* Oleg Nesterov <o...@redhat.com> [2012-10-28 18:39:31]:
> No functional changes.
>
> Now that default arch_uprobe_enable/disable_step() helpers do nothing,
> x86 has no reason to reimplement them. Change arch_uprobe_*_xol() hooks
> to do the necessary work and remove the x86-specific hooks.
>
> Signed-off-by: Oleg Nesterov <o...@redhat.com>
Acked-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com>
> ---
> arch/x86/kernel/uprobes.c | 54 +++++++++++++++-----------------------------
> 1 files changed, 19 insertions(+), 35 deletions(-)
>
> diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
> index aafa555..c71025b 100644
> --- a/arch/x86/kernel/uprobes.c
> +++ b/arch/x86/kernel/uprobes.c
> @@ -478,6 +478,11 @@ int arch_uprobe_pre_xol(struct arch_uprobe *auprobe,
> struct pt_regs *regs)
> regs->ip = current->utask->xol_vaddr;
> pre_xol_rip_insn(auprobe, regs, autask);
>
> + autask->saved_tf = !!(regs->flags & X86_EFLAGS_TF);
> + regs->flags |= X86_EFLAGS_TF;
> + if (test_tsk_thread_flag(current, TIF_BLOCKSTEP))
> + set_task_blockstep(current, false);
> +
> return 0;
> }
>
> @@ -603,6 +608,16 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe,
> struct pt_regs *regs)
> if (auprobe->fixups & UPROBE_FIX_CALL)
> result = adjust_ret_addr(regs->sp, correction);
>
> + /*
> + * arch_uprobe_pre_xol() doesn't save the state of TIF_BLOCKSTEP
> + * so we can get an extra SIGTRAP if we do not clear TF. We need
> + * to examine the opcode to make it right.
> + */
> + if (utask->autask.saved_tf)
> + send_sig(SIGTRAP, current, 0);
> + else if (!(auprobe->fixups & UPROBE_FIX_SETF))
> + regs->flags &= ~X86_EFLAGS_TF;
> +
> return result;
> }
>
> @@ -647,6 +662,10 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe,
> struct pt_regs *regs)
> current->thread.trap_nr = utask->autask.saved_trap_nr;
> handle_riprel_post_xol(auprobe, regs, NULL);
> instruction_pointer_set(regs, utask->vaddr);
> +
> + /* clear TF if it was set by us in arch_uprobe_pre_xol() */
> + if (!utask->autask.saved_tf)
> + regs->flags &= ~X86_EFLAGS_TF;
> }
>
> /*
> @@ -676,38 +695,3 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe,
> struct pt_regs *regs)
> send_sig(SIGTRAP, current, 0);
> return ret;
> }
> -
> -void arch_uprobe_enable_step(struct arch_uprobe *auprobe)
> -{
> - struct task_struct *task = current;
> - struct arch_uprobe_task *autask = &task->utask->autask;
> - struct pt_regs *regs = task_pt_regs(task);
> -
> - autask->saved_tf = !!(regs->flags & X86_EFLAGS_TF);
> -
> - regs->flags |= X86_EFLAGS_TF;
> - if (test_tsk_thread_flag(task, TIF_BLOCKSTEP))
> - set_task_blockstep(task, false);
> -}
> -
> -void arch_uprobe_disable_step(struct arch_uprobe *auprobe)
> -{
> - struct task_struct *task = current;
> - struct arch_uprobe_task *autask = &task->utask->autask;
> - bool trapped = (task->utask->state == UTASK_SSTEP_TRAPPED);
> - struct pt_regs *regs = task_pt_regs(task);
> - /*
> - * The state of TIF_BLOCKSTEP was not saved so we can get an extra
> - * SIGTRAP if we do not clear TF. We need to examine the opcode to
> - * make it right.
> - */
> - if (unlikely(trapped)) {
> - if (!autask->saved_tf)
> - regs->flags &= ~X86_EFLAGS_TF;
> - } else {
> - if (autask->saved_tf)
> - send_sig(SIGTRAP, task, 0);
> - else if (!(auprobe->fixups & UPROBE_FIX_SETF))
> - regs->flags &= ~X86_EFLAGS_TF;
> - }
> -}
> --
> 1.5.5.1
>
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