From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@arm.linux.org.uk (Russell King - ARM Linux) Date: Mon, 5 Jul 2010 19:14:21 +0100 Subject: [PATCH v2 0/8] Initial implementation of kdump for ARM In-Reply-To: <4C31FC27.4010102@stericsson.com> References: <20100611063605.GB11156@esdhcp04058.research.nokia.com> <4C2DE024.8060308@stericsson.com> <20100705082835.GA32178@gw.healthdatacare.com> <4C31AD62.6070805@stericsson.com> <20100705101852.GA19338@n2100.arm.linux.org.uk> <4C31B527.8060401@stericsson.com> <20100705135552.GB19338@n2100.arm.linux.org.uk> <4C31E6C4.8030200@stericsson.com> <20100705141926.GA23860@n2100.arm.linux.org.uk> <4C31FC27.4010102@stericsson.com> Message-ID: <20100705181421.GA27771@n2100.arm.linux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Jul 05, 2010 at 05:37:11PM +0200, Per Fransson wrote: > On 07/05/2010 04:19 PM, Russell King - ARM Linux wrote: > > On Mon, Jul 05, 2010 at 04:05:56PM +0200, Per Fransson wrote: > >> Well, I had another suggestion in my last mail. > > > > Which is going to need per-CPU type support in order to achieve. Do > > we really want to implement relocate_new_kernel for each of the 24 > > CPU types which we currently support? > > > > Perhaps not. Couldn't the variable delay be macrofied then, i.e. a > macro like > > MMU_DISABLED_DELAY_AND_EXEC() > > which would do nothing for an appropriate amount of time and put the > instruction in the last MMU mapped slot? There is no "appropriate amount of time" - some CPUs depend on many effects that a "3 nops and you'll be fine" approach doesn't work. Also, what about kernels that support multiple different CPU types.