On 11/23/2011 10:47 AM, Josh Boyer wrote: > On Mon, Nov 14, 2011 at 12:41 AM, Suzuki K. Poulose <suz...@in.ibm.com> wrote: >> The current implementation of CONFIG_RELOCATABLE in BookE is based >> on mapping the page aligned kernel load address to KERNELBASE. This >> approach however is not enough for platforms, where the TLB page size >> is large (e.g, 256M on 44x). So we are renaming the RELOCATABLE used >> currently in BookE to DYNAMIC_MEMSTART to reflect the actual method.
Should reword the config help to make it clear what the alignment restriction is, or where to find the information for a particular platform. Someone reading "page aligned" without any context that we're talking about special large pages is going to think 4K -- and on e500, many large page sizes are supported, so the required alignment is found in Linux init code rather than a CPU manual. >> >> The CONFIG_RELOCATABLE for PPC32(BookE) based on processing of the >> dynamic relocations will be introduced in the later in the patch series. >> >> This change would allow the use of the old method of RELOCATABLE for >> platforms which can afford to enforce the page alignment (platforms with >> smaller TLB size). > > I'm OK with the general direction, but this touches a lot of non-4xx > code. I'd prefer it if Ben took this directly on whatever final > solution is done. > >> I haven tested this change only on 440x. I don't have an FSL BookE to verify >> the changes there. >> >> Scott, >> Could you please test this patch on FSL and let me know the results ? > > Scott, did you ever get around to testing this? In my opinion, this > shouldn't go in without a Tested-by: from someone that tried it on an > FSL platform. Booted OK for me on e500v2 with RAM starting at 256M. Tested-by: Scott Wood <scottw...@freescale.com> > We add DYNAMIC_MEMSTART for 32-bit, and we have RELOCATABLE for > 64-bit. Then throughout almost the rest of the patch, all we're doing > is duplicating what RELOCATABLE already did (e.g. if ! either thing). > It works, but it is kind of ugly. > > Instead, could we define a helper config variable that can be used in > place of that construct? Something like: > > config NONSTATIC_KERNEL (or whatever) > bool > default n > > ... > > config DYNAMIC_MEMSTART > <blah> > select NONSTATIC_KERNEL > > ... > > config RELOCATABLE > <blah> > select NONSTATIC_KERNEL I agree. -Scott _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
