Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Kernel Probes (KProbes) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation; either version 2 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program; if not, write to the Free Software |
| 16 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 17 | * |
| 18 | * Copyright (C) IBM Corporation, 2002, 2004 |
| 19 | * |
| 20 | * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel |
| 21 | * Probes initial implementation ( includes contributions from |
| 22 | * Rusty Russell). |
| 23 | * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes |
| 24 | * interface to access function arguments. |
| 25 | * 2004-Nov Ananth N Mavinakayanahalli <ananth@in.ibm.com> kprobes port |
| 26 | * for PPC64 |
| 27 | */ |
| 28 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <linux/kprobes.h> |
| 30 | #include <linux/ptrace.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | #include <linux/preempt.h> |
Prasanna S Panchamukhi | 50e21f2 | 2006-03-26 01:38:24 -0800 | [diff] [blame] | 32 | #include <linux/module.h> |
Christoph Hellwig | 1eeb66a | 2007-05-08 00:27:03 -0700 | [diff] [blame] | 33 | #include <linux/kdebug.h> |
Rusty Lynch | 7e1048b | 2005-06-23 00:09:25 -0700 | [diff] [blame] | 34 | #include <asm/cacheflush.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | #include <asm/sstep.h> |
Prasanna S Panchamukhi | 50e21f2 | 2006-03-26 01:38:24 -0800 | [diff] [blame] | 36 | #include <asm/uaccess.h> |
Kumar Gala | f827962 | 2008-06-26 02:01:37 -0500 | [diff] [blame] | 37 | #include <asm/system.h> |
| 38 | |
Dave Kleikamp | 172ae2e | 2010-02-08 11:50:57 +0000 | [diff] [blame] | 39 | #ifdef CONFIG_PPC_ADV_DEBUG_REGS |
Kumar Gala | f827962 | 2008-06-26 02:01:37 -0500 | [diff] [blame] | 40 | #define MSR_SINGLESTEP (MSR_DE) |
| 41 | #else |
| 42 | #define MSR_SINGLESTEP (MSR_SE) |
| 43 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 45 | DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; |
| 46 | DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | |
Masami Hiramatsu | f438d91 | 2007-10-16 01:27:49 -0700 | [diff] [blame] | 48 | struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}}; |
| 49 | |
Prasanna S Panchamukhi | bb144a8 | 2005-09-06 15:19:29 -0700 | [diff] [blame] | 50 | int __kprobes arch_prepare_kprobe(struct kprobe *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | { |
Ananth N Mavinakayanahalli | 63224d1e8 | 2005-06-08 15:49:41 -0700 | [diff] [blame] | 52 | int ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | kprobe_opcode_t insn = *p->addr; |
| 54 | |
Ananth N Mavinakayanahalli | 63224d1e8 | 2005-06-08 15:49:41 -0700 | [diff] [blame] | 55 | if ((unsigned long)p->addr & 0x03) { |
| 56 | printk("Attempt to register kprobe at an unaligned address\n"); |
| 57 | ret = -EINVAL; |
Kumar Gala | 8209003 | 2007-02-06 22:55:19 -0600 | [diff] [blame] | 58 | } else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) { |
| 59 | printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n"); |
Ananth N Mavinakayanahalli | 63224d1e8 | 2005-06-08 15:49:41 -0700 | [diff] [blame] | 60 | ret = -EINVAL; |
| 61 | } |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 62 | |
Kumar Gala | f827962 | 2008-06-26 02:01:37 -0500 | [diff] [blame] | 63 | /* insn must be on a special executable page on ppc64. This is |
| 64 | * not explicitly required on ppc32 (right now), but it doesn't hurt */ |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 65 | if (!ret) { |
Ananth N Mavinakayanahalli | 2d8ab6a | 2005-10-01 13:14:17 -0400 | [diff] [blame] | 66 | p->ainsn.insn = get_insn_slot(); |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 67 | if (!p->ainsn.insn) |
| 68 | ret = -ENOMEM; |
| 69 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 71 | if (!ret) { |
Ananth N Mavinakayanahalli | e6349a95 | 2007-04-18 15:57:51 +1000 | [diff] [blame] | 72 | memcpy(p->ainsn.insn, p->addr, |
| 73 | MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 74 | p->opcode = *p->addr; |
Ananth N Mavinakayanahalli | 83db3dd | 2006-08-11 17:01:34 +0530 | [diff] [blame] | 75 | flush_icache_range((unsigned long)p->ainsn.insn, |
| 76 | (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t)); |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 77 | } |
| 78 | |
Ananth N Mavinakayanahalli | e6349a95 | 2007-04-18 15:57:51 +1000 | [diff] [blame] | 79 | p->ainsn.boostable = 0; |
Anil S Keshavamurthy | 49a2a1b | 2006-01-09 20:52:43 -0800 | [diff] [blame] | 80 | return ret; |
Rusty Lynch | 7e1048b | 2005-06-23 00:09:25 -0700 | [diff] [blame] | 81 | } |
| 82 | |
Prasanna S Panchamukhi | bb144a8 | 2005-09-06 15:19:29 -0700 | [diff] [blame] | 83 | void __kprobes arch_arm_kprobe(struct kprobe *p) |
Rusty Lynch | 7e1048b | 2005-06-23 00:09:25 -0700 | [diff] [blame] | 84 | { |
| 85 | *p->addr = BREAKPOINT_INSTRUCTION; |
| 86 | flush_icache_range((unsigned long) p->addr, |
| 87 | (unsigned long) p->addr + sizeof(kprobe_opcode_t)); |
| 88 | } |
| 89 | |
Prasanna S Panchamukhi | bb144a8 | 2005-09-06 15:19:29 -0700 | [diff] [blame] | 90 | void __kprobes arch_disarm_kprobe(struct kprobe *p) |
Rusty Lynch | 7e1048b | 2005-06-23 00:09:25 -0700 | [diff] [blame] | 91 | { |
| 92 | *p->addr = p->opcode; |
| 93 | flush_icache_range((unsigned long) p->addr, |
| 94 | (unsigned long) p->addr + sizeof(kprobe_opcode_t)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | } |
| 96 | |
Ananth N Mavinakayanahalli | 0498b63 | 2006-01-09 20:52:46 -0800 | [diff] [blame] | 97 | void __kprobes arch_remove_kprobe(struct kprobe *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | { |
Masami Hiramatsu | 1294156 | 2009-01-06 14:41:50 -0800 | [diff] [blame] | 99 | if (p->ainsn.insn) { |
| 100 | free_insn_slot(p->ainsn.insn, 0); |
| 101 | p->ainsn.insn = NULL; |
| 102 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | } |
| 104 | |
Prasanna S Panchamukhi | 46dbe2f | 2006-04-18 22:22:01 -0700 | [diff] [blame] | 105 | static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | { |
Kumar Gala | b76e59d | 2008-06-26 01:57:58 -0500 | [diff] [blame] | 107 | /* We turn off async exceptions to ensure that the single step will |
| 108 | * be for the instruction we have the kprobe on, if we dont its |
| 109 | * possible we'd get the single step reported for an exception handler |
| 110 | * like Decrementer or External Interrupt */ |
| 111 | regs->msr &= ~MSR_EE; |
Kumar Gala | f827962 | 2008-06-26 02:01:37 -0500 | [diff] [blame] | 112 | regs->msr |= MSR_SINGLESTEP; |
Dave Kleikamp | 172ae2e | 2010-02-08 11:50:57 +0000 | [diff] [blame] | 113 | #ifdef CONFIG_PPC_ADV_DEBUG_REGS |
Kumar Gala | f827962 | 2008-06-26 02:01:37 -0500 | [diff] [blame] | 114 | regs->msr &= ~MSR_CE; |
| 115 | mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM); |
| 116 | #endif |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 117 | |
Ananth N Mavinakayanahalli | 0ccde0a | 2006-04-28 17:38:42 +0530 | [diff] [blame] | 118 | /* |
| 119 | * On powerpc we should single step on the original |
| 120 | * instruction even if the probed insn is a trap |
| 121 | * variant as values in regs could play a part in |
| 122 | * if the trap is taken or not |
| 123 | */ |
| 124 | regs->nip = (unsigned long)p->ainsn.insn; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | } |
| 126 | |
Prasanna S Panchamukhi | 46dbe2f | 2006-04-18 22:22:01 -0700 | [diff] [blame] | 127 | static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) |
Prasanna S Panchamukhi | 42cc206 | 2005-06-23 00:09:38 -0700 | [diff] [blame] | 128 | { |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 129 | kcb->prev_kprobe.kp = kprobe_running(); |
| 130 | kcb->prev_kprobe.status = kcb->kprobe_status; |
| 131 | kcb->prev_kprobe.saved_msr = kcb->kprobe_saved_msr; |
Prasanna S Panchamukhi | 42cc206 | 2005-06-23 00:09:38 -0700 | [diff] [blame] | 132 | } |
| 133 | |
Prasanna S Panchamukhi | 46dbe2f | 2006-04-18 22:22:01 -0700 | [diff] [blame] | 134 | static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) |
Prasanna S Panchamukhi | 42cc206 | 2005-06-23 00:09:38 -0700 | [diff] [blame] | 135 | { |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 136 | __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp; |
| 137 | kcb->kprobe_status = kcb->prev_kprobe.status; |
| 138 | kcb->kprobe_saved_msr = kcb->prev_kprobe.saved_msr; |
| 139 | } |
| 140 | |
Prasanna S Panchamukhi | 46dbe2f | 2006-04-18 22:22:01 -0700 | [diff] [blame] | 141 | static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 142 | struct kprobe_ctlblk *kcb) |
| 143 | { |
| 144 | __get_cpu_var(current_kprobe) = p; |
| 145 | kcb->kprobe_saved_msr = regs->msr; |
Prasanna S Panchamukhi | 42cc206 | 2005-06-23 00:09:38 -0700 | [diff] [blame] | 146 | } |
| 147 | |
Christoph Hellwig | 4c4308c | 2007-05-08 00:34:14 -0700 | [diff] [blame] | 148 | void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, |
Prasanna S Panchamukhi | bb144a8 | 2005-09-06 15:19:29 -0700 | [diff] [blame] | 149 | struct pt_regs *regs) |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 150 | { |
Christoph Hellwig | 4c4308c | 2007-05-08 00:34:14 -0700 | [diff] [blame] | 151 | ri->ret_addr = (kprobe_opcode_t *)regs->link; |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 152 | |
Christoph Hellwig | 4c4308c | 2007-05-08 00:34:14 -0700 | [diff] [blame] | 153 | /* Replace the return addr with trampoline addr */ |
| 154 | regs->link = (unsigned long)kretprobe_trampoline; |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 155 | } |
| 156 | |
Prasanna S Panchamukhi | 46dbe2f | 2006-04-18 22:22:01 -0700 | [diff] [blame] | 157 | static int __kprobes kprobe_handler(struct pt_regs *regs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | { |
| 159 | struct kprobe *p; |
| 160 | int ret = 0; |
| 161 | unsigned int *addr = (unsigned int *)regs->nip; |
Ananth N Mavinakayanahalli | d217d54 | 2005-11-07 01:00:14 -0800 | [diff] [blame] | 162 | struct kprobe_ctlblk *kcb; |
| 163 | |
| 164 | /* |
| 165 | * We don't want to be preempted for the entire |
| 166 | * duration of kprobe processing |
| 167 | */ |
| 168 | preempt_disable(); |
| 169 | kcb = get_kprobe_ctlblk(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | |
| 171 | /* Check we're not actually recursing */ |
| 172 | if (kprobe_running()) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | p = get_kprobe(addr); |
| 174 | if (p) { |
Keshavamurthy Anil S | deac66a | 2005-09-06 15:19:35 -0700 | [diff] [blame] | 175 | kprobe_opcode_t insn = *p->ainsn.insn; |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 176 | if (kcb->kprobe_status == KPROBE_HIT_SS && |
Keshavamurthy Anil S | deac66a | 2005-09-06 15:19:35 -0700 | [diff] [blame] | 177 | is_trap(insn)) { |
Kumar Gala | f827962 | 2008-06-26 02:01:37 -0500 | [diff] [blame] | 178 | /* Turn off 'trace' bits */ |
| 179 | regs->msr &= ~MSR_SINGLESTEP; |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 180 | regs->msr |= kcb->kprobe_saved_msr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | goto no_kprobe; |
| 182 | } |
Prasanna S Panchamukhi | 42cc206 | 2005-06-23 00:09:38 -0700 | [diff] [blame] | 183 | /* We have reentered the kprobe_handler(), since |
| 184 | * another probe was hit while within the handler. |
| 185 | * We here save the original kprobes variables and |
| 186 | * just single step on the instruction of the new probe |
| 187 | * without calling any user handlers. |
| 188 | */ |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 189 | save_previous_kprobe(kcb); |
| 190 | set_current_kprobe(p, regs, kcb); |
| 191 | kcb->kprobe_saved_msr = regs->msr; |
Keshavamurthy Anil S | bf8d5c5 | 2005-12-12 00:37:34 -0800 | [diff] [blame] | 192 | kprobes_inc_nmissed_count(p); |
Prasanna S Panchamukhi | 42cc206 | 2005-06-23 00:09:38 -0700 | [diff] [blame] | 193 | prepare_singlestep(p, regs); |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 194 | kcb->kprobe_status = KPROBE_REENTER; |
Prasanna S Panchamukhi | 42cc206 | 2005-06-23 00:09:38 -0700 | [diff] [blame] | 195 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 196 | } else { |
Keshavamurthy Anil S | eb3a729 | 2006-01-11 12:17:42 -0800 | [diff] [blame] | 197 | if (*addr != BREAKPOINT_INSTRUCTION) { |
| 198 | /* If trap variant, then it belongs not to us */ |
| 199 | kprobe_opcode_t cur_insn = *addr; |
| 200 | if (is_trap(cur_insn)) |
| 201 | goto no_kprobe; |
| 202 | /* The breakpoint instruction was removed by |
| 203 | * another cpu right after we hit, no further |
| 204 | * handling of this interrupt is appropriate |
| 205 | */ |
| 206 | ret = 1; |
| 207 | goto no_kprobe; |
| 208 | } |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 209 | p = __get_cpu_var(current_kprobe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | if (p->break_handler && p->break_handler(p, regs)) { |
| 211 | goto ss_probe; |
| 212 | } |
| 213 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 214 | goto no_kprobe; |
| 215 | } |
| 216 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | p = get_kprobe(addr); |
| 218 | if (!p) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 219 | if (*addr != BREAKPOINT_INSTRUCTION) { |
| 220 | /* |
| 221 | * PowerPC has multiple variants of the "trap" |
| 222 | * instruction. If the current instruction is a |
| 223 | * trap variant, it could belong to someone else |
| 224 | */ |
| 225 | kprobe_opcode_t cur_insn = *addr; |
Keshavamurthy Anil S | deac66a | 2005-09-06 15:19:35 -0700 | [diff] [blame] | 226 | if (is_trap(cur_insn)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 227 | goto no_kprobe; |
| 228 | /* |
| 229 | * The breakpoint instruction was removed right |
| 230 | * after we hit it. Another cpu has removed |
| 231 | * either a probepoint or a debugger breakpoint |
| 232 | * at this address. In either case, no further |
| 233 | * handling of this interrupt is appropriate. |
| 234 | */ |
| 235 | ret = 1; |
| 236 | } |
| 237 | /* Not one of ours: let kernel handle it */ |
| 238 | goto no_kprobe; |
| 239 | } |
| 240 | |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 241 | kcb->kprobe_status = KPROBE_HIT_ACTIVE; |
| 242 | set_current_kprobe(p, regs, kcb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 243 | if (p->pre_handler && p->pre_handler(p, regs)) |
| 244 | /* handler has already set things up, so skip ss setup */ |
| 245 | return 1; |
| 246 | |
| 247 | ss_probe: |
Ananth N Mavinakayanahalli | e6349a95 | 2007-04-18 15:57:51 +1000 | [diff] [blame] | 248 | if (p->ainsn.boostable >= 0) { |
| 249 | unsigned int insn = *p->ainsn.insn; |
| 250 | |
| 251 | /* regs->nip is also adjusted if emulate_step returns 1 */ |
| 252 | ret = emulate_step(regs, insn); |
| 253 | if (ret > 0) { |
| 254 | /* |
| 255 | * Once this instruction has been boosted |
| 256 | * successfully, set the boostable flag |
| 257 | */ |
| 258 | if (unlikely(p->ainsn.boostable == 0)) |
| 259 | p->ainsn.boostable = 1; |
| 260 | |
| 261 | if (p->post_handler) |
| 262 | p->post_handler(p, regs, 0); |
| 263 | |
| 264 | kcb->kprobe_status = KPROBE_HIT_SSDONE; |
| 265 | reset_current_kprobe(); |
| 266 | preempt_enable_no_resched(); |
| 267 | return 1; |
| 268 | } else if (ret < 0) { |
| 269 | /* |
| 270 | * We don't allow kprobes on mtmsr(d)/rfi(d), etc. |
| 271 | * So, we should never get here... but, its still |
| 272 | * good to catch them, just in case... |
| 273 | */ |
| 274 | printk("Can't step on instruction %x\n", insn); |
| 275 | BUG(); |
| 276 | } else if (ret == 0) |
| 277 | /* This instruction can't be boosted */ |
| 278 | p->ainsn.boostable = -1; |
| 279 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | prepare_singlestep(p, regs); |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 281 | kcb->kprobe_status = KPROBE_HIT_SS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 282 | return 1; |
| 283 | |
| 284 | no_kprobe: |
Ananth N Mavinakayanahalli | d217d54 | 2005-11-07 01:00:14 -0800 | [diff] [blame] | 285 | preempt_enable_no_resched(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 286 | return ret; |
| 287 | } |
| 288 | |
| 289 | /* |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 290 | * Function return probe trampoline: |
| 291 | * - init_kprobes() establishes a probepoint here |
| 292 | * - When the probed function returns, this probe |
| 293 | * causes the handlers to fire |
| 294 | */ |
Ananth N Mavinakayanahalli | 66200ea | 2008-02-15 21:59:17 +1100 | [diff] [blame] | 295 | static void __used kretprobe_trampoline_holder(void) |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 296 | { |
| 297 | asm volatile(".global kretprobe_trampoline\n" |
| 298 | "kretprobe_trampoline:\n" |
| 299 | "nop\n"); |
| 300 | } |
| 301 | |
| 302 | /* |
| 303 | * Called when the probe at kretprobe trampoline is hit |
| 304 | */ |
Ananth N Mavinakayanahalli | 66200ea | 2008-02-15 21:59:17 +1100 | [diff] [blame] | 305 | static int __kprobes trampoline_probe_handler(struct kprobe *p, |
| 306 | struct pt_regs *regs) |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 307 | { |
bibo,mao | 62c27be | 2006-10-02 02:17:33 -0700 | [diff] [blame] | 308 | struct kretprobe_instance *ri = NULL; |
bibo,mao | 99219a3 | 2006-10-02 02:17:35 -0700 | [diff] [blame] | 309 | struct hlist_head *head, empty_rp; |
bibo,mao | 62c27be | 2006-10-02 02:17:33 -0700 | [diff] [blame] | 310 | struct hlist_node *node, *tmp; |
Ananth N Mavinakayanahalli | 991a51d | 2005-11-07 01:00:14 -0800 | [diff] [blame] | 311 | unsigned long flags, orig_ret_address = 0; |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 312 | unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; |
| 313 | |
bibo,mao | 99219a3 | 2006-10-02 02:17:35 -0700 | [diff] [blame] | 314 | INIT_HLIST_HEAD(&empty_rp); |
Srinivasa D S | ef53d9c | 2008-07-25 01:46:04 -0700 | [diff] [blame] | 315 | kretprobe_hash_lock(current, &head, &flags); |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 316 | |
| 317 | /* |
| 318 | * It is possible to have multiple instances associated with a given |
| 319 | * task either because an multiple functions in the call path |
Frederik Schwarzer | 025dfda | 2008-10-16 19:02:37 +0200 | [diff] [blame] | 320 | * have a return probe installed on them, and/or more than one return |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 321 | * return probe was registered for a target function. |
| 322 | * |
| 323 | * We can handle this because: |
| 324 | * - instances are always inserted at the head of the list |
| 325 | * - when multiple return probes are registered for the same |
bibo,mao | 62c27be | 2006-10-02 02:17:33 -0700 | [diff] [blame] | 326 | * function, the first instance's ret_addr will point to the |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 327 | * real return address, and all the rest will point to |
| 328 | * kretprobe_trampoline |
| 329 | */ |
| 330 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { |
bibo,mao | 62c27be | 2006-10-02 02:17:33 -0700 | [diff] [blame] | 331 | if (ri->task != current) |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 332 | /* another task is sharing our hash bucket */ |
bibo,mao | 62c27be | 2006-10-02 02:17:33 -0700 | [diff] [blame] | 333 | continue; |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 334 | |
| 335 | if (ri->rp && ri->rp->handler) |
| 336 | ri->rp->handler(ri, regs); |
| 337 | |
| 338 | orig_ret_address = (unsigned long)ri->ret_addr; |
bibo,mao | 99219a3 | 2006-10-02 02:17:35 -0700 | [diff] [blame] | 339 | recycle_rp_inst(ri, &empty_rp); |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 340 | |
| 341 | if (orig_ret_address != trampoline_address) |
| 342 | /* |
| 343 | * This is the real return address. Any other |
| 344 | * instances associated with this task are for |
| 345 | * other calls deeper on the call stack |
| 346 | */ |
| 347 | break; |
| 348 | } |
| 349 | |
Ananth N Mavinakayanahalli | 0f95b7f | 2007-05-08 00:28:27 -0700 | [diff] [blame] | 350 | kretprobe_assert(ri, orig_ret_address, trampoline_address); |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 351 | regs->nip = orig_ret_address; |
| 352 | |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 353 | reset_current_kprobe(); |
Srinivasa D S | ef53d9c | 2008-07-25 01:46:04 -0700 | [diff] [blame] | 354 | kretprobe_hash_unlock(current, &flags); |
Ananth N Mavinakayanahalli | 66ff2d0 | 2005-11-07 01:00:07 -0800 | [diff] [blame] | 355 | preempt_enable_no_resched(); |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 356 | |
bibo,mao | 99219a3 | 2006-10-02 02:17:35 -0700 | [diff] [blame] | 357 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
| 358 | hlist_del(&ri->hlist); |
| 359 | kfree(ri); |
| 360 | } |
bibo,mao | 62c27be | 2006-10-02 02:17:33 -0700 | [diff] [blame] | 361 | /* |
| 362 | * By returning a non-zero value, we are telling |
| 363 | * kprobe_handler() that we don't want the post_handler |
| 364 | * to run (and have re-enabled preemption) |
| 365 | */ |
| 366 | return 1; |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 367 | } |
| 368 | |
| 369 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 370 | * Called after single-stepping. p->addr is the address of the |
| 371 | * instruction whose first byte has been replaced by the "breakpoint" |
| 372 | * instruction. To avoid the SMP problems that can occur when we |
| 373 | * temporarily put back the original opcode to single-step, we |
| 374 | * single-stepped a copy of the instruction. The address of this |
| 375 | * copy is p->ainsn.insn. |
| 376 | */ |
Prasanna S Panchamukhi | bb144a8 | 2005-09-06 15:19:29 -0700 | [diff] [blame] | 377 | static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 378 | { |
| 379 | int ret; |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 380 | unsigned int insn = *p->ainsn.insn; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 381 | |
| 382 | regs->nip = (unsigned long)p->addr; |
Ananth N Mavinakayanahalli | 9ec4b1f | 2005-06-27 15:17:01 -0700 | [diff] [blame] | 383 | ret = emulate_step(regs, insn); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | if (ret == 0) |
| 385 | regs->nip = (unsigned long)p->addr + 4; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 386 | } |
| 387 | |
Prasanna S Panchamukhi | 46dbe2f | 2006-04-18 22:22:01 -0700 | [diff] [blame] | 388 | static int __kprobes post_kprobe_handler(struct pt_regs *regs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 389 | { |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 390 | struct kprobe *cur = kprobe_running(); |
| 391 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
| 392 | |
| 393 | if (!cur) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | return 0; |
| 395 | |
Kumar Gala | b76e59d | 2008-06-26 01:57:58 -0500 | [diff] [blame] | 396 | /* make sure we got here for instruction we have a kprobe on */ |
| 397 | if (((unsigned long)cur->ainsn.insn + 4) != regs->nip) |
| 398 | return 0; |
| 399 | |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 400 | if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { |
| 401 | kcb->kprobe_status = KPROBE_HIT_SSDONE; |
| 402 | cur->post_handler(cur, regs, 0); |
Prasanna S Panchamukhi | 42cc206 | 2005-06-23 00:09:38 -0700 | [diff] [blame] | 403 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 404 | |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 405 | resume_execution(cur, regs); |
| 406 | regs->msr |= kcb->kprobe_saved_msr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 407 | |
Prasanna S Panchamukhi | 42cc206 | 2005-06-23 00:09:38 -0700 | [diff] [blame] | 408 | /*Restore back the original saved kprobes variables and continue. */ |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 409 | if (kcb->kprobe_status == KPROBE_REENTER) { |
| 410 | restore_previous_kprobe(kcb); |
Prasanna S Panchamukhi | 42cc206 | 2005-06-23 00:09:38 -0700 | [diff] [blame] | 411 | goto out; |
| 412 | } |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 413 | reset_current_kprobe(); |
Prasanna S Panchamukhi | 42cc206 | 2005-06-23 00:09:38 -0700 | [diff] [blame] | 414 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | preempt_enable_no_resched(); |
| 416 | |
| 417 | /* |
| 418 | * if somebody else is singlestepping across a probe point, msr |
Kumar Gala | f827962 | 2008-06-26 02:01:37 -0500 | [diff] [blame] | 419 | * will have DE/SE set, in which case, continue the remaining processing |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 420 | * of do_debug, as if this is not a probe hit. |
| 421 | */ |
Kumar Gala | f827962 | 2008-06-26 02:01:37 -0500 | [diff] [blame] | 422 | if (regs->msr & MSR_SINGLESTEP) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | return 0; |
| 424 | |
| 425 | return 1; |
| 426 | } |
| 427 | |
Christoph Hellwig | 9f90b99 | 2007-04-30 11:56:46 +0100 | [diff] [blame] | 428 | int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 429 | { |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 430 | struct kprobe *cur = kprobe_running(); |
| 431 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
Prasanna S Panchamukhi | 50e21f2 | 2006-03-26 01:38:24 -0800 | [diff] [blame] | 432 | const struct exception_table_entry *entry; |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 433 | |
Prasanna S Panchamukhi | 50e21f2 | 2006-03-26 01:38:24 -0800 | [diff] [blame] | 434 | switch(kcb->kprobe_status) { |
| 435 | case KPROBE_HIT_SS: |
| 436 | case KPROBE_REENTER: |
| 437 | /* |
| 438 | * We are here because the instruction being single |
| 439 | * stepped caused a page fault. We reset the current |
| 440 | * kprobe and the nip points back to the probe address |
| 441 | * and allow the page fault handler to continue as a |
| 442 | * normal page fault. |
| 443 | */ |
| 444 | regs->nip = (unsigned long)cur->addr; |
Kumar Gala | f827962 | 2008-06-26 02:01:37 -0500 | [diff] [blame] | 445 | regs->msr &= ~MSR_SINGLESTEP; /* Turn off 'trace' bits */ |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 446 | regs->msr |= kcb->kprobe_saved_msr; |
Prasanna S Panchamukhi | 50e21f2 | 2006-03-26 01:38:24 -0800 | [diff] [blame] | 447 | if (kcb->kprobe_status == KPROBE_REENTER) |
| 448 | restore_previous_kprobe(kcb); |
| 449 | else |
| 450 | reset_current_kprobe(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 451 | preempt_enable_no_resched(); |
Prasanna S Panchamukhi | 50e21f2 | 2006-03-26 01:38:24 -0800 | [diff] [blame] | 452 | break; |
| 453 | case KPROBE_HIT_ACTIVE: |
| 454 | case KPROBE_HIT_SSDONE: |
| 455 | /* |
| 456 | * We increment the nmissed count for accounting, |
| 457 | * we can also use npre/npostfault count for accouting |
| 458 | * these specific fault cases. |
| 459 | */ |
| 460 | kprobes_inc_nmissed_count(cur); |
| 461 | |
| 462 | /* |
| 463 | * We come here because instructions in the pre/post |
| 464 | * handler caused the page_fault, this could happen |
| 465 | * if handler tries to access user space by |
| 466 | * copy_from_user(), get_user() etc. Let the |
| 467 | * user-specified handler try to fix it first. |
| 468 | */ |
| 469 | if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) |
| 470 | return 1; |
| 471 | |
| 472 | /* |
| 473 | * In case the user-specified fault handler returned |
| 474 | * zero, try to fix up. |
| 475 | */ |
| 476 | if ((entry = search_exception_tables(regs->nip)) != NULL) { |
| 477 | regs->nip = entry->fixup; |
| 478 | return 1; |
| 479 | } |
| 480 | |
| 481 | /* |
| 482 | * fixup_exception() could not handle it, |
| 483 | * Let do_page_fault() fix it. |
| 484 | */ |
| 485 | break; |
| 486 | default: |
| 487 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 488 | } |
| 489 | return 0; |
| 490 | } |
| 491 | |
| 492 | /* |
| 493 | * Wrapper routine to for handling exceptions. |
| 494 | */ |
Prasanna S Panchamukhi | bb144a8 | 2005-09-06 15:19:29 -0700 | [diff] [blame] | 495 | int __kprobes kprobe_exceptions_notify(struct notifier_block *self, |
| 496 | unsigned long val, void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 497 | { |
| 498 | struct die_args *args = (struct die_args *)data; |
| 499 | int ret = NOTIFY_DONE; |
| 500 | |
bibo,mao | 2326c77 | 2006-03-26 01:38:21 -0800 | [diff] [blame] | 501 | if (args->regs && user_mode(args->regs)) |
| 502 | return ret; |
| 503 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 504 | switch (val) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 505 | case DIE_BPT: |
| 506 | if (kprobe_handler(args->regs)) |
| 507 | ret = NOTIFY_STOP; |
| 508 | break; |
| 509 | case DIE_SSTEP: |
| 510 | if (post_kprobe_handler(args->regs)) |
| 511 | ret = NOTIFY_STOP; |
| 512 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 513 | default: |
| 514 | break; |
| 515 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | return ret; |
| 517 | } |
| 518 | |
Michael Ellerman | 3d7e338 | 2007-07-19 01:48:11 -0700 | [diff] [blame] | 519 | #ifdef CONFIG_PPC64 |
| 520 | unsigned long arch_deref_entry_point(void *entry) |
| 521 | { |
Michael Ellerman | 80d267f | 2008-05-23 14:22:21 +1000 | [diff] [blame] | 522 | return ((func_descr_t *)entry)->entry; |
Michael Ellerman | 3d7e338 | 2007-07-19 01:48:11 -0700 | [diff] [blame] | 523 | } |
| 524 | #endif |
| 525 | |
Prasanna S Panchamukhi | bb144a8 | 2005-09-06 15:19:29 -0700 | [diff] [blame] | 526 | int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 527 | { |
| 528 | struct jprobe *jp = container_of(p, struct jprobe, kp); |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 529 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 530 | |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 531 | memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 532 | |
| 533 | /* setup return addr to the jprobe handler routine */ |
Michael Ellerman | 3d7e338 | 2007-07-19 01:48:11 -0700 | [diff] [blame] | 534 | regs->nip = arch_deref_entry_point(jp->entry); |
Kumar Gala | 8209003 | 2007-02-06 22:55:19 -0600 | [diff] [blame] | 535 | #ifdef CONFIG_PPC64 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 536 | regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc); |
Kumar Gala | 8209003 | 2007-02-06 22:55:19 -0600 | [diff] [blame] | 537 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 538 | |
| 539 | return 1; |
| 540 | } |
| 541 | |
Ananth N Mavinakayanahalli | 66200ea | 2008-02-15 21:59:17 +1100 | [diff] [blame] | 542 | void __used __kprobes jprobe_return(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 543 | { |
| 544 | asm volatile("trap" ::: "memory"); |
| 545 | } |
| 546 | |
Ananth N Mavinakayanahalli | 66200ea | 2008-02-15 21:59:17 +1100 | [diff] [blame] | 547 | static void __used __kprobes jprobe_return_end(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | { |
| 549 | }; |
| 550 | |
Prasanna S Panchamukhi | bb144a8 | 2005-09-06 15:19:29 -0700 | [diff] [blame] | 551 | int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 552 | { |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 553 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
| 554 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 555 | /* |
| 556 | * FIXME - we should ideally be validating that we got here 'cos |
| 557 | * of the "trap" in jprobe_return() above, before restoring the |
| 558 | * saved regs... |
| 559 | */ |
Ananth N Mavinakayanahalli | 0dc036c | 2005-11-07 01:00:10 -0800 | [diff] [blame] | 560 | memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs)); |
Ananth N Mavinakayanahalli | d217d54 | 2005-11-07 01:00:14 -0800 | [diff] [blame] | 561 | preempt_enable_no_resched(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 562 | return 1; |
| 563 | } |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 564 | |
| 565 | static struct kprobe trampoline_p = { |
| 566 | .addr = (kprobe_opcode_t *) &kretprobe_trampoline, |
| 567 | .pre_handler = trampoline_probe_handler |
| 568 | }; |
| 569 | |
Rusty Lynch | 6772926 | 2005-07-05 18:54:50 -0700 | [diff] [blame] | 570 | int __init arch_init_kprobes(void) |
Rusty Lynch | 97f7943 | 2005-06-27 15:17:15 -0700 | [diff] [blame] | 571 | { |
| 572 | return register_kprobe(&trampoline_p); |
| 573 | } |
Ananth N Mavinakayanahalli | bf8f6e5b | 2007-05-08 00:34:16 -0700 | [diff] [blame] | 574 | |
| 575 | int __kprobes arch_trampoline_kprobe(struct kprobe *p) |
| 576 | { |
| 577 | if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline) |
| 578 | return 1; |
| 579 | |
| 580 | return 0; |
| 581 | } |