lkml.org 
[lkml]   [2011]   [Oct]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 12/X] uprobes: x86: introduce abort_xol()
On Fri, Oct 21, 2011 at 06:42:21PM +0200, Oleg Nesterov wrote:
> On 10/21, Ananth N Mavinakayanahalli wrote:

...

> > 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


\
 
 \ /
  Last update: 2011-10-22 09:11    [from the cache]
©2003-2011 Jasper Spaans