Re: [GIT PULL] x86/asm changes for v5.6

From: Borislav Petkov
Date: Tue Jan 28 2020 - 17:31:29 EST


On Tue, Jan 28, 2020 at 01:04:19PM -0800, Linus Torvalds wrote:
> On Tue, Jan 28, 2020 at 12:41 PM Luck, Tony <tony.luck@xxxxxxxxx> wrote:
> >
> > Is there still some easy way to get gdb to disassemble from /dev/kmem
> > to see what we ended up with after all the patching?
>
> Hmm. No, I think it's all gone.
>
> It _used_ to be easy to just do "objdump --disassemble /proc/kcore" as
> root, but I think we've broken that long ago.

Either booting with "debug-alternative" on baremetal or starting a guest
and stopping it with gdb and examining the patched memory is what I've
been using to hack on the alternatives in past years. Guest won't help
you a whole lot with FSRM but you could "force it", for example.

--
Regards/Gruss,
Boris.

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