> Overall, the monolithic natural of Linux Kernel and its strict licensing terms made it hard to get code upstreamed back or to write properly modularized driver extensions.
The postmarketOS folks are doing it, starting from downstream OEM Linux kernels, and the patches are being accepted on LKML. It's a lot of work because so much ARM hardware is its own weird mixture of long-supported basic IP blocks and newer stuff with its own quirks, and ARM has nothing like the plug-and-play hardware enumeration of modern x86 systems. So untangling all of this just takes a lot of time and effort. But this has nothing to do with Linux per se; it's all about the ARM system architecture itself and the SoC-based industry that has sprung up around it.
And no, running a microkernel-based system won't help at all, because any hardware that's part of the SoC can read or write arbitrary memory hence your driver can (perhaps unwittingly) subvert the very same security mechanisms you're supposedly relying on. Not to mention that some of these drivers handle, e.g. voltage regulators that will happily fry your hardware irreversibly if poked the wrong way. All of this stuff is inherently part of the trusted base of your system, so you're not going to do any better than what Linux already gives you.
The postmarketOS folks are doing it, starting from downstream OEM Linux kernels, and the patches are being accepted on LKML. It's a lot of work because so much ARM hardware is its own weird mixture of long-supported basic IP blocks and newer stuff with its own quirks, and ARM has nothing like the plug-and-play hardware enumeration of modern x86 systems. So untangling all of this just takes a lot of time and effort. But this has nothing to do with Linux per se; it's all about the ARM system architecture itself and the SoC-based industry that has sprung up around it.
And no, running a microkernel-based system won't help at all, because any hardware that's part of the SoC can read or write arbitrary memory hence your driver can (perhaps unwittingly) subvert the very same security mechanisms you're supposedly relying on. Not to mention that some of these drivers handle, e.g. voltage regulators that will happily fry your hardware irreversibly if poked the wrong way. All of this stuff is inherently part of the trusted base of your system, so you're not going to do any better than what Linux already gives you.