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>
11 /* lower bits are used as flags */
12 #define TD_MAGIC_MASK 0xfffffff0
13 #define TD_FLAGS_MASK (~TD_MAGIC_MASK)
15 #define __DEFINE_TD_MAGIC(m) ((m) & TD_MAGIC_MASK)
17 #define TD_MAGIC __DEFINE_TD_MAGIC(0xbebebebe)
18 #define TD_OFFSET 1 /* skip STACK_END_MAGIC */
19 #define TD_PREFIX "[TASK_DATA] "
24 } __attribute__((packed));
26 #define get_magic(td) ((td)->magic & TD_MAGIC_MASK)
27 #define get_flags(td) ((td)->magic & TD_FLAGS_MASK)
29 static inline struct task_data *__td(struct task_struct *task)
31 return (struct task_data *)(end_of_stack(task) + TD_OFFSET);
34 static inline bool __td_check(struct task_data *td)
36 return (get_magic(td) == TD_MAGIC);
39 static inline void __td_init(struct task_data *td, void *data,
42 td->magic = TD_MAGIC | (flags & TD_FLAGS_MASK);
46 static inline void __td_free(struct task_data *td)
48 unsigned long flags = get_flags(td);
49 bool ok = __td_check(td);
51 /* freeing the data if consistency check fails is dangerous:
52 * better leave it as a memory leak instead */
54 if ((flags & SWAP_TD_FREE) && td->data)
61 WARN(!ok, TD_PREFIX "td(%p) check failed: %08lx", td, get_magic(td));
64 void *swap_task_data_get(struct task_struct *task, int *ok)
66 struct task_data *td = __td(task);
73 EXPORT_SYMBOL_GPL(swap_task_data_get);
75 void swap_task_data_set(struct task_struct *task, void *data,
78 struct task_data *td = __td(task);
80 __td_init(td, data, flags);
82 EXPORT_SYMBOL_GPL(swap_task_data_set);
84 static int copy_process_ret_handler(struct kretprobe_instance *ri,
87 struct task_struct *task;
89 task = (struct task_struct *)regs_return_value(regs);
91 swap_task_data_clean(task);
96 static int do_exit_handler(struct kprobe *p, struct pt_regs *regs)
98 struct task_data *td = __td(current);
105 static struct kretprobe copy_process_rp = {
106 .handler = copy_process_ret_handler
109 static struct kprobe do_exit_probe = {
110 .pre_handler = do_exit_handler
113 static int __task_data_init(void *data)
115 struct task_struct *g, *t;
119 addr = swap_ksyms_substr("copy_process");
121 printk(TD_PREFIX "Cannot find address for copy_process\n");
124 copy_process_rp.kp.addr = (kprobe_opcode_t *)addr;
125 ret = swap_register_kretprobe(©_process_rp);
129 addr = swap_ksyms_substr("do_exit");
131 printk(TD_PREFIX "Cannot find address for do_exit\n");
134 do_exit_probe.addr = (kprobe_opcode_t *)addr;
135 ret = swap_register_kprobe(&do_exit_probe);
137 goto unreg_copy_process;
139 do_each_thread(g, t) {
140 swap_task_data_clean(t);
141 } while_each_thread(g, t);
146 swap_unregister_kretprobe(©_process_rp);
149 printk(TD_PREFIX "0x%lx: probe registration failed\n", addr);
154 static int __task_data_exit(void *data)
156 struct task_struct *g, *t;
157 struct task_data *td;
159 swap_unregister_kprobe(&do_exit_probe);
160 swap_unregister_kretprobe(©_process_rp);
162 do_each_thread(g, t) {
165 } while_each_thread(g, t);
170 static int task_data_init(void)
174 /* stop_machine: cannot get tasklist_lock from module */
175 ret = stop_machine(__task_data_init, NULL, NULL);
177 printk(TD_PREFIX "task data initialization failed: %d\n", ret);
182 static void task_data_exit(void)
186 /* stop_machine: the same here */
187 ret = stop_machine(__task_data_exit, ©_process_rp, NULL);
189 printk(TD_PREFIX "task data cleanup failed: %d\n", ret);
190 /* something went wrong: at least make sure we unregister
191 * all the installed probes */
192 swap_unregister_kprobe(&do_exit_probe);
193 swap_unregister_kretprobe(©_process_rp);
197 SWAP_LIGHT_INIT_MODULE(NULL, task_data_init, task_data_exit, NULL, NULL);
200 MODULE_LICENSE("GPL");
201 MODULE_DESCRIPTION("SWAP Task Data Module");