[RFC] kprobe'ing conditionally executed instructions

From: David Long
Date: Fri Dec 11 2015 - 00:06:13 EST


There is a moderate amount of code already in kprobes on ARM and the current ARMv8 patch to deal with conditional execution of instructions. One aspect of how this is handled is that instructions that fail their predicate and are not (technically) executed are also not treated as a hit kprobe. Steve Capper has suggested that the probe handling should still take place because we stepped through the instruction even if it was effectively a nop. This would be a significant change in how it currently works on 32-bit ARM, and a change in the patch for ARMv8 (although it's not likely to be much of a change in the kernel code).

I need input on this. Do people have opinions?

-dl

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