Contributors: 11
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| K.Prasad |
163 |
58.42% |
2 |
12.50% |
| Frédéric Weisbecker |
63 |
22.58% |
5 |
31.25% |
| Will Deacon |
28 |
10.04% |
1 |
6.25% |
| Tejun Heo |
11 |
3.94% |
1 |
6.25% |
| Arnd Bergmann |
5 |
1.79% |
1 |
6.25% |
| Ingo Molnar |
2 |
0.72% |
1 |
6.25% |
| Avi Kivity |
2 |
0.72% |
1 |
6.25% |
| Thomas Gleixner |
2 |
0.72% |
1 |
6.25% |
| Rong Tao |
1 |
0.36% |
1 |
6.25% |
| Chen Jiahao |
1 |
0.36% |
1 |
6.25% |
| Rusty Russell |
1 |
0.36% |
1 |
6.25% |
| Total |
279 |
|
16 |
|
// 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>
static 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);
#ifdef CONFIG_MODULE_UNLOAD
__symbol_put(ksym_name);
#endif
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");