From mboxrd@z Thu Jan 1 00:00:00 1970 From: oleg@redhat.com (Oleg Nesterov) Date: Tue, 9 Aug 2016 20:49:44 +0200 Subject: [PATCH 5/5] arm64: Add uprobe support In-Reply-To: References: Message-ID: <20160809184943.GA17112@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 08/02, Pratyush Anand wrote: > > This patch adds support for uprobe on ARM64 architecture. I know nothing about ARM, so I can't actually review this change. But it looks good to me ;) Just one note, > +int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) > +{ > + struct uprobe_task *utask = current->utask; > + > + /* saved fault code is restored in post_xol */ > + utask->autask.saved_fault_code = current->thread.fault_code; > + > + /* An invalid fault code between pre/post xol event */ > + current->thread.fault_code = UPROBE_INV_FAULT_CODE; > + > + /* Instruction point to execute ol */ > + instruction_pointer_set(regs, utask->xol_vaddr); > + > + user_enable_single_step(current); I don't think we want user_{enable,disable{_single_step in the long term, please look at 9bd1190a11c9d2 "uprobes/x86: Do not (ab)use TIF_SINGLESTEP /user_*_single_step() for single-stepping". it seems that ARM64 sets/clears TIF_SINGLESTEP. You can also lool at saved_tf logic, probably ARM64 needs the same. However, I agree we can do this later and initial version can use these ptrace helpers. Oleg.