2 * Copyright (C) 2009 by David Brownell
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the
16 * Free Software Foundation, Inc.,
17 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
26 #include <jtag/jtag.h>
28 #include "breakpoints.h"
29 #include "target_type.h"
30 #include "arm_opcodes.h"
35 * Implements various ARM DPM operations using architectural debug registers.
36 * These routines layer over core-specific communication methods to cope with
37 * implementation differences between cores like ARM1136 and Cortex-A8.
40 /*----------------------------------------------------------------------*/
46 /* Read coprocessor */
47 static int dpm_mrc(struct target
*target
, int cpnum
,
48 uint32_t op1
, uint32_t op2
, uint32_t CRn
, uint32_t CRm
,
51 struct arm
*arm
= target_to_arm(target
);
52 struct arm_dpm
*dpm
= arm
->dpm
;
55 retval
= dpm
->prepare(dpm
);
56 if (retval
!= ERROR_OK
)
59 LOG_DEBUG("MRC p%d, %d, r0, c%d, c%d, %d", cpnum
,
61 (int) CRm
, (int) op2
);
63 /* read coprocessor register into R0; return via DCC */
64 retval
= dpm
->instr_read_data_r0(dpm
,
65 ARMV4_5_MRC(cpnum
, op1
, 0, CRn
, CRm
, op2
),
68 /* (void) */ dpm
->finish(dpm
);
72 static int dpm_mcr(struct target
*target
, int cpnum
,
73 uint32_t op1
, uint32_t op2
, uint32_t CRn
, uint32_t CRm
,
76 struct arm
*arm
= target_to_arm(target
);
77 struct arm_dpm
*dpm
= arm
->dpm
;
80 retval
= dpm
->prepare(dpm
);
81 if (retval
!= ERROR_OK
)
84 LOG_DEBUG("MCR p%d, %d, r0, c%d, c%d, %d", cpnum
,
86 (int) CRm
, (int) op2
);
88 /* read DCC into r0; then write coprocessor register from R0 */
89 retval
= dpm
->instr_write_data_r0(dpm
,
90 ARMV4_5_MCR(cpnum
, op1
, 0, CRn
, CRm
, op2
),
93 /* (void) */ dpm
->finish(dpm
);
97 /*----------------------------------------------------------------------*/
100 * Register access utilities
103 /* Toggles between recorded core mode (USR, SVC, etc) and a temporary one.
104 * Routines *must* restore the original mode before returning!!
106 static int dpm_modeswitch(struct arm_dpm
*dpm
, enum arm_mode mode
)
111 /* restore previous mode */
112 if (mode
== ARM_MODE_ANY
)
113 cpsr
= buf_get_u32(dpm
->arm
->cpsr
->value
, 0, 32);
115 /* else force to the specified mode */
119 retval
= dpm
->instr_write_data_r0(dpm
, ARMV4_5_MSR_GP(0, 0xf, 0), cpsr
);
121 if (dpm
->instr_cpsr_sync
)
122 retval
= dpm
->instr_cpsr_sync(dpm
);
127 /* just read the register -- rely on the core mode being right */
128 static int dpm_read_reg(struct arm_dpm
*dpm
, struct reg
*r
, unsigned regnum
)
135 /* return via DCC: "MCR p14, 0, Rnum, c0, c5, 0" */
136 retval
= dpm
->instr_read_data_dcc(dpm
,
137 ARMV4_5_MCR(14, 0, regnum
, 0, 5, 0),
141 /* "MOV r0, pc"; then return via DCC */
142 retval
= dpm
->instr_read_data_r0(dpm
, 0xe1a0000f, &value
);
144 /* NOTE: this seems like a slightly awkward place to update
145 * this value ... but if the PC gets written (the only way
146 * to change what we compute), the arch spec says subsequent
147 * reads return values which are "unpredictable". So this
148 * is always right except in those broken-by-intent cases.
150 switch (dpm
->arm
->core_state
) {
154 case ARM_STATE_THUMB
:
155 case ARM_STATE_THUMB_EE
:
158 case ARM_STATE_JAZELLE
:
159 /* core-specific ... ? */
160 LOG_WARNING("Jazelle PC adjustment unknown");
165 /* 16: "MRS r0, CPSR"; then return via DCC
166 * 17: "MRS r0, SPSR"; then return via DCC
168 retval
= dpm
->instr_read_data_r0(dpm
,
169 ARMV4_5_MRS(0, regnum
& 1),
174 if (retval
== ERROR_OK
) {
175 buf_set_u32(r
->value
, 0, 32, value
);
178 LOG_DEBUG("READ: %s, %8.8x", r
->name
, (unsigned) value
);
184 /* just write the register -- rely on the core mode being right */
185 static int dpm_write_reg(struct arm_dpm
*dpm
, struct reg
*r
, unsigned regnum
)
188 uint32_t value
= buf_get_u32(r
->value
, 0, 32);
192 /* load register from DCC: "MRC p14, 0, Rnum, c0, c5, 0" */
193 retval
= dpm
->instr_write_data_dcc(dpm
,
194 ARMV4_5_MRC(14, 0, regnum
, 0, 5, 0),
198 /* read r0 from DCC; then "MOV pc, r0" */
199 retval
= dpm
->instr_write_data_r0(dpm
, 0xe1a0f000, value
);
202 /* 16: read r0 from DCC, then "MSR r0, CPSR_cxsf"
203 * 17: read r0 from DCC, then "MSR r0, SPSR_cxsf"
205 retval
= dpm
->instr_write_data_r0(dpm
,
206 ARMV4_5_MSR_GP(0, 0xf, regnum
& 1),
209 if (regnum
== 16 && dpm
->instr_cpsr_sync
)
210 retval
= dpm
->instr_cpsr_sync(dpm
);
215 if (retval
== ERROR_OK
) {
217 LOG_DEBUG("WRITE: %s, %8.8x", r
->name
, (unsigned) value
);
224 * Read basic registers of the the current context: R0 to R15, and CPSR;
225 * sets the core mode (such as USR or IRQ) and state (such as ARM or Thumb).
226 * In normal operation this is called on entry to halting debug state,
227 * possibly after some other operations supporting restore of debug state
228 * or making sure the CPU is fully idle (drain write buffer, etc).
230 int arm_dpm_read_current_registers(struct arm_dpm
*dpm
)
232 struct arm
*arm
= dpm
->arm
;
237 retval
= dpm
->prepare(dpm
);
238 if (retval
!= ERROR_OK
)
241 /* read R0 first (it's used for scratch), then CPSR */
242 r
= arm
->core_cache
->reg_list
+ 0;
244 retval
= dpm_read_reg(dpm
, r
, 0);
245 if (retval
!= ERROR_OK
)
250 retval
= dpm
->instr_read_data_r0(dpm
, ARMV4_5_MRS(0, 0), &cpsr
);
251 if (retval
!= ERROR_OK
)
254 /* update core mode and state, plus shadow mapping for R8..R14 */
255 arm_set_cpsr(arm
, cpsr
);
257 /* REVISIT we can probably avoid reading R1..R14, saving time... */
258 for (unsigned i
= 1; i
< 16; i
++) {
259 r
= arm_reg_current(arm
, i
);
263 retval
= dpm_read_reg(dpm
, r
, i
);
264 if (retval
!= ERROR_OK
)
268 /* NOTE: SPSR ignored (if it's even relevant). */
270 /* REVISIT the debugger can trigger various exceptions. See the
271 * ARMv7A architecture spec, section C5.7, for more info about
272 * what defenses are needed; v6 debug has the most issues.
276 /* (void) */ dpm
->finish(dpm
);
280 /* Avoid needless I/O ... leave breakpoints and watchpoints alone
281 * unless they're removed, or need updating because of single-stepping
282 * or running debugger code.
284 static int dpm_maybe_update_bpwp(struct arm_dpm
*dpm
, bool bpwp
,
285 struct dpm_bpwp
*xp
, int *set_p
)
287 int retval
= ERROR_OK
;
294 /* removed or startup; we must disable it */
299 /* disabled, but we must set it */
300 xp
->dirty
= disable
= false;
305 /* set, but we must temporarily disable it */
306 xp
->dirty
= disable
= true;
311 retval
= dpm
->bpwp_disable(dpm
, xp
->number
);
313 retval
= dpm
->bpwp_enable(dpm
, xp
->number
,
314 xp
->address
, xp
->control
);
316 if (retval
!= ERROR_OK
)
317 LOG_ERROR("%s: can't %s HW bp/wp %d",
318 disable
? "disable" : "enable",
319 target_name(dpm
->arm
->target
),
326 * Writes all modified core registers for all processor modes. In normal
327 * operation this is called on exit from halting debug state.
329 * @param dpm: represents the processor
330 * @param bpwp: true ensures breakpoints and watchpoints are set,
331 * false ensures they are cleared
333 int arm_dpm_write_dirty_registers(struct arm_dpm
*dpm
, bool bpwp
)
335 struct arm
*arm
= dpm
->arm
;
336 struct reg_cache
*cache
= arm
->core_cache
;
340 retval
= dpm
->prepare(dpm
);
341 if (retval
!= ERROR_OK
)
344 /* enable/disable hardware breakpoints */
345 for (unsigned i
= 0; i
< dpm
->nbp
; i
++) {
346 struct dpm_bp
*dbp
= dpm
->dbp
+ i
;
347 struct breakpoint
*bp
= dbp
->bp
;
349 retval
= dpm_maybe_update_bpwp(dpm
, bpwp
, &dbp
->bpwp
,
350 bp
? &bp
->set
: NULL
);
353 /* enable/disable watchpoints */
354 for (unsigned i
= 0; i
< dpm
->nwp
; i
++) {
355 struct dpm_wp
*dwp
= dpm
->dwp
+ i
;
356 struct watchpoint
*wp
= dwp
->wp
;
358 retval
= dpm_maybe_update_bpwp(dpm
, bpwp
, &dwp
->bpwp
,
359 wp
? &wp
->set
: NULL
);
362 /* NOTE: writes to breakpoint and watchpoint registers might
363 * be queued, and need (efficient/batched) flushing later.
366 /* Scan the registers until we find one that's both dirty and
367 * eligible for flushing. Flush that and everything else that
368 * shares the same core mode setting. Typically this won't
369 * actually find anything to do...
372 enum arm_mode mode
= ARM_MODE_ANY
;
376 /* check everything except our scratch register R0 */
377 for (unsigned i
= 1; i
< cache
->num_regs
; i
++) {
381 /* also skip PC, CPSR, and non-dirty */
384 if (arm
->cpsr
== cache
->reg_list
+ i
)
386 if (!cache
->reg_list
[i
].dirty
)
389 r
= cache
->reg_list
[i
].arch_info
;
392 /* may need to pick and set a mode */
397 mode
= tmode
= r
->mode
;
399 /* cope with special cases */
402 /* r8..r12 "anything but FIQ" case;
403 * we "know" core mode is accurate
404 * since we haven't changed it yet
406 if (arm
->core_mode
== ARM_MODE_FIQ
409 tmode
= ARM_MODE_USR
;
417 /* REVISIT error checks */
418 if (tmode
!= ARM_MODE_ANY
)
419 retval
= dpm_modeswitch(dpm
, tmode
);
424 retval
= dpm_write_reg(dpm
,
432 /* Restore original CPSR ... assuming either that we changed it,
433 * or it's dirty. Must write PC to ensure the return address is
434 * defined, and must not write it before CPSR.
436 retval
= dpm_modeswitch(dpm
, ARM_MODE_ANY
);
437 arm
->cpsr
->dirty
= false;
439 retval
= dpm_write_reg(dpm
, &cache
->reg_list
[15], 15);
440 cache
->reg_list
[15].dirty
= false;
442 /* flush R0 -- it's *very* dirty by now */
443 retval
= dpm_write_reg(dpm
, &cache
->reg_list
[0], 0);
444 cache
->reg_list
[0].dirty
= false;
446 /* (void) */ dpm
->finish(dpm
);
451 /* Returns ARM_MODE_ANY or temporary mode to use while reading the
452 * specified register ... works around flakiness from ARM core calls.
453 * Caller already filtered out SPSR access; mode is never MODE_SYS
456 static enum arm_mode
dpm_mapmode(struct arm
*arm
,
457 unsigned num
, enum arm_mode mode
)
459 enum arm_mode amode
= arm
->core_mode
;
461 /* don't switch if the mode is already correct */
462 if (amode
== ARM_MODE_SYS
)
463 amode
= ARM_MODE_USR
;
468 /* don't switch for non-shadowed registers (r0..r7, r15/pc, cpsr) */
473 /* r8..r12 aren't shadowed for anything except FIQ */
475 if (mode
== ARM_MODE_FIQ
)
478 /* r13/sp, and r14/lr are always shadowed */
483 LOG_WARNING("invalid register #%u", num
);
491 * Standard ARM register accessors ... there are three methods
492 * in "struct arm", to support individual read/write and bulk read
496 static int arm_dpm_read_core_reg(struct target
*target
, struct reg
*r
,
497 int regnum
, enum arm_mode mode
)
499 struct arm_dpm
*dpm
= target_to_arm(target
)->dpm
;
502 if (regnum
< 0 || regnum
> 16)
503 return ERROR_INVALID_ARGUMENTS
;
506 if (mode
!= ARM_MODE_ANY
)
509 mode
= dpm_mapmode(dpm
->arm
, regnum
, mode
);
511 /* REVISIT what happens if we try to read SPSR in a core mode
512 * which has no such register?
515 retval
= dpm
->prepare(dpm
);
516 if (retval
!= ERROR_OK
)
519 if (mode
!= ARM_MODE_ANY
) {
520 retval
= dpm_modeswitch(dpm
, mode
);
521 if (retval
!= ERROR_OK
)
525 retval
= dpm_read_reg(dpm
, r
, regnum
);
526 /* always clean up, regardless of error */
528 if (mode
!= ARM_MODE_ANY
)
529 /* (void) */ dpm_modeswitch(dpm
, ARM_MODE_ANY
);
532 /* (void) */ dpm
->finish(dpm
);
536 static int arm_dpm_write_core_reg(struct target
*target
, struct reg
*r
,
537 int regnum
, enum arm_mode mode
, uint32_t value
)
539 struct arm_dpm
*dpm
= target_to_arm(target
)->dpm
;
543 if (regnum
< 0 || regnum
> 16)
544 return ERROR_INVALID_ARGUMENTS
;
547 if (mode
!= ARM_MODE_ANY
)
550 mode
= dpm_mapmode(dpm
->arm
, regnum
, mode
);
552 /* REVISIT what happens if we try to write SPSR in a core mode
553 * which has no such register?
556 retval
= dpm
->prepare(dpm
);
557 if (retval
!= ERROR_OK
)
560 if (mode
!= ARM_MODE_ANY
) {
561 retval
= dpm_modeswitch(dpm
, mode
);
562 if (retval
!= ERROR_OK
)
566 retval
= dpm_write_reg(dpm
, r
, regnum
);
567 /* always clean up, regardless of error */
569 if (mode
!= ARM_MODE_ANY
)
570 /* (void) */ dpm_modeswitch(dpm
, ARM_MODE_ANY
);
573 /* (void) */ dpm
->finish(dpm
);
577 static int arm_dpm_full_context(struct target
*target
)
579 struct arm
*arm
= target_to_arm(target
);
580 struct arm_dpm
*dpm
= arm
->dpm
;
581 struct reg_cache
*cache
= arm
->core_cache
;
585 retval
= dpm
->prepare(dpm
);
586 if (retval
!= ERROR_OK
)
590 enum arm_mode mode
= ARM_MODE_ANY
;
594 /* We "know" arm_dpm_read_current_registers() was called so
595 * the unmapped registers (R0..R7, PC, AND CPSR) and some
596 * view of R8..R14 are current. We also "know" oddities of
597 * register mapping: special cases for R8..R12 and SPSR.
599 * Pick some mode with unread registers and read them all.
602 for (unsigned i
= 0; i
< cache
->num_regs
; i
++) {
605 if (cache
->reg_list
[i
].valid
)
607 r
= cache
->reg_list
[i
].arch_info
;
609 /* may need to pick a mode and set CPSR */
614 /* For R8..R12 when we've entered debug
615 * state in FIQ mode... patch mode.
617 if (mode
== ARM_MODE_ANY
)
620 /* REVISIT error checks */
621 retval
= dpm_modeswitch(dpm
, mode
);
626 /* CPSR was read, so "R16" must mean SPSR */
627 retval
= dpm_read_reg(dpm
,
629 (r
->num
== 16) ? 17 : r
->num
);
635 retval
= dpm_modeswitch(dpm
, ARM_MODE_ANY
);
636 /* (void) */ dpm
->finish(dpm
);
642 /*----------------------------------------------------------------------*/
645 * Breakpoint and Watchpoint support.
647 * Hardware {break,watch}points are usually left active, to minimize
648 * debug entry/exit costs. When they are set or cleared, it's done in
649 * batches. Also, DPM-conformant hardware can update debug registers
650 * regardless of whether the CPU is running or halted ... though that
651 * fact isn't currently leveraged.
654 static int dpm_watchpoint_setup(struct arm_dpm
*dpm
, unsigned index
,
655 struct watchpoint
*wp
)
657 uint32_t addr
= wp
->address
;
660 /* this hardware doesn't support data value matching or masking */
661 if (wp
->value
|| wp
->mask
!= ~(uint32_t)0) {
662 LOG_DEBUG("watchpoint values and masking not supported");
663 return ERROR_TARGET_RESOURCE_NOT_AVAILABLE
;
666 control
= (1 << 0) /* enable */
667 | (3 << 1); /* both user and privileged access */
681 /* Match 1, 2, or all 4 byte addresses in this word.
683 * FIXME: v7 hardware allows lengths up to 2 GB, and has eight
684 * byte address select bits. Support larger wp->length, if addr
685 * is suitably aligned.
687 switch (wp
->length
) {
689 control
|= (1 << (addr
& 3)) << 5;
693 /* require 2-byte alignment */
695 control
|= (3 << (addr
& 2)) << 5;
700 /* require 4-byte alignment */
707 LOG_DEBUG("bad watchpoint length or alignment");
708 return ERROR_INVALID_ARGUMENTS
;
711 /* other control bits:
712 * bits 9:12 == 0 ... only checking up to four byte addresses (v7 only)
713 * bits 15:14 == 0 ... both secure and nonsecure states (v6.1+ only)
714 * bit 20 == 0 ... not linked to a context ID
715 * bit 28:24 == 0 ... not ignoring N LSBs (v7 only)
718 dpm
->dwp
[index
].wp
= wp
;
719 dpm
->dwp
[index
].bpwp
.address
= addr
& ~3;
720 dpm
->dwp
[index
].bpwp
.control
= control
;
721 dpm
->dwp
[index
].bpwp
.dirty
= true;
723 /* hardware is updated in write_dirty_registers() */
728 static int dpm_add_watchpoint(struct target
*target
, struct watchpoint
*wp
)
730 struct arm
*arm
= target_to_arm(target
);
731 struct arm_dpm
*dpm
= arm
->dpm
;
732 int retval
= ERROR_TARGET_RESOURCE_NOT_AVAILABLE
;
734 if (dpm
->bpwp_enable
) {
735 for (unsigned i
= 0; i
< dpm
->nwp
; i
++) {
736 if (!dpm
->dwp
[i
].wp
) {
737 retval
= dpm_watchpoint_setup(dpm
, i
, wp
);
746 static int dpm_remove_watchpoint(struct target
*target
, struct watchpoint
*wp
)
748 struct arm
*arm
= target_to_arm(target
);
749 struct arm_dpm
*dpm
= arm
->dpm
;
750 int retval
= ERROR_INVALID_ARGUMENTS
;
752 for (unsigned i
= 0; i
< dpm
->nwp
; i
++) {
753 if (dpm
->dwp
[i
].wp
== wp
) {
754 dpm
->dwp
[i
].wp
= NULL
;
755 dpm
->dwp
[i
].bpwp
.dirty
= true;
757 /* hardware is updated in write_dirty_registers() */
766 void arm_dpm_report_wfar(struct arm_dpm
*dpm
, uint32_t addr
)
768 switch (dpm
->arm
->core_state
) {
772 case ARM_STATE_THUMB
:
773 case ARM_STATE_THUMB_EE
:
776 case ARM_STATE_JAZELLE
:
783 /*----------------------------------------------------------------------*/
786 * Other debug and support utilities
789 void arm_dpm_report_dscr(struct arm_dpm
*dpm
, uint32_t dscr
)
791 struct target
*target
= dpm
->arm
->target
;
795 /* Examine debug reason */
796 switch (DSCR_ENTRY(dscr
)) {
797 case 6: /* Data abort (v6 only) */
798 case 7: /* Prefetch abort (v6 only) */
799 /* FALL THROUGH -- assume a v6 core in abort mode */
800 case 0: /* HALT request from debugger */
802 target
->debug_reason
= DBG_REASON_DBGRQ
;
804 case 1: /* HW breakpoint */
805 case 3: /* SW BKPT */
806 case 5: /* vector catch */
807 target
->debug_reason
= DBG_REASON_BREAKPOINT
;
809 case 2: /* asynch watchpoint */
810 case 10: /* precise watchpoint */
811 target
->debug_reason
= DBG_REASON_WATCHPOINT
;
814 target
->debug_reason
= DBG_REASON_UNDEFINED
;
819 /*----------------------------------------------------------------------*/
822 * Setup and management support.
826 * Hooks up this DPM to its associated target; call only once.
827 * Initially this only covers the register cache.
829 * Oh, and watchpoints. Yeah.
831 int arm_dpm_setup(struct arm_dpm
*dpm
)
833 struct arm
*arm
= dpm
->arm
;
834 struct target
*target
= arm
->target
;
835 struct reg_cache
*cache
;
839 /* register access setup */
840 arm
->full_context
= arm_dpm_full_context
;
841 arm
->read_core_reg
= arm_dpm_read_core_reg
;
842 arm
->write_core_reg
= arm_dpm_write_core_reg
;
844 cache
= arm_build_reg_cache(target
, arm
);
848 *register_get_last_cache_p(&target
->reg_cache
) = cache
;
850 /* coprocessor access setup */
854 /* breakpoint and watchpoint setup */
855 target
->type
->add_watchpoint
= dpm_add_watchpoint
;
856 target
->type
->remove_watchpoint
= dpm_remove_watchpoint
;
858 /* FIXME add breakpoint support */
859 /* FIXME add vector catch support */
861 dpm
->nbp
= 1 + ((dpm
->didr
>> 24) & 0xf);
862 dpm
->dbp
= calloc(dpm
->nbp
, sizeof *dpm
->dbp
);
864 dpm
->nwp
= 1 + ((dpm
->didr
>> 28) & 0xf);
865 dpm
->dwp
= calloc(dpm
->nwp
, sizeof *dpm
->dwp
);
867 if (!dpm
->dbp
|| !dpm
->dwp
) {
873 LOG_INFO("%s: hardware has %d breakpoints, %d watchpoints",
874 target_name(target
), dpm
->nbp
, dpm
->nwp
);
876 /* REVISIT ... and some of those breakpoints could match
877 * execution context IDs...
884 * Reinitializes DPM state at the beginning of a new debug session
885 * or after a reset which may have affected the debug module.
887 int arm_dpm_initialize(struct arm_dpm
*dpm
)
889 /* Disable all breakpoints and watchpoints at startup. */
890 if (dpm
->bpwp_disable
) {
893 for (i
= 0; i
< dpm
->nbp
; i
++) {
894 dpm
->dbp
[i
].bpwp
.number
= i
;
895 (void) dpm
->bpwp_disable(dpm
, i
);
897 for (i
= 0; i
< dpm
->nwp
; i
++) {
898 dpm
->dwp
[i
].bpwp
.number
= 16 + i
;
899 (void) dpm
->bpwp_disable(dpm
, 16 + i
);
902 LOG_WARNING("%s: can't disable breakpoints and watchpoints",
903 target_name(dpm
->arm
->target
));