Hi Bjorn, On Fri, Oct 05, 2018 at 12:31:45PM -0500, Bjorn Helgaas wrote: > [+cc arm64 folks, LKML: This conversation is about this patch: > > https://lore.kernel.org/linux-pci/20180918235848.26694-3-keith.busch@xxxxxxxxx > > which fixes some PCIe AER error injection bugs, but also makes the error > injector dependent on DYNAMIC_FTRACE_WITH_REGS, which not all arches > support. Note that this question is only about the error *injection* > module used for testing. It doesn't affect AER support itself.] > > On Thu, Oct 04, 2018 at 04:11:37PM -0600, Keith Busch wrote: > > In case this went unnoticed, patch 2's aer_inject using ftrace hooks > > to pci config accessors is really cool and fixes several kernel crashes > > I encountered, but it may not work on every architecture. I'm not sure > > how widely aer_inject is used, so maybe there are no concerns with the > > DYNAMIC_FTRACE_WITH_REGS dependency, but I just want to reemphasize that > > dependency in case there are valid objections. > > Oh, indeed, I hadn't noticed this arch dependency. AFAICT, the new > DYNAMIC_FTRACE_WITH_REGS dependency means aer_inject will work only > on these arches: > > arm # if (!XIP_KERNEL) && !CPU_ENDIAN_BE32 && MMU > powerpc # if PPC64 && CPU_LITTLE_ENDIAN > riscv # ARCH_RV64I only > s390 > x86 > > Notably missing is arm64, which has DYNAMIC_FTRACE but not > DYNAMIC_FTRACE_WITH_REGS. Thanks for the heads-up here. This feature is currently in development for arm64: http://lkml.kernel.org/r/20181001141648.1DBED68BDF@xxxxxxxxxxxxxxxx but the latest review comments suggest that it's a fair way from ready yet, so I wouldn't hold your breath. Will
