ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/samples/hw_breakpoint/data_breakpoint.c b/marvell/linux/samples/hw_breakpoint/data_breakpoint.c
new file mode 100644
index 0000000..418c46f
--- /dev/null
+++ b/marvell/linux/samples/hw_breakpoint/data_breakpoint.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * data_breakpoint.c - Sample HW Breakpoint file to watch kernel data address
+ *
+ * usage: insmod data_breakpoint.ko ksym=<ksym_name>
+ *
+ * This file is a kernel module that places a breakpoint over ksym_name kernel
+ * variable using Hardware Breakpoint register. The corresponding handler which
+ * prints a backtrace is invoked every time a write operation is performed on
+ * that variable.
+ *
+ * Copyright (C) IBM Corporation, 2009
+ *
+ * Author: K.Prasad <prasad@linux.vnet.ibm.com>
+ */
+#include <linux/module.h> /* Needed by all modules */
+#include <linux/kernel.h> /* Needed for KERN_INFO */
+#include <linux/init.h> /* Needed for the macros */
+#include <linux/kallsyms.h>
+
+#include <linux/perf_event.h>
+#include <linux/hw_breakpoint.h>
+
+struct perf_event * __percpu *sample_hbp;
+
+static char ksym_name[KSYM_NAME_LEN] = "jiffies";
+module_param_string(ksym, ksym_name, KSYM_NAME_LEN, S_IRUGO);
+MODULE_PARM_DESC(ksym, "Kernel symbol to monitor; this module will report any"
+ " write operations on the kernel symbol");
+
+static void sample_hbp_handler(struct perf_event *bp,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ printk(KERN_INFO "%s value is changed\n", ksym_name);
+ dump_stack();
+ printk(KERN_INFO "Dump stack from sample_hbp_handler\n");
+}
+
+static int __init hw_break_module_init(void)
+{
+ int ret;
+ struct perf_event_attr attr;
+ void *addr = __symbol_get(ksym_name);
+
+ if (!addr)
+ return -ENXIO;
+
+ hw_breakpoint_init(&attr);
+ attr.bp_addr = (unsigned long)addr;
+ attr.bp_len = HW_BREAKPOINT_LEN_4;
+ attr.bp_type = HW_BREAKPOINT_W;
+
+ sample_hbp = register_wide_hw_breakpoint(&attr, sample_hbp_handler, NULL);
+ if (IS_ERR((void __force *)sample_hbp)) {
+ ret = PTR_ERR((void __force *)sample_hbp);
+ goto fail;
+ }
+
+ printk(KERN_INFO "HW Breakpoint for %s write installed\n", ksym_name);
+
+ return 0;
+
+fail:
+ printk(KERN_INFO "Breakpoint registration failed\n");
+
+ return ret;
+}
+
+static void __exit hw_break_module_exit(void)
+{
+ unregister_wide_hw_breakpoint(sample_hbp);
+ symbol_put(ksym_name);
+ printk(KERN_INFO "HW Breakpoint for %s write uninstalled\n", ksym_name);
+}
+
+module_init(hw_break_module_init);
+module_exit(hw_break_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("K.Prasad");
+MODULE_DESCRIPTION("ksym breakpoint");