2 * linux/arch/arm/kernel/ptrace.c
5 * edited by Linus Torvalds
6 * ARM modifications Copyright (C) 2000 Russell King
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
12 #include <linux/kernel.h>
13 #include <linux/sched.h>
15 #include <linux/smp.h>
16 #include <linux/smp_lock.h>
17 #include <linux/ptrace.h>
18 #include <linux/user.h>
19 #include <linux/security.h>
20 #include <linux/init.h>
21 #include <linux/signal.h>
23 #include <asm/uaccess.h>
24 #include <asm/pgtable.h>
25 #include <asm/system.h>
26 #include <asm/traps.h>
33 * does not yet catch signals sent when the child dies.
34 * in exit.c or in signal.c.
39 * Breakpoint SWI instruction: SWI &9F0001
41 #define BREAKINST_ARM 0xef9f0001
42 #define BREAKINST_THUMB 0xdf00 /* fill this in later */
45 * New breakpoints - use an undefined instruction. The ARM architecture
46 * reference manual guarantees that the following instruction space
47 * will produce an undefined instruction exception on all CPUs:
49 * ARM: xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
50 * Thumb: 1101 1110 xxxx xxxx
52 #define BREAKINST_ARM 0xe7f001f0
53 #define BREAKINST_THUMB 0xde01
57 * this routine will get a word off of the processes privileged stack.
58 * the offset is how far from the base addr as stored in the THREAD.
59 * this routine assumes that all the privileged stacks are in our
62 static inline long get_user_reg(struct task_struct
*task
, int offset
)
64 return task_pt_regs(task
)->uregs
[offset
];
68 * this routine will put a word on the processes privileged stack.
69 * the offset is how far from the base addr as stored in the THREAD.
70 * this routine assumes that all the privileged stacks are in our
74 put_user_reg(struct task_struct
*task
, int offset
, long data
)
76 struct pt_regs newregs
, *regs
= task_pt_regs(task
);
80 newregs
.uregs
[offset
] = data
;
82 if (valid_user_regs(&newregs
)) {
83 regs
->uregs
[offset
] = data
;
91 read_u32(struct task_struct
*task
, unsigned long addr
, u32
*res
)
95 ret
= access_process_vm(task
, addr
, res
, sizeof(*res
), 0);
97 return ret
== sizeof(*res
) ? 0 : -EIO
;
101 read_instr(struct task_struct
*task
, unsigned long addr
, u32
*res
)
107 ret
= access_process_vm(task
, addr
& ~1, &val
, sizeof(val
), 0);
108 ret
= ret
== sizeof(val
) ? 0 : -EIO
;
112 ret
= access_process_vm(task
, addr
& ~3, &val
, sizeof(val
), 0);
113 ret
= ret
== sizeof(val
) ? 0 : -EIO
;
120 * Get value of register `rn' (in the instruction)
123 ptrace_getrn(struct task_struct
*child
, unsigned long insn
)
125 unsigned int reg
= (insn
>> 16) & 15;
128 val
= get_user_reg(child
, reg
);
130 val
= pc_pointer(val
+ 8);
136 * Get value of operand 2 (in an ALU instruction)
139 ptrace_getaluop2(struct task_struct
*child
, unsigned long insn
)
145 if (insn
& 1 << 25) {
147 shift
= (insn
>> 8) & 15;
150 val
= get_user_reg (child
, insn
& 15);
153 shift
= (int)get_user_reg (child
, (insn
>> 8) & 15);
155 shift
= (insn
>> 7) & 31;
157 type
= (insn
>> 5) & 3;
161 case 0: val
<<= shift
; break;
162 case 1: val
>>= shift
; break;
164 val
= (((signed long)val
) >> shift
);
167 val
= (val
>> shift
) | (val
<< (32 - shift
));
174 * Get value of operand 2 (in a LDR instruction)
177 ptrace_getldrop2(struct task_struct
*child
, unsigned long insn
)
183 val
= get_user_reg(child
, insn
& 15);
184 shift
= (insn
>> 7) & 31;
185 type
= (insn
>> 5) & 3;
188 case 0: val
<<= shift
; break;
189 case 1: val
>>= shift
; break;
191 val
= (((signed long)val
) >> shift
);
194 val
= (val
>> shift
) | (val
<< (32 - shift
));
200 #define OP_MASK 0x01e00000
201 #define OP_AND 0x00000000
202 #define OP_EOR 0x00200000
203 #define OP_SUB 0x00400000
204 #define OP_RSB 0x00600000
205 #define OP_ADD 0x00800000
206 #define OP_ADC 0x00a00000
207 #define OP_SBC 0x00c00000
208 #define OP_RSC 0x00e00000
209 #define OP_ORR 0x01800000
210 #define OP_MOV 0x01a00000
211 #define OP_BIC 0x01c00000
212 #define OP_MVN 0x01e00000
215 get_branch_address(struct task_struct
*child
, unsigned long pc
, unsigned long insn
)
219 switch (insn
& 0x0e000000) {
225 long aluop1
, aluop2
, ccbit
;
227 if ((insn
& 0x0fffffd0) == 0x012fff10) {
231 alt
= get_user_reg(child
, insn
& 15);
236 if ((insn
& 0xf000) != 0xf000)
239 aluop1
= ptrace_getrn(child
, insn
);
240 aluop2
= ptrace_getaluop2(child
, insn
);
241 ccbit
= get_user_reg(child
, REG_PSR
) & PSR_C_BIT
? 1 : 0;
243 switch (insn
& OP_MASK
) {
244 case OP_AND
: alt
= aluop1
& aluop2
; break;
245 case OP_EOR
: alt
= aluop1
^ aluop2
; break;
246 case OP_SUB
: alt
= aluop1
- aluop2
; break;
247 case OP_RSB
: alt
= aluop2
- aluop1
; break;
248 case OP_ADD
: alt
= aluop1
+ aluop2
; break;
249 case OP_ADC
: alt
= aluop1
+ aluop2
+ ccbit
; break;
250 case OP_SBC
: alt
= aluop1
- aluop2
+ ccbit
; break;
251 case OP_RSC
: alt
= aluop2
- aluop1
+ ccbit
; break;
252 case OP_ORR
: alt
= aluop1
| aluop2
; break;
253 case OP_MOV
: alt
= aluop2
; break;
254 case OP_BIC
: alt
= aluop1
& ~aluop2
; break;
255 case OP_MVN
: alt
= ~aluop2
; break;
265 if ((insn
& 0x0010f000) == 0x0010f000) {
268 base
= ptrace_getrn(child
, insn
);
269 if (insn
& 1 << 24) {
272 if (insn
& 0x02000000)
273 aluop2
= ptrace_getldrop2(child
, insn
);
275 aluop2
= insn
& 0xfff;
282 if (read_u32(child
, base
, &alt
) == 0)
283 alt
= pc_pointer(alt
);
291 if ((insn
& 0x00108000) == 0x00108000) {
293 unsigned int nr_regs
;
295 if (insn
& (1 << 23)) {
296 nr_regs
= hweight16(insn
& 65535) << 2;
298 if (!(insn
& (1 << 24)))
301 if (insn
& (1 << 24))
307 base
= ptrace_getrn(child
, insn
);
309 if (read_u32(child
, base
+ nr_regs
, &alt
) == 0)
310 alt
= pc_pointer(alt
);
320 /* It's a branch/branch link: instead of trying to
321 * figure out whether the branch will be taken or not,
322 * we'll put a breakpoint at both locations. This is
323 * simpler, more reliable, and probably not a whole lot
324 * slower than the alternative approach of emulating the
327 displ
= (insn
& 0x00ffffff) << 8;
328 displ
= (displ
>> 6) + 8;
329 if (displ
!= 0 && displ
!= 4)
339 swap_insn(struct task_struct
*task
, unsigned long addr
,
340 void *old_insn
, void *new_insn
, int size
)
344 ret
= access_process_vm(task
, addr
, old_insn
, size
, 0);
346 ret
= access_process_vm(task
, addr
, new_insn
, size
, 1);
351 add_breakpoint(struct task_struct
*task
, struct debug_info
*dbg
, unsigned long addr
)
353 int nr
= dbg
->nsaved
;
356 u32 new_insn
= BREAKINST_ARM
;
359 res
= swap_insn(task
, addr
, &dbg
->bp
[nr
].insn
, &new_insn
, 4);
362 dbg
->bp
[nr
].address
= addr
;
366 printk(KERN_ERR
"ptrace: too many breakpoints\n");
370 * Clear one breakpoint in the user program. We copy what the hardware
371 * does and use bit 0 of the address to indicate whether this is a Thumb
372 * breakpoint or an ARM breakpoint.
374 static void clear_breakpoint(struct task_struct
*task
, struct debug_entry
*bp
)
376 unsigned long addr
= bp
->address
;
377 union debug_insn old_insn
;
381 ret
= swap_insn(task
, addr
& ~1, &old_insn
.thumb
,
384 if (ret
!= 2 || old_insn
.thumb
!= BREAKINST_THUMB
)
385 printk(KERN_ERR
"%s:%d: corrupted Thumb breakpoint at "
386 "0x%08lx (0x%04x)\n", task
->comm
, task
->pid
,
387 addr
, old_insn
.thumb
);
389 ret
= swap_insn(task
, addr
& ~3, &old_insn
.arm
,
392 if (ret
!= 4 || old_insn
.arm
!= BREAKINST_ARM
)
393 printk(KERN_ERR
"%s:%d: corrupted ARM breakpoint at "
394 "0x%08lx (0x%08x)\n", task
->comm
, task
->pid
,
399 void ptrace_set_bpt(struct task_struct
*child
)
401 struct pt_regs
*regs
;
406 regs
= task_pt_regs(child
);
407 pc
= instruction_pointer(regs
);
409 if (thumb_mode(regs
)) {
410 printk(KERN_WARNING
"ptrace: can't handle thumb mode\n");
414 res
= read_instr(child
, pc
, &insn
);
416 struct debug_info
*dbg
= &child
->thread
.debug
;
421 alt
= get_branch_address(child
, pc
, insn
);
423 add_breakpoint(child
, dbg
, alt
);
426 * Note that we ignore the result of setting the above
427 * breakpoint since it may fail. When it does, this is
428 * not so much an error, but a forewarning that we may
429 * be receiving a prefetch abort shortly.
431 * If we don't set this breakpoint here, then we can
432 * lose control of the thread during single stepping.
434 if (!alt
|| predicate(insn
) != PREDICATE_ALWAYS
)
435 add_breakpoint(child
, dbg
, pc
+ 4);
440 * Ensure no single-step breakpoint is pending. Returns non-zero
441 * value if child was being single-stepped.
443 void ptrace_cancel_bpt(struct task_struct
*child
)
445 int i
, nsaved
= child
->thread
.debug
.nsaved
;
447 child
->thread
.debug
.nsaved
= 0;
450 printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved
);
454 for (i
= 0; i
< nsaved
; i
++)
455 clear_breakpoint(child
, &child
->thread
.debug
.bp
[i
]);
459 * Called by kernel/ptrace.c when detaching..
461 * Make sure the single step bit is not set.
463 void ptrace_disable(struct task_struct
*child
)
465 child
->ptrace
&= ~PT_SINGLESTEP
;
466 ptrace_cancel_bpt(child
);
470 * Handle hitting a breakpoint.
472 void ptrace_break(struct task_struct
*tsk
, struct pt_regs
*regs
)
476 ptrace_cancel_bpt(tsk
);
478 info
.si_signo
= SIGTRAP
;
480 info
.si_code
= TRAP_BRKPT
;
481 info
.si_addr
= (void __user
*)instruction_pointer(regs
);
483 force_sig_info(SIGTRAP
, &info
, tsk
);
486 static int break_trap(struct pt_regs
*regs
, unsigned int instr
)
488 ptrace_break(current
, regs
);
492 static struct undef_hook arm_break_hook
= {
493 .instr_mask
= 0x0fffffff,
494 .instr_val
= 0x07f001f0,
495 .cpsr_mask
= PSR_T_BIT
,
500 static struct undef_hook thumb_break_hook
= {
501 .instr_mask
= 0xffff,
503 .cpsr_mask
= PSR_T_BIT
,
504 .cpsr_val
= PSR_T_BIT
,
508 static int __init
ptrace_break_init(void)
510 register_undef_hook(&arm_break_hook
);
511 register_undef_hook(&thumb_break_hook
);
515 core_initcall(ptrace_break_init
);
518 * Read the word at offset "off" into the "struct user". We
519 * actually access the pt_regs stored on the kernel stack.
521 static int ptrace_read_user(struct task_struct
*tsk
, unsigned long off
,
522 unsigned long __user
*ret
)
526 if (off
& 3 || off
>= sizeof(struct user
))
530 if (off
< sizeof(struct pt_regs
))
531 tmp
= get_user_reg(tsk
, off
>> 2);
533 return put_user(tmp
, ret
);
537 * Write the word at offset "off" into "struct user". We
538 * actually access the pt_regs stored on the kernel stack.
540 static int ptrace_write_user(struct task_struct
*tsk
, unsigned long off
,
543 if (off
& 3 || off
>= sizeof(struct user
))
546 if (off
>= sizeof(struct pt_regs
))
549 return put_user_reg(tsk
, off
>> 2, val
);
553 * Get all user integer registers.
555 static int ptrace_getregs(struct task_struct
*tsk
, void __user
*uregs
)
557 struct pt_regs
*regs
= task_pt_regs(tsk
);
559 return copy_to_user(uregs
, regs
, sizeof(struct pt_regs
)) ? -EFAULT
: 0;
563 * Set all user integer registers.
565 static int ptrace_setregs(struct task_struct
*tsk
, void __user
*uregs
)
567 struct pt_regs newregs
;
571 if (copy_from_user(&newregs
, uregs
, sizeof(struct pt_regs
)) == 0) {
572 struct pt_regs
*regs
= task_pt_regs(tsk
);
575 if (valid_user_regs(&newregs
)) {
585 * Get the child FPU state.
587 static int ptrace_getfpregs(struct task_struct
*tsk
, void __user
*ufp
)
589 return copy_to_user(ufp
, &task_thread_info(tsk
)->fpstate
,
590 sizeof(struct user_fp
)) ? -EFAULT
: 0;
594 * Set the child FPU state.
596 static int ptrace_setfpregs(struct task_struct
*tsk
, void __user
*ufp
)
598 struct thread_info
*thread
= task_thread_info(tsk
);
599 thread
->used_cp
[1] = thread
->used_cp
[2] = 1;
600 return copy_from_user(&thread
->fpstate
, ufp
,
601 sizeof(struct user_fp
)) ? -EFAULT
: 0;
607 * Get the child iWMMXt state.
609 static int ptrace_getwmmxregs(struct task_struct
*tsk
, void __user
*ufp
)
611 struct thread_info
*thread
= task_thread_info(tsk
);
613 if (!test_ti_thread_flag(thread
, TIF_USING_IWMMXT
))
615 iwmmxt_task_disable(thread
); /* force it to ram */
616 return copy_to_user(ufp
, &thread
->fpstate
.iwmmxt
, IWMMXT_SIZE
)
621 * Set the child iWMMXt state.
623 static int ptrace_setwmmxregs(struct task_struct
*tsk
, void __user
*ufp
)
625 struct thread_info
*thread
= task_thread_info(tsk
);
627 if (!test_ti_thread_flag(thread
, TIF_USING_IWMMXT
))
629 iwmmxt_task_release(thread
); /* force a reload */
630 return copy_from_user(&thread
->fpstate
.iwmmxt
, ufp
, IWMMXT_SIZE
)
638 * Get the child Crunch state.
640 static int ptrace_getcrunchregs(struct task_struct
*tsk
, void __user
*ufp
)
642 struct thread_info
*thread
= task_thread_info(tsk
);
644 crunch_task_disable(thread
); /* force it to ram */
645 return copy_to_user(ufp
, &thread
->crunchstate
, CRUNCH_SIZE
)
650 * Set the child Crunch state.
652 static int ptrace_setcrunchregs(struct task_struct
*tsk
, void __user
*ufp
)
654 struct thread_info
*thread
= task_thread_info(tsk
);
656 crunch_task_release(thread
); /* force a reload */
657 return copy_from_user(&thread
->crunchstate
, ufp
, CRUNCH_SIZE
)
662 long arch_ptrace(struct task_struct
*child
, long request
, long addr
, long data
)
669 * read word at location "addr" in the child process.
671 case PTRACE_PEEKTEXT
:
672 case PTRACE_PEEKDATA
:
673 ret
= access_process_vm(child
, addr
, &tmp
,
674 sizeof(unsigned long), 0);
675 if (ret
== sizeof(unsigned long))
676 ret
= put_user(tmp
, (unsigned long __user
*) data
);
682 ret
= ptrace_read_user(child
, addr
, (unsigned long __user
*)data
);
686 * write the word at location addr.
688 case PTRACE_POKETEXT
:
689 case PTRACE_POKEDATA
:
690 ret
= access_process_vm(child
, addr
, &data
,
691 sizeof(unsigned long), 1);
692 if (ret
== sizeof(unsigned long))
699 ret
= ptrace_write_user(child
, addr
, data
);
703 * continue/restart and stop at next (return from) syscall
708 if (!valid_signal(data
))
710 if (request
== PTRACE_SYSCALL
)
711 set_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
713 clear_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
714 child
->exit_code
= data
;
715 /* make sure single-step breakpoint is gone. */
716 child
->ptrace
&= ~PT_SINGLESTEP
;
717 ptrace_cancel_bpt(child
);
718 wake_up_process(child
);
723 * make the child exit. Best I can do is send it a sigkill.
724 * perhaps it should be put in the status that it wants to
728 /* make sure single-step breakpoint is gone. */
729 child
->ptrace
&= ~PT_SINGLESTEP
;
730 ptrace_cancel_bpt(child
);
731 if (child
->exit_state
!= EXIT_ZOMBIE
) {
732 child
->exit_code
= SIGKILL
;
733 wake_up_process(child
);
739 * execute single instruction.
741 case PTRACE_SINGLESTEP
:
743 if (!valid_signal(data
))
745 child
->ptrace
|= PT_SINGLESTEP
;
746 clear_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
747 child
->exit_code
= data
;
748 /* give it a chance to run. */
749 wake_up_process(child
);
754 ret
= ptrace_detach(child
, data
);
758 ret
= ptrace_getregs(child
, (void __user
*)data
);
762 ret
= ptrace_setregs(child
, (void __user
*)data
);
765 case PTRACE_GETFPREGS
:
766 ret
= ptrace_getfpregs(child
, (void __user
*)data
);
769 case PTRACE_SETFPREGS
:
770 ret
= ptrace_setfpregs(child
, (void __user
*)data
);
774 case PTRACE_GETWMMXREGS
:
775 ret
= ptrace_getwmmxregs(child
, (void __user
*)data
);
778 case PTRACE_SETWMMXREGS
:
779 ret
= ptrace_setwmmxregs(child
, (void __user
*)data
);
783 case PTRACE_GET_THREAD_AREA
:
784 ret
= put_user(task_thread_info(child
)->tp_value
,
785 (unsigned long __user
*) data
);
788 case PTRACE_SET_SYSCALL
:
790 child
->ptrace_message
= data
;
794 case PTRACE_GETCRUNCHREGS
:
795 ret
= ptrace_getcrunchregs(child
, (void __user
*)data
);
798 case PTRACE_SETCRUNCHREGS
:
799 ret
= ptrace_setcrunchregs(child
, (void __user
*)data
);
804 ret
= ptrace_request(child
, request
, addr
, data
);
811 asmlinkage
int syscall_trace(int why
, struct pt_regs
*regs
, int scno
)
815 if (!test_thread_flag(TIF_SYSCALL_TRACE
))
817 if (!(current
->ptrace
& PT_PTRACED
))
821 * Save IP. IP is used to denote syscall entry/exit:
822 * IP = 0 -> entry, = 1 -> exit
827 current
->ptrace_message
= scno
;
829 /* the 0x80 provides a way for the tracing parent to distinguish
830 between a syscall stop and SIGTRAP delivery */
831 ptrace_notify(SIGTRAP
| ((current
->ptrace
& PT_TRACESYSGOOD
)
834 * this isn't the same as continuing with a signal, but it will do
835 * for normal use. strace only continues with a signal if the
836 * stopping signal is not SIGTRAP. -brl
838 if (current
->exit_code
) {
839 send_sig(current
->exit_code
, current
, 1);
840 current
->exit_code
= 0;
844 return current
->ptrace_message
;