On Tue, 15 Sep 2015 01:06:07 PDT (-0700), peterz@infradead.org wrote:

On Mon, Sep 14, 2015 at 03:50:43PM -0700, Palmer Dabbelt wrote:

quoted

This has a "#ifdef CONFIG_*" that used to be exposed to userspace.

The names in here are so generic that I don't think it's a good idea
to expose them to userspace (or even the rest of the kernel).  Since
there's only one kernel user, it's been moved to that file.

Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
Reviewed-by: Andrew Waterman <redacted>
Reviewed-by: Albert Ou <aou@eecs.berkeley.edu>
---
 include/uapi/linux/hw_breakpoint.h | 10 ----------
 kernel/events/hw_breakpoint.c      | 10 ++++++++++
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/include/uapi/linux/hw_breakpoint.h b/include/uapi/linux/hw_breakpoint.h
index b04000a2296a..7a6a5a7f9511 100644
--- a/include/uapi/linux/hw_breakpoint.h
+++ b/include/uapi/linux/hw_breakpoint.h

@@ -17,14 +17,4 @@ enum {
 	HW_BREAKPOINT_INVALID   = HW_BREAKPOINT_RW | HW_BREAKPOINT_X,
 };

-enum bp_type_idx {
-	TYPE_INST 	= 0,
-#ifdef CONFIG_HAVE_MIXED_BREAKPOINTS_REGS
-	TYPE_DATA	= 0,
-#else
-	TYPE_DATA	= 1,
-#endif
-	TYPE_MAX
-};

This is rather unfortunate; you are correct that the naming is too
generic (and I tend to agree), but I think these values are required by
userspace to fill out:

  perf_event_attr::bp_type

So removing them will break things.

Frederic?

perf_event_open(2) says

       bp_type (since Linux 2.6.33)
              This chooses the breakpoint type.  It is one of:

              HW_BREAKPOINT_EMPTY
                     No breakpoint.

              HW_BREAKPOINT_R
                     Count when we read the memory location.

              HW_BREAKPOINT_W
                     Count when we write the memory location.

              HW_BREAKPOINT_RW
                     Count when we read or write the memory location.

              HW_BREAKPOINT_X
                     Count when we execute code at the memory location.

              The values can be combined via a bitwise or, but the combination
              of HW_BREAKPOINT_R or HW_BREAKPOINT_W  with  HW_BREAKPOINT_X  is
              not allowed.

so I think removing this enum from userspace is OK.  Did I miss
something?