On Tue, 2014-11-18 at 01:32 -0500, David Long wrote: > From: Sandeepa Prabhu <sandeepa.pra...@linaro.org> > > Add support for basic kernel probes(kprobes) and jump probes > (jprobes) for ARM64. > > Kprobes will utilize software breakpoint and single step debug > exceptions supported on ARM v8. > > software breakpoint is placed at the probe address to trap the > kernel execution into kprobe handler. > > ARM v8 support single stepping to be enabled while exception return > (ERET) with next PC in exception return address (ELR_EL1). > kprobe handler prepares a executable memory slot for out-of-line > execution with the copy of the original instruction under probe, and > enable single stepping from the instruction slot. With this scheme, > the instruction is executed with the exact same register context > 'except PC' that points to instruction slot. > > Debug mask(PSTATE.D) is enabled only when single stepping a recursive > kprobes i.e. during kprobes reenter so that probes instruction can be > single stepped within the kprobe handler -exception- context.
Does this mean that at the point the probed instruction is single-stepped there is nothing extra that has been pushed on on the kernel stack by any kprobes handling code? I just want to check that you aren't going to hit the problems that the 32-bit kprobes code is currently being fixed for [1]. The simulated instructions in patch 2 don't access the stack, so they are safe from the problem. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-November/303525.html -- Tixy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
