On Sun, 26 Apr 2015 18:16:09 +0200 Borislav Petkov <[email protected]> wrote:
> > Yeah, it is removed but it adds a bunch of ugly ifdeffery which makes > the code even more unreadable than it is :-\ > I wasn't to happy about the nested ifdefs either, but given my inexperience in the kernel code I didn't want to push things around too much. It should be possible to better hide the X86_32 pointer wizardry in a macro, but I wouldn't trust myself submitting patches for code I didn't run. Perhaps I should and just ask for testers. > > In the future, please CC me on microcode loader patches. > Will do. > > * why do you even bother - BLK_DEV_INITRD gets enabled on all distro > kernels and almost everything running Linux so why bother? Or do you > have a special use case which doesn't want BLK_DEV_INITRD. I'd be > interested to hear about it. > I trimmed my kernel config down to what I need, think I need or don't trust myself to know if I can disable it. There is nothing actually hindering me from using an initrd, so this patch, at least for me personally, does not have a high priority to become mainlined. It still would be nice of course. I had some segfaults due to the broken lock elision features of my CPU and found out that built-in microcode isn't considered (in the stable kernel). When I saw your patch for loading built-in microcode I simply thought that this would allow me to have early microcode patching without the need of an initrd. Boot-time might be improved by this and of course a few bytes are saved, but all in all probably not noteworthy. I did it, because (I thought) I can. > * the early loader was done with initrd in mind and it was/still is its > main source for microcode blobs early in the boot. So if we want to > make it not-mandatory, then the driver needs to be reorganized so that > builtin blobs and initrd blobs loading paths are cleanly untangled. The > ifdeffery thing might work now but is certainly not future-proof so it > would need to be designed in a cleaner way. > > Perhaps something like a microcode cache of patches the AMD loader has, > all decoupled from the loading paths or so... I don't have a good idea > right now. I'll have to think about it. > It seems logical that the code was written with initrd in mind for early boot. What would be the downside of a microcode cache? I didn't follow the whole flow of how the CPUs get to their microcode patches, but I thought the mc_saved* stuff did caching of the microcode, since scan_microcode, the only user of load_builtin_intel_microcode, is only called for the BSP and the other cores thus seem to get it from somewhere else. Thanks, Alexander Hirsch -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
