coresight: A DLKM to abort trace on userspace abort
A DLKM to abort tracing on an user space data, prefetch or
undefined instruction abort.
Change-Id: Iaba14628601ea6d3649e05423f8570131eea39f7
Signed-off-by: Pushkar Joshi <pushkarj@codeaurora.org>
diff --git a/drivers/coresight/Kconfig b/drivers/coresight/Kconfig
index 1219af1..a23fff0 100644
--- a/drivers/coresight/Kconfig
+++ b/drivers/coresight/Kconfig
@@ -30,3 +30,12 @@
For production builds, you should probably say 'N' here to avoid
potential power, performance and memory penalty.
+
+config CONTROL_TRACE
+ tristate "Turn on to control tracing"
+ help
+ Builds module to abort tracing on a user space data, instruction
+ or prefetch abort.
+
+ For production builds, you should probably say 'N' here to avoid
+ potential power, performance and memory penalty.
diff --git a/drivers/coresight/Makefile b/drivers/coresight/Makefile
index 4ee93cf..a2815de 100644
--- a/drivers/coresight/Makefile
+++ b/drivers/coresight/Makefile
@@ -1,3 +1,3 @@
-
+obj-$(CONFIG_CONTROL_TRACE) += control_trace.o
obj-$(CONFIG_OF) += of_coresight.o
obj-$(CONFIG_MSM_QDSS) += coresight.o coresight-csr.o coresight-tmc.o coresight-tpiu.o coresight-etb.o coresight-funnel.o coresight-replicator.o coresight-stm.o coresight-etm.o
diff --git a/drivers/coresight/control_trace.c b/drivers/coresight/control_trace.c
new file mode 100644
index 0000000..aa8bfc5
--- /dev/null
+++ b/drivers/coresight/control_trace.c
@@ -0,0 +1,71 @@
+/* Copyright (c) 2012, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+/*
+ * DLKM to register a callback with a ftrace event
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/tracepoint.h>
+#include <linux/coresight.h>
+
+#include <trace/events/exception.h>
+
+static void abort_coresight_tracing(void *ignore, struct task_struct *task,\
+ unsigned long addr, unsigned int fsr)
+{
+ coresight_abort();
+ pr_debug("control_trace: task_name: %s, addr: %lu, fsr:%u",\
+ (char *)task->comm, addr, fsr);
+}
+
+static void abort_tracing_undef_instr(void *ignore, struct pt_regs *regs,\
+ void *pc)
+{
+ if (user_mode(regs)) {
+ coresight_abort();
+ pr_debug("control_trace: pc: %p", pc);
+ }
+}
+
+static int __init control_trace_init(void)
+{
+ int ret_user_fault, ret_undef_instr;
+ ret_user_fault = register_trace_user_fault(abort_coresight_tracing,\
+ NULL);
+ ret_undef_instr = register_trace_undef_instr(abort_tracing_undef_instr,\
+ NULL);
+ if (ret_user_fault != 0 || ret_undef_instr != 0) {
+ pr_info("control_trace: Module Not Registered\n");
+ return (ret_user_fault < 0 ?\
+ ret_user_fault : ret_undef_instr);
+ }
+ pr_info("control_trace: Module Registered\n");
+ return 0;
+}
+
+module_init(control_trace_init);
+
+static void __exit control_trace_exit(void)
+{
+ unregister_trace_user_fault(abort_coresight_tracing, NULL);
+ unregister_trace_undef_instr(abort_tracing_undef_instr, NULL);
+ pr_info("control_trace: Module Removed\n");
+}
+
+module_exit(control_trace_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Kernel Module to abort tracing");