uprobes: allow ignoring of probe hits

Allow arches to decided to ignore a probe hit.  ARM will use this to
only call handlers if the conditions to execute a conditionally executed
instruction are satisfied.

Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 307d87c0991a..04709b66369d 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1804,6 +1804,11 @@ static bool handle_trampoline(struct pt_regs *regs)
         return true;
 }
 
+bool __weak arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs)
+{
+        return false;
+}
+
 /*
  * Run handler and ask thread to singlestep.
  * Ensure all non-fatal signals cannot interrupt thread while it singlesteps.
@@ -1858,7 +1863,11 @@ static void handle_swbp(struct pt_regs *regs)
         if (!get_utask())
                 goto out;
 
+        if (arch_uprobe_ignore(&uprobe->arch, regs))
+                goto out;
+
         handler_chain(uprobe, regs);
+
         if (can_skip_sstep(uprobe, regs))
                 goto out;