2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License version 2 as
4 * published by the Free Software Foundation.
6 * This program is distributed in the hope that it will be useful,
7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 * GNU General Public License for more details.
11 * You should have received a copy of the GNU General Public License
12 * along with this program; if not, write to the Free Software
13 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
15 * Copyright (C) 2009, 2010 ARM Limited
17 * Author: Will Deacon <will.deacon@arm.com>
21 * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility,
22 * using the CPU's debug registers.
24 #define pr_fmt(fmt) "hw-breakpoint: " fmt
26 #include <linux/errno.h>
27 #include <linux/hardirq.h>
28 #include <linux/perf_event.h>
29 #include <linux/hw_breakpoint.h>
30 #include <linux/smp.h>
32 #include <asm/cacheflush.h>
33 #include <asm/cputype.h>
34 #include <asm/current.h>
35 #include <asm/hw_breakpoint.h>
36 #include <asm/kdebug.h>
37 #include <asm/system.h>
38 #include <asm/traps.h>
40 /* Breakpoint currently in use for each BRP. */
41 static DEFINE_PER_CPU(struct perf_event
*, bp_on_reg
[ARM_MAX_BRP
]);
43 /* Watchpoint currently in use for each WRP. */
44 static DEFINE_PER_CPU(struct perf_event
*, wp_on_reg
[ARM_MAX_WRP
]);
46 /* Number of BRP/WRP registers on this CPU. */
47 static int core_num_brps
;
48 static int core_num_reserved_brps
;
49 static int core_num_wrps
;
51 /* Debug architecture version. */
54 /* Maximum supported watchpoint length. */
55 static u8 max_watchpoint_len
;
57 #define READ_WB_REG_CASE(OP2, M, VAL) \
58 case ((OP2 << 4) + M): \
59 ARM_DBG_READ(c ## M, OP2, VAL); \
62 #define WRITE_WB_REG_CASE(OP2, M, VAL) \
63 case ((OP2 << 4) + M): \
64 ARM_DBG_WRITE(c ## M, OP2, VAL);\
67 #define GEN_READ_WB_REG_CASES(OP2, VAL) \
68 READ_WB_REG_CASE(OP2, 0, VAL); \
69 READ_WB_REG_CASE(OP2, 1, VAL); \
70 READ_WB_REG_CASE(OP2, 2, VAL); \
71 READ_WB_REG_CASE(OP2, 3, VAL); \
72 READ_WB_REG_CASE(OP2, 4, VAL); \
73 READ_WB_REG_CASE(OP2, 5, VAL); \
74 READ_WB_REG_CASE(OP2, 6, VAL); \
75 READ_WB_REG_CASE(OP2, 7, VAL); \
76 READ_WB_REG_CASE(OP2, 8, VAL); \
77 READ_WB_REG_CASE(OP2, 9, VAL); \
78 READ_WB_REG_CASE(OP2, 10, VAL); \
79 READ_WB_REG_CASE(OP2, 11, VAL); \
80 READ_WB_REG_CASE(OP2, 12, VAL); \
81 READ_WB_REG_CASE(OP2, 13, VAL); \
82 READ_WB_REG_CASE(OP2, 14, VAL); \
83 READ_WB_REG_CASE(OP2, 15, VAL)
85 #define GEN_WRITE_WB_REG_CASES(OP2, VAL) \
86 WRITE_WB_REG_CASE(OP2, 0, VAL); \
87 WRITE_WB_REG_CASE(OP2, 1, VAL); \
88 WRITE_WB_REG_CASE(OP2, 2, VAL); \
89 WRITE_WB_REG_CASE(OP2, 3, VAL); \
90 WRITE_WB_REG_CASE(OP2, 4, VAL); \
91 WRITE_WB_REG_CASE(OP2, 5, VAL); \
92 WRITE_WB_REG_CASE(OP2, 6, VAL); \
93 WRITE_WB_REG_CASE(OP2, 7, VAL); \
94 WRITE_WB_REG_CASE(OP2, 8, VAL); \
95 WRITE_WB_REG_CASE(OP2, 9, VAL); \
96 WRITE_WB_REG_CASE(OP2, 10, VAL); \
97 WRITE_WB_REG_CASE(OP2, 11, VAL); \
98 WRITE_WB_REG_CASE(OP2, 12, VAL); \
99 WRITE_WB_REG_CASE(OP2, 13, VAL); \
100 WRITE_WB_REG_CASE(OP2, 14, VAL); \
101 WRITE_WB_REG_CASE(OP2, 15, VAL)
103 static u32
read_wb_reg(int n
)
108 GEN_READ_WB_REG_CASES(ARM_OP2_BVR
, val
);
109 GEN_READ_WB_REG_CASES(ARM_OP2_BCR
, val
);
110 GEN_READ_WB_REG_CASES(ARM_OP2_WVR
, val
);
111 GEN_READ_WB_REG_CASES(ARM_OP2_WCR
, val
);
113 pr_warning("attempt to read from unknown breakpoint "
120 static void write_wb_reg(int n
, u32 val
)
123 GEN_WRITE_WB_REG_CASES(ARM_OP2_BVR
, val
);
124 GEN_WRITE_WB_REG_CASES(ARM_OP2_BCR
, val
);
125 GEN_WRITE_WB_REG_CASES(ARM_OP2_WVR
, val
);
126 GEN_WRITE_WB_REG_CASES(ARM_OP2_WCR
, val
);
128 pr_warning("attempt to write to unknown breakpoint "
134 /* Determine debug architecture. */
135 static u8
get_debug_arch(void)
139 /* Do we implement the extended CPUID interface? */
140 if (((read_cpuid_id() >> 16) & 0xf) != 0xf) {
141 pr_warning("CPUID feature registers not supported. "
142 "Assuming v6 debug is present.\n");
143 return ARM_DEBUG_ARCH_V6
;
146 ARM_DBG_READ(c0
, 0, didr
);
147 return (didr
>> 16) & 0xf;
150 u8
arch_get_debug_arch(void)
155 /* Determine number of BRP register available. */
156 static int get_num_brp_resources(void)
159 ARM_DBG_READ(c0
, 0, didr
);
160 return ((didr
>> 24) & 0xf) + 1;
163 /* Does this core support mismatch breakpoints? */
164 static int core_has_mismatch_brps(void)
166 return (get_debug_arch() >= ARM_DEBUG_ARCH_V7_ECP14
&&
167 get_num_brp_resources() > 1);
170 /* Determine number of usable WRPs available. */
171 static int get_num_wrps(void)
174 * FIXME: When a watchpoint fires, the only way to work out which
175 * watchpoint it was is by disassembling the faulting instruction
176 * and working out the address of the memory access.
178 * Furthermore, we can only do this if the watchpoint was precise
179 * since imprecise watchpoints prevent us from calculating register
182 * Providing we have more than 1 breakpoint register, we only report
183 * a single watchpoint register for the time being. This way, we always
184 * know which watchpoint fired. In the future we can either add a
185 * disassembler and address generation emulator, or we can insert a
186 * check to see if the DFAR is set on watchpoint exception entry
187 * [the ARM ARM states that the DFAR is UNKNOWN, but experience shows
188 * that it is set on some implementations].
194 ARM_DBG_READ(c0
, 0, didr
);
195 wrps
= ((didr
>> 28) & 0xf) + 1;
199 if (core_has_mismatch_brps() && wrps
>= get_num_brp_resources())
200 wrps
= get_num_brp_resources() - 1;
205 /* We reserve one breakpoint for each watchpoint. */
206 static int get_num_reserved_brps(void)
208 if (core_has_mismatch_brps())
209 return get_num_wrps();
213 /* Determine number of usable BRPs available. */
214 static int get_num_brps(void)
216 int brps
= get_num_brp_resources();
217 if (core_has_mismatch_brps())
218 brps
-= get_num_reserved_brps();
222 int hw_breakpoint_slots(int type
)
225 * We can be called early, so don't rely on
226 * our static variables being initialised.
230 return get_num_brps();
232 return get_num_wrps();
234 pr_warning("unknown slot type: %d\n", type
);
240 * In order to access the breakpoint/watchpoint control registers,
241 * we must be running in debug monitor mode. Unfortunately, we can
242 * be put into halting debug mode at any time by an external debugger
243 * but there is nothing we can do to prevent that.
245 static int enable_monitor_mode(void)
250 ARM_DBG_READ(c1
, 0, dscr
);
252 /* Ensure that halting mode is disabled. */
253 if (WARN_ONCE(dscr
& ARM_DSCR_HDBGEN
, "halting debug mode enabled."
254 "Unable to access hardware resources.")) {
259 /* Write to the corresponding DSCR. */
260 switch (debug_arch
) {
261 case ARM_DEBUG_ARCH_V6
:
262 case ARM_DEBUG_ARCH_V6_1
:
263 ARM_DBG_WRITE(c1
, 0, (dscr
| ARM_DSCR_MDBGEN
));
265 case ARM_DEBUG_ARCH_V7_ECP14
:
266 ARM_DBG_WRITE(c2
, 2, (dscr
| ARM_DSCR_MDBGEN
));
273 /* Check that the write made it through. */
274 ARM_DBG_READ(c1
, 0, dscr
);
275 if (WARN_ONCE(!(dscr
& ARM_DSCR_MDBGEN
),
276 "failed to enable monitor mode.")) {
285 * Check if 8-bit byte-address select is available.
286 * This clobbers WRP 0.
288 static u8
get_max_wp_len(void)
291 struct arch_hw_breakpoint_ctrl ctrl
;
294 if (debug_arch
< ARM_DEBUG_ARCH_V7_ECP14
)
297 if (enable_monitor_mode())
300 memset(&ctrl
, 0, sizeof(ctrl
));
301 ctrl
.len
= ARM_BREAKPOINT_LEN_8
;
302 ctrl_reg
= encode_ctrl_reg(ctrl
);
304 write_wb_reg(ARM_BASE_WVR
, 0);
305 write_wb_reg(ARM_BASE_WCR
, ctrl_reg
);
306 if ((read_wb_reg(ARM_BASE_WCR
) & ctrl_reg
) == ctrl_reg
)
313 u8
arch_get_max_wp_len(void)
315 return max_watchpoint_len
;
319 * Handler for reactivating a suspended watchpoint when the single
320 * step `mismatch' breakpoint is triggered.
322 static void wp_single_step_handler(struct perf_event
*bp
, int unused
,
323 struct perf_sample_data
*data
,
324 struct pt_regs
*regs
)
326 perf_event_enable(counter_arch_bp(bp
)->suspended_wp
);
327 unregister_hw_breakpoint(bp
);
330 static int bp_is_single_step(struct perf_event
*bp
)
332 return bp
->overflow_handler
== wp_single_step_handler
;
336 * Install a perf counter breakpoint.
338 int arch_install_hw_breakpoint(struct perf_event
*bp
)
340 struct arch_hw_breakpoint
*info
= counter_arch_bp(bp
);
341 struct perf_event
**slot
, **slots
;
342 int i
, max_slots
, ctrl_base
, val_base
, ret
= 0;
344 /* Ensure that we are in monitor mode and halting mode is disabled. */
345 ret
= enable_monitor_mode();
349 if (info
->ctrl
.type
== ARM_BREAKPOINT_EXECUTE
) {
351 ctrl_base
= ARM_BASE_BCR
;
352 val_base
= ARM_BASE_BVR
;
353 slots
= __get_cpu_var(bp_on_reg
);
354 max_slots
= core_num_brps
;
356 if (bp_is_single_step(bp
)) {
357 info
->ctrl
.mismatch
= 1;
364 ctrl_base
= ARM_BASE_WCR
;
365 val_base
= ARM_BASE_WVR
;
366 slots
= __get_cpu_var(wp_on_reg
);
367 max_slots
= core_num_wrps
;
370 for (i
= 0; i
< max_slots
; ++i
) {
379 if (WARN_ONCE(i
== max_slots
, "Can't find any breakpoint slot")) {
385 /* Setup the address register. */
386 write_wb_reg(val_base
+ i
, info
->address
);
388 /* Setup the control register. */
389 write_wb_reg(ctrl_base
+ i
, encode_ctrl_reg(info
->ctrl
) | 0x1);
395 void arch_uninstall_hw_breakpoint(struct perf_event
*bp
)
397 struct arch_hw_breakpoint
*info
= counter_arch_bp(bp
);
398 struct perf_event
**slot
, **slots
;
399 int i
, max_slots
, base
;
401 if (info
->ctrl
.type
== ARM_BREAKPOINT_EXECUTE
) {
404 slots
= __get_cpu_var(bp_on_reg
);
405 max_slots
= core_num_brps
;
407 if (bp_is_single_step(bp
)) {
415 slots
= __get_cpu_var(wp_on_reg
);
416 max_slots
= core_num_wrps
;
419 /* Remove the breakpoint. */
420 for (i
= 0; i
< max_slots
; ++i
) {
429 if (WARN_ONCE(i
== max_slots
, "Can't find any breakpoint slot"))
433 /* Reset the control register. */
434 write_wb_reg(base
+ i
, 0);
437 static int get_hbp_len(u8 hbp_len
)
439 unsigned int len_in_bytes
= 0;
442 case ARM_BREAKPOINT_LEN_1
:
445 case ARM_BREAKPOINT_LEN_2
:
448 case ARM_BREAKPOINT_LEN_4
:
451 case ARM_BREAKPOINT_LEN_8
:
460 * Check whether bp virtual address is in kernel space.
462 int arch_check_bp_in_kernelspace(struct perf_event
*bp
)
466 struct arch_hw_breakpoint
*info
= counter_arch_bp(bp
);
469 len
= get_hbp_len(info
->ctrl
.len
);
471 return (va
>= TASK_SIZE
) && ((va
+ len
- 1) >= TASK_SIZE
);
475 * Extract generic type and length encodings from an arch_hw_breakpoint_ctrl.
476 * Hopefully this will disappear when ptrace can bypass the conversion
477 * to generic breakpoint descriptions.
479 int arch_bp_generic_fields(struct arch_hw_breakpoint_ctrl ctrl
,
480 int *gen_len
, int *gen_type
)
484 case ARM_BREAKPOINT_EXECUTE
:
485 *gen_type
= HW_BREAKPOINT_X
;
487 case ARM_BREAKPOINT_LOAD
:
488 *gen_type
= HW_BREAKPOINT_R
;
490 case ARM_BREAKPOINT_STORE
:
491 *gen_type
= HW_BREAKPOINT_W
;
493 case ARM_BREAKPOINT_LOAD
| ARM_BREAKPOINT_STORE
:
494 *gen_type
= HW_BREAKPOINT_RW
;
502 case ARM_BREAKPOINT_LEN_1
:
503 *gen_len
= HW_BREAKPOINT_LEN_1
;
505 case ARM_BREAKPOINT_LEN_2
:
506 *gen_len
= HW_BREAKPOINT_LEN_2
;
508 case ARM_BREAKPOINT_LEN_4
:
509 *gen_len
= HW_BREAKPOINT_LEN_4
;
511 case ARM_BREAKPOINT_LEN_8
:
512 *gen_len
= HW_BREAKPOINT_LEN_8
;
522 * Construct an arch_hw_breakpoint from a perf_event.
524 static int arch_build_bp_info(struct perf_event
*bp
)
526 struct arch_hw_breakpoint
*info
= counter_arch_bp(bp
);
529 switch (bp
->attr
.bp_type
) {
530 case HW_BREAKPOINT_X
:
531 info
->ctrl
.type
= ARM_BREAKPOINT_EXECUTE
;
533 case HW_BREAKPOINT_R
:
534 info
->ctrl
.type
= ARM_BREAKPOINT_LOAD
;
536 case HW_BREAKPOINT_W
:
537 info
->ctrl
.type
= ARM_BREAKPOINT_STORE
;
539 case HW_BREAKPOINT_RW
:
540 info
->ctrl
.type
= ARM_BREAKPOINT_LOAD
| ARM_BREAKPOINT_STORE
;
547 switch (bp
->attr
.bp_len
) {
548 case HW_BREAKPOINT_LEN_1
:
549 info
->ctrl
.len
= ARM_BREAKPOINT_LEN_1
;
551 case HW_BREAKPOINT_LEN_2
:
552 info
->ctrl
.len
= ARM_BREAKPOINT_LEN_2
;
554 case HW_BREAKPOINT_LEN_4
:
555 info
->ctrl
.len
= ARM_BREAKPOINT_LEN_4
;
557 case HW_BREAKPOINT_LEN_8
:
558 info
->ctrl
.len
= ARM_BREAKPOINT_LEN_8
;
559 if ((info
->ctrl
.type
!= ARM_BREAKPOINT_EXECUTE
)
560 && max_watchpoint_len
>= 8)
567 * Breakpoints must be of length 2 (thumb) or 4 (ARM) bytes.
568 * Watchpoints can be of length 1, 2, 4 or 8 bytes if supported
569 * by the hardware and must be aligned to the appropriate number of
572 if (info
->ctrl
.type
== ARM_BREAKPOINT_EXECUTE
&&
573 info
->ctrl
.len
!= ARM_BREAKPOINT_LEN_2
&&
574 info
->ctrl
.len
!= ARM_BREAKPOINT_LEN_4
)
578 info
->address
= bp
->attr
.bp_addr
;
581 info
->ctrl
.privilege
= ARM_BREAKPOINT_USER
;
582 if (arch_check_bp_in_kernelspace(bp
) && !bp_is_single_step(bp
))
583 info
->ctrl
.privilege
|= ARM_BREAKPOINT_PRIV
;
586 info
->ctrl
.enabled
= !bp
->attr
.disabled
;
589 info
->ctrl
.mismatch
= 0;
595 * Validate the arch-specific HW Breakpoint register settings.
597 int arch_validate_hwbkpt_settings(struct perf_event
*bp
)
599 struct arch_hw_breakpoint
*info
= counter_arch_bp(bp
);
601 u32 offset
, alignment_mask
= 0x3;
603 /* Build the arch_hw_breakpoint. */
604 ret
= arch_build_bp_info(bp
);
608 /* Check address alignment. */
609 if (info
->ctrl
.len
== ARM_BREAKPOINT_LEN_8
)
610 alignment_mask
= 0x7;
611 offset
= info
->address
& alignment_mask
;
617 /* Allow single byte watchpoint. */
618 if (info
->ctrl
.len
== ARM_BREAKPOINT_LEN_1
)
621 /* Allow halfword watchpoints and breakpoints. */
622 if (info
->ctrl
.len
== ARM_BREAKPOINT_LEN_2
)
629 info
->address
&= ~alignment_mask
;
630 info
->ctrl
.len
<<= offset
;
633 * Currently we rely on an overflow handler to take
634 * care of single-stepping the breakpoint when it fires.
635 * In the case of userspace breakpoints on a core with V7 debug,
636 * we can use the mismatch feature as a poor-man's hardware single-step.
638 if (WARN_ONCE(!bp
->overflow_handler
&&
639 (arch_check_bp_in_kernelspace(bp
) || !core_has_mismatch_brps()),
640 "overflow handler required but none found")) {
647 static void update_mismatch_flag(int idx
, int flag
)
649 struct perf_event
*bp
= __get_cpu_var(bp_on_reg
[idx
]);
650 struct arch_hw_breakpoint
*info
;
655 info
= counter_arch_bp(bp
);
657 /* Update the mismatch field to enter/exit `single-step' mode */
658 if (!bp
->overflow_handler
&& info
->ctrl
.mismatch
!= flag
) {
659 info
->ctrl
.mismatch
= flag
;
660 write_wb_reg(ARM_BASE_BCR
+ idx
, encode_ctrl_reg(info
->ctrl
) | 0x1);
664 static void watchpoint_handler(unsigned long unknown
, struct pt_regs
*regs
)
667 struct perf_event
*bp
, **slots
= __get_cpu_var(wp_on_reg
);
668 struct arch_hw_breakpoint
*info
;
669 struct perf_event_attr attr
;
671 /* Without a disassembler, we can only handle 1 watchpoint. */
672 BUG_ON(core_num_wrps
> 1);
674 hw_breakpoint_init(&attr
);
675 attr
.bp_addr
= regs
->ARM_pc
& ~0x3;
676 attr
.bp_len
= HW_BREAKPOINT_LEN_4
;
677 attr
.bp_type
= HW_BREAKPOINT_X
;
679 for (i
= 0; i
< core_num_wrps
; ++i
) {
682 if (slots
[i
] == NULL
) {
688 * The DFAR is an unknown value. Since we only allow a
689 * single watchpoint, we can set the trigger to the lowest
690 * possible faulting address.
692 info
= counter_arch_bp(slots
[i
]);
693 info
->trigger
= slots
[i
]->attr
.bp_addr
;
694 pr_debug("watchpoint fired: address = 0x%x\n", info
->trigger
);
695 perf_bp_event(slots
[i
], regs
);
698 * If no overflow handler is present, insert a temporary
699 * mismatch breakpoint so we can single-step over the
700 * watchpoint trigger.
702 if (!slots
[i
]->overflow_handler
) {
703 bp
= register_user_hw_breakpoint(&attr
,
704 wp_single_step_handler
,
706 counter_arch_bp(bp
)->suspended_wp
= slots
[i
];
707 perf_event_disable(slots
[i
]);
714 static void breakpoint_handler(unsigned long unknown
, struct pt_regs
*regs
)
718 u32 ctrl_reg
, val
, addr
;
719 struct perf_event
*bp
, **slots
= __get_cpu_var(bp_on_reg
);
720 struct arch_hw_breakpoint
*info
;
721 struct arch_hw_breakpoint_ctrl ctrl
;
723 /* The exception entry code places the amended lr in the PC. */
726 for (i
= 0; i
< core_num_brps
+ core_num_reserved_brps
; ++i
) {
738 /* Check if the breakpoint value matches. */
739 val
= read_wb_reg(ARM_BASE_BVR
+ i
);
740 if (val
!= (addr
& ~0x3))
743 /* Possible match, check the byte address select to confirm. */
744 ctrl_reg
= read_wb_reg(ARM_BASE_BCR
+ i
);
745 decode_ctrl_reg(ctrl_reg
, &ctrl
);
746 if ((1 << (addr
& 0x3)) & ctrl
.len
) {
748 info
= counter_arch_bp(bp
);
749 info
->trigger
= addr
;
753 if ((mismatch
&& !info
->ctrl
.mismatch
) || bp_is_single_step(bp
)) {
754 pr_debug("breakpoint fired: address = 0x%x\n", addr
);
755 perf_bp_event(bp
, regs
);
758 update_mismatch_flag(i
, mismatch
);
764 * Called from either the Data Abort Handler [watchpoint] or the
765 * Prefetch Abort Handler [breakpoint] with preemption disabled.
767 static int hw_breakpoint_pending(unsigned long addr
, unsigned int fsr
,
768 struct pt_regs
*regs
)
773 /* We must be called with preemption disabled. */
774 WARN_ON(preemptible());
776 /* We only handle watchpoints and hardware breakpoints. */
777 ARM_DBG_READ(c1
, 0, dscr
);
779 /* Perform perf callbacks. */
780 switch (ARM_DSCR_MOE(dscr
)) {
781 case ARM_ENTRY_BREAKPOINT
:
782 breakpoint_handler(addr
, regs
);
784 case ARM_ENTRY_ASYNC_WATCHPOINT
:
785 WARN(1, "Asynchronous watchpoint exception taken. Debugging results may be unreliable\n");
786 case ARM_ENTRY_SYNC_WATCHPOINT
:
787 watchpoint_handler(addr
, regs
);
790 ret
= 1; /* Unhandled fault. */
794 * Re-enable preemption after it was disabled in the
795 * low-level exception handling code.
803 * One-time initialisation.
805 static void reset_ctrl_regs(void *unused
)
810 * v7 debug contains save and restore registers so that debug state
811 * can be maintained across low-power modes without leaving
812 * the debug logic powered up. It is IMPLEMENTATION DEFINED whether
813 * we can write to the debug registers out of reset, so we must
814 * unlock the OS Lock Access Register to avoid taking undefined
815 * instruction exceptions later on.
817 if (debug_arch
>= ARM_DEBUG_ARCH_V7_ECP14
) {
819 * Unconditionally clear the lock by writing a value
820 * other than 0xC5ACCE55 to the access register.
822 asm volatile("mcr p14, 0, %0, c1, c0, 4" : : "r" (0));
826 if (enable_monitor_mode())
829 /* We must also reset any reserved registers. */
830 for (i
= 0; i
< core_num_brps
+ core_num_reserved_brps
; ++i
) {
831 write_wb_reg(ARM_BASE_BCR
+ i
, 0UL);
832 write_wb_reg(ARM_BASE_BVR
+ i
, 0UL);
835 for (i
= 0; i
< core_num_wrps
; ++i
) {
836 write_wb_reg(ARM_BASE_WCR
+ i
, 0UL);
837 write_wb_reg(ARM_BASE_WVR
+ i
, 0UL);
841 static int __cpuinit
dbg_reset_notify(struct notifier_block
*self
,
842 unsigned long action
, void *cpu
)
844 if (action
== CPU_ONLINE
)
845 smp_call_function_single((int)cpu
, reset_ctrl_regs
, NULL
, 1);
849 static struct notifier_block __cpuinitdata dbg_reset_nb
= {
850 .notifier_call
= dbg_reset_notify
,
853 static int __init
arch_hw_breakpoint_init(void)
858 debug_arch
= get_debug_arch();
860 if (debug_arch
> ARM_DEBUG_ARCH_V7_ECP14
) {
861 pr_info("debug architecture 0x%x unsupported.\n", debug_arch
);
866 /* Determine how many BRPs/WRPs are available. */
867 core_num_brps
= get_num_brps();
868 core_num_reserved_brps
= get_num_reserved_brps();
869 core_num_wrps
= get_num_wrps();
871 pr_info("found %d breakpoint and %d watchpoint registers.\n",
872 core_num_brps
+ core_num_reserved_brps
, core_num_wrps
);
874 if (core_num_reserved_brps
)
875 pr_info("%d breakpoint(s) reserved for watchpoint "
876 "single-step.\n", core_num_reserved_brps
);
878 ARM_DBG_READ(c1
, 0, dscr
);
879 if (dscr
& ARM_DSCR_HDBGEN
) {
880 pr_warning("halting debug mode enabled. Assuming maximum "
881 "watchpoint size of 4 bytes.");
884 * Reset the breakpoint resources. We assume that a halting
885 * debugger will leave the world in a nice state for us.
887 smp_call_function(reset_ctrl_regs
, NULL
, 1);
888 reset_ctrl_regs(NULL
);
890 /* Work out the maximum supported watchpoint length. */
891 max_watchpoint_len
= get_max_wp_len();
892 pr_info("maximum watchpoint size is %u bytes.\n",
896 /* Register debug fault handler. */
897 hook_fault_code(2, hw_breakpoint_pending
, SIGTRAP
, TRAP_HWBKPT
,
898 "watchpoint debug exception");
899 hook_ifault_code(2, hw_breakpoint_pending
, SIGTRAP
, TRAP_HWBKPT
,
900 "breakpoint debug exception");
902 /* Register hotplug notifier. */
903 register_cpu_notifier(&dbg_reset_nb
);
907 arch_initcall(arch_hw_breakpoint_init
);
909 void hw_breakpoint_pmu_read(struct perf_event
*bp
)
914 * Dummy function to register with die_notifier.
916 int hw_breakpoint_exceptions_notify(struct notifier_block
*unused
,
917 unsigned long val
, void *data
)