1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 #ifndef _LINUX_UPROBES_H 3 #define _LINUX_UPROBES_H 4 /* 5 * User-space Probes (UProbes) 6 * 7 * Copyright (C) IBM Corporation, 2008-2012 8 * Authors: 9 * Srikar Dronamraju 10 * Jim Keniston 11 * Copyright (C) 2011-2012 Red Hat, Inc., Peter Zijlstra 12 */ 13 14 #include <linux/errno.h> 15 #include <linux/rbtree.h> 16 #include <linux/types.h> 17 #include <linux/wait.h> 18 #include <linux/timer.h> 19 #include <linux/seqlock.h> 20 21 struct uprobe; 22 struct vm_area_struct; 23 struct mm_struct; 24 struct inode; 25 struct notifier_block; 26 struct page; 27 28 /* 29 * Allowed return values from uprobe consumer's handler callback 30 * with following meaning: 31 * 32 * UPROBE_HANDLER_REMOVE 33 * - Remove the uprobe breakpoint from current->mm. 34 * UPROBE_HANDLER_IGNORE 35 * - Ignore ret_handler callback for this consumer. 36 */ 37 #define UPROBE_HANDLER_REMOVE 1 38 #define UPROBE_HANDLER_IGNORE 2 39 40 #define MAX_URETPROBE_DEPTH 64 41 42 #define UPROBE_NO_TRAMPOLINE_VADDR (~0UL) 43 44 struct uprobe_consumer { 45 /* 46 * handler() can return UPROBE_HANDLER_REMOVE to signal the need to 47 * unregister uprobe for current process. If UPROBE_HANDLER_REMOVE is 48 * returned, filter() callback has to be implemented as well and it 49 * should return false to "confirm" the decision to uninstall uprobe 50 * for the current process. If filter() is omitted or returns true, 51 * UPROBE_HANDLER_REMOVE is effectively ignored. 52 */ 53 int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs, __u64 *data); 54 int (*ret_handler)(struct uprobe_consumer *self, 55 unsigned long func, 56 struct pt_regs *regs, __u64 *data); 57 bool (*filter)(struct uprobe_consumer *self, struct mm_struct *mm); 58 59 struct list_head cons_node; 60 61 __u64 id; /* set when uprobe_consumer is registered */ 62 }; 63 64 #ifdef CONFIG_UPROBES 65 #include <asm/uprobes.h> 66 67 enum uprobe_task_state { 68 UTASK_RUNNING, 69 UTASK_SSTEP, 70 UTASK_SSTEP_ACK, 71 UTASK_SSTEP_TRAPPED, 72 }; 73 74 /* The state of hybrid-lifetime uprobe inside struct return_instance */ 75 enum hprobe_state { 76 HPROBE_LEASED, /* uretprobes_srcu-protected uprobe */ 77 HPROBE_STABLE, /* refcounted uprobe */ 78 HPROBE_GONE, /* NULL uprobe, SRCU expired, refcount failed */ 79 HPROBE_CONSUMED, /* uprobe "consumed" by uretprobe handler */ 80 }; 81 82 /* 83 * Hybrid lifetime uprobe. Represents a uprobe instance that could be either 84 * SRCU protected (with SRCU protection eventually potentially timing out), 85 * refcounted using uprobe->ref, or there could be no valid uprobe (NULL). 86 * 87 * hprobe's internal state is setup such that background timer thread can 88 * atomically "downgrade" temporarily RCU-protected uprobe into refcounted one 89 * (or no uprobe, if refcounting failed). 90 * 91 * *stable* pointer always point to the uprobe (or could be NULL if there is 92 * was no valid underlying uprobe to begin with). 93 * 94 * *leased* pointer is the key to achieving race-free atomic lifetime state 95 * transition and can have three possible states: 96 * - either the same non-NULL value as *stable*, in which case uprobe is 97 * SRCU-protected; 98 * - NULL, in which case uprobe (if there is any) is refcounted; 99 * - special __UPROBE_DEAD value, which represents an uprobe that was SRCU 100 * protected initially, but SRCU period timed out and we attempted to 101 * convert it to refcounted, but refcount_inc_not_zero() failed, because 102 * uprobe effectively went away (the last consumer unsubscribed). In this 103 * case it's important to know that *stable* pointer (which still has 104 * non-NULL uprobe pointer) shouldn't be used, because lifetime of 105 * underlying uprobe is not guaranteed anymore. __UPROBE_DEAD is just an 106 * internal marker and is handled transparently by hprobe_fetch() helper. 107 * 108 * When uprobe is SRCU-protected, we also record srcu_idx value, necessary for 109 * SRCU unlocking. 110 * 111 * See hprobe_expire() and hprobe_fetch() for details of race-free uprobe 112 * state transitioning details. It all hinges on atomic xchg() over *leaded* 113 * pointer. *stable* pointer, once initially set, is not modified concurrently. 114 */ 115 struct hprobe { 116 enum hprobe_state state; 117 int srcu_idx; 118 struct uprobe *uprobe; 119 }; 120 121 /* 122 * uprobe_task: Metadata of a task while it singlesteps. 123 */ 124 struct uprobe_task { 125 enum uprobe_task_state state; 126 127 unsigned int depth; 128 struct return_instance *return_instances; 129 130 struct return_instance *ri_pool; 131 struct timer_list ri_timer; 132 seqcount_t ri_seqcount; 133 134 union { 135 struct { 136 struct arch_uprobe_task autask; 137 unsigned long vaddr; 138 }; 139 140 struct { 141 struct callback_head dup_xol_work; 142 unsigned long dup_xol_addr; 143 }; 144 }; 145 146 struct uprobe *active_uprobe; 147 unsigned long xol_vaddr; 148 bool signal_denied; 149 150 struct arch_uprobe *auprobe; 151 }; 152 153 struct return_consumer { 154 __u64 cookie; 155 __u64 id; 156 }; 157 158 struct return_instance { 159 struct hprobe hprobe; 160 unsigned long func; 161 unsigned long stack; /* stack pointer */ 162 unsigned long orig_ret_vaddr; /* original return address */ 163 bool chained; /* true, if instance is nested */ 164 int cons_cnt; /* total number of session consumers */ 165 166 struct return_instance *next; /* keep as stack */ 167 struct rcu_head rcu; 168 169 /* singular pre-allocated return_consumer instance for common case */ 170 struct return_consumer consumer; 171 /* 172 * extra return_consumer instances for rare cases of multiple session consumers, 173 * contains (cons_cnt - 1) elements 174 */ 175 struct return_consumer *extra_consumers; 176 } ____cacheline_aligned; 177 178 enum rp_check { 179 RP_CHECK_CALL, 180 RP_CHECK_CHAIN_CALL, 181 RP_CHECK_RET, 182 }; 183 184 struct xol_area; 185 186 struct uprobes_state { 187 struct xol_area *xol_area; 188 }; 189 190 extern void __init uprobes_init(void); 191 extern int set_swbp(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr); 192 extern int set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr); 193 extern bool is_swbp_insn(uprobe_opcode_t *insn); 194 extern bool is_trap_insn(uprobe_opcode_t *insn); 195 extern unsigned long uprobe_get_swbp_addr(struct pt_regs *regs); 196 extern unsigned long uprobe_get_trap_addr(struct pt_regs *regs); 197 extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t); 198 extern struct uprobe *uprobe_register(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc); 199 extern int uprobe_apply(struct uprobe *uprobe, struct uprobe_consumer *uc, bool); 200 extern void uprobe_unregister_nosync(struct uprobe *uprobe, struct uprobe_consumer *uc); 201 extern void uprobe_unregister_sync(void); 202 extern int uprobe_mmap(struct vm_area_struct *vma); 203 extern void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end); 204 extern void uprobe_start_dup_mmap(void); 205 extern void uprobe_end_dup_mmap(void); 206 extern void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm); 207 extern void uprobe_free_utask(struct task_struct *t); 208 extern void uprobe_copy_process(struct task_struct *t, unsigned long flags); 209 extern int uprobe_post_sstep_notifier(struct pt_regs *regs); 210 extern int uprobe_pre_sstep_notifier(struct pt_regs *regs); 211 extern void uprobe_notify_resume(struct pt_regs *regs); 212 extern bool uprobe_deny_signal(void); 213 extern bool arch_uprobe_skip_sstep(struct arch_uprobe *aup, struct pt_regs *regs); 214 extern void uprobe_clear_state(struct mm_struct *mm); 215 extern int arch_uprobe_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long addr); 216 extern int arch_uprobe_pre_xol(struct arch_uprobe *aup, struct pt_regs *regs); 217 extern int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs); 218 extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk); 219 extern int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data); 220 extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs); 221 extern unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs); 222 extern bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx, struct pt_regs *regs); 223 extern bool arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs); 224 extern void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr, 225 void *src, unsigned long len); 226 extern void uprobe_handle_trampoline(struct pt_regs *regs); 227 extern void *arch_uprobe_trampoline(unsigned long *psize); 228 extern unsigned long uprobe_get_trampoline_vaddr(void); 229 #else /* !CONFIG_UPROBES */ 230 struct uprobes_state { 231 }; 232 233 static inline void uprobes_init(void) 234 { 235 } 236 237 #define uprobe_get_trap_addr(regs) instruction_pointer(regs) 238 239 static inline struct uprobe * 240 uprobe_register(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc) 241 { 242 return ERR_PTR(-ENOSYS); 243 } 244 static inline int 245 uprobe_apply(struct uprobe* uprobe, struct uprobe_consumer *uc, bool add) 246 { 247 return -ENOSYS; 248 } 249 static inline void 250 uprobe_unregister_nosync(struct uprobe *uprobe, struct uprobe_consumer *uc) 251 { 252 } 253 static inline void uprobe_unregister_sync(void) 254 { 255 } 256 static inline int uprobe_mmap(struct vm_area_struct *vma) 257 { 258 return 0; 259 } 260 static inline void 261 uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end) 262 { 263 } 264 static inline void uprobe_start_dup_mmap(void) 265 { 266 } 267 static inline void uprobe_end_dup_mmap(void) 268 { 269 } 270 static inline void 271 uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm) 272 { 273 } 274 static inline void uprobe_notify_resume(struct pt_regs *regs) 275 { 276 } 277 static inline bool uprobe_deny_signal(void) 278 { 279 return false; 280 } 281 static inline void uprobe_free_utask(struct task_struct *t) 282 { 283 } 284 static inline void uprobe_copy_process(struct task_struct *t, unsigned long flags) 285 { 286 } 287 static inline void uprobe_clear_state(struct mm_struct *mm) 288 { 289 } 290 #endif /* !CONFIG_UPROBES */ 291 #endif /* _LINUX_UPROBES_H */ 292