On Wed, Apr 14, 2021 at 05:22:58PM +0900, Masami Hiramatsu wrote: > Hi Jisheng, > > On Wed, 14 Apr 2021 15:27:28 +0800 > Jisheng Zhang <jisheng.zh...@synaptics.com> wrote: > > \ > > > > > > On Tue, 13 Apr 2021 18:03:24 +0800 > > > Jisheng Zhang <jisheng.zh...@synaptics.com> wrote: > > > > > > > Use the __vmalloc_node_range() to simplify x86's alloc_insn_page() > > > > implementation. > > > > > > Have you checked this is equivarent to the original code on all > > > architecture? IIRC, some arch has a special module_alloc(), > > > > > Indeed, this isn't equivarent to the original code. FWICT, the > > > differences on x86 are: > > > > > 1) module_alloc() allocates a special vmalloc range > > > 2) module_alloc() randomizes the return address via. module_load_offset() > > > 3) module_alloc() also supports kasan instrumentation by > > > kasan_module_alloc() > > > > > But I'm not sure whether the above differences are useful for kprobes ss > > > insn slot page or not. Take 1) for example, special range in module_alloc > > > is due to relative jump limitation, modules need to call kernel .text. > > > does > > > kprobes ss ins slot needs this limitation too? > > > > Oops, I found this wonderful thread: > > https://www.lkml.org/lkml/2020/7/28/1413 > > > > So kprobes ss ins slot page "must be in the range of relative branching only > > for x86 and arm" > > Yes, at this moment. (Not sure we can introduce similar feature on other arch > too) > > > > > And Jarkko's "arch/x86: kprobes: Remove MODULES dependency" series look > > much better. The last version is v5, I'm not sure whether Jarkko will > > send new version to mainline the series. > > I hope so. If module_alloc() itself is implemented on the generic > text_alloc(), > I can replace the module_alloc() with text_alloc().
I can of course look into this too. Right now in two vacation coming back end of this month. /Jarkko
