tools/testing/selftests/rseq/rseq.h

   1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */
   2 /*
   3  * rseq.h
   4  *
   5  * (C) Copyright 2016-2018 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   6  */
   7
   8 #ifndef RSEQ_H
   9 #define RSEQ_H
  10
  11 #include <stdint.h>
  12 #include <stdbool.h>
  13 #include <pthread.h>
  14 #include <signal.h>
  15 #include <sched.h>
  16 #include <errno.h>
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <stddef.h>
  20 #include "rseq-abi.h"
  21 #include "compiler.h"
  22
  23 #ifndef rseq_sizeof_field
  24 #define rseq_sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
  25 #endif
  26
  27 #ifndef rseq_offsetofend
  28 #define rseq_offsetofend(TYPE, MEMBER) \
  29         (offsetof(TYPE, MEMBER) + rseq_sizeof_field(TYPE, MEMBER))
  30 #endif
  31
  32 /*
  33  * Empty code injection macros, override when testing.
  34  * It is important to consider that the ASM injection macros need to be
  35  * fully reentrant (e.g. do not modify the stack).
  36  */
  37 #ifndef RSEQ_INJECT_ASM
  38 #define RSEQ_INJECT_ASM(n)
  39 #endif
  40
  41 #ifndef RSEQ_INJECT_C
  42 #define RSEQ_INJECT_C(n)
  43 #endif
  44
  45 #ifndef RSEQ_INJECT_INPUT
  46 #define RSEQ_INJECT_INPUT
  47 #endif
  48
  49 #ifndef RSEQ_INJECT_CLOBBER
  50 #define RSEQ_INJECT_CLOBBER
  51 #endif
  52
  53 #ifndef RSEQ_INJECT_FAILED
  54 #define RSEQ_INJECT_FAILED
  55 #endif
  56
  57 #include "rseq-thread-pointer.h"
  58
  59 /* Offset from the thread pointer to the rseq area. */
  60 extern ptrdiff_t rseq_offset;
  61
  62 /*
  63  * Size of the registered rseq area. 0 if the registration was
  64  * unsuccessful.
  65  */
  66 extern unsigned int rseq_size;
  67
  68 /* Flags used during rseq registration. */
  69 extern unsigned int rseq_flags;
  70
  71 enum rseq_mo {
  72         RSEQ_MO_RELAXED = 0,
  73         RSEQ_MO_CONSUME = 1,    /* Unused */
  74         RSEQ_MO_ACQUIRE = 2,    /* Unused */
  75         RSEQ_MO_RELEASE = 3,
  76         RSEQ_MO_ACQ_REL = 4,    /* Unused */
  77         RSEQ_MO_SEQ_CST = 5,    /* Unused */
  78 };
  79
  80 enum rseq_percpu_mode {
  81         RSEQ_PERCPU_CPU_ID = 0,
  82         RSEQ_PERCPU_MM_CID = 1,
  83 };
  84
  85 static inline struct rseq_abi *rseq_get_abi(void)
  86 {
  87         return (struct rseq_abi *) ((uintptr_t) rseq_thread_pointer() + rseq_offset);
  88 }
  89
  90 #define rseq_likely(x)          __builtin_expect(!!(x), 1)
  91 #define rseq_unlikely(x)        __builtin_expect(!!(x), 0)
  92 #define rseq_barrier()          __asm__ __volatile__("" : : : "memory")
  93
  94 #define RSEQ_ACCESS_ONCE(x)     (*(__volatile__  __typeof__(x) *)&(x))
  95 #define RSEQ_WRITE_ONCE(x, v)   __extension__ ({ RSEQ_ACCESS_ONCE(x) = (v); })
  96 #define RSEQ_READ_ONCE(x)       RSEQ_ACCESS_ONCE(x)
  97
  98 #define __rseq_str_1(x) #x
  99 #define __rseq_str(x)           __rseq_str_1(x)
 100
 101 #define rseq_log(fmt, args...)                                                 \
 102         fprintf(stderr, fmt "(in %s() at " __FILE__ ":" __rseq_str(__LINE__)"\n", \
 103                 ## args, __func__)
 104
 105 #define rseq_bug(fmt, args...)          \
 106         do {                            \
 107                 rseq_log(fmt, ##args);  \
 108                 abort();                \
 109         } while (0)
 110
 111 #if defined(__x86_64__) || defined(__i386__)
 112 #include <rseq-x86.h>
 113 #elif defined(__ARMEL__)
 114 #include <rseq-arm.h>
 115 #elif defined (__AARCH64EL__)
 116 #include <rseq-arm64.h>
 117 #elif defined(__PPC__)
 118 #include <rseq-ppc.h>
 119 #elif defined(__mips__)
 120 #include <rseq-mips.h>
 121 #elif defined(__s390__)
 122 #include <rseq-s390.h>
 123 #elif defined(__riscv)
 124 #include <rseq-riscv.h>
 125 #else
 126 #error unsupported target
 127 #endif
 128
 129 /*
 130  * Register rseq for the current thread. This needs to be called once
 131  * by any thread which uses restartable sequences, before they start
 132  * using restartable sequences, to ensure restartable sequences
 133  * succeed. A restartable sequence executed from a non-registered
 134  * thread will always fail.
 135  */
 136 int rseq_register_current_thread(void);
 137
 138 /*
 139  * Unregister rseq for current thread.
 140  */
 141 int rseq_unregister_current_thread(void);
 142
 143 /*
 144  * Restartable sequence fallback for reading the current CPU number.
 145  */
 146 int32_t rseq_fallback_current_cpu(void);
 147
 148 /*
 149  * Restartable sequence fallback for reading the current node number.
 150  */
 151 int32_t rseq_fallback_current_node(void);
 152
 153 /*
 154  * Values returned can be either the current CPU number, -1 (rseq is
 155  * uninitialized), or -2 (rseq initialization has failed).
 156  */
 157 static inline int32_t rseq_current_cpu_raw(void)
 158 {
 159         return RSEQ_ACCESS_ONCE(rseq_get_abi()->cpu_id);
 160 }
 161
 162 /*
 163  * Returns a possible CPU number, which is typically the current CPU.
 164  * The returned CPU number can be used to prepare for an rseq critical
 165  * section, which will confirm whether the cpu number is indeed the
 166  * current one, and whether rseq is initialized.
 167  *
 168  * The CPU number returned by rseq_cpu_start should always be validated
 169  * by passing it to a rseq asm sequence, or by comparing it to the
 170  * return value of rseq_current_cpu_raw() if the rseq asm sequence
 171  * does not need to be invoked.
 172  */
 173 static inline uint32_t rseq_cpu_start(void)
 174 {
 175         return RSEQ_ACCESS_ONCE(rseq_get_abi()->cpu_id_start);
 176 }
 177
 178 static inline uint32_t rseq_current_cpu(void)
 179 {
 180         int32_t cpu;
 181
 182         cpu = rseq_current_cpu_raw();
 183         if (rseq_unlikely(cpu < 0))
 184                 cpu = rseq_fallback_current_cpu();
 185         return cpu;
 186 }
 187
 188 static inline bool rseq_node_id_available(void)
 189 {
 190         return (int) rseq_size >= rseq_offsetofend(struct rseq_abi, node_id);
 191 }
 192
 193 /*
 194  * Current NUMA node number.
 195  */
 196 static inline uint32_t rseq_current_node_id(void)
 197 {
 198         assert(rseq_node_id_available());
 199         return RSEQ_ACCESS_ONCE(rseq_get_abi()->node_id);
 200 }
 201
 202 static inline bool rseq_mm_cid_available(void)
 203 {
 204         return (int) rseq_size >= rseq_offsetofend(struct rseq_abi, mm_cid);
 205 }
 206
 207 static inline uint32_t rseq_current_mm_cid(void)
 208 {
 209         return RSEQ_ACCESS_ONCE(rseq_get_abi()->mm_cid);
 210 }
 211
 212 static inline void rseq_clear_rseq_cs(void)
 213 {
 214         RSEQ_WRITE_ONCE(rseq_get_abi()->rseq_cs.arch.ptr, 0);
 215 }
 216
 217 /*
 218  * rseq_prepare_unload() should be invoked by each thread executing a rseq
 219  * critical section at least once between their last critical section and
 220  * library unload of the library defining the rseq critical section (struct
 221  * rseq_cs) or the code referred to by the struct rseq_cs start_ip and
 222  * post_commit_offset fields. This also applies to use of rseq in code
 223  * generated by JIT: rseq_prepare_unload() should be invoked at least once by
 224  * each thread executing a rseq critical section before reclaim of the memory
 225  * holding the struct rseq_cs or reclaim of the code pointed to by struct
 226  * rseq_cs start_ip and post_commit_offset fields.
 227  */
 228 static inline void rseq_prepare_unload(void)
 229 {
 230         rseq_clear_rseq_cs();
 231 }
 232
 233 static inline __attribute__((always_inline))
 234 int rseq_cmpeqv_storev(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
 235                        intptr_t *v, intptr_t expect,
 236                        intptr_t newv, int cpu)
 237 {
 238         if (rseq_mo != RSEQ_MO_RELAXED)
 239                 return -1;
 240         switch (percpu_mode) {
 241         case RSEQ_PERCPU_CPU_ID:
 242                 return rseq_cmpeqv_storev_relaxed_cpu_id(v, expect, newv, cpu);
 243         case RSEQ_PERCPU_MM_CID:
 244                 return rseq_cmpeqv_storev_relaxed_mm_cid(v, expect, newv, cpu);
 245         }
 246         return -1;
 247 }
 248
 249 /*
 250  * Compare @v against @expectnot. When it does _not_ match, load @v
 251  * into @load, and store the content of *@v + voffp into @v.
 252  */
 253 static inline __attribute__((always_inline))
 254 int rseq_cmpnev_storeoffp_load(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
 255                                intptr_t *v, intptr_t expectnot, long voffp, intptr_t *load,
 256                                int cpu)
 257 {
 258         if (rseq_mo != RSEQ_MO_RELAXED)
 259                 return -1;
 260         switch (percpu_mode) {
 261         case RSEQ_PERCPU_CPU_ID:
 262                 return rseq_cmpnev_storeoffp_load_relaxed_cpu_id(v, expectnot, voffp, load, cpu);
 263         case RSEQ_PERCPU_MM_CID:
 264                 return rseq_cmpnev_storeoffp_load_relaxed_mm_cid(v, expectnot, voffp, load, cpu);
 265         }
 266         return -1;
 267 }
 268
 269 static inline __attribute__((always_inline))
 270 int rseq_addv(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
 271               intptr_t *v, intptr_t count, int cpu)
 272 {
 273         if (rseq_mo != RSEQ_MO_RELAXED)
 274                 return -1;
 275         switch (percpu_mode) {
 276         case RSEQ_PERCPU_CPU_ID:
 277                 return rseq_addv_relaxed_cpu_id(v, count, cpu);
 278         case RSEQ_PERCPU_MM_CID:
 279                 return rseq_addv_relaxed_mm_cid(v, count, cpu);
 280         }
 281         return -1;
 282 }
 283
 284 #ifdef RSEQ_ARCH_HAS_OFFSET_DEREF_ADDV
 285 /*
 286  *   pval = *(ptr+off)
 287  *  *pval += inc;
 288  */
 289 static inline __attribute__((always_inline))
 290 int rseq_offset_deref_addv(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
 291                            intptr_t *ptr, long off, intptr_t inc, int cpu)
 292 {
 293         if (rseq_mo != RSEQ_MO_RELAXED)
 294                 return -1;
 295         switch (percpu_mode) {
 296         case RSEQ_PERCPU_CPU_ID:
 297                 return rseq_offset_deref_addv_relaxed_cpu_id(ptr, off, inc, cpu);
 298         case RSEQ_PERCPU_MM_CID:
 299                 return rseq_offset_deref_addv_relaxed_mm_cid(ptr, off, inc, cpu);
 300         }
 301         return -1;
 302 }
 303 #endif
 304
 305 static inline __attribute__((always_inline))
 306 int rseq_cmpeqv_trystorev_storev(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
 307                                  intptr_t *v, intptr_t expect,
 308                                  intptr_t *v2, intptr_t newv2,
 309                                  intptr_t newv, int cpu)
 310 {
 311         switch (rseq_mo) {
 312         case RSEQ_MO_RELAXED:
 313                 switch (percpu_mode) {
 314                 case RSEQ_PERCPU_CPU_ID:
 315                         return rseq_cmpeqv_trystorev_storev_relaxed_cpu_id(v, expect, v2, newv2, newv, cpu);
 316                 case RSEQ_PERCPU_MM_CID:
 317                         return rseq_cmpeqv_trystorev_storev_relaxed_mm_cid(v, expect, v2, newv2, newv, cpu);
 318                 }
 319                 return -1;
 320         case RSEQ_MO_RELEASE:
 321                 switch (percpu_mode) {
 322                 case RSEQ_PERCPU_CPU_ID:
 323                         return rseq_cmpeqv_trystorev_storev_release_cpu_id(v, expect, v2, newv2, newv, cpu);
 324                 case RSEQ_PERCPU_MM_CID:
 325                         return rseq_cmpeqv_trystorev_storev_release_mm_cid(v, expect, v2, newv2, newv, cpu);
 326                 }
 327                 return -1;
 328         default:
 329                 return -1;
 330         }
 331 }
 332
 333 static inline __attribute__((always_inline))
 334 int rseq_cmpeqv_cmpeqv_storev(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
 335                               intptr_t *v, intptr_t expect,
 336                               intptr_t *v2, intptr_t expect2,
 337                               intptr_t newv, int cpu)
 338 {
 339         if (rseq_mo != RSEQ_MO_RELAXED)
 340                 return -1;
 341         switch (percpu_mode) {
 342         case RSEQ_PERCPU_CPU_ID:
 343                 return rseq_cmpeqv_cmpeqv_storev_relaxed_cpu_id(v, expect, v2, expect2, newv, cpu);
 344         case RSEQ_PERCPU_MM_CID:
 345                 return rseq_cmpeqv_cmpeqv_storev_relaxed_mm_cid(v, expect, v2, expect2, newv, cpu);
 346         }
 347         return -1;
 348 }
 349
 350 static inline __attribute__((always_inline))
 351 int rseq_cmpeqv_trymemcpy_storev(enum rseq_mo rseq_mo, enum rseq_percpu_mode percpu_mode,
 352                                  intptr_t *v, intptr_t expect,
 353                                  void *dst, void *src, size_t len,
 354                                  intptr_t newv, int cpu)
 355 {
 356         switch (rseq_mo) {
 357         case RSEQ_MO_RELAXED:
 358                 switch (percpu_mode) {
 359                 case RSEQ_PERCPU_CPU_ID:
 360                         return rseq_cmpeqv_trymemcpy_storev_relaxed_cpu_id(v, expect, dst, src, len, newv, cpu);
 361                 case RSEQ_PERCPU_MM_CID:
 362                         return rseq_cmpeqv_trymemcpy_storev_relaxed_mm_cid(v, expect, dst, src, len, newv, cpu);
 363                 }
 364                 return -1;
 365         case RSEQ_MO_RELEASE:
 366                 switch (percpu_mode) {
 367                 case RSEQ_PERCPU_CPU_ID:
 368                         return rseq_cmpeqv_trymemcpy_storev_release_cpu_id(v, expect, dst, src, len, newv, cpu);
 369                 case RSEQ_PERCPU_MM_CID:
 370                         return rseq_cmpeqv_trymemcpy_storev_release_mm_cid(v, expect, dst, src, len, newv, cpu);
 371                 }
 372                 return -1;
 373         default:
 374                 return -1;
 375         }
 376 }
 377
 378 #endif  /* RSEQ_H_ */