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)
66 void *swap_task_data_get(struct task_struct *task, int *ok)
68 struct task_data *td = __td(task);
75 EXPORT_SYMBOL_GPL(swap_task_data_get);
77 void swap_task_data_set(struct task_struct *task, void *data,
80 struct task_data *td = __td(task);
82 __td_init(td, data, flags);
84 EXPORT_SYMBOL_GPL(swap_task_data_set);
87 static atomic_t start_flag = ATOMIC_INIT(0);
89 static int copy_process_ret_handler(struct kretprobe_instance *ri,
92 struct task_struct *task;
94 if (atomic_read(&start_flag) == 0)
97 task = (struct task_struct *)regs_return_value(regs);
99 swap_task_data_clean(task);
104 static int do_exit_handler(struct kprobe *p, struct pt_regs *regs)
106 struct task_data *td;
108 if (atomic_read(&start_flag) == 0)
117 static struct kretprobe copy_process_rp = {
118 .handler = copy_process_ret_handler
121 static struct kprobe do_exit_probe = {
122 .pre_handler = do_exit_handler
125 static int __task_data_init(void *data)
127 struct task_struct *g, *t;
129 /* set start_flags */
130 atomic_set(&start_flag, 1);
132 do_each_thread(g, t) {
133 swap_task_data_clean(t);
134 } while_each_thread(g, t);
139 static int __task_data_exit(void *data)
141 struct task_struct *g, *t;
142 struct task_data *td;
144 do_each_thread(g, t) {
147 } while_each_thread(g, t);
149 /* reset start_flags */
150 atomic_set(&start_flag, 0);
155 static void task_data_start(void)
159 ret = swap_register_kprobe(&do_exit_probe);
161 pr_err(TD_PREFIX "register on 'do_exit' failed: ret=%d\n", ret);
165 ret = swap_register_kretprobe(©_process_rp);
167 swap_unregister_kprobe(&do_exit_probe);
168 pr_err(TD_PREFIX "register on 'copy_process' failed: ret=%d\n", ret);
172 /* stop_machine: cannot get tasklist_lock from module */
173 ret = stop_machine(__task_data_init, NULL, NULL);
175 printk(TD_PREFIX "task data initialization failed: %d\n", ret);
178 static void task_data_stop(void)
182 /* stop_machine: the same here */
183 ret = stop_machine(__task_data_exit, NULL, NULL);
185 printk(TD_PREFIX "task data cleanup failed: %d\n", ret);
186 /* something went wrong: at least make sure we unregister
187 * all the installed probes */
188 swap_unregister_kprobe(&do_exit_probe);
191 swap_unregister_kretprobe(©_process_rp);
192 swap_unregister_kprobe(&do_exit_probe);
195 static int task_data_once(void)
199 sym = "copy_process";
200 copy_process_rp.kp.addr = (kprobe_opcode_t *)swap_ksyms_substr(sym);
201 if (copy_process_rp.kp.addr == NULL)
205 do_exit_probe.addr = (kprobe_opcode_t *)swap_ksyms_substr(sym);
206 if (do_exit_probe.addr == NULL)
212 pr_err(TD_PREFIX "ERROR: symbol %s(...) not found\n", sym);
216 static int task_data_init(void)
220 __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);
228 if (__task_data_cbs_stop_h < 0) {
229 ret = __task_data_cbs_stop_h;
230 us_manager_unreg_cb(__task_data_cbs_start_h);
231 printk(KERN_ERR TD_PREFIX "stop_cb registration failed\n");
238 static void task_data_exit(void)
240 us_manager_unreg_cb(__task_data_cbs_start_h);
241 us_manager_unreg_cb(__task_data_cbs_stop_h);
244 SWAP_LIGHT_INIT_MODULE(task_data_once, task_data_init, task_data_exit,
247 MODULE_LICENSE("GPL");
248 MODULE_DESCRIPTION("SWAP Task Data Module");