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/config.h>
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
16 #include <linux/smp.h>
17 #include <linux/smp_lock.h>
18 #include <linux/ptrace.h>
19 #include <linux/user.h>
20 #include <linux/security.h>
21 #include <linux/init.h>
22 #include <linux/signal.h>
24 #include <asm/uaccess.h>
25 #include <asm/pgtable.h>
26 #include <asm/system.h>
27 #include <asm/traps.h>
34 * does not yet catch signals sent when the child dies.
35 * in exit.c or in signal.c.
40 * Breakpoint SWI instruction: SWI &9F0001
42 #define BREAKINST_ARM 0xef9f0001
43 #define BREAKINST_THUMB 0xdf00 /* fill this in later */
46 * New breakpoints - use an undefined instruction. The ARM architecture
47 * reference manual guarantees that the following instruction space
48 * will produce an undefined instruction exception on all CPUs:
50 * ARM: xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
51 * Thumb: 1101 1110 xxxx xxxx
53 #define BREAKINST_ARM 0xe7f001f0
54 #define BREAKINST_THUMB 0xde01
58 * this routine will get a word off of the processes privileged stack.
59 * the offset is how far from the base addr as stored in the THREAD.
60 * this routine assumes that all the privileged stacks are in our
63 static inline long get_user_reg(struct task_struct
*task
, int offset
)
65 return task_pt_regs(task
)->uregs
[offset
];
69 * this routine will put a word on the processes privileged stack.
70 * the offset is how far from the base addr as stored in the THREAD.
71 * this routine assumes that all the privileged stacks are in our
75 put_user_reg(struct task_struct
*task
, int offset
, long data
)
77 struct pt_regs newregs
, *regs
= task_pt_regs(task
);
81 newregs
.uregs
[offset
] = data
;
83 if (valid_user_regs(&newregs
)) {
84 regs
->uregs
[offset
] = data
;
92 read_u32(struct task_struct
*task
, unsigned long addr
, u32
*res
)
96 ret
= access_process_vm(task
, addr
, res
, sizeof(*res
), 0);
98 return ret
== sizeof(*res
) ? 0 : -EIO
;
102 read_instr(struct task_struct
*task
, unsigned long addr
, u32
*res
)
108 ret
= access_process_vm(task
, addr
& ~1, &val
, sizeof(val
), 0);
109 ret
= ret
== sizeof(val
) ? 0 : -EIO
;
113 ret
= access_process_vm(task
, addr
& ~3, &val
, sizeof(val
), 0);
114 ret
= ret
== sizeof(val
) ? 0 : -EIO
;
121 * Get value of register `rn' (in the instruction)
124 ptrace_getrn(struct task_struct
*child
, unsigned long insn
)
126 unsigned int reg
= (insn
>> 16) & 15;
129 val
= get_user_reg(child
, reg
);
131 val
= pc_pointer(val
+ 8);
137 * Get value of operand 2 (in an ALU instruction)
140 ptrace_getaluop2(struct task_struct
*child
, unsigned long insn
)
146 if (insn
& 1 << 25) {
148 shift
= (insn
>> 8) & 15;
151 val
= get_user_reg (child
, insn
& 15);
154 shift
= (int)get_user_reg (child
, (insn
>> 8) & 15);
156 shift
= (insn
>> 7) & 31;
158 type
= (insn
>> 5) & 3;
162 case 0: val
<<= shift
; break;
163 case 1: val
>>= shift
; break;
165 val
= (((signed long)val
) >> shift
);
168 val
= (val
>> shift
) | (val
<< (32 - shift
));
175 * Get value of operand 2 (in a LDR instruction)
178 ptrace_getldrop2(struct task_struct
*child
, unsigned long insn
)
184 val
= get_user_reg(child
, insn
& 15);
185 shift
= (insn
>> 7) & 31;
186 type
= (insn
>> 5) & 3;
189 case 0: val
<<= shift
; break;
190 case 1: val
>>= shift
; break;
192 val
= (((signed long)val
) >> shift
);
195 val
= (val
>> shift
) | (val
<< (32 - shift
));
201 #define OP_MASK 0x01e00000
202 #define OP_AND 0x00000000
203 #define OP_EOR 0x00200000
204 #define OP_SUB 0x00400000
205 #define OP_RSB 0x00600000
206 #define OP_ADD 0x00800000
207 #define OP_ADC 0x00a00000
208 #define OP_SBC 0x00c00000
209 #define OP_RSC 0x00e00000
210 #define OP_ORR 0x01800000
211 #define OP_MOV 0x01a00000
212 #define OP_BIC 0x01c00000
213 #define OP_MVN 0x01e00000
216 get_branch_address(struct task_struct
*child
, unsigned long pc
, unsigned long insn
)
220 switch (insn
& 0x0e000000) {
226 long aluop1
, aluop2
, ccbit
;
228 if ((insn
& 0x0fffffd0) == 0x012fff10) {
232 alt
= get_user_reg(child
, insn
& 15);
237 if ((insn
& 0xf000) != 0xf000)
240 aluop1
= ptrace_getrn(child
, insn
);
241 aluop2
= ptrace_getaluop2(child
, insn
);
242 ccbit
= get_user_reg(child
, REG_PSR
) & PSR_C_BIT
? 1 : 0;
244 switch (insn
& OP_MASK
) {
245 case OP_AND
: alt
= aluop1
& aluop2
; break;
246 case OP_EOR
: alt
= aluop1
^ aluop2
; break;
247 case OP_SUB
: alt
= aluop1
- aluop2
; break;
248 case OP_RSB
: alt
= aluop2
- aluop1
; break;
249 case OP_ADD
: alt
= aluop1
+ aluop2
; break;
250 case OP_ADC
: alt
= aluop1
+ aluop2
+ ccbit
; break;
251 case OP_SBC
: alt
= aluop1
- aluop2
+ ccbit
; break;
252 case OP_RSC
: alt
= aluop2
- aluop1
+ ccbit
; break;
253 case OP_ORR
: alt
= aluop1
| aluop2
; break;
254 case OP_MOV
: alt
= aluop2
; break;
255 case OP_BIC
: alt
= aluop1
& ~aluop2
; break;
256 case OP_MVN
: alt
= ~aluop2
; break;
266 if ((insn
& 0x0010f000) == 0x0010f000) {
269 base
= ptrace_getrn(child
, insn
);
270 if (insn
& 1 << 24) {
273 if (insn
& 0x02000000)
274 aluop2
= ptrace_getldrop2(child
, insn
);
276 aluop2
= insn
& 0xfff;
283 if (read_u32(child
, base
, &alt
) == 0)
284 alt
= pc_pointer(alt
);
292 if ((insn
& 0x00108000) == 0x00108000) {
294 unsigned int nr_regs
;
296 if (insn
& (1 << 23)) {
297 nr_regs
= hweight16(insn
& 65535) << 2;
299 if (!(insn
& (1 << 24)))
302 if (insn
& (1 << 24))
308 base
= ptrace_getrn(child
, insn
);
310 if (read_u32(child
, base
+ nr_regs
, &alt
) == 0)
311 alt
= pc_pointer(alt
);
321 /* It's a branch/branch link: instead of trying to
322 * figure out whether the branch will be taken or not,
323 * we'll put a breakpoint at both locations. This is
324 * simpler, more reliable, and probably not a whole lot
325 * slower than the alternative approach of emulating the
328 displ
= (insn
& 0x00ffffff) << 8;
329 displ
= (displ
>> 6) + 8;
330 if (displ
!= 0 && displ
!= 4)
340 swap_insn(struct task_struct
*task
, unsigned long addr
,
341 void *old_insn
, void *new_insn
, int size
)
345 ret
= access_process_vm(task
, addr
, old_insn
, size
, 0);
347 ret
= access_process_vm(task
, addr
, new_insn
, size
, 1);
352 add_breakpoint(struct task_struct
*task
, struct debug_info
*dbg
, unsigned long addr
)
354 int nr
= dbg
->nsaved
;
357 u32 new_insn
= BREAKINST_ARM
;
360 res
= swap_insn(task
, addr
, &dbg
->bp
[nr
].insn
, &new_insn
, 4);
363 dbg
->bp
[nr
].address
= addr
;
367 printk(KERN_ERR
"ptrace: too many breakpoints\n");
371 * Clear one breakpoint in the user program. We copy what the hardware
372 * does and use bit 0 of the address to indicate whether this is a Thumb
373 * breakpoint or an ARM breakpoint.
375 static void clear_breakpoint(struct task_struct
*task
, struct debug_entry
*bp
)
377 unsigned long addr
= bp
->address
;
378 union debug_insn old_insn
;
382 ret
= swap_insn(task
, addr
& ~1, &old_insn
.thumb
,
385 if (ret
!= 2 || old_insn
.thumb
!= BREAKINST_THUMB
)
386 printk(KERN_ERR
"%s:%d: corrupted Thumb breakpoint at "
387 "0x%08lx (0x%04x)\n", task
->comm
, task
->pid
,
388 addr
, old_insn
.thumb
);
390 ret
= swap_insn(task
, addr
& ~3, &old_insn
.arm
,
393 if (ret
!= 4 || old_insn
.arm
!= BREAKINST_ARM
)
394 printk(KERN_ERR
"%s:%d: corrupted ARM breakpoint at "
395 "0x%08lx (0x%08x)\n", task
->comm
, task
->pid
,
400 void ptrace_set_bpt(struct task_struct
*child
)
402 struct pt_regs
*regs
;
407 regs
= task_pt_regs(child
);
408 pc
= instruction_pointer(regs
);
410 if (thumb_mode(regs
)) {
411 printk(KERN_WARNING
"ptrace: can't handle thumb mode\n");
415 res
= read_instr(child
, pc
, &insn
);
417 struct debug_info
*dbg
= &child
->thread
.debug
;
422 alt
= get_branch_address(child
, pc
, insn
);
424 add_breakpoint(child
, dbg
, alt
);
427 * Note that we ignore the result of setting the above
428 * breakpoint since it may fail. When it does, this is
429 * not so much an error, but a forewarning that we may
430 * be receiving a prefetch abort shortly.
432 * If we don't set this breakpoint here, then we can
433 * lose control of the thread during single stepping.
435 if (!alt
|| predicate(insn
) != PREDICATE_ALWAYS
)
436 add_breakpoint(child
, dbg
, pc
+ 4);
441 * Ensure no single-step breakpoint is pending. Returns non-zero
442 * value if child was being single-stepped.
444 void ptrace_cancel_bpt(struct task_struct
*child
)
446 int i
, nsaved
= child
->thread
.debug
.nsaved
;
448 child
->thread
.debug
.nsaved
= 0;
451 printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved
);
455 for (i
= 0; i
< nsaved
; i
++)
456 clear_breakpoint(child
, &child
->thread
.debug
.bp
[i
]);
460 * Called by kernel/ptrace.c when detaching..
462 * Make sure the single step bit is not set.
464 void ptrace_disable(struct task_struct
*child
)
466 child
->ptrace
&= ~PT_SINGLESTEP
;
467 ptrace_cancel_bpt(child
);
471 * Handle hitting a breakpoint.
473 void ptrace_break(struct task_struct
*tsk
, struct pt_regs
*regs
)
477 ptrace_cancel_bpt(tsk
);
479 info
.si_signo
= SIGTRAP
;
481 info
.si_code
= TRAP_BRKPT
;
482 info
.si_addr
= (void __user
*)instruction_pointer(regs
);
484 force_sig_info(SIGTRAP
, &info
, tsk
);
487 static int break_trap(struct pt_regs
*regs
, unsigned int instr
)
489 ptrace_break(current
, regs
);
493 static struct undef_hook arm_break_hook
= {
494 .instr_mask
= 0x0fffffff,
495 .instr_val
= 0x07f001f0,
496 .cpsr_mask
= PSR_T_BIT
,
501 static struct undef_hook thumb_break_hook
= {
502 .instr_mask
= 0xffff,
504 .cpsr_mask
= PSR_T_BIT
,
505 .cpsr_val
= PSR_T_BIT
,
509 static int __init
ptrace_break_init(void)
511 register_undef_hook(&arm_break_hook
);
512 register_undef_hook(&thumb_break_hook
);
516 core_initcall(ptrace_break_init
);
519 * Read the word at offset "off" into the "struct user". We
520 * actually access the pt_regs stored on the kernel stack.
522 static int ptrace_read_user(struct task_struct
*tsk
, unsigned long off
,
523 unsigned long __user
*ret
)
527 if (off
& 3 || off
>= sizeof(struct user
))
531 if (off
< sizeof(struct pt_regs
))
532 tmp
= get_user_reg(tsk
, off
>> 2);
534 return put_user(tmp
, ret
);
538 * Write the word at offset "off" into "struct user". We
539 * actually access the pt_regs stored on the kernel stack.
541 static int ptrace_write_user(struct task_struct
*tsk
, unsigned long off
,
544 if (off
& 3 || off
>= sizeof(struct user
))
547 if (off
>= sizeof(struct pt_regs
))
550 return put_user_reg(tsk
, off
>> 2, val
);
554 * Get all user integer registers.
556 static int ptrace_getregs(struct task_struct
*tsk
, void __user
*uregs
)
558 struct pt_regs
*regs
= task_pt_regs(tsk
);
560 return copy_to_user(uregs
, regs
, sizeof(struct pt_regs
)) ? -EFAULT
: 0;
564 * Set all user integer registers.
566 static int ptrace_setregs(struct task_struct
*tsk
, void __user
*uregs
)
568 struct pt_regs newregs
;
572 if (copy_from_user(&newregs
, uregs
, sizeof(struct pt_regs
)) == 0) {
573 struct pt_regs
*regs
= task_pt_regs(tsk
);
576 if (valid_user_regs(&newregs
)) {
586 * Get the child FPU state.
588 static int ptrace_getfpregs(struct task_struct
*tsk
, void __user
*ufp
)
590 return copy_to_user(ufp
, &task_thread_info(tsk
)->fpstate
,
591 sizeof(struct user_fp
)) ? -EFAULT
: 0;
595 * Set the child FPU state.
597 static int ptrace_setfpregs(struct task_struct
*tsk
, void __user
*ufp
)
599 struct thread_info
*thread
= task_thread_info(tsk
);
600 thread
->used_cp
[1] = thread
->used_cp
[2] = 1;
601 return copy_from_user(&thread
->fpstate
, ufp
,
602 sizeof(struct user_fp
)) ? -EFAULT
: 0;
608 * Get the child iWMMXt state.
610 static int ptrace_getwmmxregs(struct task_struct
*tsk
, void __user
*ufp
)
612 struct thread_info
*thread
= task_thread_info(tsk
);
614 if (!test_ti_thread_flag(thread
, TIF_USING_IWMMXT
))
616 iwmmxt_task_disable(thread
); /* force it to ram */
617 return copy_to_user(ufp
, &thread
->fpstate
.iwmmxt
, IWMMXT_SIZE
)
622 * Set the child iWMMXt state.
624 static int ptrace_setwmmxregs(struct task_struct
*tsk
, void __user
*ufp
)
626 struct thread_info
*thread
= task_thread_info(tsk
);
628 if (!test_ti_thread_flag(thread
, TIF_USING_IWMMXT
))
630 iwmmxt_task_release(thread
); /* force a reload */
631 return copy_from_user(&thread
->fpstate
.iwmmxt
, ufp
, IWMMXT_SIZE
)
637 long arch_ptrace(struct task_struct
*child
, long request
, long addr
, long data
)
644 * read word at location "addr" in the child process.
646 case PTRACE_PEEKTEXT
:
647 case PTRACE_PEEKDATA
:
648 ret
= access_process_vm(child
, addr
, &tmp
,
649 sizeof(unsigned long), 0);
650 if (ret
== sizeof(unsigned long))
651 ret
= put_user(tmp
, (unsigned long __user
*) data
);
657 ret
= ptrace_read_user(child
, addr
, (unsigned long __user
*)data
);
661 * write the word at location addr.
663 case PTRACE_POKETEXT
:
664 case PTRACE_POKEDATA
:
665 ret
= access_process_vm(child
, addr
, &data
,
666 sizeof(unsigned long), 1);
667 if (ret
== sizeof(unsigned long))
674 ret
= ptrace_write_user(child
, addr
, data
);
678 * continue/restart and stop at next (return from) syscall
683 if (!valid_signal(data
))
685 if (request
== PTRACE_SYSCALL
)
686 set_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
688 clear_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
689 child
->exit_code
= data
;
690 /* make sure single-step breakpoint is gone. */
691 child
->ptrace
&= ~PT_SINGLESTEP
;
692 ptrace_cancel_bpt(child
);
693 wake_up_process(child
);
698 * make the child exit. Best I can do is send it a sigkill.
699 * perhaps it should be put in the status that it wants to
703 /* make sure single-step breakpoint is gone. */
704 child
->ptrace
&= ~PT_SINGLESTEP
;
705 ptrace_cancel_bpt(child
);
706 if (child
->exit_state
!= EXIT_ZOMBIE
) {
707 child
->exit_code
= SIGKILL
;
708 wake_up_process(child
);
714 * execute single instruction.
716 case PTRACE_SINGLESTEP
:
718 if (!valid_signal(data
))
720 child
->ptrace
|= PT_SINGLESTEP
;
721 clear_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
722 child
->exit_code
= data
;
723 /* give it a chance to run. */
724 wake_up_process(child
);
729 ret
= ptrace_detach(child
, data
);
733 ret
= ptrace_getregs(child
, (void __user
*)data
);
737 ret
= ptrace_setregs(child
, (void __user
*)data
);
740 case PTRACE_GETFPREGS
:
741 ret
= ptrace_getfpregs(child
, (void __user
*)data
);
744 case PTRACE_SETFPREGS
:
745 ret
= ptrace_setfpregs(child
, (void __user
*)data
);
749 case PTRACE_GETWMMXREGS
:
750 ret
= ptrace_getwmmxregs(child
, (void __user
*)data
);
753 case PTRACE_SETWMMXREGS
:
754 ret
= ptrace_setwmmxregs(child
, (void __user
*)data
);
758 case PTRACE_GET_THREAD_AREA
:
759 ret
= put_user(task_thread_info(child
)->tp_value
,
760 (unsigned long __user
*) data
);
763 case PTRACE_SET_SYSCALL
:
765 child
->ptrace_message
= data
;
769 ret
= ptrace_request(child
, request
, addr
, data
);
776 asmlinkage
int syscall_trace(int why
, struct pt_regs
*regs
, int scno
)
780 if (!test_thread_flag(TIF_SYSCALL_TRACE
))
782 if (!(current
->ptrace
& PT_PTRACED
))
786 * Save IP. IP is used to denote syscall entry/exit:
787 * IP = 0 -> entry, = 1 -> exit
792 current
->ptrace_message
= scno
;
794 /* the 0x80 provides a way for the tracing parent to distinguish
795 between a syscall stop and SIGTRAP delivery */
796 ptrace_notify(SIGTRAP
| ((current
->ptrace
& PT_TRACESYSGOOD
)
799 * this isn't the same as continuing with a signal, but it will do
800 * for normal use. strace only continues with a signal if the
801 * stopping signal is not SIGTRAP. -brl
803 if (current
->exit_code
) {
804 send_sig(current
->exit_code
, current
, 1);
805 current
->exit_code
= 0;
809 return current
->ptrace_message
;