On Fri, 22 Jun 2018, Russell King - ARM Linux wrote: > On Fri, Jun 22, 2018 at 12:54:18PM -0400, Nicolas Pitre wrote: > > On Fri, 22 Jun 2018, Russell King - ARM Linux wrote: > > > > > On Fri, Jun 22, 2018 at 12:21:33PM -0400, Nicolas Pitre wrote: > > > > On Fri, 22 Jun 2018, Russell King - ARM Linux wrote: > > > > > That is actually incorrect - you're too used to the dynamic fixup of > > > > > virt_to_phys() and friends now! > > > > > > > > > > Given that XIP is typically used in environments where the kernel text > > > > > is very much unmodifyable, we disable CONFIG_ARM_PATCH_PHYS_VIRT. When > > > > > disabled, we use a constant translation, based upon the build-time > > > > > CONFIG_PHYS_OFFSET and CONFIG_PAGE_OFFSET settings. > > > > > > > > > > The early assembler relies upon these settings - which must be known > > > > > before we enable the MMU. As such, DT parsing is not available to us > > > > > at that point (as we can't run any C code, because we won't be calling > > > > > it at the address it was linked for.) > > > > > > > > I think you got me wrong. I meant DT parsing at config or build time, > > > > not at run time. > > > > > > That seems backwards and complicated. It seems this would end up > > > with: > > > > > > - you configure the kernel > > > - build the dtb files > > > - reconfigure parsing a specific dtb file built in the previous step > > > - build the kernel proper > > > > ... or just stick the right value manually when prompting for > > XIP_PHYS_ADDR. Really, depending on DT is a non issue that only pulls > > the conversation away from the actual kconfig language limitation that > > needs to be overcome. > > Which is _exactly_ what we do today, so I don't see what point you're > making in this sub-thread. I was merely trying to show Geert that DT dependencies are not an issue after he brought that as an argument. Nicolas -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
