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Commit f60d24d2 authored by Frederic Weisbecker's avatar Frederic Weisbecker
Browse files

hw-breakpoints: Fix broken hw-breakpoint sample module 



The hw-breakpoint sample module has been broken during the
hw-breakpoint internals refactoring. Propagate the changes
to it.

Reported-by: default avatar"K. Prasad" <prasad@linux.vnet.ibm.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent 9f6b3c2c

kernel/hw_breakpoint.c

+2 −1
Original line number Diff line number Diff line
@@ -454,6 +454,7 @@ register_wide_hw_breakpoint(unsigned long addr, 
	/* return the error if any */

	return ERR_PTR(err);

}

EXPORT_SYMBOL_GPL(register_wide_hw_breakpoint);



/**

 * unregister_wide_hw_breakpoint - unregister a wide breakpoint in the kernel
@@ -470,7 +471,7 @@ void unregister_wide_hw_breakpoint(struct perf_event **cpu_events) 
	}

	free_percpu(cpu_events);

}



EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint);



static struct notifier_block hw_breakpoint_exceptions_nb = {

	.notifier_call = hw_breakpoint_exceptions_notify,

kernel/kallsyms.c

+1 −0
Original line number Diff line number Diff line
@@ -181,6 +181,7 @@ unsigned long kallsyms_lookup_name(const char *name) 
	}

	return module_kallsyms_lookup_name(name);

}

EXPORT_SYMBOL_GPL(kallsyms_lookup_name);



int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,

				      unsigned long),

samples/hw_breakpoint/data_breakpoint.c

+24 −19
Original line number Diff line number Diff line
@@ -27,18 +27,19 @@ 
#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 <asm/hw_breakpoint.h>

#include <linux/perf_event.h>

#include <linux/hw_breakpoint.h>



struct hw_breakpoint sample_hbp;

struct perf_event **sample_hbp;



static char ksym_name[KSYM_NAME_LEN] = "pid_max";

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");



void sample_hbp_handler(struct hw_breakpoint *temp, struct pt_regs

								*temp_regs)

static void sample_hbp_handler(struct perf_event *temp, void *data)

{

	printk(KERN_INFO "%s value is changed\n", ksym_name);

	dump_stack();
@@ -48,30 +49,34 @@ void sample_hbp_handler(struct hw_breakpoint *temp, struct pt_regs 
static int __init hw_break_module_init(void)

{

	int ret;

	unsigned long addr;



#ifdef CONFIG_X86

	sample_hbp.info.name = ksym_name;

	sample_hbp.info.type = HW_BREAKPOINT_WRITE;

	sample_hbp.info.len = HW_BREAKPOINT_LEN_4;

#endif /* CONFIG_X86 */

	addr = kallsyms_lookup_name(ksym_name);



	sample_hbp.triggered = (void *)sample_hbp_handler;

	sample_hbp = register_wide_hw_breakpoint(addr, HW_BREAKPOINT_LEN_4,

						 HW_BREAKPOINT_W | HW_BREAKPOINT_R,

						 sample_hbp_handler, true);

	if (IS_ERR(sample_hbp)) {

		ret = PTR_ERR(sample_hbp);

		goto fail;

	} else if (!sample_hbp) {

		ret = -EINVAL;

		goto fail;

	}



	printk(KERN_INFO "HW Breakpoint for %s write installed\n", ksym_name);



	ret = register_kernel_hw_breakpoint(&sample_hbp);

	return 0;



	if (ret < 0) {

fail:

	printk(KERN_INFO "Breakpoint registration failed\n");

		return ret;

	} else

		printk(KERN_INFO "HW Breakpoint for %s write installed\n",

								ksym_name);



	return 0;

	return ret;

}



static void __exit hw_break_module_exit(void)

{

	unregister_kernel_hw_breakpoint(&sample_hbp);

	unregister_wide_hw_breakpoint(sample_hbp);

	printk(KERN_INFO "HW Breakpoint for %s write uninstalled\n", ksym_name);

}