Re: Dealing with the NMI mess

[Ingo Molnar <mingo@kernel.org>]

* Maciej W. Rozycki <macro@linux-mips.org> wrote:

>  I did some work on this a few years ago, including emulating DR0-7 accesses in 
> software down the JTAG handler upon a General Detect fault to keep the kernel 
> both happy and away from real debug registers. ;) Yes, you can debug any 
> software with this stuff, including the Linux kernel: set instruction and data 
> breakpoints, single-step it, poke at all hardware registers, including 
> descriptor registers not otherwise accessible (you can set funny modes for 
> segments, also in the 64-bit mode), etc.  One complication though is you operate 
> on physical addresses when poking at memory, you can't ask the CPU's MMU to 
> remap them for you (you can walk page tables manually of course, just as the MMU 
> would).

Essentially the ICE breakpoint instruction enters SMM mode?

Thanks,

	Ingo