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6#include <linux/cpu.h>
7#include <linux/init.h>
8#include <linux/list.h>
9#include <linux/perf_event.h>
10#include <linux/sched.h>
11#include <linux/slab.h>
12#include <linux/sysctl.h>
13#include <linux/uaccess.h>
14
15#include <asm/cpufeature.h>
16#include <asm/insn.h>
17#include <asm/sysreg.h>
18#include <asm/system_misc.h>
19#include <asm/traps.h>
20#include <asm/kprobes.h>
21
22#define CREATE_TRACE_POINTS
23#include "trace-events-emulation.h"
24
25
26
27
28
29
30
31
32
33enum insn_emulation_mode {
34 INSN_UNDEF,
35 INSN_EMULATE,
36 INSN_HW,
37};
38
39enum legacy_insn_status {
40 INSN_DEPRECATED,
41 INSN_OBSOLETE,
42};
43
44struct insn_emulation_ops {
45 const char *name;
46 enum legacy_insn_status status;
47 struct undef_hook *hooks;
48 int (*set_hw_mode)(bool enable);
49};
50
51struct insn_emulation {
52 struct list_head node;
53 struct insn_emulation_ops *ops;
54 int current_mode;
55 int min;
56 int max;
57};
58
59static LIST_HEAD(insn_emulation);
60static int nr_insn_emulated __initdata;
61static DEFINE_RAW_SPINLOCK(insn_emulation_lock);
62
63static void register_emulation_hooks(struct insn_emulation_ops *ops)
64{
65 struct undef_hook *hook;
66
67 BUG_ON(!ops->hooks);
68
69 for (hook = ops->hooks; hook->instr_mask; hook++)
70 register_undef_hook(hook);
71
72 pr_notice("Registered %s emulation handler\n", ops->name);
73}
74
75static void remove_emulation_hooks(struct insn_emulation_ops *ops)
76{
77 struct undef_hook *hook;
78
79 BUG_ON(!ops->hooks);
80
81 for (hook = ops->hooks; hook->instr_mask; hook++)
82 unregister_undef_hook(hook);
83
84 pr_notice("Removed %s emulation handler\n", ops->name);
85}
86
87static void enable_insn_hw_mode(void *data)
88{
89 struct insn_emulation *insn = (struct insn_emulation *)data;
90 if (insn->ops->set_hw_mode)
91 insn->ops->set_hw_mode(true);
92}
93
94static void disable_insn_hw_mode(void *data)
95{
96 struct insn_emulation *insn = (struct insn_emulation *)data;
97 if (insn->ops->set_hw_mode)
98 insn->ops->set_hw_mode(false);
99}
100
101
102static int run_all_cpu_set_hw_mode(struct insn_emulation *insn, bool enable)
103{
104 if (!insn->ops->set_hw_mode)
105 return -EINVAL;
106 if (enable)
107 on_each_cpu(enable_insn_hw_mode, (void *)insn, true);
108 else
109 on_each_cpu(disable_insn_hw_mode, (void *)insn, true);
110 return 0;
111}
112
113
114
115
116
117
118
119static int run_all_insn_set_hw_mode(unsigned int cpu)
120{
121 int rc = 0;
122 unsigned long flags;
123 struct insn_emulation *insn;
124
125 raw_spin_lock_irqsave(&insn_emulation_lock, flags);
126 list_for_each_entry(insn, &insn_emulation, node) {
127 bool enable = (insn->current_mode == INSN_HW);
128 if (insn->ops->set_hw_mode && insn->ops->set_hw_mode(enable)) {
129 pr_warn("CPU[%u] cannot support the emulation of %s",
130 cpu, insn->ops->name);
131 rc = -EINVAL;
132 }
133 }
134 raw_spin_unlock_irqrestore(&insn_emulation_lock, flags);
135 return rc;
136}
137
138static int update_insn_emulation_mode(struct insn_emulation *insn,
139 enum insn_emulation_mode prev)
140{
141 int ret = 0;
142
143 switch (prev) {
144 case INSN_UNDEF:
145 break;
146 case INSN_EMULATE:
147 remove_emulation_hooks(insn->ops);
148 break;
149 case INSN_HW:
150 if (!run_all_cpu_set_hw_mode(insn, false))
151 pr_notice("Disabled %s support\n", insn->ops->name);
152 break;
153 }
154
155 switch (insn->current_mode) {
156 case INSN_UNDEF:
157 break;
158 case INSN_EMULATE:
159 register_emulation_hooks(insn->ops);
160 break;
161 case INSN_HW:
162 ret = run_all_cpu_set_hw_mode(insn, true);
163 if (!ret)
164 pr_notice("Enabled %s support\n", insn->ops->name);
165 break;
166 }
167
168 return ret;
169}
170
171static void __init register_insn_emulation(struct insn_emulation_ops *ops)
172{
173 unsigned long flags;
174 struct insn_emulation *insn;
175
176 insn = kzalloc(sizeof(*insn), GFP_KERNEL);
177 if (!insn)
178 return;
179
180 insn->ops = ops;
181 insn->min = INSN_UNDEF;
182
183 switch (ops->status) {
184 case INSN_DEPRECATED:
185 insn->current_mode = INSN_EMULATE;
186
187 run_all_cpu_set_hw_mode(insn, false);
188 insn->max = INSN_HW;
189 break;
190 case INSN_OBSOLETE:
191 insn->current_mode = INSN_UNDEF;
192 insn->max = INSN_EMULATE;
193 break;
194 }
195
196 raw_spin_lock_irqsave(&insn_emulation_lock, flags);
197 list_add(&insn->node, &insn_emulation);
198 nr_insn_emulated++;
199 raw_spin_unlock_irqrestore(&insn_emulation_lock, flags);
200
201
202 update_insn_emulation_mode(insn, INSN_UNDEF);
203}
204
205static int emulation_proc_handler(struct ctl_table *table, int write,
206 void *buffer, size_t *lenp,
207 loff_t *ppos)
208{
209 int ret = 0;
210 struct insn_emulation *insn = (struct insn_emulation *) table->data;
211 enum insn_emulation_mode prev_mode = insn->current_mode;
212
213 table->data = &insn->current_mode;
214 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
215
216 if (ret || !write || prev_mode == insn->current_mode)
217 goto ret;
218
219 ret = update_insn_emulation_mode(insn, prev_mode);
220 if (ret) {
221
222 insn->current_mode = prev_mode;
223 update_insn_emulation_mode(insn, INSN_UNDEF);
224 }
225ret:
226 table->data = insn;
227 return ret;
228}
229
230static void __init register_insn_emulation_sysctl(void)
231{
232 unsigned long flags;
233 int i = 0;
234 struct insn_emulation *insn;
235 struct ctl_table *insns_sysctl, *sysctl;
236
237 insns_sysctl = kcalloc(nr_insn_emulated + 1, sizeof(*sysctl),
238 GFP_KERNEL);
239 if (!insns_sysctl)
240 return;
241
242 raw_spin_lock_irqsave(&insn_emulation_lock, flags);
243 list_for_each_entry(insn, &insn_emulation, node) {
244 sysctl = &insns_sysctl[i];
245
246 sysctl->mode = 0644;
247 sysctl->maxlen = sizeof(int);
248
249 sysctl->procname = insn->ops->name;
250 sysctl->data = insn;
251 sysctl->extra1 = &insn->min;
252 sysctl->extra2 = &insn->max;
253 sysctl->proc_handler = emulation_proc_handler;
254 i++;
255 }
256 raw_spin_unlock_irqrestore(&insn_emulation_lock, flags);
257
258 register_sysctl("abi", insns_sysctl);
259}
260
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270
271
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273
274
275
276#define __SWP_LL_SC_LOOPS 4
277
278#define __user_swpX_asm(data, addr, res, temp, temp2, B) \
279do { \
280 uaccess_enable_privileged(); \
281 __asm__ __volatile__( \
282 " mov %w3, %w7\n" \
283 "0: ldxr"B" %w2, [%4]\n" \
284 "1: stxr"B" %w0, %w1, [%4]\n" \
285 " cbz %w0, 2f\n" \
286 " sub %w3, %w3, #1\n" \
287 " cbnz %w3, 0b\n" \
288 " mov %w0, %w5\n" \
289 " b 3f\n" \
290 "2:\n" \
291 " mov %w1, %w2\n" \
292 "3:\n" \
293 " .pushsection .fixup,\"ax\"\n" \
294 " .align 2\n" \
295 "4: mov %w0, %w6\n" \
296 " b 3b\n" \
297 " .popsection" \
298 _ASM_EXTABLE(0b, 4b) \
299 _ASM_EXTABLE(1b, 4b) \
300 : "=&r" (res), "+r" (data), "=&r" (temp), "=&r" (temp2) \
301 : "r" ((unsigned long)addr), "i" (-EAGAIN), \
302 "i" (-EFAULT), \
303 "i" (__SWP_LL_SC_LOOPS) \
304 : "memory"); \
305 uaccess_disable_privileged(); \
306} while (0)
307
308#define __user_swp_asm(data, addr, res, temp, temp2) \
309 __user_swpX_asm(data, addr, res, temp, temp2, "")
310#define __user_swpb_asm(data, addr, res, temp, temp2) \
311 __user_swpX_asm(data, addr, res, temp, temp2, "b")
312
313
314
315
316
317#define TYPE_SWPB (1 << 22)
318
319static int emulate_swpX(unsigned int address, unsigned int *data,
320 unsigned int type)
321{
322 unsigned int res = 0;
323
324 if ((type != TYPE_SWPB) && (address & 0x3)) {
325
326 pr_debug("SWP instruction on unaligned pointer!\n");
327 return -EFAULT;
328 }
329
330 while (1) {
331 unsigned long temp, temp2;
332
333 if (type == TYPE_SWPB)
334 __user_swpb_asm(*data, address, res, temp, temp2);
335 else
336 __user_swp_asm(*data, address, res, temp, temp2);
337
338 if (likely(res != -EAGAIN) || signal_pending(current))
339 break;
340
341 cond_resched();
342 }
343
344 return res;
345}
346
347#define ARM_OPCODE_CONDTEST_FAIL 0
348#define ARM_OPCODE_CONDTEST_PASS 1
349#define ARM_OPCODE_CONDTEST_UNCOND 2
350
351#define ARM_OPCODE_CONDITION_UNCOND 0xf
352
353static unsigned int __kprobes aarch32_check_condition(u32 opcode, u32 psr)
354{
355 u32 cc_bits = opcode >> 28;
356
357 if (cc_bits != ARM_OPCODE_CONDITION_UNCOND) {
358 if ((*aarch32_opcode_cond_checks[cc_bits])(psr))
359 return ARM_OPCODE_CONDTEST_PASS;
360 else
361 return ARM_OPCODE_CONDTEST_FAIL;
362 }
363 return ARM_OPCODE_CONDTEST_UNCOND;
364}
365
366
367
368
369
370
371static int swp_handler(struct pt_regs *regs, u32 instr)
372{
373 u32 destreg, data, type, address = 0;
374 const void __user *user_ptr;
375 int rn, rt2, res = 0;
376
377 perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc);
378
379 type = instr & TYPE_SWPB;
380
381 switch (aarch32_check_condition(instr, regs->pstate)) {
382 case ARM_OPCODE_CONDTEST_PASS:
383 break;
384 case ARM_OPCODE_CONDTEST_FAIL:
385
386 goto ret;
387 case ARM_OPCODE_CONDTEST_UNCOND:
388
389 return -EFAULT;
390 default:
391 return -EINVAL;
392 }
393
394 rn = aarch32_insn_extract_reg_num(instr, A32_RN_OFFSET);
395 rt2 = aarch32_insn_extract_reg_num(instr, A32_RT2_OFFSET);
396
397 address = (u32)regs->user_regs.regs[rn];
398 data = (u32)regs->user_regs.regs[rt2];
399 destreg = aarch32_insn_extract_reg_num(instr, A32_RT_OFFSET);
400
401 pr_debug("addr in r%d->0x%08x, dest is r%d, source in r%d->0x%08x)\n",
402 rn, address, destreg,
403 aarch32_insn_extract_reg_num(instr, A32_RT2_OFFSET), data);
404
405
406 user_ptr = (const void __user *)(unsigned long)(address & ~3);
407 if (!access_ok(user_ptr, 4)) {
408 pr_debug("SWP{B} emulation: access to 0x%08x not allowed!\n",
409 address);
410 goto fault;
411 }
412
413 res = emulate_swpX(address, &data, type);
414 if (res == -EFAULT)
415 goto fault;
416 else if (res == 0)
417 regs->user_regs.regs[destreg] = data;
418
419ret:
420 if (type == TYPE_SWPB)
421 trace_instruction_emulation("swpb", regs->pc);
422 else
423 trace_instruction_emulation("swp", regs->pc);
424
425 pr_warn_ratelimited("\"%s\" (%ld) uses obsolete SWP{B} instruction at 0x%llx\n",
426 current->comm, (unsigned long)current->pid, regs->pc);
427
428 arm64_skip_faulting_instruction(regs, 4);
429 return 0;
430
431fault:
432 pr_debug("SWP{B} emulation: access caused memory abort!\n");
433 arm64_notify_segfault(address);
434
435 return 0;
436}
437
438
439
440
441
442static struct undef_hook swp_hooks[] = {
443 {
444 .instr_mask = 0x0fb00ff0,
445 .instr_val = 0x01000090,
446 .pstate_mask = PSR_AA32_MODE_MASK,
447 .pstate_val = PSR_AA32_MODE_USR,
448 .fn = swp_handler
449 },
450 { }
451};
452
453static struct insn_emulation_ops swp_ops = {
454 .name = "swp",
455 .status = INSN_OBSOLETE,
456 .hooks = swp_hooks,
457 .set_hw_mode = NULL,
458};
459
460static int cp15barrier_handler(struct pt_regs *regs, u32 instr)
461{
462 perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc);
463
464 switch (aarch32_check_condition(instr, regs->pstate)) {
465 case ARM_OPCODE_CONDTEST_PASS:
466 break;
467 case ARM_OPCODE_CONDTEST_FAIL:
468
469 goto ret;
470 case ARM_OPCODE_CONDTEST_UNCOND:
471
472 return -EFAULT;
473 default:
474 return -EINVAL;
475 }
476
477 switch (aarch32_insn_mcr_extract_crm(instr)) {
478 case 10:
479
480
481
482
483 if (aarch32_insn_mcr_extract_opc2(instr) == 5) {
484 dmb(sy);
485 trace_instruction_emulation(
486 "mcr p15, 0, Rt, c7, c10, 5 ; dmb", regs->pc);
487 } else {
488 dsb(sy);
489 trace_instruction_emulation(
490 "mcr p15, 0, Rt, c7, c10, 4 ; dsb", regs->pc);
491 }
492 break;
493 case 5:
494
495
496
497
498
499
500 trace_instruction_emulation(
501 "mcr p15, 0, Rt, c7, c5, 4 ; isb", regs->pc);
502 break;
503 }
504
505ret:
506 pr_warn_ratelimited("\"%s\" (%ld) uses deprecated CP15 Barrier instruction at 0x%llx\n",
507 current->comm, (unsigned long)current->pid, regs->pc);
508
509 arm64_skip_faulting_instruction(regs, 4);
510 return 0;
511}
512
513static int cp15_barrier_set_hw_mode(bool enable)
514{
515 if (enable)
516 sysreg_clear_set(sctlr_el1, 0, SCTLR_EL1_CP15BEN);
517 else
518 sysreg_clear_set(sctlr_el1, SCTLR_EL1_CP15BEN, 0);
519 return 0;
520}
521
522static struct undef_hook cp15_barrier_hooks[] = {
523 {
524 .instr_mask = 0x0fff0fdf,
525 .instr_val = 0x0e070f9a,
526 .pstate_mask = PSR_AA32_MODE_MASK,
527 .pstate_val = PSR_AA32_MODE_USR,
528 .fn = cp15barrier_handler,
529 },
530 {
531 .instr_mask = 0x0fff0fff,
532 .instr_val = 0x0e070f95,
533 .pstate_mask = PSR_AA32_MODE_MASK,
534 .pstate_val = PSR_AA32_MODE_USR,
535 .fn = cp15barrier_handler,
536 },
537 { }
538};
539
540static struct insn_emulation_ops cp15_barrier_ops = {
541 .name = "cp15_barrier",
542 .status = INSN_DEPRECATED,
543 .hooks = cp15_barrier_hooks,
544 .set_hw_mode = cp15_barrier_set_hw_mode,
545};
546
547static int setend_set_hw_mode(bool enable)
548{
549 if (!cpu_supports_mixed_endian_el0())
550 return -EINVAL;
551
552 if (enable)
553 sysreg_clear_set(sctlr_el1, SCTLR_EL1_SED, 0);
554 else
555 sysreg_clear_set(sctlr_el1, 0, SCTLR_EL1_SED);
556 return 0;
557}
558
559static int compat_setend_handler(struct pt_regs *regs, u32 big_endian)
560{
561 char *insn;
562
563 perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc);
564
565 if (big_endian) {
566 insn = "setend be";
567 regs->pstate |= PSR_AA32_E_BIT;
568 } else {
569 insn = "setend le";
570 regs->pstate &= ~PSR_AA32_E_BIT;
571 }
572
573 trace_instruction_emulation(insn, regs->pc);
574 pr_warn_ratelimited("\"%s\" (%ld) uses deprecated setend instruction at 0x%llx\n",
575 current->comm, (unsigned long)current->pid, regs->pc);
576
577 return 0;
578}
579
580static int a32_setend_handler(struct pt_regs *regs, u32 instr)
581{
582 int rc = compat_setend_handler(regs, (instr >> 9) & 1);
583 arm64_skip_faulting_instruction(regs, 4);
584 return rc;
585}
586
587static int t16_setend_handler(struct pt_regs *regs, u32 instr)
588{
589 int rc = compat_setend_handler(regs, (instr >> 3) & 1);
590 arm64_skip_faulting_instruction(regs, 2);
591 return rc;
592}
593
594static struct undef_hook setend_hooks[] = {
595 {
596 .instr_mask = 0xfffffdff,
597 .instr_val = 0xf1010000,
598 .pstate_mask = PSR_AA32_MODE_MASK,
599 .pstate_val = PSR_AA32_MODE_USR,
600 .fn = a32_setend_handler,
601 },
602 {
603
604 .instr_mask = 0xfffffff7,
605 .instr_val = 0x0000b650,
606 .pstate_mask = (PSR_AA32_T_BIT | PSR_AA32_MODE_MASK),
607 .pstate_val = (PSR_AA32_T_BIT | PSR_AA32_MODE_USR),
608 .fn = t16_setend_handler,
609 },
610 {}
611};
612
613static struct insn_emulation_ops setend_ops = {
614 .name = "setend",
615 .status = INSN_DEPRECATED,
616 .hooks = setend_hooks,
617 .set_hw_mode = setend_set_hw_mode,
618};
619
620
621
622
623
624static int __init armv8_deprecated_init(void)
625{
626 if (IS_ENABLED(CONFIG_SWP_EMULATION))
627 register_insn_emulation(&swp_ops);
628
629 if (IS_ENABLED(CONFIG_CP15_BARRIER_EMULATION))
630 register_insn_emulation(&cp15_barrier_ops);
631
632 if (IS_ENABLED(CONFIG_SETEND_EMULATION)) {
633 if (system_supports_mixed_endian_el0())
634 register_insn_emulation(&setend_ops);
635 else
636 pr_info("setend instruction emulation is not supported on this system\n");
637 }
638
639 cpuhp_setup_state_nocalls(CPUHP_AP_ARM64_ISNDEP_STARTING,
640 "arm64/isndep:starting",
641 run_all_insn_set_hw_mode, NULL);
642 register_insn_emulation_sysctl();
643
644 return 0;
645}
646
647core_initcall(armv8_deprecated_init);
648
