Messages in this thread | | | Date | Sat, 22 Oct 2011 12:39:52 +0530 | From | Ananth N Mavinakayanahalli <> | Subject | Re: [PATCH 12/X] uprobes: x86: introduce abort_xol() |
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On Fri, Oct 21, 2011 at 06:42:21PM +0200, Oleg Nesterov wrote: > On 10/21, Ananth N Mavinakayanahalli wrote:
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> > For instance, on x86, it points to the next > > instruction, > > No?
At exception entry, we'd not have done the following fixup...
> /** > * get_uprobe_bkpt_addr - compute address of bkpt given post-bkpt regs > * @regs: Reflects the saved state of the task after it has hit a breakpoint > * instruction. > * Return the address of the breakpoint instruction. > */ > unsigned long __weak get_uprobe_bkpt_addr(struct pt_regs *regs) > { > return instruction_pointer(regs) - UPROBES_BKPT_INSN_SIZE; > } > > Yes, initially regs->ip points to the next insn after int3, but > utask->vaddr == get_uprobe_bkpt_addr() == addr of int3. > > Right?
Yes, we fix it up so we point to the right (breakpoint) address.
> > while on powerpc, the nip points to the breakpoint vaddr > > at the time of exception. > > I think get_uprobe_bkpt_addr() should be consistent on every arch. > That is why (I think) it is __weak.
Yes, that is the intention.
> Anyway, abort_xol() has to be arch-specific.
Agree.
Ananth
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