Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Kernel Probes (KProbes) |
| 3 | * kernel/kprobes.c |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License as published by |
| 7 | * the Free Software Foundation; either version 2 of the License, or |
| 8 | * (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program; if not, write to the Free Software |
| 17 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 18 | * |
| 19 | * Copyright (C) IBM Corporation, 2002, 2004 |
| 20 | * |
| 21 | * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel |
| 22 | * Probes initial implementation (includes suggestions from |
| 23 | * Rusty Russell). |
| 24 | * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with |
| 25 | * hlists and exceptions notifier as suggested by Andi Kleen. |
| 26 | * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes |
| 27 | * interface to access function arguments. |
| 28 | * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes |
| 29 | * exceptions notifier to be first on the priority list. |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 30 | * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston |
| 31 | * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi |
| 32 | * <prasanna@in.ibm.com> added function-return probes. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | */ |
| 34 | #include <linux/kprobes.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | #include <linux/hash.h> |
| 36 | #include <linux/init.h> |
Tim Schmielau | 4e57b68 | 2005-10-30 15:03:48 -0800 | [diff] [blame] | 37 | #include <linux/slab.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | #include <linux/module.h> |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 39 | #include <linux/moduleloader.h> |
Ananth N Mavinakayanahalli | 3a872d8 | 2006-10-02 02:17:30 -0700 | [diff] [blame] | 40 | #include <linux/kallsyms.h> |
Masami Hiramatsu | b4c6c34 | 2006-12-06 20:38:11 -0800 | [diff] [blame] | 41 | #include <linux/freezer.h> |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 42 | #include <asm-generic/sections.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | #include <asm/cacheflush.h> |
| 44 | #include <asm/errno.h> |
| 45 | #include <asm/kdebug.h> |
| 46 | |
| 47 | #define KPROBE_HASH_BITS 6 |
| 48 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) |
| 49 | |
Ananth N Mavinakayanahalli | 3a872d8 | 2006-10-02 02:17:30 -0700 | [diff] [blame] | 50 | |
| 51 | /* |
| 52 | * Some oddball architectures like 64bit powerpc have function descriptors |
| 53 | * so this must be overridable. |
| 54 | */ |
| 55 | #ifndef kprobe_lookup_name |
| 56 | #define kprobe_lookup_name(name, addr) \ |
| 57 | addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name))) |
| 58 | #endif |
| 59 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 61 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
Anil S Keshavamurthy | e6f47f9 | 2006-06-26 00:25:29 -0700 | [diff] [blame] | 62 | static atomic_t kprobe_count; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | |
Ingo Molnar | 7a7d1cf | 2006-03-23 03:00:35 -0800 | [diff] [blame] | 64 | DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 65 | DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */ |
Ananth N Mavinakayanahalli | e658452 | 2005-11-07 01:00:07 -0800 | [diff] [blame] | 66 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | |
Anil S Keshavamurthy | e6f47f9 | 2006-06-26 00:25:29 -0700 | [diff] [blame] | 68 | static struct notifier_block kprobe_page_fault_nb = { |
| 69 | .notifier_call = kprobe_exceptions_notify, |
| 70 | .priority = 0x7fffffff /* we need to notified first */ |
| 71 | }; |
| 72 | |
Anil S Keshavamurthy | 2d14e39 | 2006-01-09 20:52:41 -0800 | [diff] [blame] | 73 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 74 | /* |
| 75 | * kprobe->ainsn.insn points to the copy of the instruction to be |
| 76 | * single-stepped. x86_64, POWER4 and above have no-exec support and |
| 77 | * stepping on the instruction on a vmalloced/kmalloced/data page |
| 78 | * is a recipe for disaster |
| 79 | */ |
| 80 | #define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t))) |
| 81 | |
| 82 | struct kprobe_insn_page { |
| 83 | struct hlist_node hlist; |
| 84 | kprobe_opcode_t *insns; /* Page of instruction slots */ |
| 85 | char slot_used[INSNS_PER_PAGE]; |
| 86 | int nused; |
Masami Hiramatsu | b4c6c34 | 2006-12-06 20:38:11 -0800 | [diff] [blame] | 87 | int ngarbage; |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 88 | }; |
| 89 | |
Masami Hiramatsu | ab40c5c | 2007-01-30 14:36:06 -0800 | [diff] [blame] | 90 | enum kprobe_slot_state { |
| 91 | SLOT_CLEAN = 0, |
| 92 | SLOT_DIRTY = 1, |
| 93 | SLOT_USED = 2, |
| 94 | }; |
| 95 | |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 96 | static struct hlist_head kprobe_insn_pages; |
Masami Hiramatsu | b4c6c34 | 2006-12-06 20:38:11 -0800 | [diff] [blame] | 97 | static int kprobe_garbage_slots; |
| 98 | static int collect_garbage_slots(void); |
| 99 | |
| 100 | static int __kprobes check_safety(void) |
| 101 | { |
| 102 | int ret = 0; |
| 103 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_PM) |
| 104 | ret = freeze_processes(); |
| 105 | if (ret == 0) { |
| 106 | struct task_struct *p, *q; |
| 107 | do_each_thread(p, q) { |
| 108 | if (p != current && p->state == TASK_RUNNING && |
| 109 | p->pid != 0) { |
| 110 | printk("Check failed: %s is running\n",p->comm); |
| 111 | ret = -1; |
| 112 | goto loop_end; |
| 113 | } |
| 114 | } while_each_thread(p, q); |
| 115 | } |
| 116 | loop_end: |
| 117 | thaw_processes(); |
| 118 | #else |
| 119 | synchronize_sched(); |
| 120 | #endif |
| 121 | return ret; |
| 122 | } |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 123 | |
| 124 | /** |
| 125 | * get_insn_slot() - Find a slot on an executable page for an instruction. |
| 126 | * We allocate an executable page if there's no room on existing ones. |
| 127 | */ |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 128 | kprobe_opcode_t __kprobes *get_insn_slot(void) |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 129 | { |
| 130 | struct kprobe_insn_page *kip; |
| 131 | struct hlist_node *pos; |
| 132 | |
Masami Hiramatsu | b4c6c34 | 2006-12-06 20:38:11 -0800 | [diff] [blame] | 133 | retry: |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 134 | hlist_for_each(pos, &kprobe_insn_pages) { |
| 135 | kip = hlist_entry(pos, struct kprobe_insn_page, hlist); |
| 136 | if (kip->nused < INSNS_PER_PAGE) { |
| 137 | int i; |
| 138 | for (i = 0; i < INSNS_PER_PAGE; i++) { |
Masami Hiramatsu | ab40c5c | 2007-01-30 14:36:06 -0800 | [diff] [blame] | 139 | if (kip->slot_used[i] == SLOT_CLEAN) { |
| 140 | kip->slot_used[i] = SLOT_USED; |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 141 | kip->nused++; |
| 142 | return kip->insns + (i * MAX_INSN_SIZE); |
| 143 | } |
| 144 | } |
| 145 | /* Surprise! No unused slots. Fix kip->nused. */ |
| 146 | kip->nused = INSNS_PER_PAGE; |
| 147 | } |
| 148 | } |
| 149 | |
Masami Hiramatsu | b4c6c34 | 2006-12-06 20:38:11 -0800 | [diff] [blame] | 150 | /* If there are any garbage slots, collect it and try again. */ |
| 151 | if (kprobe_garbage_slots && collect_garbage_slots() == 0) { |
| 152 | goto retry; |
| 153 | } |
| 154 | /* All out of space. Need to allocate a new page. Use slot 0. */ |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 155 | kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL); |
| 156 | if (!kip) { |
| 157 | return NULL; |
| 158 | } |
| 159 | |
| 160 | /* |
| 161 | * Use module_alloc so this page is within +/- 2GB of where the |
| 162 | * kernel image and loaded module images reside. This is required |
| 163 | * so x86_64 can correctly handle the %rip-relative fixups. |
| 164 | */ |
| 165 | kip->insns = module_alloc(PAGE_SIZE); |
| 166 | if (!kip->insns) { |
| 167 | kfree(kip); |
| 168 | return NULL; |
| 169 | } |
| 170 | INIT_HLIST_NODE(&kip->hlist); |
| 171 | hlist_add_head(&kip->hlist, &kprobe_insn_pages); |
Masami Hiramatsu | ab40c5c | 2007-01-30 14:36:06 -0800 | [diff] [blame] | 172 | memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE); |
| 173 | kip->slot_used[0] = SLOT_USED; |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 174 | kip->nused = 1; |
Masami Hiramatsu | b4c6c34 | 2006-12-06 20:38:11 -0800 | [diff] [blame] | 175 | kip->ngarbage = 0; |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 176 | return kip->insns; |
| 177 | } |
| 178 | |
Masami Hiramatsu | b4c6c34 | 2006-12-06 20:38:11 -0800 | [diff] [blame] | 179 | /* Return 1 if all garbages are collected, otherwise 0. */ |
| 180 | static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) |
| 181 | { |
Masami Hiramatsu | ab40c5c | 2007-01-30 14:36:06 -0800 | [diff] [blame] | 182 | kip->slot_used[idx] = SLOT_CLEAN; |
Masami Hiramatsu | b4c6c34 | 2006-12-06 20:38:11 -0800 | [diff] [blame] | 183 | kip->nused--; |
| 184 | if (kip->nused == 0) { |
| 185 | /* |
| 186 | * Page is no longer in use. Free it unless |
| 187 | * it's the last one. We keep the last one |
| 188 | * so as not to have to set it up again the |
| 189 | * next time somebody inserts a probe. |
| 190 | */ |
| 191 | hlist_del(&kip->hlist); |
| 192 | if (hlist_empty(&kprobe_insn_pages)) { |
| 193 | INIT_HLIST_NODE(&kip->hlist); |
| 194 | hlist_add_head(&kip->hlist, |
| 195 | &kprobe_insn_pages); |
| 196 | } else { |
| 197 | module_free(NULL, kip->insns); |
| 198 | kfree(kip); |
| 199 | } |
| 200 | return 1; |
| 201 | } |
| 202 | return 0; |
| 203 | } |
| 204 | |
| 205 | static int __kprobes collect_garbage_slots(void) |
| 206 | { |
| 207 | struct kprobe_insn_page *kip; |
| 208 | struct hlist_node *pos, *next; |
| 209 | |
| 210 | /* Ensure no-one is preepmted on the garbages */ |
| 211 | if (check_safety() != 0) |
| 212 | return -EAGAIN; |
| 213 | |
| 214 | hlist_for_each_safe(pos, next, &kprobe_insn_pages) { |
| 215 | int i; |
| 216 | kip = hlist_entry(pos, struct kprobe_insn_page, hlist); |
| 217 | if (kip->ngarbage == 0) |
| 218 | continue; |
| 219 | kip->ngarbage = 0; /* we will collect all garbages */ |
| 220 | for (i = 0; i < INSNS_PER_PAGE; i++) { |
Masami Hiramatsu | ab40c5c | 2007-01-30 14:36:06 -0800 | [diff] [blame] | 221 | if (kip->slot_used[i] == SLOT_DIRTY && |
Masami Hiramatsu | b4c6c34 | 2006-12-06 20:38:11 -0800 | [diff] [blame] | 222 | collect_one_slot(kip, i)) |
| 223 | break; |
| 224 | } |
| 225 | } |
| 226 | kprobe_garbage_slots = 0; |
| 227 | return 0; |
| 228 | } |
| 229 | |
| 230 | void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 231 | { |
| 232 | struct kprobe_insn_page *kip; |
| 233 | struct hlist_node *pos; |
| 234 | |
| 235 | hlist_for_each(pos, &kprobe_insn_pages) { |
| 236 | kip = hlist_entry(pos, struct kprobe_insn_page, hlist); |
| 237 | if (kip->insns <= slot && |
| 238 | slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) { |
| 239 | int i = (slot - kip->insns) / MAX_INSN_SIZE; |
Masami Hiramatsu | b4c6c34 | 2006-12-06 20:38:11 -0800 | [diff] [blame] | 240 | if (dirty) { |
Masami Hiramatsu | ab40c5c | 2007-01-30 14:36:06 -0800 | [diff] [blame] | 241 | kip->slot_used[i] = SLOT_DIRTY; |
Masami Hiramatsu | b4c6c34 | 2006-12-06 20:38:11 -0800 | [diff] [blame] | 242 | kip->ngarbage++; |
| 243 | } else { |
| 244 | collect_one_slot(kip, i); |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 245 | } |
Masami Hiramatsu | b4c6c34 | 2006-12-06 20:38:11 -0800 | [diff] [blame] | 246 | break; |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 247 | } |
| 248 | } |
Masami Hiramatsu | b4c6c34 | 2006-12-06 20:38:11 -0800 | [diff] [blame] | 249 | if (dirty && (++kprobe_garbage_slots > INSNS_PER_PAGE)) { |
| 250 | collect_garbage_slots(); |
| 251 | } |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 252 | } |
Anil S Keshavamurthy | 2d14e39 | 2006-01-09 20:52:41 -0800 | [diff] [blame] | 253 | #endif |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 254 | |
Ananth N Mavinakayanahalli | e658452 | 2005-11-07 01:00:07 -0800 | [diff] [blame] | 255 | /* We have preemption disabled.. so it is safe to use __ versions */ |
| 256 | static inline void set_kprobe_instance(struct kprobe *kp) |
| 257 | { |
| 258 | __get_cpu_var(kprobe_instance) = kp; |
| 259 | } |
| 260 | |
| 261 | static inline void reset_kprobe_instance(void) |
| 262 | { |
| 263 | __get_cpu_var(kprobe_instance) = NULL; |
| 264 | } |
| 265 | |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 266 | /* |
| 267 | * This routine is called either: |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 268 | * - under the kprobe_mutex - during kprobe_[un]register() |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 269 | * OR |
Ananth N Mavinakayanahalli | d217d54 | 2005-11-07 01:00:14 -0800 | [diff] [blame] | 270 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 271 | */ |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 272 | struct kprobe __kprobes *get_kprobe(void *addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 273 | { |
| 274 | struct hlist_head *head; |
| 275 | struct hlist_node *node; |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 276 | struct kprobe *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | |
| 278 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 279 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | if (p->addr == addr) |
| 281 | return p; |
| 282 | } |
| 283 | return NULL; |
| 284 | } |
| 285 | |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 286 | /* |
| 287 | * Aggregate handlers for multiple kprobes support - these handlers |
| 288 | * take care of invoking the individual kprobe handlers on p->list |
| 289 | */ |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 290 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 291 | { |
| 292 | struct kprobe *kp; |
| 293 | |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 294 | list_for_each_entry_rcu(kp, &p->list, list) { |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 295 | if (kp->pre_handler) { |
Ananth N Mavinakayanahalli | e658452 | 2005-11-07 01:00:07 -0800 | [diff] [blame] | 296 | set_kprobe_instance(kp); |
Prasanna S Panchamukhi | 8b0914e | 2005-06-23 00:09:41 -0700 | [diff] [blame] | 297 | if (kp->pre_handler(kp, regs)) |
| 298 | return 1; |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 299 | } |
Ananth N Mavinakayanahalli | e658452 | 2005-11-07 01:00:07 -0800 | [diff] [blame] | 300 | reset_kprobe_instance(); |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 301 | } |
| 302 | return 0; |
| 303 | } |
| 304 | |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 305 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
| 306 | unsigned long flags) |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 307 | { |
| 308 | struct kprobe *kp; |
| 309 | |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 310 | list_for_each_entry_rcu(kp, &p->list, list) { |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 311 | if (kp->post_handler) { |
Ananth N Mavinakayanahalli | e658452 | 2005-11-07 01:00:07 -0800 | [diff] [blame] | 312 | set_kprobe_instance(kp); |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 313 | kp->post_handler(kp, regs, flags); |
Ananth N Mavinakayanahalli | e658452 | 2005-11-07 01:00:07 -0800 | [diff] [blame] | 314 | reset_kprobe_instance(); |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 315 | } |
| 316 | } |
| 317 | return; |
| 318 | } |
| 319 | |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 320 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
| 321 | int trapnr) |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 322 | { |
Ananth N Mavinakayanahalli | e658452 | 2005-11-07 01:00:07 -0800 | [diff] [blame] | 323 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
| 324 | |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 325 | /* |
| 326 | * if we faulted "during" the execution of a user specified |
| 327 | * probe handler, invoke just that probe's fault handler |
| 328 | */ |
Ananth N Mavinakayanahalli | e658452 | 2005-11-07 01:00:07 -0800 | [diff] [blame] | 329 | if (cur && cur->fault_handler) { |
| 330 | if (cur->fault_handler(cur, regs, trapnr)) |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 331 | return 1; |
| 332 | } |
| 333 | return 0; |
| 334 | } |
| 335 | |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 336 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
Prasanna S Panchamukhi | 8b0914e | 2005-06-23 00:09:41 -0700 | [diff] [blame] | 337 | { |
Ananth N Mavinakayanahalli | e658452 | 2005-11-07 01:00:07 -0800 | [diff] [blame] | 338 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
| 339 | int ret = 0; |
| 340 | |
| 341 | if (cur && cur->break_handler) { |
| 342 | if (cur->break_handler(cur, regs)) |
| 343 | ret = 1; |
Prasanna S Panchamukhi | 8b0914e | 2005-06-23 00:09:41 -0700 | [diff] [blame] | 344 | } |
Ananth N Mavinakayanahalli | e658452 | 2005-11-07 01:00:07 -0800 | [diff] [blame] | 345 | reset_kprobe_instance(); |
| 346 | return ret; |
Prasanna S Panchamukhi | 8b0914e | 2005-06-23 00:09:41 -0700 | [diff] [blame] | 347 | } |
| 348 | |
Keshavamurthy Anil S | bf8d5c5 | 2005-12-12 00:37:34 -0800 | [diff] [blame] | 349 | /* Walks the list and increments nmissed count for multiprobe case */ |
| 350 | void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) |
| 351 | { |
| 352 | struct kprobe *kp; |
| 353 | if (p->pre_handler != aggr_pre_handler) { |
| 354 | p->nmissed++; |
| 355 | } else { |
| 356 | list_for_each_entry_rcu(kp, &p->list, list) |
| 357 | kp->nmissed++; |
| 358 | } |
| 359 | return; |
| 360 | } |
| 361 | |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 362 | /* Called with kretprobe_lock held */ |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 363 | struct kretprobe_instance __kprobes *get_free_rp_inst(struct kretprobe *rp) |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 364 | { |
| 365 | struct hlist_node *node; |
| 366 | struct kretprobe_instance *ri; |
| 367 | hlist_for_each_entry(ri, node, &rp->free_instances, uflist) |
| 368 | return ri; |
| 369 | return NULL; |
| 370 | } |
| 371 | |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 372 | /* Called with kretprobe_lock held */ |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 373 | static struct kretprobe_instance __kprobes *get_used_rp_inst(struct kretprobe |
| 374 | *rp) |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 375 | { |
| 376 | struct hlist_node *node; |
| 377 | struct kretprobe_instance *ri; |
| 378 | hlist_for_each_entry(ri, node, &rp->used_instances, uflist) |
| 379 | return ri; |
| 380 | return NULL; |
| 381 | } |
| 382 | |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 383 | /* Called with kretprobe_lock held */ |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 384 | void __kprobes add_rp_inst(struct kretprobe_instance *ri) |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 385 | { |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 386 | /* |
| 387 | * Remove rp inst off the free list - |
| 388 | * Add it back when probed function returns |
| 389 | */ |
| 390 | hlist_del(&ri->uflist); |
Rusty Lynch | 802eae7 | 2005-06-27 15:17:08 -0700 | [diff] [blame] | 391 | |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 392 | /* Add rp inst onto table */ |
| 393 | INIT_HLIST_NODE(&ri->hlist); |
| 394 | hlist_add_head(&ri->hlist, |
Rusty Lynch | 802eae7 | 2005-06-27 15:17:08 -0700 | [diff] [blame] | 395 | &kretprobe_inst_table[hash_ptr(ri->task, KPROBE_HASH_BITS)]); |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 396 | |
| 397 | /* Also add this rp inst to the used list. */ |
| 398 | INIT_HLIST_NODE(&ri->uflist); |
| 399 | hlist_add_head(&ri->uflist, &ri->rp->used_instances); |
| 400 | } |
| 401 | |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 402 | /* Called with kretprobe_lock held */ |
bibo,mao | 99219a3 | 2006-10-02 02:17:35 -0700 | [diff] [blame] | 403 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, |
| 404 | struct hlist_head *head) |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 405 | { |
| 406 | /* remove rp inst off the rprobe_inst_table */ |
| 407 | hlist_del(&ri->hlist); |
| 408 | if (ri->rp) { |
| 409 | /* remove rp inst off the used list */ |
| 410 | hlist_del(&ri->uflist); |
| 411 | /* put rp inst back onto the free list */ |
| 412 | INIT_HLIST_NODE(&ri->uflist); |
| 413 | hlist_add_head(&ri->uflist, &ri->rp->free_instances); |
| 414 | } else |
| 415 | /* Unregistering */ |
bibo,mao | 99219a3 | 2006-10-02 02:17:35 -0700 | [diff] [blame] | 416 | hlist_add_head(&ri->hlist, head); |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 417 | } |
| 418 | |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 419 | struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk) |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 420 | { |
| 421 | return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)]; |
| 422 | } |
| 423 | |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 424 | /* |
bibo mao | c6fd91f | 2006-03-26 01:38:20 -0800 | [diff] [blame] | 425 | * This function is called from finish_task_switch when task tk becomes dead, |
| 426 | * so that we can recycle any function-return probe instances associated |
| 427 | * with this task. These left over instances represent probed functions |
| 428 | * that have been called but will never return. |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 429 | */ |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 430 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 431 | { |
bibo,mao | 62c27be | 2006-10-02 02:17:33 -0700 | [diff] [blame] | 432 | struct kretprobe_instance *ri; |
bibo,mao | 99219a3 | 2006-10-02 02:17:35 -0700 | [diff] [blame] | 433 | struct hlist_head *head, empty_rp; |
Rusty Lynch | 802eae7 | 2005-06-27 15:17:08 -0700 | [diff] [blame] | 434 | struct hlist_node *node, *tmp; |
Hien Nguyen | 0aa55e4 | 2005-06-23 00:09:26 -0700 | [diff] [blame] | 435 | unsigned long flags = 0; |
Rusty Lynch | 802eae7 | 2005-06-27 15:17:08 -0700 | [diff] [blame] | 436 | |
bibo,mao | 99219a3 | 2006-10-02 02:17:35 -0700 | [diff] [blame] | 437 | INIT_HLIST_HEAD(&empty_rp); |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 438 | spin_lock_irqsave(&kretprobe_lock, flags); |
bibo,mao | 62c27be | 2006-10-02 02:17:33 -0700 | [diff] [blame] | 439 | head = kretprobe_inst_table_head(tk); |
| 440 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { |
| 441 | if (ri->task == tk) |
bibo,mao | 99219a3 | 2006-10-02 02:17:35 -0700 | [diff] [blame] | 442 | recycle_rp_inst(ri, &empty_rp); |
bibo,mao | 62c27be | 2006-10-02 02:17:33 -0700 | [diff] [blame] | 443 | } |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 444 | spin_unlock_irqrestore(&kretprobe_lock, flags); |
bibo,mao | 99219a3 | 2006-10-02 02:17:35 -0700 | [diff] [blame] | 445 | |
| 446 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
| 447 | hlist_del(&ri->hlist); |
| 448 | kfree(ri); |
| 449 | } |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 450 | } |
| 451 | |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 452 | static inline void free_rp_inst(struct kretprobe *rp) |
| 453 | { |
| 454 | struct kretprobe_instance *ri; |
| 455 | while ((ri = get_free_rp_inst(rp)) != NULL) { |
| 456 | hlist_del(&ri->uflist); |
| 457 | kfree(ri); |
| 458 | } |
| 459 | } |
| 460 | |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 461 | /* |
Prasanna S Panchamukhi | 8b0914e | 2005-06-23 00:09:41 -0700 | [diff] [blame] | 462 | * Keep all fields in the kprobe consistent |
| 463 | */ |
| 464 | static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) |
| 465 | { |
| 466 | memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); |
| 467 | memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); |
| 468 | } |
| 469 | |
| 470 | /* |
| 471 | * Add the new probe to old_p->list. Fail if this is the |
| 472 | * second jprobe at the address - two jprobes can't coexist |
| 473 | */ |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 474 | static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p) |
Prasanna S Panchamukhi | 8b0914e | 2005-06-23 00:09:41 -0700 | [diff] [blame] | 475 | { |
Prasanna S Panchamukhi | 8b0914e | 2005-06-23 00:09:41 -0700 | [diff] [blame] | 476 | if (p->break_handler) { |
mao, bibo | 3672165 | 2006-06-26 00:25:22 -0700 | [diff] [blame] | 477 | if (old_p->break_handler) |
| 478 | return -EEXIST; |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 479 | list_add_tail_rcu(&p->list, &old_p->list); |
mao, bibo | 3672165 | 2006-06-26 00:25:22 -0700 | [diff] [blame] | 480 | old_p->break_handler = aggr_break_handler; |
Prasanna S Panchamukhi | 8b0914e | 2005-06-23 00:09:41 -0700 | [diff] [blame] | 481 | } else |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 482 | list_add_rcu(&p->list, &old_p->list); |
mao, bibo | 3672165 | 2006-06-26 00:25:22 -0700 | [diff] [blame] | 483 | if (p->post_handler && !old_p->post_handler) |
| 484 | old_p->post_handler = aggr_post_handler; |
Prasanna S Panchamukhi | 8b0914e | 2005-06-23 00:09:41 -0700 | [diff] [blame] | 485 | return 0; |
| 486 | } |
| 487 | |
| 488 | /* |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 489 | * Fill in the required fields of the "manager kprobe". Replace the |
| 490 | * earlier kprobe in the hlist with the manager kprobe |
| 491 | */ |
| 492 | static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
| 493 | { |
Prasanna S Panchamukhi | 8b0914e | 2005-06-23 00:09:41 -0700 | [diff] [blame] | 494 | copy_kprobe(p, ap); |
bibo, mao | a9ad965 | 2006-07-30 03:03:26 -0700 | [diff] [blame] | 495 | flush_insn_slot(ap); |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 496 | ap->addr = p->addr; |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 497 | ap->pre_handler = aggr_pre_handler; |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 498 | ap->fault_handler = aggr_fault_handler; |
mao, bibo | 3672165 | 2006-06-26 00:25:22 -0700 | [diff] [blame] | 499 | if (p->post_handler) |
| 500 | ap->post_handler = aggr_post_handler; |
| 501 | if (p->break_handler) |
| 502 | ap->break_handler = aggr_break_handler; |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 503 | |
| 504 | INIT_LIST_HEAD(&ap->list); |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 505 | list_add_rcu(&p->list, &ap->list); |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 506 | |
Keshavamurthy Anil S | adad0f3 | 2005-12-12 00:37:12 -0800 | [diff] [blame] | 507 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 508 | } |
| 509 | |
| 510 | /* |
| 511 | * This is the second or subsequent kprobe at the address - handle |
| 512 | * the intricacies |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 513 | */ |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 514 | static int __kprobes register_aggr_kprobe(struct kprobe *old_p, |
| 515 | struct kprobe *p) |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 516 | { |
| 517 | int ret = 0; |
| 518 | struct kprobe *ap; |
| 519 | |
Prasanna S Panchamukhi | 8b0914e | 2005-06-23 00:09:41 -0700 | [diff] [blame] | 520 | if (old_p->pre_handler == aggr_pre_handler) { |
| 521 | copy_kprobe(old_p, p); |
| 522 | ret = add_new_kprobe(old_p, p); |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 523 | } else { |
Keshavamurthy Anil S | a0d5006 | 2006-01-09 20:52:46 -0800 | [diff] [blame] | 524 | ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL); |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 525 | if (!ap) |
| 526 | return -ENOMEM; |
| 527 | add_aggr_kprobe(ap, old_p); |
Prasanna S Panchamukhi | 8b0914e | 2005-06-23 00:09:41 -0700 | [diff] [blame] | 528 | copy_kprobe(ap, p); |
| 529 | ret = add_new_kprobe(ap, p); |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 530 | } |
| 531 | return ret; |
| 532 | } |
| 533 | |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 534 | static int __kprobes in_kprobes_functions(unsigned long addr) |
| 535 | { |
| 536 | if (addr >= (unsigned long)__kprobes_text_start |
| 537 | && addr < (unsigned long)__kprobes_text_end) |
| 538 | return -EINVAL; |
| 539 | return 0; |
| 540 | } |
| 541 | |
Keshavamurthy Anil S | df019b1 | 2006-01-11 12:17:41 -0800 | [diff] [blame] | 542 | static int __kprobes __register_kprobe(struct kprobe *p, |
| 543 | unsigned long called_from) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 544 | { |
| 545 | int ret = 0; |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 546 | struct kprobe *old_p; |
Keshavamurthy Anil S | df019b1 | 2006-01-11 12:17:41 -0800 | [diff] [blame] | 547 | struct module *probed_mod; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | |
Ananth N Mavinakayanahalli | 3a872d8 | 2006-10-02 02:17:30 -0700 | [diff] [blame] | 549 | /* |
| 550 | * If we have a symbol_name argument look it up, |
| 551 | * and add it to the address. That way the addr |
| 552 | * field can either be global or relative to a symbol. |
| 553 | */ |
| 554 | if (p->symbol_name) { |
| 555 | if (p->addr) |
| 556 | return -EINVAL; |
| 557 | kprobe_lookup_name(p->symbol_name, p->addr); |
| 558 | } |
| 559 | |
| 560 | if (!p->addr) |
| 561 | return -EINVAL; |
| 562 | p->addr = (kprobe_opcode_t *)(((char *)p->addr)+ p->offset); |
| 563 | |
Mao, Bibo | b3e55c7 | 2005-12-12 00:37:00 -0800 | [diff] [blame] | 564 | if ((!kernel_text_address((unsigned long) p->addr)) || |
| 565 | in_kprobes_functions((unsigned long) p->addr)) |
| 566 | return -EINVAL; |
| 567 | |
Keshavamurthy Anil S | df019b1 | 2006-01-11 12:17:41 -0800 | [diff] [blame] | 568 | p->mod_refcounted = 0; |
| 569 | /* Check are we probing a module */ |
| 570 | if ((probed_mod = module_text_address((unsigned long) p->addr))) { |
| 571 | struct module *calling_mod = module_text_address(called_from); |
| 572 | /* We must allow modules to probe themself and |
| 573 | * in this case avoid incrementing the module refcount, |
| 574 | * so as to allow unloading of self probing modules. |
| 575 | */ |
| 576 | if (calling_mod && (calling_mod != probed_mod)) { |
| 577 | if (unlikely(!try_module_get(probed_mod))) |
| 578 | return -EINVAL; |
| 579 | p->mod_refcounted = 1; |
| 580 | } else |
| 581 | probed_mod = NULL; |
| 582 | } |
Mao, Bibo | b3e55c7 | 2005-12-12 00:37:00 -0800 | [diff] [blame] | 583 | |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 584 | p->nmissed = 0; |
Ingo Molnar | 7a7d1cf | 2006-03-23 03:00:35 -0800 | [diff] [blame] | 585 | mutex_lock(&kprobe_mutex); |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 586 | old_p = get_kprobe(p->addr); |
| 587 | if (old_p) { |
| 588 | ret = register_aggr_kprobe(old_p, p); |
Anil S Keshavamurthy | e6f47f9 | 2006-06-26 00:25:29 -0700 | [diff] [blame] | 589 | if (!ret) |
| 590 | atomic_inc(&kprobe_count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 591 | goto out; |
| 592 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 593 | |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 594 | if ((ret = arch_prepare_kprobe(p)) != 0) |
| 595 | goto out; |
| 596 | |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 597 | INIT_HLIST_NODE(&p->hlist); |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 598 | hlist_add_head_rcu(&p->hlist, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 599 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
| 600 | |
Anil S Keshavamurthy | e6f47f9 | 2006-06-26 00:25:29 -0700 | [diff] [blame] | 601 | if (atomic_add_return(1, &kprobe_count) == \ |
| 602 | (ARCH_INACTIVE_KPROBE_COUNT + 1)) |
| 603 | register_page_fault_notifier(&kprobe_page_fault_nb); |
| 604 | |
bibo,mao | 62c27be | 2006-10-02 02:17:33 -0700 | [diff] [blame] | 605 | arch_arm_kprobe(p); |
Rusty Lynch | 7e1048b | 2005-06-23 00:09:25 -0700 | [diff] [blame] | 606 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 607 | out: |
Ingo Molnar | 7a7d1cf | 2006-03-23 03:00:35 -0800 | [diff] [blame] | 608 | mutex_unlock(&kprobe_mutex); |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 609 | |
Keshavamurthy Anil S | df019b1 | 2006-01-11 12:17:41 -0800 | [diff] [blame] | 610 | if (ret && probed_mod) |
| 611 | module_put(probed_mod); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 612 | return ret; |
| 613 | } |
| 614 | |
Keshavamurthy Anil S | df019b1 | 2006-01-11 12:17:41 -0800 | [diff] [blame] | 615 | int __kprobes register_kprobe(struct kprobe *p) |
| 616 | { |
| 617 | return __register_kprobe(p, |
| 618 | (unsigned long)__builtin_return_address(0)); |
| 619 | } |
| 620 | |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 621 | void __kprobes unregister_kprobe(struct kprobe *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 622 | { |
Mao, Bibo | b3e55c7 | 2005-12-12 00:37:00 -0800 | [diff] [blame] | 623 | struct module *mod; |
Keshavamurthy Anil S | f709b12 | 2006-01-09 20:52:44 -0800 | [diff] [blame] | 624 | struct kprobe *old_p, *list_p; |
| 625 | int cleanup_p; |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 626 | |
Ingo Molnar | 7a7d1cf | 2006-03-23 03:00:35 -0800 | [diff] [blame] | 627 | mutex_lock(&kprobe_mutex); |
Ananth N Mavinakayanahalli | 64f562c | 2005-05-05 16:15:42 -0700 | [diff] [blame] | 628 | old_p = get_kprobe(p->addr); |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 629 | if (unlikely(!old_p)) { |
Ingo Molnar | 7a7d1cf | 2006-03-23 03:00:35 -0800 | [diff] [blame] | 630 | mutex_unlock(&kprobe_mutex); |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 631 | return; |
| 632 | } |
Keshavamurthy Anil S | f709b12 | 2006-01-09 20:52:44 -0800 | [diff] [blame] | 633 | if (p != old_p) { |
| 634 | list_for_each_entry_rcu(list_p, &old_p->list, list) |
| 635 | if (list_p == p) |
| 636 | /* kprobe p is a valid probe */ |
| 637 | goto valid_p; |
Ingo Molnar | 7a7d1cf | 2006-03-23 03:00:35 -0800 | [diff] [blame] | 638 | mutex_unlock(&kprobe_mutex); |
Keshavamurthy Anil S | f709b12 | 2006-01-09 20:52:44 -0800 | [diff] [blame] | 639 | return; |
| 640 | } |
| 641 | valid_p: |
| 642 | if ((old_p == p) || ((old_p->pre_handler == aggr_pre_handler) && |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 643 | (p->list.next == &old_p->list) && |
Keshavamurthy Anil S | f709b12 | 2006-01-09 20:52:44 -0800 | [diff] [blame] | 644 | (p->list.prev == &old_p->list))) { |
| 645 | /* Only probe on the hash list */ |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 646 | arch_disarm_kprobe(p); |
| 647 | hlist_del_rcu(&old_p->hlist); |
Keshavamurthy Anil S | f709b12 | 2006-01-09 20:52:44 -0800 | [diff] [blame] | 648 | cleanup_p = 1; |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 649 | } else { |
| 650 | list_del_rcu(&p->list); |
Keshavamurthy Anil S | f709b12 | 2006-01-09 20:52:44 -0800 | [diff] [blame] | 651 | cleanup_p = 0; |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 652 | } |
Mao, Bibo | b3e55c7 | 2005-12-12 00:37:00 -0800 | [diff] [blame] | 653 | |
Ingo Molnar | 7a7d1cf | 2006-03-23 03:00:35 -0800 | [diff] [blame] | 654 | mutex_unlock(&kprobe_mutex); |
Mao, Bibo | b3e55c7 | 2005-12-12 00:37:00 -0800 | [diff] [blame] | 655 | |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 656 | synchronize_sched(); |
Keshavamurthy Anil S | df019b1 | 2006-01-11 12:17:41 -0800 | [diff] [blame] | 657 | if (p->mod_refcounted && |
| 658 | (mod = module_text_address((unsigned long)p->addr))) |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 659 | module_put(mod); |
| 660 | |
| 661 | if (cleanup_p) { |
Keshavamurthy Anil S | f709b12 | 2006-01-09 20:52:44 -0800 | [diff] [blame] | 662 | if (p != old_p) { |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 663 | list_del_rcu(&p->list); |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 664 | kfree(old_p); |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 665 | } |
Ananth N Mavinakayanahalli | 0498b63 | 2006-01-09 20:52:46 -0800 | [diff] [blame] | 666 | arch_remove_kprobe(p); |
mao, bibo | 3672165 | 2006-06-26 00:25:22 -0700 | [diff] [blame] | 667 | } else { |
| 668 | mutex_lock(&kprobe_mutex); |
| 669 | if (p->break_handler) |
| 670 | old_p->break_handler = NULL; |
| 671 | if (p->post_handler){ |
| 672 | list_for_each_entry_rcu(list_p, &old_p->list, list){ |
| 673 | if (list_p->post_handler){ |
| 674 | cleanup_p = 2; |
| 675 | break; |
| 676 | } |
| 677 | } |
| 678 | if (cleanup_p == 0) |
| 679 | old_p->post_handler = NULL; |
| 680 | } |
| 681 | mutex_unlock(&kprobe_mutex); |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 682 | } |
Anil S Keshavamurthy | e6f47f9 | 2006-06-26 00:25:29 -0700 | [diff] [blame] | 683 | |
| 684 | /* Call unregister_page_fault_notifier() |
| 685 | * if no probes are active |
| 686 | */ |
| 687 | mutex_lock(&kprobe_mutex); |
| 688 | if (atomic_add_return(-1, &kprobe_count) == \ |
| 689 | ARCH_INACTIVE_KPROBE_COUNT) |
| 690 | unregister_page_fault_notifier(&kprobe_page_fault_nb); |
| 691 | mutex_unlock(&kprobe_mutex); |
| 692 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 693 | } |
| 694 | |
| 695 | static struct notifier_block kprobe_exceptions_nb = { |
| 696 | .notifier_call = kprobe_exceptions_notify, |
Anil S Keshavamurthy | 3d5631e | 2006-06-26 00:25:28 -0700 | [diff] [blame] | 697 | .priority = 0x7fffffff /* we need to be notified first */ |
| 698 | }; |
| 699 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 700 | |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 701 | int __kprobes register_jprobe(struct jprobe *jp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 702 | { |
| 703 | /* Todo: Verify probepoint is a function entry point */ |
| 704 | jp->kp.pre_handler = setjmp_pre_handler; |
| 705 | jp->kp.break_handler = longjmp_break_handler; |
| 706 | |
Keshavamurthy Anil S | df019b1 | 2006-01-11 12:17:41 -0800 | [diff] [blame] | 707 | return __register_kprobe(&jp->kp, |
| 708 | (unsigned long)__builtin_return_address(0)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 709 | } |
| 710 | |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 711 | void __kprobes unregister_jprobe(struct jprobe *jp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 712 | { |
| 713 | unregister_kprobe(&jp->kp); |
| 714 | } |
| 715 | |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 716 | #ifdef ARCH_SUPPORTS_KRETPROBES |
| 717 | |
Adrian Bunk | e65cefe | 2006-02-03 03:03:42 -0800 | [diff] [blame] | 718 | /* |
| 719 | * This kprobe pre_handler is registered with every kretprobe. When probe |
| 720 | * hits it will set up the return probe. |
| 721 | */ |
| 722 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
| 723 | struct pt_regs *regs) |
| 724 | { |
| 725 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); |
| 726 | unsigned long flags = 0; |
| 727 | |
| 728 | /*TODO: consider to only swap the RA after the last pre_handler fired */ |
| 729 | spin_lock_irqsave(&kretprobe_lock, flags); |
| 730 | arch_prepare_kretprobe(rp, regs); |
| 731 | spin_unlock_irqrestore(&kretprobe_lock, flags); |
| 732 | return 0; |
| 733 | } |
| 734 | |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 735 | int __kprobes register_kretprobe(struct kretprobe *rp) |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 736 | { |
| 737 | int ret = 0; |
| 738 | struct kretprobe_instance *inst; |
| 739 | int i; |
| 740 | |
| 741 | rp->kp.pre_handler = pre_handler_kretprobe; |
Ananth N Mavinakayanahalli | 7522a84 | 2006-04-20 02:43:11 -0700 | [diff] [blame] | 742 | rp->kp.post_handler = NULL; |
| 743 | rp->kp.fault_handler = NULL; |
| 744 | rp->kp.break_handler = NULL; |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 745 | |
| 746 | /* Pre-allocate memory for max kretprobe instances */ |
| 747 | if (rp->maxactive <= 0) { |
| 748 | #ifdef CONFIG_PREEMPT |
| 749 | rp->maxactive = max(10, 2 * NR_CPUS); |
| 750 | #else |
| 751 | rp->maxactive = NR_CPUS; |
| 752 | #endif |
| 753 | } |
| 754 | INIT_HLIST_HEAD(&rp->used_instances); |
| 755 | INIT_HLIST_HEAD(&rp->free_instances); |
| 756 | for (i = 0; i < rp->maxactive; i++) { |
| 757 | inst = kmalloc(sizeof(struct kretprobe_instance), GFP_KERNEL); |
| 758 | if (inst == NULL) { |
| 759 | free_rp_inst(rp); |
| 760 | return -ENOMEM; |
| 761 | } |
| 762 | INIT_HLIST_NODE(&inst->uflist); |
| 763 | hlist_add_head(&inst->uflist, &rp->free_instances); |
| 764 | } |
| 765 | |
| 766 | rp->nmissed = 0; |
| 767 | /* Establish function entry probe point */ |
Keshavamurthy Anil S | df019b1 | 2006-01-11 12:17:41 -0800 | [diff] [blame] | 768 | if ((ret = __register_kprobe(&rp->kp, |
| 769 | (unsigned long)__builtin_return_address(0))) != 0) |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 770 | free_rp_inst(rp); |
| 771 | return ret; |
| 772 | } |
| 773 | |
| 774 | #else /* ARCH_SUPPORTS_KRETPROBES */ |
| 775 | |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 776 | int __kprobes register_kretprobe(struct kretprobe *rp) |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 777 | { |
| 778 | return -ENOSYS; |
| 779 | } |
| 780 | |
| 781 | #endif /* ARCH_SUPPORTS_KRETPROBES */ |
| 782 | |
Prasanna S Panchamukhi | d0aaff9 | 2005-09-06 15:19:26 -0700 | [diff] [blame] | 783 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 784 | { |
| 785 | unsigned long flags; |
| 786 | struct kretprobe_instance *ri; |
| 787 | |
| 788 | unregister_kprobe(&rp->kp); |
| 789 | /* No race here */ |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 790 | spin_lock_irqsave(&kretprobe_lock, flags); |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 791 | while ((ri = get_used_rp_inst(rp)) != NULL) { |
| 792 | ri->rp = NULL; |
| 793 | hlist_del(&ri->uflist); |
| 794 | } |
Ananth N Mavinakayanahalli | 3516a46 | 2005-11-07 01:00:13 -0800 | [diff] [blame] | 795 | spin_unlock_irqrestore(&kretprobe_lock, flags); |
Ananth N Mavinakayanahalli | 278ff95 | 2006-02-03 03:03:43 -0800 | [diff] [blame] | 796 | free_rp_inst(rp); |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 797 | } |
| 798 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 799 | static int __init init_kprobes(void) |
| 800 | { |
| 801 | int i, err = 0; |
| 802 | |
| 803 | /* FIXME allocate the probe table, currently defined statically */ |
| 804 | /* initialize all list heads */ |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 805 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 806 | INIT_HLIST_HEAD(&kprobe_table[i]); |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 807 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
| 808 | } |
Anil S Keshavamurthy | e6f47f9 | 2006-06-26 00:25:29 -0700 | [diff] [blame] | 809 | atomic_set(&kprobe_count, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 810 | |
Rusty Lynch | 6772926 | 2005-07-05 18:54:50 -0700 | [diff] [blame] | 811 | err = arch_init_kprobes(); |
Rusty Lynch | 802eae7 | 2005-06-27 15:17:08 -0700 | [diff] [blame] | 812 | if (!err) |
| 813 | err = register_die_notifier(&kprobe_exceptions_nb); |
| 814 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 815 | return err; |
| 816 | } |
| 817 | |
| 818 | __initcall(init_kprobes); |
| 819 | |
| 820 | EXPORT_SYMBOL_GPL(register_kprobe); |
| 821 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
| 822 | EXPORT_SYMBOL_GPL(register_jprobe); |
| 823 | EXPORT_SYMBOL_GPL(unregister_jprobe); |
| 824 | EXPORT_SYMBOL_GPL(jprobe_return); |
Hien Nguyen | b94cce9 | 2005-06-23 00:09:19 -0700 | [diff] [blame] | 825 | EXPORT_SYMBOL_GPL(register_kretprobe); |
| 826 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
| 827 | |