> 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. CONFIG_PHYS_OFFSET (RAM address) and CONFIG_XIP_PHYS_ADDR (ROM address) are set today in kconfig. Instead of having them hard coded, they could be global variables set during boot. CONFIG_XIP_PHYS_ADDR could be determined by looking at the value of the PC. CONFIG_PHYS_OFFSET is still the issue because that has to be passed in via boot register. > I suppose someone who was sufficiently motivated could write assembly- > based parsing of DT to extract the memory regions and work out what the > right settings are. Is there really the motivation to do that - there > was a burst of XIP interest a few releases ago but it seems to have > tailed off. Because at least for me, by simply removing the !ARCH_MULTIPLATFORM dependency for setting XIP_KERNEL works perfectly fine for building and running kernels. So, it's hard to justify doing a lot more work than what can be done today with just 1 line edit. I still test every kernel release to make XIP_KERNEL still works. Actually, I just tested 4.18.0-rc1 this morning. Chris -- 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
