Merge tag 'xtensa-20200410' of git://github.com/jcmvbkbc/linux-xtensa

[linux-2.6-microblaze.git] / samples / hw_breakpoint / data_breakpoint.c

diff --git a/samples/hw_breakpoint/data_breakpoint.c b/samples/hw_breakpoint/data_breakpoint.c
index c585047..418c46f 100644 (file)
--- a/samples/hw_breakpoint/data_breakpoint.c
+++ b/samples/hw_breakpoint/data_breakpoint.c
@@ -23,7 +23,7 @@
 
 struct perf_event * __percpu *sample_hbp;
 
-static char ksym_name[KSYM_NAME_LEN] = "pid_max";
+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");
@@ -41,11 +41,15 @@ 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 = kallsyms_lookup_name(ksym_name);
+       attr.bp_addr = (unsigned long)addr;
        attr.bp_len = HW_BREAKPOINT_LEN_4;
-       attr.bp_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R;
+       attr.bp_type = HW_BREAKPOINT_W;
 
        sample_hbp = register_wide_hw_breakpoint(&attr, sample_hbp_handler, NULL);
        if (IS_ERR((void __force *)sample_hbp)) {
@@ -66,6 +70,7 @@ fail:
 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);
 }