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/list.h> 33 #include <linux/notifier.h> 34 #include <linux/smp.h> 35 #include <linux/percpu.h> 36 #include <linux/spinlock.h> 37 #include <linux/rcupdate.h> 38 #include <linux/mutex.h> 39 40 #ifdef CONFIG_KPROBES 41 #include <asm/kprobes.h> 42 43 /* kprobe_status settings */ 44 #define KPROBE_HIT_ACTIVE 0x00000001 45 #define KPROBE_HIT_SS 0x00000002 46 #define KPROBE_REENTER 0x00000004 47 #define KPROBE_HIT_SSDONE 0x00000008 48 49 /* Attach to insert probes on any functions which should be ignored*/ 50 #define __kprobes __attribute__((__section__(".kprobes.text"))) 51 52 struct kprobe; 53 struct pt_regs; 54 struct kretprobe; 55 struct kretprobe_instance; 56 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *); 57 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *); 58 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *, 59 unsigned long flags); 60 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *, 61 int trapnr); 62 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *, 63 struct pt_regs *); 64 65 struct kprobe { 66 struct hlist_node hlist; 67 68 /* list of kprobes for multi-handler support */ 69 struct list_head list; 70 71 /* Indicates that the corresponding module has been ref counted */ 72 unsigned int mod_refcounted; 73 74 /*count the number of times this probe was temporarily disarmed */ 75 unsigned long nmissed; 76 77 /* location of the probe point */ 78 kprobe_opcode_t *addr; 79 80 /* Allow user to indicate symbol name of the probe point */ 81 const char *symbol_name; 82 83 /* Offset into the symbol */ 84 unsigned int offset; 85 86 /* Called before addr is executed. */ 87 kprobe_pre_handler_t pre_handler; 88 89 /* Called after addr is executed, unless... */ 90 kprobe_post_handler_t post_handler; 91 92 /* ... called if executing addr causes a fault (eg. page fault). 93 * Return 1 if it handled fault, otherwise kernel will see it. */ 94 kprobe_fault_handler_t fault_handler; 95 96 /* ... called if breakpoint trap occurs in probe handler. 97 * Return 1 if it handled break, otherwise kernel will see it. */ 98 kprobe_break_handler_t break_handler; 99 100 /* Saved opcode (which has been replaced with breakpoint) */ 101 kprobe_opcode_t opcode; 102 103 /* copy of the original instruction */ 104 struct arch_specific_insn ainsn; 105 }; 106 107 /* 108 * Special probe type that uses setjmp-longjmp type tricks to resume 109 * execution at a specified entry with a matching prototype corresponding 110 * to the probed function - a trick to enable arguments to become 111 * accessible seamlessly by probe handling logic. 112 * Note: 113 * Because of the way compilers allocate stack space for local variables 114 * etc upfront, regardless of sub-scopes within a function, this mirroring 115 * principle currently works only for probes placed on function entry points. 116 */ 117 struct jprobe { 118 struct kprobe kp; 119 void *entry; /* probe handling code to jump to */ 120 }; 121 122 /* For backward compatibility with old code using JPROBE_ENTRY() */ 123 #define JPROBE_ENTRY(handler) (handler) 124 125 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 126 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 127 128 #ifdef ARCH_SUPPORTS_KRETPROBES 129 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, 130 struct pt_regs *regs); 131 extern int arch_trampoline_kprobe(struct kprobe *p); 132 #else /* ARCH_SUPPORTS_KRETPROBES */ 133 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 134 struct pt_regs *regs) 135 { 136 } 137 static inline int arch_trampoline_kprobe(struct kprobe *p) 138 { 139 return 0; 140 } 141 #endif /* ARCH_SUPPORTS_KRETPROBES */ 142 /* 143 * Function-return probe - 144 * Note: 145 * User needs to provide a handler function, and initialize maxactive. 146 * maxactive - The maximum number of instances of the probed function that 147 * can be active concurrently. 148 * nmissed - tracks the number of times the probed function's return was 149 * ignored, due to maxactive being too low. 150 * 151 */ 152 struct kretprobe { 153 struct kprobe kp; 154 kretprobe_handler_t handler; 155 kretprobe_handler_t entry_handler; 156 int maxactive; 157 int nmissed; 158 size_t data_size; 159 struct hlist_head free_instances; 160 struct hlist_head used_instances; 161 }; 162 163 struct kretprobe_instance { 164 struct hlist_node uflist; /* either on free list or used list */ 165 struct hlist_node hlist; 166 struct kretprobe *rp; 167 kprobe_opcode_t *ret_addr; 168 struct task_struct *task; 169 char data[0]; 170 }; 171 172 struct kretprobe_blackpoint { 173 const char *name; 174 void *addr; 175 }; 176 extern struct kretprobe_blackpoint kretprobe_blacklist[]; 177 178 static inline void kretprobe_assert(struct kretprobe_instance *ri, 179 unsigned long orig_ret_address, unsigned long trampoline_address) 180 { 181 if (!orig_ret_address || (orig_ret_address == trampoline_address)) { 182 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n", 183 ri->rp, ri->rp->kp.addr); 184 BUG(); 185 } 186 } 187 188 #ifdef CONFIG_KPROBES_SANITY_TEST 189 extern int init_test_probes(void); 190 #else 191 static inline int init_test_probes(void) 192 { 193 return 0; 194 } 195 #endif /* CONFIG_KPROBES_SANITY_TEST */ 196 197 extern spinlock_t kretprobe_lock; 198 extern struct mutex kprobe_mutex; 199 extern int arch_prepare_kprobe(struct kprobe *p); 200 extern void arch_arm_kprobe(struct kprobe *p); 201 extern void arch_disarm_kprobe(struct kprobe *p); 202 extern int arch_init_kprobes(void); 203 extern void show_registers(struct pt_regs *regs); 204 extern kprobe_opcode_t *get_insn_slot(void); 205 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty); 206 extern void kprobes_inc_nmissed_count(struct kprobe *p); 207 208 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 209 struct kprobe *get_kprobe(void *addr); 210 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 211 212 /* kprobe_running() will just return the current_kprobe on this CPU */ 213 static inline struct kprobe *kprobe_running(void) 214 { 215 return (__get_cpu_var(current_kprobe)); 216 } 217 218 static inline void reset_current_kprobe(void) 219 { 220 __get_cpu_var(current_kprobe) = NULL; 221 } 222 223 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 224 { 225 return (&__get_cpu_var(kprobe_ctlblk)); 226 } 227 228 int register_kprobe(struct kprobe *p); 229 void unregister_kprobe(struct kprobe *p); 230 int setjmp_pre_handler(struct kprobe *, struct pt_regs *); 231 int longjmp_break_handler(struct kprobe *, struct pt_regs *); 232 int register_jprobe(struct jprobe *p); 233 void unregister_jprobe(struct jprobe *p); 234 void jprobe_return(void); 235 unsigned long arch_deref_entry_point(void *); 236 237 int register_kretprobe(struct kretprobe *rp); 238 void unregister_kretprobe(struct kretprobe *rp); 239 240 void kprobe_flush_task(struct task_struct *tk); 241 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); 242 243 #else /* CONFIG_KPROBES */ 244 245 #define __kprobes /**/ 246 struct jprobe; 247 struct kretprobe; 248 249 static inline struct kprobe *kprobe_running(void) 250 { 251 return NULL; 252 } 253 static inline int register_kprobe(struct kprobe *p) 254 { 255 return -ENOSYS; 256 } 257 static inline void unregister_kprobe(struct kprobe *p) 258 { 259 } 260 static inline int register_jprobe(struct jprobe *p) 261 { 262 return -ENOSYS; 263 } 264 static inline void unregister_jprobe(struct jprobe *p) 265 { 266 } 267 static inline void jprobe_return(void) 268 { 269 } 270 static inline int register_kretprobe(struct kretprobe *rp) 271 { 272 return -ENOSYS; 273 } 274 static inline void unregister_kretprobe(struct kretprobe *rp) 275 { 276 } 277 static inline void kprobe_flush_task(struct task_struct *tk) 278 { 279 } 280 #endif /* CONFIG_KPROBES */ 281 #endif /* _LINUX_KPROBES_H */ 282