Re: [PATCH v2 4/4] uprobes/powerpc: Make use of generic routinesto enable single step

From: Suzuki K. Poulose
Date: Tue Dec 18 2012 - 00:11:19 EST

On 12/15/2012 01:32 AM, Oleg Nesterov wrote:
On 12/03, Suzuki K. Poulose wrote:

Replace the ptrace helpers with the powerpc generic routines to
enable/disable single step. We save/restore the MSR (and DCBR for BookE)
across for the operation. We don't have to disable the single step,
as restoring the MSR/DBCR would restore the previous state.

Obviously I can't review this series (although it looks fine to me).

Just one note,

@@ -121,7 +132,7 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)

WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR);

- uprobe_restore_context_sstep(&utask->autask);
+ uprobe_restore_context_sstep(&utask->autask, regs);

I am not sure ppc needs this, but note that x86 does a bit more.

Not only we need to restore the "single-step" state, we need to
send SIGTRAP if it was not set by us. The same for _skip_sstep.

Ok. I will investigate that part and do the necessary.


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