x86, ptrace: overflow signal API
Establish the user API for sending a user-defined signal to the traced task on a BTS buffer overflow.
This should complete the user API for the BTS ptrace extension.
The patches so far implement wrap-around overflow handling as is needed for debugging.
The remaining open is another overflow handling mechanism that sends a signal to the traced task on a buffer overflow.
This will take some more time from my side.
Since, from a user perspective, this occurs behind the scenes, the patch set should already be useful. More features may/will be added on top of it (overflow signal, pageable back-up buffers, kernel tracing, core file support, profiling, ...).
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/asm-x86/ptrace-abi.h b/include/asm-x86/ptrace-abi.h
index bcf6704..b3b9e02 100644
--- a/include/asm-x86/ptrace-abi.h
+++ b/include/asm-x86/ptrace-abi.h
@@ -88,11 +88,13 @@
unsigned int size;
/* bitmask of below flags */
unsigned int flags;
+ /* buffer overflow signal */
+ unsigned int signal;
};
#define PTRACE_BTS_O_TRACE 0x1 /* branch trace */
#define PTRACE_BTS_O_SCHED 0x2 /* scheduling events w/ jiffies */
-#define PTRACE_BTS_O_SIGNAL 0x4 /* send SIG? on buffer overflow
+#define PTRACE_BTS_O_SIGNAL 0x4 /* send SIG<signal> on buffer overflow
instead of wrapping around */
#define PTRACE_BTS_O_CUT_SIZE 0x8 /* cut requested size to max available
instead of failing */