Messages in this thread | | | Subject | Re: [PATCH 2/5] uprobes: introduce uprobe_switch_to() | From | Peter Zijlstra <> | Date | Mon, 28 Nov 2011 20:53:38 +0100 |
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On Mon, 2011-11-28 at 20:06 +0100, Oleg Nesterov wrote: > +void uprobe_switch_to(struct task_struct *curr) > +{ > + struct uprobe_task *utask = curr->utask; > + struct pt_regs *regs = task_pt_regs(curr); > + > + if (!utask || utask->state != UTASK_SSTEP) > + return; > + > + if (!(regs->flags & X86_EFLAGS_TF)) > + return; > + > + set_xol_ip(regs); > +}
> void __weak set_xol_ip(struct pt_regs *regs) > { > + int cpu = smp_processor_id(); > + struct uprobe_task *utask = current->utask; > + struct uprobe *uprobe = utask->active_uprobe; > + > + memcpy(uprobe_xol_slots[cpu], uprobe->insn, MAX_UINSN_BYTES); > + > + utask->xol_vaddr = fix_to_virt(UPROBE_XOL_FIRST_PAGE) > + + UPROBES_XOL_SLOT_BYTES * cpu; > + set_instruction_pointer(regs, utask->xol_vaddr); > }
So uprobe_switch_to() will always reset the IP to the start of the slot? That sounds wrong, things like the RIP relative stuff needs multiple instructions.
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