1 #ifndef _LINUX_KPROBES_H 2 #define _LINUX_KPROBES_H 3 /* 4 * Kernel Probes (KProbes) 5 * include/linux/kprobes.h 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 20 * 21 * Copyright (C) IBM Corporation, 2002, 2004 22 * 23 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel 24 * Probes initial implementation ( includes suggestions from 25 * Rusty Russell). 26 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes 27 * interface to access function arguments. 28 * 2005-May Hien Nguyen <hien@us.ibm.com> and Jim Keniston 29 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi 30 * <prasanna@in.ibm.com> added function-return probes. 31 */ 32 #include <linux/linkage.h> 33 #include <linux/list.h> 34 #include <linux/notifier.h> 35 #include <linux/smp.h> 36 #include <linux/percpu.h> 37 #include <linux/spinlock.h> 38 #include <linux/rcupdate.h> 39 #include <linux/mutex.h> 40 41 #ifdef CONFIG_KPROBES 42 #include <asm/kprobes.h> 43 44 /* kprobe_status settings */ 45 #define KPROBE_HIT_ACTIVE 0x00000001 46 #define KPROBE_HIT_SS 0x00000002 47 #define KPROBE_REENTER 0x00000004 48 #define KPROBE_HIT_SSDONE 0x00000008 49 50 /* Attach to insert probes on any functions which should be ignored*/ 51 #define __kprobes __attribute__((__section__(".kprobes.text"))) notrace 52 53 struct kprobe; 54 struct pt_regs; 55 struct kretprobe; 56 struct kretprobe_instance; 57 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *); 58 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *); 59 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *, 60 unsigned long flags); 61 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *, 62 int trapnr); 63 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *, 64 struct pt_regs *); 65 66 struct kprobe { 67 struct hlist_node hlist; 68 69 /* list of kprobes for multi-handler support */ 70 struct list_head list; 71 72 /*count the number of times this probe was temporarily disarmed */ 73 unsigned long nmissed; 74 75 /* location of the probe point */ 76 kprobe_opcode_t *addr; 77 78 /* Allow user to indicate symbol name of the probe point */ 79 const char *symbol_name; 80 81 /* Offset into the symbol */ 82 unsigned int offset; 83 84 /* Called before addr is executed. */ 85 kprobe_pre_handler_t pre_handler; 86 87 /* Called after addr is executed, unless... */ 88 kprobe_post_handler_t post_handler; 89 90 /* ... called if executing addr causes a fault (eg. page fault). 91 * Return 1 if it handled fault, otherwise kernel will see it. */ 92 kprobe_fault_handler_t fault_handler; 93 94 /* ... called if breakpoint trap occurs in probe handler. 95 * Return 1 if it handled break, otherwise kernel will see it. */ 96 kprobe_break_handler_t break_handler; 97 98 /* Saved opcode (which has been replaced with breakpoint) */ 99 kprobe_opcode_t opcode; 100 101 /* copy of the original instruction */ 102 struct arch_specific_insn ainsn; 103 104 /* Indicates various status flags. Protected by kprobe_mutex. */ 105 u32 flags; 106 }; 107 108 /* Kprobe status flags */ 109 #define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */ 110 111 static inline int kprobe_gone(struct kprobe *p) 112 { 113 return p->flags & KPROBE_FLAG_GONE; 114 } 115 116 /* 117 * Special probe type that uses setjmp-longjmp type tricks to resume 118 * execution at a specified entry with a matching prototype corresponding 119 * to the probed function - a trick to enable arguments to become 120 * accessible seamlessly by probe handling logic. 121 * Note: 122 * Because of the way compilers allocate stack space for local variables 123 * etc upfront, regardless of sub-scopes within a function, this mirroring 124 * principle currently works only for probes placed on function entry points. 125 */ 126 struct jprobe { 127 struct kprobe kp; 128 void *entry; /* probe handling code to jump to */ 129 }; 130 131 /* For backward compatibility with old code using JPROBE_ENTRY() */ 132 #define JPROBE_ENTRY(handler) (handler) 133 134 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 135 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 136 137 #ifdef CONFIG_KRETPROBES 138 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, 139 struct pt_regs *regs); 140 extern int arch_trampoline_kprobe(struct kprobe *p); 141 #else /* CONFIG_KRETPROBES */ 142 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 143 struct pt_regs *regs) 144 { 145 } 146 static inline int arch_trampoline_kprobe(struct kprobe *p) 147 { 148 return 0; 149 } 150 #endif /* CONFIG_KRETPROBES */ 151 /* 152 * Function-return probe - 153 * Note: 154 * User needs to provide a handler function, and initialize maxactive. 155 * maxactive - The maximum number of instances of the probed function that 156 * can be active concurrently. 157 * nmissed - tracks the number of times the probed function's return was 158 * ignored, due to maxactive being too low. 159 * 160 */ 161 struct kretprobe { 162 struct kprobe kp; 163 kretprobe_handler_t handler; 164 kretprobe_handler_t entry_handler; 165 int maxactive; 166 int nmissed; 167 size_t data_size; 168 struct hlist_head free_instances; 169 spinlock_t lock; 170 }; 171 172 struct kretprobe_instance { 173 struct hlist_node hlist; 174 struct kretprobe *rp; 175 kprobe_opcode_t *ret_addr; 176 struct task_struct *task; 177 char data[0]; 178 }; 179 180 struct kretprobe_blackpoint { 181 const char *name; 182 void *addr; 183 }; 184 185 struct kprobe_blackpoint { 186 const char *name; 187 unsigned long start_addr; 188 unsigned long range; 189 }; 190 191 extern struct kretprobe_blackpoint kretprobe_blacklist[]; 192 193 static inline void kretprobe_assert(struct kretprobe_instance *ri, 194 unsigned long orig_ret_address, unsigned long trampoline_address) 195 { 196 if (!orig_ret_address || (orig_ret_address == trampoline_address)) { 197 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n", 198 ri->rp, ri->rp->kp.addr); 199 BUG(); 200 } 201 } 202 203 #ifdef CONFIG_KPROBES_SANITY_TEST 204 extern int init_test_probes(void); 205 #else 206 static inline int init_test_probes(void) 207 { 208 return 0; 209 } 210 #endif /* CONFIG_KPROBES_SANITY_TEST */ 211 212 extern int arch_prepare_kprobe(struct kprobe *p); 213 extern void arch_arm_kprobe(struct kprobe *p); 214 extern void arch_disarm_kprobe(struct kprobe *p); 215 extern int arch_init_kprobes(void); 216 extern void show_registers(struct pt_regs *regs); 217 extern kprobe_opcode_t *get_insn_slot(void); 218 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty); 219 extern void kprobes_inc_nmissed_count(struct kprobe *p); 220 221 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 222 struct kprobe *get_kprobe(void *addr); 223 void kretprobe_hash_lock(struct task_struct *tsk, 224 struct hlist_head **head, unsigned long *flags); 225 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags); 226 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 227 228 /* kprobe_running() will just return the current_kprobe on this CPU */ 229 static inline struct kprobe *kprobe_running(void) 230 { 231 return (__get_cpu_var(current_kprobe)); 232 } 233 234 static inline void reset_current_kprobe(void) 235 { 236 __get_cpu_var(current_kprobe) = NULL; 237 } 238 239 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 240 { 241 return (&__get_cpu_var(kprobe_ctlblk)); 242 } 243 244 int register_kprobe(struct kprobe *p); 245 void unregister_kprobe(struct kprobe *p); 246 int register_kprobes(struct kprobe **kps, int num); 247 void unregister_kprobes(struct kprobe **kps, int num); 248 int setjmp_pre_handler(struct kprobe *, struct pt_regs *); 249 int longjmp_break_handler(struct kprobe *, struct pt_regs *); 250 int register_jprobe(struct jprobe *p); 251 void unregister_jprobe(struct jprobe *p); 252 int register_jprobes(struct jprobe **jps, int num); 253 void unregister_jprobes(struct jprobe **jps, int num); 254 void jprobe_return(void); 255 unsigned long arch_deref_entry_point(void *); 256 257 int register_kretprobe(struct kretprobe *rp); 258 void unregister_kretprobe(struct kretprobe *rp); 259 int register_kretprobes(struct kretprobe **rps, int num); 260 void unregister_kretprobes(struct kretprobe **rps, int num); 261 262 void kprobe_flush_task(struct task_struct *tk); 263 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); 264 265 #else /* CONFIG_KPROBES */ 266 267 #define __kprobes notrace 268 struct jprobe; 269 struct kretprobe; 270 271 static inline struct kprobe *get_kprobe(void *addr) 272 { 273 return NULL; 274 } 275 static inline struct kprobe *kprobe_running(void) 276 { 277 return NULL; 278 } 279 static inline int register_kprobe(struct kprobe *p) 280 { 281 return -ENOSYS; 282 } 283 static inline int register_kprobes(struct kprobe **kps, int num) 284 { 285 return -ENOSYS; 286 } 287 static inline void unregister_kprobe(struct kprobe *p) 288 { 289 } 290 static inline void unregister_kprobes(struct kprobe **kps, int num) 291 { 292 } 293 static inline int register_jprobe(struct jprobe *p) 294 { 295 return -ENOSYS; 296 } 297 static inline int register_jprobes(struct jprobe **jps, int num) 298 { 299 return -ENOSYS; 300 } 301 static inline void unregister_jprobe(struct jprobe *p) 302 { 303 } 304 static inline void unregister_jprobes(struct jprobe **jps, int num) 305 { 306 } 307 static inline void jprobe_return(void) 308 { 309 } 310 static inline int register_kretprobe(struct kretprobe *rp) 311 { 312 return -ENOSYS; 313 } 314 static inline int register_kretprobes(struct kretprobe **rps, int num) 315 { 316 return -ENOSYS; 317 } 318 static inline void unregister_kretprobe(struct kretprobe *rp) 319 { 320 } 321 static inline void unregister_kretprobes(struct kretprobe **rps, int num) 322 { 323 } 324 static inline void kprobe_flush_task(struct task_struct *tk) 325 { 326 } 327 #endif /* CONFIG_KPROBES */ 328 #endif /* _LINUX_KPROBES_H */ 329