diff options
Diffstat (limited to 'samples/hw_breakpoint/data_breakpoint.c')
| -rw-r--r-- | samples/hw_breakpoint/data_breakpoint.c | 34 |
1 files changed, 14 insertions, 20 deletions
diff --git a/samples/hw_breakpoint/data_breakpoint.c b/samples/hw_breakpoint/data_breakpoint.c index ef7f32291852..fbb03b66dcbd 100644 --- a/samples/hw_breakpoint/data_breakpoint.c +++ b/samples/hw_breakpoint/data_breakpoint.c @@ -1,20 +1,7 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * data_breakpoint.c - Sample HW Breakpoint file to watch kernel data address * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * 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. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. - * * usage: insmod data_breakpoint.ko ksym=<ksym_name> * * This file is a kernel module that places a breakpoint over ksym_name kernel @@ -34,9 +21,9 @@ #include <linux/perf_event.h> #include <linux/hw_breakpoint.h> -struct perf_event * __percpu *sample_hbp; +static 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"); @@ -54,15 +41,19 @@ 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)) { - ret = PTR_ERR((void __force *)sample_hbp); + if (IS_ERR_PCPU(sample_hbp)) { + ret = PTR_ERR_PCPU(sample_hbp); goto fail; } @@ -79,6 +70,9 @@ fail: static void __exit hw_break_module_exit(void) { unregister_wide_hw_breakpoint(sample_hbp); +#ifdef CONFIG_MODULE_UNLOAD + __symbol_put(ksym_name); +#endif printk(KERN_INFO "HW Breakpoint for %s write uninstalled\n", ksym_name); } |