1 #include <linux/kernel.h>
2 #include <linux/module.h>
3 #include <linux/sched.h>
4 #include <linux/stop_machine.h>
5 #include <linux/slab.h>
6 #include <kprobe/swap_kprobes.h>
7 #include <ksyms/ksyms.h>
8 #include <master/swap_initializer.h>
9 #include <us_manager/callbacks.h>
10 #include "task_data.h"
12 /* lower bits are used as flags */
13 #define TD_MAGIC_MASK 0xfffffff0
14 #define TD_FLAGS_MASK (~TD_MAGIC_MASK)
16 #define __DEFINE_TD_MAGIC(m) ((m) & TD_MAGIC_MASK)
18 #define TD_MAGIC __DEFINE_TD_MAGIC(0xbebebebe)
19 #define TD_OFFSET 1 /* skip STACK_END_MAGIC */
20 #define TD_PREFIX "[TASK_DATA] "
25 } __attribute__((packed));
27 #define get_magic(td) ((td)->magic & TD_MAGIC_MASK)
28 #define get_flags(td) ((td)->magic & TD_FLAGS_MASK)
30 static int __task_data_cbs_start_h = -1;
31 static int __task_data_cbs_stop_h = -1;
33 static inline struct task_data *__td(struct task_struct *task)
35 return (struct task_data *)(end_of_stack(task) + TD_OFFSET);
38 static inline bool __td_check(struct task_data *td)
40 return (get_magic(td) == TD_MAGIC);
43 static inline void __td_init(struct task_data *td, void *data,
46 td->magic = TD_MAGIC | (flags & TD_FLAGS_MASK);
50 static inline void __td_free(struct task_data *td)
52 unsigned long flags = get_flags(td);
53 bool ok = __td_check(td);
55 /* freeing the data if consistency check fails is dangerous:
56 * better leave it as a memory leak instead */
58 if ((flags & SWAP_TD_FREE) && td->data)
65 WARN(!ok, TD_PREFIX "td(%p) check failed: %08lx", td, get_magic(td));
68 void *swap_task_data_get(struct task_struct *task, int *ok)
70 struct task_data *td = __td(task);
77 EXPORT_SYMBOL_GPL(swap_task_data_get);
79 void swap_task_data_set(struct task_struct *task, void *data,
82 struct task_data *td = __td(task);
84 __td_init(td, data, flags);
86 EXPORT_SYMBOL_GPL(swap_task_data_set);
88 static int copy_process_ret_handler(struct kretprobe_instance *ri,
91 struct task_struct *task;
93 task = (struct task_struct *)regs_return_value(regs);
95 swap_task_data_clean(task);
100 static int do_exit_handler(struct kprobe *p, struct pt_regs *regs)
102 struct task_data *td = __td(current);
109 static struct kretprobe copy_process_rp = {
110 .handler = copy_process_ret_handler
113 static struct kprobe do_exit_probe = {
114 .pre_handler = do_exit_handler
117 static int __set_helper_probes(void)
122 addr = swap_ksyms_substr("copy_process");
124 printk(TD_PREFIX "Cannot find address for copy_process\n");
127 copy_process_rp.kp.addr = (kprobe_opcode_t *)addr;
128 ret = swap_register_kretprobe(©_process_rp);
132 addr = swap_ksyms_substr("do_exit");
134 printk(TD_PREFIX "Cannot find address for do_exit\n");
137 do_exit_probe.addr = (kprobe_opcode_t *)addr;
138 ret = swap_register_kprobe(&do_exit_probe);
140 goto unreg_copy_process;
145 swap_unregister_kretprobe(©_process_rp);
148 printk(TD_PREFIX "0x%lx: probe registration failed\n", addr);
153 static void __remove_helper_probes(void)
155 swap_unregister_kretprobe(©_process_rp);
156 swap_unregister_kprobe(&do_exit_probe);
159 static int __task_data_init(void *data)
161 struct task_struct *g, *t;
163 do_each_thread(g, t) {
164 swap_task_data_clean(t);
165 } while_each_thread(g, t);
172 static int __task_data_exit(void *data)
174 struct task_struct *g, *t;
175 struct task_data *td;
177 do_each_thread(g, t) {
180 } while_each_thread(g, t);
185 static void task_data_start(void)
189 ret = __set_helper_probes();
193 /* stop_machine: cannot get tasklist_lock from module */
194 ret = stop_machine(__task_data_init, NULL, NULL);
196 printk(TD_PREFIX "task data initialization failed: %d\n", ret);
199 static void task_data_stop(void)
203 __remove_helper_probes();
205 /* stop_machine: the same here */
206 ret = stop_machine(__task_data_exit, NULL, NULL);
208 printk(TD_PREFIX "task data cleanup failed: %d\n", ret);
209 /* something went wrong: at least make sure we unregister
210 * all the installed probes */
211 swap_unregister_kprobe(&do_exit_probe);
215 static int task_data_init(void)
219 __task_data_cbs_start_h = us_manager_reg_cb(START_CB, task_data_start);
221 if (__task_data_cbs_start_h < 0) {
222 ret = __task_data_cbs_start_h;
223 printk(KERN_ERR TD_PREFIX "start_cb registration failed\n");
227 __task_data_cbs_stop_h = us_manager_reg_cb(STOP_CB_TD, task_data_stop);
229 if (__task_data_cbs_stop_h < 0) {
230 ret = __task_data_cbs_stop_h;
231 us_manager_unreg_cb(__task_data_cbs_start_h);
232 printk(KERN_ERR TD_PREFIX "stop_cb registration failed\n");
239 static void task_data_exit(void)
241 us_manager_unreg_cb(__task_data_cbs_start_h);
242 us_manager_unreg_cb(__task_data_cbs_stop_h);
245 SWAP_LIGHT_INIT_MODULE(NULL, task_data_init, task_data_exit, NULL, NULL);
248 MODULE_LICENSE("GPL");
249 MODULE_DESCRIPTION("SWAP Task Data Module");