2 * Copyright (C) 2014 ARM Limited
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
10 #include <linux/init.h>
11 #include <linux/list.h>
12 #include <linux/perf_event.h>
13 #include <linux/sched.h>
14 #include <linux/slab.h>
15 #include <linux/sysctl.h>
18 #include <asm/opcodes.h>
19 #include <asm/system_misc.h>
20 #include <asm/traps.h>
21 #include <asm/uaccess.h>
22 #include <asm/cpufeature.h>
24 #define CREATE_TRACE_POINTS
25 #include "trace-events-emulation.h"
28 * The runtime support for deprecated instruction support can be in one of
29 * following three states -
32 * 1 = emulate (software emulation)
33 * 2 = hw (supported in hardware)
35 enum insn_emulation_mode
{
41 enum legacy_insn_status
{
46 struct insn_emulation_ops
{
48 enum legacy_insn_status status
;
49 struct undef_hook
*hooks
;
50 int (*set_hw_mode
)(bool enable
);
53 struct insn_emulation
{
54 struct list_head node
;
55 struct insn_emulation_ops
*ops
;
61 static LIST_HEAD(insn_emulation
);
62 static int nr_insn_emulated
;
63 static DEFINE_RAW_SPINLOCK(insn_emulation_lock
);
65 static void register_emulation_hooks(struct insn_emulation_ops
*ops
)
67 struct undef_hook
*hook
;
71 for (hook
= ops
->hooks
; hook
->instr_mask
; hook
++)
72 register_undef_hook(hook
);
74 pr_notice("Registered %s emulation handler\n", ops
->name
);
77 static void remove_emulation_hooks(struct insn_emulation_ops
*ops
)
79 struct undef_hook
*hook
;
83 for (hook
= ops
->hooks
; hook
->instr_mask
; hook
++)
84 unregister_undef_hook(hook
);
86 pr_notice("Removed %s emulation handler\n", ops
->name
);
89 static void enable_insn_hw_mode(void *data
)
91 struct insn_emulation
*insn
= (struct insn_emulation
*)data
;
92 if (insn
->ops
->set_hw_mode
)
93 insn
->ops
->set_hw_mode(true);
96 static void disable_insn_hw_mode(void *data
)
98 struct insn_emulation
*insn
= (struct insn_emulation
*)data
;
99 if (insn
->ops
->set_hw_mode
)
100 insn
->ops
->set_hw_mode(false);
103 /* Run set_hw_mode(mode) on all active CPUs */
104 static int run_all_cpu_set_hw_mode(struct insn_emulation
*insn
, bool enable
)
106 if (!insn
->ops
->set_hw_mode
)
109 on_each_cpu(enable_insn_hw_mode
, (void *)insn
, true);
111 on_each_cpu(disable_insn_hw_mode
, (void *)insn
, true);
116 * Run set_hw_mode for all insns on a starting CPU.
118 * 0 - If all the hooks ran successfully.
119 * -EINVAL - At least one hook is not supported by the CPU.
121 static int run_all_insn_set_hw_mode(unsigned long cpu
)
125 struct insn_emulation
*insn
;
127 raw_spin_lock_irqsave(&insn_emulation_lock
, flags
);
128 list_for_each_entry(insn
, &insn_emulation
, node
) {
129 bool enable
= (insn
->current_mode
== INSN_HW
);
130 if (insn
->ops
->set_hw_mode
&& insn
->ops
->set_hw_mode(enable
)) {
131 pr_warn("CPU[%ld] cannot support the emulation of %s",
132 cpu
, insn
->ops
->name
);
136 raw_spin_unlock_irqrestore(&insn_emulation_lock
, flags
);
140 static int update_insn_emulation_mode(struct insn_emulation
*insn
,
141 enum insn_emulation_mode prev
)
146 case INSN_UNDEF
: /* Nothing to be done */
149 remove_emulation_hooks(insn
->ops
);
152 if (!run_all_cpu_set_hw_mode(insn
, false))
153 pr_notice("Disabled %s support\n", insn
->ops
->name
);
157 switch (insn
->current_mode
) {
161 register_emulation_hooks(insn
->ops
);
164 ret
= run_all_cpu_set_hw_mode(insn
, true);
166 pr_notice("Enabled %s support\n", insn
->ops
->name
);
173 static void register_insn_emulation(struct insn_emulation_ops
*ops
)
176 struct insn_emulation
*insn
;
178 insn
= kzalloc(sizeof(*insn
), GFP_KERNEL
);
180 insn
->min
= INSN_UNDEF
;
182 switch (ops
->status
) {
183 case INSN_DEPRECATED
:
184 insn
->current_mode
= INSN_EMULATE
;
185 /* Disable the HW mode if it was turned on at early boot time */
186 run_all_cpu_set_hw_mode(insn
, false);
190 insn
->current_mode
= INSN_UNDEF
;
191 insn
->max
= INSN_EMULATE
;
195 raw_spin_lock_irqsave(&insn_emulation_lock
, flags
);
196 list_add(&insn
->node
, &insn_emulation
);
198 raw_spin_unlock_irqrestore(&insn_emulation_lock
, flags
);
200 /* Register any handlers if required */
201 update_insn_emulation_mode(insn
, INSN_UNDEF
);
204 static int emulation_proc_handler(struct ctl_table
*table
, int write
,
205 void __user
*buffer
, size_t *lenp
,
209 struct insn_emulation
*insn
= (struct insn_emulation
*) table
->data
;
210 enum insn_emulation_mode prev_mode
= insn
->current_mode
;
212 table
->data
= &insn
->current_mode
;
213 ret
= proc_dointvec_minmax(table
, write
, buffer
, lenp
, ppos
);
215 if (ret
|| !write
|| prev_mode
== insn
->current_mode
)
218 ret
= update_insn_emulation_mode(insn
, prev_mode
);
220 /* Mode change failed, revert to previous mode. */
221 insn
->current_mode
= prev_mode
;
222 update_insn_emulation_mode(insn
, INSN_UNDEF
);
229 static struct ctl_table ctl_abi
[] = {
237 static void register_insn_emulation_sysctl(struct ctl_table
*table
)
241 struct insn_emulation
*insn
;
242 struct ctl_table
*insns_sysctl
, *sysctl
;
244 insns_sysctl
= kzalloc(sizeof(*sysctl
) * (nr_insn_emulated
+ 1),
247 raw_spin_lock_irqsave(&insn_emulation_lock
, flags
);
248 list_for_each_entry(insn
, &insn_emulation
, node
) {
249 sysctl
= &insns_sysctl
[i
];
252 sysctl
->maxlen
= sizeof(int);
254 sysctl
->procname
= insn
->ops
->name
;
256 sysctl
->extra1
= &insn
->min
;
257 sysctl
->extra2
= &insn
->max
;
258 sysctl
->proc_handler
= emulation_proc_handler
;
261 raw_spin_unlock_irqrestore(&insn_emulation_lock
, flags
);
263 table
->child
= insns_sysctl
;
264 register_sysctl_table(table
);
268 * Implement emulation of the SWP/SWPB instructions using load-exclusive and
271 * Syntax of SWP{B} instruction: SWP{B}<c> <Rt>, <Rt2>, [<Rn>]
272 * Where: Rt = destination
278 * Error-checking SWP macros implemented using ldxr{b}/stxr{b}
280 #define __user_swpX_asm(data, addr, res, temp, B) \
281 __asm__ __volatile__( \
283 "0: ldxr"B" %w1, [%3]\n" \
284 "1: stxr"B" %w0, %w2, [%3]\n" \
288 " .pushsection .fixup,\"ax\"\n" \
290 "3: mov %w0, %w5\n" \
293 " .pushsection __ex_table,\"a\"\n" \
298 : "=&r" (res), "+r" (data), "=&r" (temp) \
299 : "r" (addr), "i" (-EAGAIN), "i" (-EFAULT) \
302 #define __user_swp_asm(data, addr, res, temp) \
303 __user_swpX_asm(data, addr, res, temp, "")
304 #define __user_swpb_asm(data, addr, res, temp) \
305 __user_swpX_asm(data, addr, res, temp, "b")
308 * Bit 22 of the instruction encoding distinguishes between
309 * the SWP and SWPB variants (bit set means SWPB).
311 #define TYPE_SWPB (1 << 22)
314 * Set up process info to signal segmentation fault - called on access error.
316 static void set_segfault(struct pt_regs
*regs
, unsigned long addr
)
320 down_read(¤t
->mm
->mmap_sem
);
321 if (find_vma(current
->mm
, addr
) == NULL
)
322 info
.si_code
= SEGV_MAPERR
;
324 info
.si_code
= SEGV_ACCERR
;
325 up_read(¤t
->mm
->mmap_sem
);
327 info
.si_signo
= SIGSEGV
;
329 info
.si_addr
= (void *) instruction_pointer(regs
);
331 pr_debug("SWP{B} emulation: access caused memory abort!\n");
332 arm64_notify_die("Illegal memory access", regs
, &info
, 0);
335 static int emulate_swpX(unsigned int address
, unsigned int *data
,
338 unsigned int res
= 0;
340 if ((type
!= TYPE_SWPB
) && (address
& 0x3)) {
341 /* SWP to unaligned address not permitted */
342 pr_debug("SWP instruction on unaligned pointer!\n");
349 if (type
== TYPE_SWPB
)
350 __user_swpb_asm(*data
, address
, res
, temp
);
352 __user_swp_asm(*data
, address
, res
, temp
);
354 if (likely(res
!= -EAGAIN
) || signal_pending(current
))
364 * swp_handler logs the id of calling process, dissects the instruction, sanity
365 * checks the memory location, calls emulate_swpX for the actual operation and
366 * deals with fixup/error handling before returning
368 static int swp_handler(struct pt_regs
*regs
, u32 instr
)
370 u32 destreg
, data
, type
, address
= 0;
371 int rn
, rt2
, res
= 0;
373 perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS
, 1, regs
, regs
->pc
);
375 type
= instr
& TYPE_SWPB
;
377 switch (arm_check_condition(instr
, regs
->pstate
)) {
378 case ARM_OPCODE_CONDTEST_PASS
:
380 case ARM_OPCODE_CONDTEST_FAIL
:
381 /* Condition failed - return to next instruction */
383 case ARM_OPCODE_CONDTEST_UNCOND
:
384 /* If unconditional encoding - not a SWP, undef */
390 rn
= aarch32_insn_extract_reg_num(instr
, A32_RN_OFFSET
);
391 rt2
= aarch32_insn_extract_reg_num(instr
, A32_RT2_OFFSET
);
393 address
= (u32
)regs
->user_regs
.regs
[rn
];
394 data
= (u32
)regs
->user_regs
.regs
[rt2
];
395 destreg
= aarch32_insn_extract_reg_num(instr
, A32_RT_OFFSET
);
397 pr_debug("addr in r%d->0x%08x, dest is r%d, source in r%d->0x%08x)\n",
398 rn
, address
, destreg
,
399 aarch32_insn_extract_reg_num(instr
, A32_RT2_OFFSET
), data
);
401 /* Check access in reasonable access range for both SWP and SWPB */
402 if (!access_ok(VERIFY_WRITE
, (address
& ~3), 4)) {
403 pr_debug("SWP{B} emulation: access to 0x%08x not allowed!\n",
408 res
= emulate_swpX(address
, &data
, type
);
412 regs
->user_regs
.regs
[destreg
] = data
;
415 if (type
== TYPE_SWPB
)
416 trace_instruction_emulation("swpb", regs
->pc
);
418 trace_instruction_emulation("swp", regs
->pc
);
420 pr_warn_ratelimited("\"%s\" (%ld) uses obsolete SWP{B} instruction at 0x%llx\n",
421 current
->comm
, (unsigned long)current
->pid
, regs
->pc
);
427 set_segfault(regs
, address
);
433 * Only emulate SWP/SWPB executed in ARM state/User mode.
434 * The kernel must be SWP free and SWP{B} does not exist in Thumb.
436 static struct undef_hook swp_hooks
[] = {
438 .instr_mask
= 0x0fb00ff0,
439 .instr_val
= 0x01000090,
440 .pstate_mask
= COMPAT_PSR_MODE_MASK
,
441 .pstate_val
= COMPAT_PSR_MODE_USR
,
447 static struct insn_emulation_ops swp_ops
= {
449 .status
= INSN_OBSOLETE
,
454 static int cp15barrier_handler(struct pt_regs
*regs
, u32 instr
)
456 perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS
, 1, regs
, regs
->pc
);
458 switch (arm_check_condition(instr
, regs
->pstate
)) {
459 case ARM_OPCODE_CONDTEST_PASS
:
461 case ARM_OPCODE_CONDTEST_FAIL
:
462 /* Condition failed - return to next instruction */
464 case ARM_OPCODE_CONDTEST_UNCOND
:
465 /* If unconditional encoding - not a barrier instruction */
471 switch (aarch32_insn_mcr_extract_crm(instr
)) {
474 * dmb - mcr p15, 0, Rt, c7, c10, 5
475 * dsb - mcr p15, 0, Rt, c7, c10, 4
477 if (aarch32_insn_mcr_extract_opc2(instr
) == 5) {
479 trace_instruction_emulation(
480 "mcr p15, 0, Rt, c7, c10, 5 ; dmb", regs
->pc
);
483 trace_instruction_emulation(
484 "mcr p15, 0, Rt, c7, c10, 4 ; dsb", regs
->pc
);
489 * isb - mcr p15, 0, Rt, c7, c5, 4
491 * Taking an exception or returning from one acts as an
492 * instruction barrier. So no explicit barrier needed here.
494 trace_instruction_emulation(
495 "mcr p15, 0, Rt, c7, c5, 4 ; isb", regs
->pc
);
500 pr_warn_ratelimited("\"%s\" (%ld) uses deprecated CP15 Barrier instruction at 0x%llx\n",
501 current
->comm
, (unsigned long)current
->pid
, regs
->pc
);
507 static inline void config_sctlr_el1(u32 clear
, u32 set
)
511 asm volatile("mrs %0, sctlr_el1" : "=r" (val
));
514 asm volatile("msr sctlr_el1, %0" : : "r" (val
));
517 static int cp15_barrier_set_hw_mode(bool enable
)
520 config_sctlr_el1(0, SCTLR_EL1_CP15BEN
);
522 config_sctlr_el1(SCTLR_EL1_CP15BEN
, 0);
526 static struct undef_hook cp15_barrier_hooks
[] = {
528 .instr_mask
= 0x0fff0fdf,
529 .instr_val
= 0x0e070f9a,
530 .pstate_mask
= COMPAT_PSR_MODE_MASK
,
531 .pstate_val
= COMPAT_PSR_MODE_USR
,
532 .fn
= cp15barrier_handler
,
535 .instr_mask
= 0x0fff0fff,
536 .instr_val
= 0x0e070f95,
537 .pstate_mask
= COMPAT_PSR_MODE_MASK
,
538 .pstate_val
= COMPAT_PSR_MODE_USR
,
539 .fn
= cp15barrier_handler
,
544 static struct insn_emulation_ops cp15_barrier_ops
= {
545 .name
= "cp15_barrier",
546 .status
= INSN_DEPRECATED
,
547 .hooks
= cp15_barrier_hooks
,
548 .set_hw_mode
= cp15_barrier_set_hw_mode
,
551 static int setend_set_hw_mode(bool enable
)
553 if (!cpu_supports_mixed_endian_el0())
557 config_sctlr_el1(SCTLR_EL1_SED
, 0);
559 config_sctlr_el1(0, SCTLR_EL1_SED
);
563 static int compat_setend_handler(struct pt_regs
*regs
, u32 big_endian
)
567 perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS
, 1, regs
, regs
->pc
);
571 regs
->pstate
|= COMPAT_PSR_E_BIT
;
574 regs
->pstate
&= ~COMPAT_PSR_E_BIT
;
577 trace_instruction_emulation(insn
, regs
->pc
);
578 pr_warn_ratelimited("\"%s\" (%ld) uses deprecated setend instruction at 0x%llx\n",
579 current
->comm
, (unsigned long)current
->pid
, regs
->pc
);
584 static int a32_setend_handler(struct pt_regs
*regs
, u32 instr
)
586 int rc
= compat_setend_handler(regs
, (instr
>> 9) & 1);
591 static int t16_setend_handler(struct pt_regs
*regs
, u32 instr
)
593 int rc
= compat_setend_handler(regs
, (instr
>> 3) & 1);
598 static struct undef_hook setend_hooks
[] = {
600 .instr_mask
= 0xfffffdff,
601 .instr_val
= 0xf1010000,
602 .pstate_mask
= COMPAT_PSR_MODE_MASK
,
603 .pstate_val
= COMPAT_PSR_MODE_USR
,
604 .fn
= a32_setend_handler
,
608 .instr_mask
= 0x0000fff7,
609 .instr_val
= 0x0000b650,
610 .pstate_mask
= (COMPAT_PSR_T_BIT
| COMPAT_PSR_MODE_MASK
),
611 .pstate_val
= (COMPAT_PSR_T_BIT
| COMPAT_PSR_MODE_USR
),
612 .fn
= t16_setend_handler
,
617 static struct insn_emulation_ops setend_ops
= {
619 .status
= INSN_DEPRECATED
,
620 .hooks
= setend_hooks
,
621 .set_hw_mode
= setend_set_hw_mode
,
624 static int insn_cpu_hotplug_notify(struct notifier_block
*b
,
625 unsigned long action
, void *hcpu
)
628 if ((action
& ~CPU_TASKS_FROZEN
) == CPU_STARTING
)
629 rc
= run_all_insn_set_hw_mode((unsigned long)hcpu
);
631 return notifier_from_errno(rc
);
634 static struct notifier_block insn_cpu_hotplug_notifier
= {
635 .notifier_call
= insn_cpu_hotplug_notify
,
639 * Invoked as late_initcall, since not needed before init spawned.
641 static int __init
armv8_deprecated_init(void)
643 if (IS_ENABLED(CONFIG_SWP_EMULATION
))
644 register_insn_emulation(&swp_ops
);
646 if (IS_ENABLED(CONFIG_CP15_BARRIER_EMULATION
))
647 register_insn_emulation(&cp15_barrier_ops
);
649 if (IS_ENABLED(CONFIG_SETEND_EMULATION
)) {
650 if(system_supports_mixed_endian_el0())
651 register_insn_emulation(&setend_ops
);
653 pr_info("setend instruction emulation is not supported on the system");
656 register_cpu_notifier(&insn_cpu_hotplug_notifier
);
657 register_insn_emulation_sysctl(ctl_abi
);
662 late_initcall(armv8_deprecated_init
);