On Thursday, June 21, 2018 1, Nicolas Pitre wrote: > > I've just sent a patch to do that. > > Your patch isn't wrong per se. But it is not enough. The issue here > would be easily fixed with some kconfig extension so that: > > - If XIP or NOMMU is selected then only one target in the multiplatform > set can be selected, basically turning it into a choice menu. > > - If more than one multiplatform targets is selected then XIP and NOMMU > can no longere be selected. > Over the years I tried to tackle this issue in multiple different ways, while still staying in the limitations of kbuild. Basically, everything was shot down for one reason or another (or the only way to do it is really ugly...so I didn't even ask). kbuild doesn't really have a mutually exclusive property that can be dynamically set/cleared. In the end, I saw only 2 paths for adding XIP to ARM MMU builds: 1) Modify kbuild to give the ability as stated above. 2) Make XIP builds somehow be able to run at multiple physical address by modifying the binaries post-build (Arnd's suggestion). What I have been doing is simply applying this patch to arch/arm/Kconifg before every XIP KERNEL build: config XIP_KERNEL bool "Kernel Execute-In-Place from ROM" - depends on !ARM_LPAE && !ARCH_MULTIPLATFORM + depends on !ARM_LPAE help Execute-In-Place allows the kernel to run from non-volatile storage directly addressable by the CPU, such as NOR flash. This saves RAM 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
