can't do that, because flush_cache_all() on some CPUs requires the > proper MMU mappings to be in place, and you can't get those mappings > in place because you don't have the V:P offsets fixed up in the kernel. > Welcome to the chicken and egg problem. This problem is fixed in this case by having the p2v and v2p code sites using an out-of-line non optimized computation until those sites are runtime patched with the inlined optimized computation we have today. Nicolas