* Oleg Nesterov <o...@redhat.com> [2012-12-30 16:47:22]:
> Change handle_swbp() to set regs->ip = bp_vaddr in advance, this is
> what consumer->handler() needs but uprobe_get_swbp_addr() is not
> exported.
>
> This also simplifies the code and makes it more consistent across
> the supported architectures. handle_swbp() becomes the only caller
> of uprobe_get_swbp_addr().
>
> Signed-off-by: Oleg Nesterov <o...@redhat.com>
Acked-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com>
> ---
> arch/x86/kernel/uprobes.c | 1 -
> kernel/events/uprobes.c | 15 +++++++--------
> kernel/trace/trace_uprobe.c | 4 ++--
> 3 files changed, 9 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
> index 4e33a35..0ba4cfb 100644
> --- a/arch/x86/kernel/uprobes.c
> +++ b/arch/x86/kernel/uprobes.c
> @@ -681,7 +681,6 @@ static bool __skip_sstep(struct arch_uprobe *auprobe,
> struct pt_regs *regs)
> continue;
>
> if (auprobe->insn[i] == 0x90) {
> - regs->ip = uprobe_get_swbp_addr(regs);
> regs->ip += i + 1;
> return true;
> }
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index 59b6e97..f883813 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -1504,6 +1504,10 @@ static void handle_swbp(struct pt_regs *regs)
> }
> return;
> }
> +
> + /* change it in advance for ->handler() and restart */
> + instruction_pointer_set(regs, bp_vaddr);
> +
> /*
> * TODO: move copy_insn/etc into _register and remove this hack.
> * After we hit the bp, _unregister + _register can install the
> @@ -1511,14 +1515,14 @@ static void handle_swbp(struct pt_regs *regs)
> */
> smp_rmb(); /* pairs with wmb() in install_breakpoint() */
> if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags)))
> - goto restart;
> + goto out;
>
> utask = current->utask;
> if (!utask) {
> utask = add_utask();
> /* Cannot allocate; re-execute the instruction. */
> if (!utask)
> - goto restart;
> + goto out;
> }
>
> handler_chain(uprobe, regs);
> @@ -1531,12 +1535,7 @@ static void handle_swbp(struct pt_regs *regs)
> return;
> }
>
> -restart:
> - /*
> - * cannot singlestep; cannot skip instruction;
> - * re-execute the instruction.
> - */
> - instruction_pointer_set(regs, bp_vaddr);
> + /* can_skip_sstep() succeeded, or restart if can't singlestep */
> out:
> put_uprobe(uprobe);
> }
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index 38eee92..52caead 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -488,7 +488,7 @@ static void uprobe_trace_func(struct trace_uprobe *tu,
> struct pt_regs *regs)
> return;
>
> entry = ring_buffer_event_data(event);
> - entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));
> + entry->ip = instruction_pointer(task_pt_regs(current));
> data = (u8 *)&entry[1];
> for (i = 0; i < tu->nr_args; i++)
> call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
> @@ -663,7 +663,7 @@ static void uprobe_perf_func(struct trace_uprobe *tu,
> struct pt_regs *regs)
> if (!entry)
> goto out;
>
> - entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));
> + entry->ip = instruction_pointer(task_pt_regs(current));
> data = (u8 *)&entry[1];
> for (i = 0; i < tu->nr_args; i++)
> call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
> --
> 1.5.5.1
>
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