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1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */
2 /*
3  * rseq-x86.h
4  *
5  * (C) Copyright 2016-2018 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
6  */
7 
8 #include <stdint.h>
9 
10 #define RSEQ_SIG	0x53053053
11 
12 #ifdef __x86_64__
13 
14 #define rseq_smp_mb()	\
15 	__asm__ __volatile__ ("lock; addl $0,-128(%%rsp)" ::: "memory", "cc")
16 #define rseq_smp_rmb()	rseq_barrier()
17 #define rseq_smp_wmb()	rseq_barrier()
18 
19 #define rseq_smp_load_acquire(p)					\
20 __extension__ ({							\
21 	__typeof(*p) ____p1 = RSEQ_READ_ONCE(*p);			\
22 	rseq_barrier();							\
23 	____p1;								\
24 })
25 
26 #define rseq_smp_acquire__after_ctrl_dep()	rseq_smp_rmb()
27 
28 #define rseq_smp_store_release(p, v)					\
29 do {									\
30 	rseq_barrier();							\
31 	RSEQ_WRITE_ONCE(*p, v);						\
32 } while (0)
33 
34 #ifdef RSEQ_SKIP_FASTPATH
35 #include "rseq-skip.h"
36 #else /* !RSEQ_SKIP_FASTPATH */
37 
38 #define __RSEQ_ASM_DEFINE_TABLE(label, version, flags,			\
39 				start_ip, post_commit_offset, abort_ip)	\
40 		".pushsection __rseq_table, \"aw\"\n\t"			\
41 		".balign 32\n\t"					\
42 		__rseq_str(label) ":\n\t"				\
43 		".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
44 		".quad " __rseq_str(start_ip) ", " __rseq_str(post_commit_offset) ", " __rseq_str(abort_ip) "\n\t" \
45 		".popsection\n\t"
46 
47 #define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
48 	__RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip,		\
49 				(post_commit_ip - start_ip), abort_ip)
50 
51 #define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs)		\
52 		RSEQ_INJECT_ASM(1)					\
53 		"leaq " __rseq_str(cs_label) "(%%rip), %%rax\n\t"	\
54 		"movq %%rax, %[" __rseq_str(rseq_cs) "]\n\t"		\
55 		__rseq_str(label) ":\n\t"
56 
57 #define RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, label)		\
58 		RSEQ_INJECT_ASM(2)					\
59 		"cmpl %[" __rseq_str(cpu_id) "], %[" __rseq_str(current_cpu_id) "]\n\t" \
60 		"jnz " __rseq_str(label) "\n\t"
61 
62 #define RSEQ_ASM_DEFINE_ABORT(label, teardown, abort_label)		\
63 		".pushsection __rseq_failure, \"ax\"\n\t"		\
64 		/* Disassembler-friendly signature: nopl <sig>(%rip). */\
65 		".byte 0x0f, 0x1f, 0x05\n\t"				\
66 		".long " __rseq_str(RSEQ_SIG) "\n\t"			\
67 		__rseq_str(label) ":\n\t"				\
68 		teardown						\
69 		"jmp %l[" __rseq_str(abort_label) "]\n\t"		\
70 		".popsection\n\t"
71 
72 #define RSEQ_ASM_DEFINE_CMPFAIL(label, teardown, cmpfail_label)		\
73 		".pushsection __rseq_failure, \"ax\"\n\t"		\
74 		__rseq_str(label) ":\n\t"				\
75 		teardown						\
76 		"jmp %l[" __rseq_str(cmpfail_label) "]\n\t"		\
77 		".popsection\n\t"
78 
79 static inline __attribute__((always_inline))
rseq_cmpeqv_storev(intptr_t * v,intptr_t expect,intptr_t newv,int cpu)80 int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, int cpu)
81 {
82 	RSEQ_INJECT_C(9)
83 
84 	__asm__ __volatile__ goto (
85 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
86 		/* Start rseq by storing table entry pointer into rseq_cs. */
87 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
88 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
89 		RSEQ_INJECT_ASM(3)
90 		"cmpq %[v], %[expect]\n\t"
91 		"jnz %l[cmpfail]\n\t"
92 		RSEQ_INJECT_ASM(4)
93 #ifdef RSEQ_COMPARE_TWICE
94 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
95 		"cmpq %[v], %[expect]\n\t"
96 		"jnz %l[error2]\n\t"
97 #endif
98 		/* final store */
99 		"movq %[newv], %[v]\n\t"
100 		"2:\n\t"
101 		RSEQ_INJECT_ASM(5)
102 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
103 		: /* gcc asm goto does not allow outputs */
104 		: [cpu_id]		"r" (cpu),
105 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
106 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
107 		  [v]			"m" (*v),
108 		  [expect]		"r" (expect),
109 		  [newv]		"r" (newv)
110 		: "memory", "cc", "rax"
111 		  RSEQ_INJECT_CLOBBER
112 		: abort, cmpfail
113 #ifdef RSEQ_COMPARE_TWICE
114 		  , error1, error2
115 #endif
116 	);
117 	return 0;
118 abort:
119 	RSEQ_INJECT_FAILED
120 	return -1;
121 cmpfail:
122 	return 1;
123 #ifdef RSEQ_COMPARE_TWICE
124 error1:
125 	rseq_bug("cpu_id comparison failed");
126 error2:
127 	rseq_bug("expected value comparison failed");
128 #endif
129 }
130 
131 /*
132  * Compare @v against @expectnot. When it does _not_ match, load @v
133  * into @load, and store the content of *@v + voffp into @v.
134  */
135 static inline __attribute__((always_inline))
rseq_cmpnev_storeoffp_load(intptr_t * v,intptr_t expectnot,off_t voffp,intptr_t * load,int cpu)136 int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
137 			       off_t voffp, intptr_t *load, int cpu)
138 {
139 	RSEQ_INJECT_C(9)
140 
141 	__asm__ __volatile__ goto (
142 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
143 		/* Start rseq by storing table entry pointer into rseq_cs. */
144 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
145 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
146 		RSEQ_INJECT_ASM(3)
147 		"movq %[v], %%rbx\n\t"
148 		"cmpq %%rbx, %[expectnot]\n\t"
149 		"je %l[cmpfail]\n\t"
150 		RSEQ_INJECT_ASM(4)
151 #ifdef RSEQ_COMPARE_TWICE
152 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
153 		"movq %[v], %%rbx\n\t"
154 		"cmpq %%rbx, %[expectnot]\n\t"
155 		"je %l[error2]\n\t"
156 #endif
157 		"movq %%rbx, %[load]\n\t"
158 		"addq %[voffp], %%rbx\n\t"
159 		"movq (%%rbx), %%rbx\n\t"
160 		/* final store */
161 		"movq %%rbx, %[v]\n\t"
162 		"2:\n\t"
163 		RSEQ_INJECT_ASM(5)
164 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
165 		: /* gcc asm goto does not allow outputs */
166 		: [cpu_id]		"r" (cpu),
167 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
168 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
169 		  /* final store input */
170 		  [v]			"m" (*v),
171 		  [expectnot]		"r" (expectnot),
172 		  [voffp]		"er" (voffp),
173 		  [load]		"m" (*load)
174 		: "memory", "cc", "rax", "rbx"
175 		  RSEQ_INJECT_CLOBBER
176 		: abort, cmpfail
177 #ifdef RSEQ_COMPARE_TWICE
178 		  , error1, error2
179 #endif
180 	);
181 	return 0;
182 abort:
183 	RSEQ_INJECT_FAILED
184 	return -1;
185 cmpfail:
186 	return 1;
187 #ifdef RSEQ_COMPARE_TWICE
188 error1:
189 	rseq_bug("cpu_id comparison failed");
190 error2:
191 	rseq_bug("expected value comparison failed");
192 #endif
193 }
194 
195 static inline __attribute__((always_inline))
rseq_addv(intptr_t * v,intptr_t count,int cpu)196 int rseq_addv(intptr_t *v, intptr_t count, int cpu)
197 {
198 	RSEQ_INJECT_C(9)
199 
200 	__asm__ __volatile__ goto (
201 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
202 		/* Start rseq by storing table entry pointer into rseq_cs. */
203 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
204 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
205 		RSEQ_INJECT_ASM(3)
206 #ifdef RSEQ_COMPARE_TWICE
207 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
208 #endif
209 		/* final store */
210 		"addq %[count], %[v]\n\t"
211 		"2:\n\t"
212 		RSEQ_INJECT_ASM(4)
213 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
214 		: /* gcc asm goto does not allow outputs */
215 		: [cpu_id]		"r" (cpu),
216 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
217 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
218 		  /* final store input */
219 		  [v]			"m" (*v),
220 		  [count]		"er" (count)
221 		: "memory", "cc", "rax"
222 		  RSEQ_INJECT_CLOBBER
223 		: abort
224 #ifdef RSEQ_COMPARE_TWICE
225 		  , error1
226 #endif
227 	);
228 	return 0;
229 abort:
230 	RSEQ_INJECT_FAILED
231 	return -1;
232 #ifdef RSEQ_COMPARE_TWICE
233 error1:
234 	rseq_bug("cpu_id comparison failed");
235 #endif
236 }
237 
238 static inline __attribute__((always_inline))
rseq_cmpeqv_trystorev_storev(intptr_t * v,intptr_t expect,intptr_t * v2,intptr_t newv2,intptr_t newv,int cpu)239 int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,
240 				 intptr_t *v2, intptr_t newv2,
241 				 intptr_t newv, int cpu)
242 {
243 	RSEQ_INJECT_C(9)
244 
245 	__asm__ __volatile__ goto (
246 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
247 		/* Start rseq by storing table entry pointer into rseq_cs. */
248 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
249 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
250 		RSEQ_INJECT_ASM(3)
251 		"cmpq %[v], %[expect]\n\t"
252 		"jnz %l[cmpfail]\n\t"
253 		RSEQ_INJECT_ASM(4)
254 #ifdef RSEQ_COMPARE_TWICE
255 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
256 		"cmpq %[v], %[expect]\n\t"
257 		"jnz %l[error2]\n\t"
258 #endif
259 		/* try store */
260 		"movq %[newv2], %[v2]\n\t"
261 		RSEQ_INJECT_ASM(5)
262 		/* final store */
263 		"movq %[newv], %[v]\n\t"
264 		"2:\n\t"
265 		RSEQ_INJECT_ASM(6)
266 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
267 		: /* gcc asm goto does not allow outputs */
268 		: [cpu_id]		"r" (cpu),
269 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
270 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
271 		  /* try store input */
272 		  [v2]			"m" (*v2),
273 		  [newv2]		"r" (newv2),
274 		  /* final store input */
275 		  [v]			"m" (*v),
276 		  [expect]		"r" (expect),
277 		  [newv]		"r" (newv)
278 		: "memory", "cc", "rax"
279 		  RSEQ_INJECT_CLOBBER
280 		: abort, cmpfail
281 #ifdef RSEQ_COMPARE_TWICE
282 		  , error1, error2
283 #endif
284 	);
285 	return 0;
286 abort:
287 	RSEQ_INJECT_FAILED
288 	return -1;
289 cmpfail:
290 	return 1;
291 #ifdef RSEQ_COMPARE_TWICE
292 error1:
293 	rseq_bug("cpu_id comparison failed");
294 error2:
295 	rseq_bug("expected value comparison failed");
296 #endif
297 }
298 
299 /* x86-64 is TSO. */
300 static inline __attribute__((always_inline))
rseq_cmpeqv_trystorev_storev_release(intptr_t * v,intptr_t expect,intptr_t * v2,intptr_t newv2,intptr_t newv,int cpu)301 int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect,
302 					 intptr_t *v2, intptr_t newv2,
303 					 intptr_t newv, int cpu)
304 {
305 	return rseq_cmpeqv_trystorev_storev(v, expect, v2, newv2, newv, cpu);
306 }
307 
308 static inline __attribute__((always_inline))
rseq_cmpeqv_cmpeqv_storev(intptr_t * v,intptr_t expect,intptr_t * v2,intptr_t expect2,intptr_t newv,int cpu)309 int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect,
310 			      intptr_t *v2, intptr_t expect2,
311 			      intptr_t newv, int cpu)
312 {
313 	RSEQ_INJECT_C(9)
314 
315 	__asm__ __volatile__ goto (
316 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
317 		/* Start rseq by storing table entry pointer into rseq_cs. */
318 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
319 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
320 		RSEQ_INJECT_ASM(3)
321 		"cmpq %[v], %[expect]\n\t"
322 		"jnz %l[cmpfail]\n\t"
323 		RSEQ_INJECT_ASM(4)
324 		"cmpq %[v2], %[expect2]\n\t"
325 		"jnz %l[cmpfail]\n\t"
326 		RSEQ_INJECT_ASM(5)
327 #ifdef RSEQ_COMPARE_TWICE
328 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
329 		"cmpq %[v], %[expect]\n\t"
330 		"jnz %l[error2]\n\t"
331 		"cmpq %[v2], %[expect2]\n\t"
332 		"jnz %l[error3]\n\t"
333 #endif
334 		/* final store */
335 		"movq %[newv], %[v]\n\t"
336 		"2:\n\t"
337 		RSEQ_INJECT_ASM(6)
338 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
339 		: /* gcc asm goto does not allow outputs */
340 		: [cpu_id]		"r" (cpu),
341 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
342 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
343 		  /* cmp2 input */
344 		  [v2]			"m" (*v2),
345 		  [expect2]		"r" (expect2),
346 		  /* final store input */
347 		  [v]			"m" (*v),
348 		  [expect]		"r" (expect),
349 		  [newv]		"r" (newv)
350 		: "memory", "cc", "rax"
351 		  RSEQ_INJECT_CLOBBER
352 		: abort, cmpfail
353 #ifdef RSEQ_COMPARE_TWICE
354 		  , error1, error2, error3
355 #endif
356 	);
357 	return 0;
358 abort:
359 	RSEQ_INJECT_FAILED
360 	return -1;
361 cmpfail:
362 	return 1;
363 #ifdef RSEQ_COMPARE_TWICE
364 error1:
365 	rseq_bug("cpu_id comparison failed");
366 error2:
367 	rseq_bug("1st expected value comparison failed");
368 error3:
369 	rseq_bug("2nd expected value comparison failed");
370 #endif
371 }
372 
373 static inline __attribute__((always_inline))
rseq_cmpeqv_trymemcpy_storev(intptr_t * v,intptr_t expect,void * dst,void * src,size_t len,intptr_t newv,int cpu)374 int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect,
375 				 void *dst, void *src, size_t len,
376 				 intptr_t newv, int cpu)
377 {
378 	uint64_t rseq_scratch[3];
379 
380 	RSEQ_INJECT_C(9)
381 
382 	__asm__ __volatile__ goto (
383 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
384 		"movq %[src], %[rseq_scratch0]\n\t"
385 		"movq %[dst], %[rseq_scratch1]\n\t"
386 		"movq %[len], %[rseq_scratch2]\n\t"
387 		/* Start rseq by storing table entry pointer into rseq_cs. */
388 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
389 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
390 		RSEQ_INJECT_ASM(3)
391 		"cmpq %[v], %[expect]\n\t"
392 		"jnz 5f\n\t"
393 		RSEQ_INJECT_ASM(4)
394 #ifdef RSEQ_COMPARE_TWICE
395 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
396 		"cmpq %[v], %[expect]\n\t"
397 		"jnz 7f\n\t"
398 #endif
399 		/* try memcpy */
400 		"test %[len], %[len]\n\t" \
401 		"jz 333f\n\t" \
402 		"222:\n\t" \
403 		"movb (%[src]), %%al\n\t" \
404 		"movb %%al, (%[dst])\n\t" \
405 		"inc %[src]\n\t" \
406 		"inc %[dst]\n\t" \
407 		"dec %[len]\n\t" \
408 		"jnz 222b\n\t" \
409 		"333:\n\t" \
410 		RSEQ_INJECT_ASM(5)
411 		/* final store */
412 		"movq %[newv], %[v]\n\t"
413 		"2:\n\t"
414 		RSEQ_INJECT_ASM(6)
415 		/* teardown */
416 		"movq %[rseq_scratch2], %[len]\n\t"
417 		"movq %[rseq_scratch1], %[dst]\n\t"
418 		"movq %[rseq_scratch0], %[src]\n\t"
419 		RSEQ_ASM_DEFINE_ABORT(4,
420 			"movq %[rseq_scratch2], %[len]\n\t"
421 			"movq %[rseq_scratch1], %[dst]\n\t"
422 			"movq %[rseq_scratch0], %[src]\n\t",
423 			abort)
424 		RSEQ_ASM_DEFINE_CMPFAIL(5,
425 			"movq %[rseq_scratch2], %[len]\n\t"
426 			"movq %[rseq_scratch1], %[dst]\n\t"
427 			"movq %[rseq_scratch0], %[src]\n\t",
428 			cmpfail)
429 #ifdef RSEQ_COMPARE_TWICE
430 		RSEQ_ASM_DEFINE_CMPFAIL(6,
431 			"movq %[rseq_scratch2], %[len]\n\t"
432 			"movq %[rseq_scratch1], %[dst]\n\t"
433 			"movq %[rseq_scratch0], %[src]\n\t",
434 			error1)
435 		RSEQ_ASM_DEFINE_CMPFAIL(7,
436 			"movq %[rseq_scratch2], %[len]\n\t"
437 			"movq %[rseq_scratch1], %[dst]\n\t"
438 			"movq %[rseq_scratch0], %[src]\n\t",
439 			error2)
440 #endif
441 		: /* gcc asm goto does not allow outputs */
442 		: [cpu_id]		"r" (cpu),
443 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
444 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
445 		  /* final store input */
446 		  [v]			"m" (*v),
447 		  [expect]		"r" (expect),
448 		  [newv]		"r" (newv),
449 		  /* try memcpy input */
450 		  [dst]			"r" (dst),
451 		  [src]			"r" (src),
452 		  [len]			"r" (len),
453 		  [rseq_scratch0]	"m" (rseq_scratch[0]),
454 		  [rseq_scratch1]	"m" (rseq_scratch[1]),
455 		  [rseq_scratch2]	"m" (rseq_scratch[2])
456 		: "memory", "cc", "rax"
457 		  RSEQ_INJECT_CLOBBER
458 		: abort, cmpfail
459 #ifdef RSEQ_COMPARE_TWICE
460 		  , error1, error2
461 #endif
462 	);
463 	return 0;
464 abort:
465 	RSEQ_INJECT_FAILED
466 	return -1;
467 cmpfail:
468 	return 1;
469 #ifdef RSEQ_COMPARE_TWICE
470 error1:
471 	rseq_bug("cpu_id comparison failed");
472 error2:
473 	rseq_bug("expected value comparison failed");
474 #endif
475 }
476 
477 /* x86-64 is TSO. */
478 static inline __attribute__((always_inline))
rseq_cmpeqv_trymemcpy_storev_release(intptr_t * v,intptr_t expect,void * dst,void * src,size_t len,intptr_t newv,int cpu)479 int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect,
480 					 void *dst, void *src, size_t len,
481 					 intptr_t newv, int cpu)
482 {
483 	return rseq_cmpeqv_trymemcpy_storev(v, expect, dst, src, len,
484 					    newv, cpu);
485 }
486 
487 #endif /* !RSEQ_SKIP_FASTPATH */
488 
489 #elif __i386__
490 
491 #define rseq_smp_mb()	\
492 	__asm__ __volatile__ ("lock; addl $0,-128(%%esp)" ::: "memory", "cc")
493 #define rseq_smp_rmb()	\
494 	__asm__ __volatile__ ("lock; addl $0,-128(%%esp)" ::: "memory", "cc")
495 #define rseq_smp_wmb()	\
496 	__asm__ __volatile__ ("lock; addl $0,-128(%%esp)" ::: "memory", "cc")
497 
498 #define rseq_smp_load_acquire(p)					\
499 __extension__ ({							\
500 	__typeof(*p) ____p1 = RSEQ_READ_ONCE(*p);			\
501 	rseq_smp_mb();							\
502 	____p1;								\
503 })
504 
505 #define rseq_smp_acquire__after_ctrl_dep()	rseq_smp_rmb()
506 
507 #define rseq_smp_store_release(p, v)					\
508 do {									\
509 	rseq_smp_mb();							\
510 	RSEQ_WRITE_ONCE(*p, v);						\
511 } while (0)
512 
513 #ifdef RSEQ_SKIP_FASTPATH
514 #include "rseq-skip.h"
515 #else /* !RSEQ_SKIP_FASTPATH */
516 
517 /*
518  * Use eax as scratch register and take memory operands as input to
519  * lessen register pressure. Especially needed when compiling in O0.
520  */
521 #define __RSEQ_ASM_DEFINE_TABLE(label, version, flags,			\
522 				start_ip, post_commit_offset, abort_ip)	\
523 		".pushsection __rseq_table, \"aw\"\n\t"			\
524 		".balign 32\n\t"					\
525 		__rseq_str(label) ":\n\t"				\
526 		".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
527 		".long " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
528 		".popsection\n\t"
529 
530 #define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
531 	__RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip,		\
532 				(post_commit_ip - start_ip), abort_ip)
533 
534 #define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs)		\
535 		RSEQ_INJECT_ASM(1)					\
536 		"movl $" __rseq_str(cs_label) ", %[rseq_cs]\n\t"	\
537 		__rseq_str(label) ":\n\t"
538 
539 #define RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, label)		\
540 		RSEQ_INJECT_ASM(2)					\
541 		"cmpl %[" __rseq_str(cpu_id) "], %[" __rseq_str(current_cpu_id) "]\n\t" \
542 		"jnz " __rseq_str(label) "\n\t"
543 
544 #define RSEQ_ASM_DEFINE_ABORT(label, teardown, abort_label)		\
545 		".pushsection __rseq_failure, \"ax\"\n\t"		\
546 		/* Disassembler-friendly signature: nopl <sig>. */	\
547 		".byte 0x0f, 0x1f, 0x05\n\t"				\
548 		".long " __rseq_str(RSEQ_SIG) "\n\t"			\
549 		__rseq_str(label) ":\n\t"				\
550 		teardown						\
551 		"jmp %l[" __rseq_str(abort_label) "]\n\t"		\
552 		".popsection\n\t"
553 
554 #define RSEQ_ASM_DEFINE_CMPFAIL(label, teardown, cmpfail_label)		\
555 		".pushsection __rseq_failure, \"ax\"\n\t"		\
556 		__rseq_str(label) ":\n\t"				\
557 		teardown						\
558 		"jmp %l[" __rseq_str(cmpfail_label) "]\n\t"		\
559 		".popsection\n\t"
560 
561 static inline __attribute__((always_inline))
rseq_cmpeqv_storev(intptr_t * v,intptr_t expect,intptr_t newv,int cpu)562 int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, int cpu)
563 {
564 	RSEQ_INJECT_C(9)
565 
566 	__asm__ __volatile__ goto (
567 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
568 		/* Start rseq by storing table entry pointer into rseq_cs. */
569 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
570 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
571 		RSEQ_INJECT_ASM(3)
572 		"cmpl %[v], %[expect]\n\t"
573 		"jnz %l[cmpfail]\n\t"
574 		RSEQ_INJECT_ASM(4)
575 #ifdef RSEQ_COMPARE_TWICE
576 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
577 		"cmpl %[v], %[expect]\n\t"
578 		"jnz %l[error2]\n\t"
579 #endif
580 		/* final store */
581 		"movl %[newv], %[v]\n\t"
582 		"2:\n\t"
583 		RSEQ_INJECT_ASM(5)
584 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
585 		: /* gcc asm goto does not allow outputs */
586 		: [cpu_id]		"r" (cpu),
587 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
588 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
589 		  [v]			"m" (*v),
590 		  [expect]		"r" (expect),
591 		  [newv]		"r" (newv)
592 		: "memory", "cc", "eax"
593 		  RSEQ_INJECT_CLOBBER
594 		: abort, cmpfail
595 #ifdef RSEQ_COMPARE_TWICE
596 		  , error1, error2
597 #endif
598 	);
599 	return 0;
600 abort:
601 	RSEQ_INJECT_FAILED
602 	return -1;
603 cmpfail:
604 	return 1;
605 #ifdef RSEQ_COMPARE_TWICE
606 error1:
607 	rseq_bug("cpu_id comparison failed");
608 error2:
609 	rseq_bug("expected value comparison failed");
610 #endif
611 }
612 
613 /*
614  * Compare @v against @expectnot. When it does _not_ match, load @v
615  * into @load, and store the content of *@v + voffp into @v.
616  */
617 static inline __attribute__((always_inline))
rseq_cmpnev_storeoffp_load(intptr_t * v,intptr_t expectnot,off_t voffp,intptr_t * load,int cpu)618 int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
619 			       off_t voffp, intptr_t *load, int cpu)
620 {
621 	RSEQ_INJECT_C(9)
622 
623 	__asm__ __volatile__ goto (
624 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
625 		/* Start rseq by storing table entry pointer into rseq_cs. */
626 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
627 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
628 		RSEQ_INJECT_ASM(3)
629 		"movl %[v], %%ebx\n\t"
630 		"cmpl %%ebx, %[expectnot]\n\t"
631 		"je %l[cmpfail]\n\t"
632 		RSEQ_INJECT_ASM(4)
633 #ifdef RSEQ_COMPARE_TWICE
634 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
635 		"movl %[v], %%ebx\n\t"
636 		"cmpl %%ebx, %[expectnot]\n\t"
637 		"je %l[error2]\n\t"
638 #endif
639 		"movl %%ebx, %[load]\n\t"
640 		"addl %[voffp], %%ebx\n\t"
641 		"movl (%%ebx), %%ebx\n\t"
642 		/* final store */
643 		"movl %%ebx, %[v]\n\t"
644 		"2:\n\t"
645 		RSEQ_INJECT_ASM(5)
646 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
647 		: /* gcc asm goto does not allow outputs */
648 		: [cpu_id]		"r" (cpu),
649 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
650 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
651 		  /* final store input */
652 		  [v]			"m" (*v),
653 		  [expectnot]		"r" (expectnot),
654 		  [voffp]		"ir" (voffp),
655 		  [load]		"m" (*load)
656 		: "memory", "cc", "eax", "ebx"
657 		  RSEQ_INJECT_CLOBBER
658 		: abort, cmpfail
659 #ifdef RSEQ_COMPARE_TWICE
660 		  , error1, error2
661 #endif
662 	);
663 	return 0;
664 abort:
665 	RSEQ_INJECT_FAILED
666 	return -1;
667 cmpfail:
668 	return 1;
669 #ifdef RSEQ_COMPARE_TWICE
670 error1:
671 	rseq_bug("cpu_id comparison failed");
672 error2:
673 	rseq_bug("expected value comparison failed");
674 #endif
675 }
676 
677 static inline __attribute__((always_inline))
rseq_addv(intptr_t * v,intptr_t count,int cpu)678 int rseq_addv(intptr_t *v, intptr_t count, int cpu)
679 {
680 	RSEQ_INJECT_C(9)
681 
682 	__asm__ __volatile__ goto (
683 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
684 		/* Start rseq by storing table entry pointer into rseq_cs. */
685 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
686 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
687 		RSEQ_INJECT_ASM(3)
688 #ifdef RSEQ_COMPARE_TWICE
689 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
690 #endif
691 		/* final store */
692 		"addl %[count], %[v]\n\t"
693 		"2:\n\t"
694 		RSEQ_INJECT_ASM(4)
695 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
696 		: /* gcc asm goto does not allow outputs */
697 		: [cpu_id]		"r" (cpu),
698 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
699 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
700 		  /* final store input */
701 		  [v]			"m" (*v),
702 		  [count]		"ir" (count)
703 		: "memory", "cc", "eax"
704 		  RSEQ_INJECT_CLOBBER
705 		: abort
706 #ifdef RSEQ_COMPARE_TWICE
707 		  , error1
708 #endif
709 	);
710 	return 0;
711 abort:
712 	RSEQ_INJECT_FAILED
713 	return -1;
714 #ifdef RSEQ_COMPARE_TWICE
715 error1:
716 	rseq_bug("cpu_id comparison failed");
717 #endif
718 }
719 
720 static inline __attribute__((always_inline))
rseq_cmpeqv_trystorev_storev(intptr_t * v,intptr_t expect,intptr_t * v2,intptr_t newv2,intptr_t newv,int cpu)721 int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,
722 				 intptr_t *v2, intptr_t newv2,
723 				 intptr_t newv, int cpu)
724 {
725 	RSEQ_INJECT_C(9)
726 
727 	__asm__ __volatile__ goto (
728 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
729 		/* Start rseq by storing table entry pointer into rseq_cs. */
730 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
731 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
732 		RSEQ_INJECT_ASM(3)
733 		"cmpl %[v], %[expect]\n\t"
734 		"jnz %l[cmpfail]\n\t"
735 		RSEQ_INJECT_ASM(4)
736 #ifdef RSEQ_COMPARE_TWICE
737 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
738 		"cmpl %[v], %[expect]\n\t"
739 		"jnz %l[error2]\n\t"
740 #endif
741 		/* try store */
742 		"movl %[newv2], %%eax\n\t"
743 		"movl %%eax, %[v2]\n\t"
744 		RSEQ_INJECT_ASM(5)
745 		/* final store */
746 		"movl %[newv], %[v]\n\t"
747 		"2:\n\t"
748 		RSEQ_INJECT_ASM(6)
749 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
750 		: /* gcc asm goto does not allow outputs */
751 		: [cpu_id]		"r" (cpu),
752 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
753 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
754 		  /* try store input */
755 		  [v2]			"m" (*v2),
756 		  [newv2]		"m" (newv2),
757 		  /* final store input */
758 		  [v]			"m" (*v),
759 		  [expect]		"r" (expect),
760 		  [newv]		"r" (newv)
761 		: "memory", "cc", "eax"
762 		  RSEQ_INJECT_CLOBBER
763 		: abort, cmpfail
764 #ifdef RSEQ_COMPARE_TWICE
765 		  , error1, error2
766 #endif
767 	);
768 	return 0;
769 abort:
770 	RSEQ_INJECT_FAILED
771 	return -1;
772 cmpfail:
773 	return 1;
774 #ifdef RSEQ_COMPARE_TWICE
775 error1:
776 	rseq_bug("cpu_id comparison failed");
777 error2:
778 	rseq_bug("expected value comparison failed");
779 #endif
780 }
781 
782 static inline __attribute__((always_inline))
rseq_cmpeqv_trystorev_storev_release(intptr_t * v,intptr_t expect,intptr_t * v2,intptr_t newv2,intptr_t newv,int cpu)783 int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect,
784 					 intptr_t *v2, intptr_t newv2,
785 					 intptr_t newv, int cpu)
786 {
787 	RSEQ_INJECT_C(9)
788 
789 	__asm__ __volatile__ goto (
790 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
791 		/* Start rseq by storing table entry pointer into rseq_cs. */
792 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
793 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
794 		RSEQ_INJECT_ASM(3)
795 		"movl %[expect], %%eax\n\t"
796 		"cmpl %[v], %%eax\n\t"
797 		"jnz %l[cmpfail]\n\t"
798 		RSEQ_INJECT_ASM(4)
799 #ifdef RSEQ_COMPARE_TWICE
800 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
801 		"movl %[expect], %%eax\n\t"
802 		"cmpl %[v], %%eax\n\t"
803 		"jnz %l[error2]\n\t"
804 #endif
805 		/* try store */
806 		"movl %[newv2], %[v2]\n\t"
807 		RSEQ_INJECT_ASM(5)
808 		"lock; addl $0,-128(%%esp)\n\t"
809 		/* final store */
810 		"movl %[newv], %[v]\n\t"
811 		"2:\n\t"
812 		RSEQ_INJECT_ASM(6)
813 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
814 		: /* gcc asm goto does not allow outputs */
815 		: [cpu_id]		"r" (cpu),
816 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
817 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
818 		  /* try store input */
819 		  [v2]			"m" (*v2),
820 		  [newv2]		"r" (newv2),
821 		  /* final store input */
822 		  [v]			"m" (*v),
823 		  [expect]		"m" (expect),
824 		  [newv]		"r" (newv)
825 		: "memory", "cc", "eax"
826 		  RSEQ_INJECT_CLOBBER
827 		: abort, cmpfail
828 #ifdef RSEQ_COMPARE_TWICE
829 		  , error1, error2
830 #endif
831 	);
832 	return 0;
833 abort:
834 	RSEQ_INJECT_FAILED
835 	return -1;
836 cmpfail:
837 	return 1;
838 #ifdef RSEQ_COMPARE_TWICE
839 error1:
840 	rseq_bug("cpu_id comparison failed");
841 error2:
842 	rseq_bug("expected value comparison failed");
843 #endif
844 
845 }
846 
847 static inline __attribute__((always_inline))
rseq_cmpeqv_cmpeqv_storev(intptr_t * v,intptr_t expect,intptr_t * v2,intptr_t expect2,intptr_t newv,int cpu)848 int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect,
849 			      intptr_t *v2, intptr_t expect2,
850 			      intptr_t newv, int cpu)
851 {
852 	RSEQ_INJECT_C(9)
853 
854 	__asm__ __volatile__ goto (
855 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
856 		/* Start rseq by storing table entry pointer into rseq_cs. */
857 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
858 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
859 		RSEQ_INJECT_ASM(3)
860 		"cmpl %[v], %[expect]\n\t"
861 		"jnz %l[cmpfail]\n\t"
862 		RSEQ_INJECT_ASM(4)
863 		"cmpl %[expect2], %[v2]\n\t"
864 		"jnz %l[cmpfail]\n\t"
865 		RSEQ_INJECT_ASM(5)
866 #ifdef RSEQ_COMPARE_TWICE
867 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
868 		"cmpl %[v], %[expect]\n\t"
869 		"jnz %l[error2]\n\t"
870 		"cmpl %[expect2], %[v2]\n\t"
871 		"jnz %l[error3]\n\t"
872 #endif
873 		"movl %[newv], %%eax\n\t"
874 		/* final store */
875 		"movl %%eax, %[v]\n\t"
876 		"2:\n\t"
877 		RSEQ_INJECT_ASM(6)
878 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
879 		: /* gcc asm goto does not allow outputs */
880 		: [cpu_id]		"r" (cpu),
881 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
882 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
883 		  /* cmp2 input */
884 		  [v2]			"m" (*v2),
885 		  [expect2]		"r" (expect2),
886 		  /* final store input */
887 		  [v]			"m" (*v),
888 		  [expect]		"r" (expect),
889 		  [newv]		"m" (newv)
890 		: "memory", "cc", "eax"
891 		  RSEQ_INJECT_CLOBBER
892 		: abort, cmpfail
893 #ifdef RSEQ_COMPARE_TWICE
894 		  , error1, error2, error3
895 #endif
896 	);
897 	return 0;
898 abort:
899 	RSEQ_INJECT_FAILED
900 	return -1;
901 cmpfail:
902 	return 1;
903 #ifdef RSEQ_COMPARE_TWICE
904 error1:
905 	rseq_bug("cpu_id comparison failed");
906 error2:
907 	rseq_bug("1st expected value comparison failed");
908 error3:
909 	rseq_bug("2nd expected value comparison failed");
910 #endif
911 }
912 
913 /* TODO: implement a faster memcpy. */
914 static inline __attribute__((always_inline))
rseq_cmpeqv_trymemcpy_storev(intptr_t * v,intptr_t expect,void * dst,void * src,size_t len,intptr_t newv,int cpu)915 int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect,
916 				 void *dst, void *src, size_t len,
917 				 intptr_t newv, int cpu)
918 {
919 	uint32_t rseq_scratch[3];
920 
921 	RSEQ_INJECT_C(9)
922 
923 	__asm__ __volatile__ goto (
924 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
925 		"movl %[src], %[rseq_scratch0]\n\t"
926 		"movl %[dst], %[rseq_scratch1]\n\t"
927 		"movl %[len], %[rseq_scratch2]\n\t"
928 		/* Start rseq by storing table entry pointer into rseq_cs. */
929 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
930 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
931 		RSEQ_INJECT_ASM(3)
932 		"movl %[expect], %%eax\n\t"
933 		"cmpl %%eax, %[v]\n\t"
934 		"jnz 5f\n\t"
935 		RSEQ_INJECT_ASM(4)
936 #ifdef RSEQ_COMPARE_TWICE
937 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
938 		"movl %[expect], %%eax\n\t"
939 		"cmpl %%eax, %[v]\n\t"
940 		"jnz 7f\n\t"
941 #endif
942 		/* try memcpy */
943 		"test %[len], %[len]\n\t" \
944 		"jz 333f\n\t" \
945 		"222:\n\t" \
946 		"movb (%[src]), %%al\n\t" \
947 		"movb %%al, (%[dst])\n\t" \
948 		"inc %[src]\n\t" \
949 		"inc %[dst]\n\t" \
950 		"dec %[len]\n\t" \
951 		"jnz 222b\n\t" \
952 		"333:\n\t" \
953 		RSEQ_INJECT_ASM(5)
954 		"movl %[newv], %%eax\n\t"
955 		/* final store */
956 		"movl %%eax, %[v]\n\t"
957 		"2:\n\t"
958 		RSEQ_INJECT_ASM(6)
959 		/* teardown */
960 		"movl %[rseq_scratch2], %[len]\n\t"
961 		"movl %[rseq_scratch1], %[dst]\n\t"
962 		"movl %[rseq_scratch0], %[src]\n\t"
963 		RSEQ_ASM_DEFINE_ABORT(4,
964 			"movl %[rseq_scratch2], %[len]\n\t"
965 			"movl %[rseq_scratch1], %[dst]\n\t"
966 			"movl %[rseq_scratch0], %[src]\n\t",
967 			abort)
968 		RSEQ_ASM_DEFINE_CMPFAIL(5,
969 			"movl %[rseq_scratch2], %[len]\n\t"
970 			"movl %[rseq_scratch1], %[dst]\n\t"
971 			"movl %[rseq_scratch0], %[src]\n\t",
972 			cmpfail)
973 #ifdef RSEQ_COMPARE_TWICE
974 		RSEQ_ASM_DEFINE_CMPFAIL(6,
975 			"movl %[rseq_scratch2], %[len]\n\t"
976 			"movl %[rseq_scratch1], %[dst]\n\t"
977 			"movl %[rseq_scratch0], %[src]\n\t",
978 			error1)
979 		RSEQ_ASM_DEFINE_CMPFAIL(7,
980 			"movl %[rseq_scratch2], %[len]\n\t"
981 			"movl %[rseq_scratch1], %[dst]\n\t"
982 			"movl %[rseq_scratch0], %[src]\n\t",
983 			error2)
984 #endif
985 		: /* gcc asm goto does not allow outputs */
986 		: [cpu_id]		"r" (cpu),
987 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
988 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
989 		  /* final store input */
990 		  [v]			"m" (*v),
991 		  [expect]		"m" (expect),
992 		  [newv]		"m" (newv),
993 		  /* try memcpy input */
994 		  [dst]			"r" (dst),
995 		  [src]			"r" (src),
996 		  [len]			"r" (len),
997 		  [rseq_scratch0]	"m" (rseq_scratch[0]),
998 		  [rseq_scratch1]	"m" (rseq_scratch[1]),
999 		  [rseq_scratch2]	"m" (rseq_scratch[2])
1000 		: "memory", "cc", "eax"
1001 		  RSEQ_INJECT_CLOBBER
1002 		: abort, cmpfail
1003 #ifdef RSEQ_COMPARE_TWICE
1004 		  , error1, error2
1005 #endif
1006 	);
1007 	return 0;
1008 abort:
1009 	RSEQ_INJECT_FAILED
1010 	return -1;
1011 cmpfail:
1012 	return 1;
1013 #ifdef RSEQ_COMPARE_TWICE
1014 error1:
1015 	rseq_bug("cpu_id comparison failed");
1016 error2:
1017 	rseq_bug("expected value comparison failed");
1018 #endif
1019 }
1020 
1021 /* TODO: implement a faster memcpy. */
1022 static inline __attribute__((always_inline))
rseq_cmpeqv_trymemcpy_storev_release(intptr_t * v,intptr_t expect,void * dst,void * src,size_t len,intptr_t newv,int cpu)1023 int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect,
1024 					 void *dst, void *src, size_t len,
1025 					 intptr_t newv, int cpu)
1026 {
1027 	uint32_t rseq_scratch[3];
1028 
1029 	RSEQ_INJECT_C(9)
1030 
1031 	__asm__ __volatile__ goto (
1032 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
1033 		"movl %[src], %[rseq_scratch0]\n\t"
1034 		"movl %[dst], %[rseq_scratch1]\n\t"
1035 		"movl %[len], %[rseq_scratch2]\n\t"
1036 		/* Start rseq by storing table entry pointer into rseq_cs. */
1037 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
1038 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
1039 		RSEQ_INJECT_ASM(3)
1040 		"movl %[expect], %%eax\n\t"
1041 		"cmpl %%eax, %[v]\n\t"
1042 		"jnz 5f\n\t"
1043 		RSEQ_INJECT_ASM(4)
1044 #ifdef RSEQ_COMPARE_TWICE
1045 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
1046 		"movl %[expect], %%eax\n\t"
1047 		"cmpl %%eax, %[v]\n\t"
1048 		"jnz 7f\n\t"
1049 #endif
1050 		/* try memcpy */
1051 		"test %[len], %[len]\n\t" \
1052 		"jz 333f\n\t" \
1053 		"222:\n\t" \
1054 		"movb (%[src]), %%al\n\t" \
1055 		"movb %%al, (%[dst])\n\t" \
1056 		"inc %[src]\n\t" \
1057 		"inc %[dst]\n\t" \
1058 		"dec %[len]\n\t" \
1059 		"jnz 222b\n\t" \
1060 		"333:\n\t" \
1061 		RSEQ_INJECT_ASM(5)
1062 		"lock; addl $0,-128(%%esp)\n\t"
1063 		"movl %[newv], %%eax\n\t"
1064 		/* final store */
1065 		"movl %%eax, %[v]\n\t"
1066 		"2:\n\t"
1067 		RSEQ_INJECT_ASM(6)
1068 		/* teardown */
1069 		"movl %[rseq_scratch2], %[len]\n\t"
1070 		"movl %[rseq_scratch1], %[dst]\n\t"
1071 		"movl %[rseq_scratch0], %[src]\n\t"
1072 		RSEQ_ASM_DEFINE_ABORT(4,
1073 			"movl %[rseq_scratch2], %[len]\n\t"
1074 			"movl %[rseq_scratch1], %[dst]\n\t"
1075 			"movl %[rseq_scratch0], %[src]\n\t",
1076 			abort)
1077 		RSEQ_ASM_DEFINE_CMPFAIL(5,
1078 			"movl %[rseq_scratch2], %[len]\n\t"
1079 			"movl %[rseq_scratch1], %[dst]\n\t"
1080 			"movl %[rseq_scratch0], %[src]\n\t",
1081 			cmpfail)
1082 #ifdef RSEQ_COMPARE_TWICE
1083 		RSEQ_ASM_DEFINE_CMPFAIL(6,
1084 			"movl %[rseq_scratch2], %[len]\n\t"
1085 			"movl %[rseq_scratch1], %[dst]\n\t"
1086 			"movl %[rseq_scratch0], %[src]\n\t",
1087 			error1)
1088 		RSEQ_ASM_DEFINE_CMPFAIL(7,
1089 			"movl %[rseq_scratch2], %[len]\n\t"
1090 			"movl %[rseq_scratch1], %[dst]\n\t"
1091 			"movl %[rseq_scratch0], %[src]\n\t",
1092 			error2)
1093 #endif
1094 		: /* gcc asm goto does not allow outputs */
1095 		: [cpu_id]		"r" (cpu),
1096 		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
1097 		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
1098 		  /* final store input */
1099 		  [v]			"m" (*v),
1100 		  [expect]		"m" (expect),
1101 		  [newv]		"m" (newv),
1102 		  /* try memcpy input */
1103 		  [dst]			"r" (dst),
1104 		  [src]			"r" (src),
1105 		  [len]			"r" (len),
1106 		  [rseq_scratch0]	"m" (rseq_scratch[0]),
1107 		  [rseq_scratch1]	"m" (rseq_scratch[1]),
1108 		  [rseq_scratch2]	"m" (rseq_scratch[2])
1109 		: "memory", "cc", "eax"
1110 		  RSEQ_INJECT_CLOBBER
1111 		: abort, cmpfail
1112 #ifdef RSEQ_COMPARE_TWICE
1113 		  , error1, error2
1114 #endif
1115 	);
1116 	return 0;
1117 abort:
1118 	RSEQ_INJECT_FAILED
1119 	return -1;
1120 cmpfail:
1121 	return 1;
1122 #ifdef RSEQ_COMPARE_TWICE
1123 error1:
1124 	rseq_bug("cpu_id comparison failed");
1125 error2:
1126 	rseq_bug("expected value comparison failed");
1127 #endif
1128 }
1129 
1130 #endif /* !RSEQ_SKIP_FASTPATH */
1131 
1132 #endif
1133