Messages in this thread | | | Date | Thu, 5 Mar 2015 09:35:19 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v2 07/15] x86/lib/copy_user_64.S: Convert to ALTERNATIVE_2 |
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On Thu, Mar 05, 2015 at 01:32:49AM +0100, Ingo Molnar wrote: > We could also do a (limited) relink during early bootup, as part of > the alternatives patching pass in essence: for that we need to stick > the relocation info into a section and put that into the vmlinux.
Oh, you want us to do our own asm inlining, so to speak, and save us even a CALL. Well, that would be more involved and saving a single CALL is making me question the effort.
Also, with shifted virtual addresses at boot time, debuggability becomes a serious pain because "objdump -D vmlinux" output is worthless all of a sudden.
For example, even during doing those patches, I had to go and dump kernel memory to see what actually gets patched in. And without kvm and the monitor console, I would've had a serious hard time. If you change larger portions of the kernel at early boot, that might make the whole endeavor of debugging a serious undertaking. I already dread the moment when I'd have to look at a kaslr'ed splat.
We'll see.
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply. --
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