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>
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 * Get the address of the live pt_regs for the specified task.
58 * These are saved onto the top kernel stack when the process
61 * Note: if a user thread is execve'd from kernel space, the
62 * kernel stack will not be empty on entry to the kernel, so
63 * ptracing these tasks will fail.
65 static inline struct pt_regs
*
66 get_user_regs(struct task_struct
*task
)
68 return (struct pt_regs
*)
69 ((unsigned long)task
->thread_info
+ THREAD_SIZE
-
70 8 - sizeof(struct pt_regs
));
74 * this routine will get a word off of the processes privileged stack.
75 * the offset is how far from the base addr as stored in the THREAD.
76 * this routine assumes that all the privileged stacks are in our
79 static inline long get_user_reg(struct task_struct
*task
, int offset
)
81 return get_user_regs(task
)->uregs
[offset
];
85 * this routine will put a word on the processes privileged stack.
86 * the offset is how far from the base addr as stored in the THREAD.
87 * this routine assumes that all the privileged stacks are in our
91 put_user_reg(struct task_struct
*task
, int offset
, long data
)
93 struct pt_regs newregs
, *regs
= get_user_regs(task
);
97 newregs
.uregs
[offset
] = data
;
99 if (valid_user_regs(&newregs
)) {
100 regs
->uregs
[offset
] = data
;
108 read_u32(struct task_struct
*task
, unsigned long addr
, u32
*res
)
112 ret
= access_process_vm(task
, addr
, res
, sizeof(*res
), 0);
114 return ret
== sizeof(*res
) ? 0 : -EIO
;
118 read_instr(struct task_struct
*task
, unsigned long addr
, u32
*res
)
124 ret
= access_process_vm(task
, addr
& ~1, &val
, sizeof(val
), 0);
125 ret
= ret
== sizeof(val
) ? 0 : -EIO
;
129 ret
= access_process_vm(task
, addr
& ~3, &val
, sizeof(val
), 0);
130 ret
= ret
== sizeof(val
) ? 0 : -EIO
;
137 * Get value of register `rn' (in the instruction)
140 ptrace_getrn(struct task_struct
*child
, unsigned long insn
)
142 unsigned int reg
= (insn
>> 16) & 15;
145 val
= get_user_reg(child
, reg
);
147 val
= pc_pointer(val
+ 8);
153 * Get value of operand 2 (in an ALU instruction)
156 ptrace_getaluop2(struct task_struct
*child
, unsigned long insn
)
162 if (insn
& 1 << 25) {
164 shift
= (insn
>> 8) & 15;
167 val
= get_user_reg (child
, insn
& 15);
170 shift
= (int)get_user_reg (child
, (insn
>> 8) & 15);
172 shift
= (insn
>> 7) & 31;
174 type
= (insn
>> 5) & 3;
178 case 0: val
<<= shift
; break;
179 case 1: val
>>= shift
; break;
181 val
= (((signed long)val
) >> shift
);
184 val
= (val
>> shift
) | (val
<< (32 - shift
));
191 * Get value of operand 2 (in a LDR instruction)
194 ptrace_getldrop2(struct task_struct
*child
, unsigned long insn
)
200 val
= get_user_reg(child
, insn
& 15);
201 shift
= (insn
>> 7) & 31;
202 type
= (insn
>> 5) & 3;
205 case 0: val
<<= shift
; break;
206 case 1: val
>>= shift
; break;
208 val
= (((signed long)val
) >> shift
);
211 val
= (val
>> shift
) | (val
<< (32 - shift
));
217 #define OP_MASK 0x01e00000
218 #define OP_AND 0x00000000
219 #define OP_EOR 0x00200000
220 #define OP_SUB 0x00400000
221 #define OP_RSB 0x00600000
222 #define OP_ADD 0x00800000
223 #define OP_ADC 0x00a00000
224 #define OP_SBC 0x00c00000
225 #define OP_RSC 0x00e00000
226 #define OP_ORR 0x01800000
227 #define OP_MOV 0x01a00000
228 #define OP_BIC 0x01c00000
229 #define OP_MVN 0x01e00000
232 get_branch_address(struct task_struct
*child
, unsigned long pc
, unsigned long insn
)
236 switch (insn
& 0x0e000000) {
242 long aluop1
, aluop2
, ccbit
;
244 if ((insn
& 0xf000) != 0xf000)
247 aluop1
= ptrace_getrn(child
, insn
);
248 aluop2
= ptrace_getaluop2(child
, insn
);
249 ccbit
= get_user_reg(child
, REG_PSR
) & PSR_C_BIT
? 1 : 0;
251 switch (insn
& OP_MASK
) {
252 case OP_AND
: alt
= aluop1
& aluop2
; break;
253 case OP_EOR
: alt
= aluop1
^ aluop2
; break;
254 case OP_SUB
: alt
= aluop1
- aluop2
; break;
255 case OP_RSB
: alt
= aluop2
- aluop1
; break;
256 case OP_ADD
: alt
= aluop1
+ aluop2
; break;
257 case OP_ADC
: alt
= aluop1
+ aluop2
+ ccbit
; break;
258 case OP_SBC
: alt
= aluop1
- aluop2
+ ccbit
; break;
259 case OP_RSC
: alt
= aluop2
- aluop1
+ ccbit
; break;
260 case OP_ORR
: alt
= aluop1
| aluop2
; break;
261 case OP_MOV
: alt
= aluop2
; break;
262 case OP_BIC
: alt
= aluop1
& ~aluop2
; break;
263 case OP_MVN
: alt
= ~aluop2
; break;
273 if ((insn
& 0x0010f000) == 0x0010f000) {
276 base
= ptrace_getrn(child
, insn
);
277 if (insn
& 1 << 24) {
280 if (insn
& 0x02000000)
281 aluop2
= ptrace_getldrop2(child
, insn
);
283 aluop2
= insn
& 0xfff;
290 if (read_u32(child
, base
, &alt
) == 0)
291 alt
= pc_pointer(alt
);
299 if ((insn
& 0x00108000) == 0x00108000) {
301 unsigned int nr_regs
;
303 if (insn
& (1 << 23)) {
304 nr_regs
= hweight16(insn
& 65535) << 2;
306 if (!(insn
& (1 << 24)))
309 if (insn
& (1 << 24))
315 base
= ptrace_getrn(child
, insn
);
317 if (read_u32(child
, base
+ nr_regs
, &alt
) == 0)
318 alt
= pc_pointer(alt
);
328 /* It's a branch/branch link: instead of trying to
329 * figure out whether the branch will be taken or not,
330 * we'll put a breakpoint at both locations. This is
331 * simpler, more reliable, and probably not a whole lot
332 * slower than the alternative approach of emulating the
335 displ
= (insn
& 0x00ffffff) << 8;
336 displ
= (displ
>> 6) + 8;
337 if (displ
!= 0 && displ
!= 4)
347 swap_insn(struct task_struct
*task
, unsigned long addr
,
348 void *old_insn
, void *new_insn
, int size
)
352 ret
= access_process_vm(task
, addr
, old_insn
, size
, 0);
354 ret
= access_process_vm(task
, addr
, new_insn
, size
, 1);
359 add_breakpoint(struct task_struct
*task
, struct debug_info
*dbg
, unsigned long addr
)
361 int nr
= dbg
->nsaved
;
364 u32 new_insn
= BREAKINST_ARM
;
367 res
= swap_insn(task
, addr
, &dbg
->bp
[nr
].insn
, &new_insn
, 4);
370 dbg
->bp
[nr
].address
= addr
;
374 printk(KERN_ERR
"ptrace: too many breakpoints\n");
378 * Clear one breakpoint in the user program. We copy what the hardware
379 * does and use bit 0 of the address to indicate whether this is a Thumb
380 * breakpoint or an ARM breakpoint.
382 static void clear_breakpoint(struct task_struct
*task
, struct debug_entry
*bp
)
384 unsigned long addr
= bp
->address
;
385 union debug_insn old_insn
;
389 ret
= swap_insn(task
, addr
& ~1, &old_insn
.thumb
,
392 if (ret
!= 2 || old_insn
.thumb
!= BREAKINST_THUMB
)
393 printk(KERN_ERR
"%s:%d: corrupted Thumb breakpoint at "
394 "0x%08lx (0x%04x)\n", task
->comm
, task
->pid
,
395 addr
, old_insn
.thumb
);
397 ret
= swap_insn(task
, addr
& ~3, &old_insn
.arm
,
400 if (ret
!= 4 || old_insn
.arm
!= BREAKINST_ARM
)
401 printk(KERN_ERR
"%s:%d: corrupted ARM breakpoint at "
402 "0x%08lx (0x%08x)\n", task
->comm
, task
->pid
,
407 void ptrace_set_bpt(struct task_struct
*child
)
409 struct pt_regs
*regs
;
414 regs
= get_user_regs(child
);
415 pc
= instruction_pointer(regs
);
417 if (thumb_mode(regs
)) {
418 printk(KERN_WARNING
"ptrace: can't handle thumb mode\n");
422 res
= read_instr(child
, pc
, &insn
);
424 struct debug_info
*dbg
= &child
->thread
.debug
;
429 alt
= get_branch_address(child
, pc
, insn
);
431 add_breakpoint(child
, dbg
, alt
);
434 * Note that we ignore the result of setting the above
435 * breakpoint since it may fail. When it does, this is
436 * not so much an error, but a forewarning that we may
437 * be receiving a prefetch abort shortly.
439 * If we don't set this breakpoint here, then we can
440 * lose control of the thread during single stepping.
442 if (!alt
|| predicate(insn
) != PREDICATE_ALWAYS
)
443 add_breakpoint(child
, dbg
, pc
+ 4);
448 * Ensure no single-step breakpoint is pending. Returns non-zero
449 * value if child was being single-stepped.
451 void ptrace_cancel_bpt(struct task_struct
*child
)
453 int i
, nsaved
= child
->thread
.debug
.nsaved
;
455 child
->thread
.debug
.nsaved
= 0;
458 printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved
);
462 for (i
= 0; i
< nsaved
; i
++)
463 clear_breakpoint(child
, &child
->thread
.debug
.bp
[i
]);
467 * Called by kernel/ptrace.c when detaching..
469 * Make sure the single step bit is not set.
471 void ptrace_disable(struct task_struct
*child
)
473 child
->ptrace
&= ~PT_SINGLESTEP
;
474 ptrace_cancel_bpt(child
);
478 * Handle hitting a breakpoint.
480 void ptrace_break(struct task_struct
*tsk
, struct pt_regs
*regs
)
484 ptrace_cancel_bpt(tsk
);
486 info
.si_signo
= SIGTRAP
;
488 info
.si_code
= TRAP_BRKPT
;
489 info
.si_addr
= (void __user
*)instruction_pointer(regs
);
491 force_sig_info(SIGTRAP
, &info
, tsk
);
494 static int break_trap(struct pt_regs
*regs
, unsigned int instr
)
496 ptrace_break(current
, regs
);
500 static struct undef_hook arm_break_hook
= {
501 .instr_mask
= 0x0fffffff,
502 .instr_val
= 0x07f001f0,
503 .cpsr_mask
= PSR_T_BIT
,
508 static struct undef_hook thumb_break_hook
= {
509 .instr_mask
= 0xffff,
511 .cpsr_mask
= PSR_T_BIT
,
512 .cpsr_val
= PSR_T_BIT
,
516 static int __init
ptrace_break_init(void)
518 register_undef_hook(&arm_break_hook
);
519 register_undef_hook(&thumb_break_hook
);
523 core_initcall(ptrace_break_init
);
526 * Read the word at offset "off" into the "struct user". We
527 * actually access the pt_regs stored on the kernel stack.
529 static int ptrace_read_user(struct task_struct
*tsk
, unsigned long off
,
530 unsigned long __user
*ret
)
534 if (off
& 3 || off
>= sizeof(struct user
))
538 if (off
< sizeof(struct pt_regs
))
539 tmp
= get_user_reg(tsk
, off
>> 2);
541 return put_user(tmp
, ret
);
545 * Write the word at offset "off" into "struct user". We
546 * actually access the pt_regs stored on the kernel stack.
548 static int ptrace_write_user(struct task_struct
*tsk
, unsigned long off
,
551 if (off
& 3 || off
>= sizeof(struct user
))
554 if (off
>= sizeof(struct pt_regs
))
557 return put_user_reg(tsk
, off
>> 2, val
);
561 * Get all user integer registers.
563 static int ptrace_getregs(struct task_struct
*tsk
, void __user
*uregs
)
565 struct pt_regs
*regs
= get_user_regs(tsk
);
567 return copy_to_user(uregs
, regs
, sizeof(struct pt_regs
)) ? -EFAULT
: 0;
571 * Set all user integer registers.
573 static int ptrace_setregs(struct task_struct
*tsk
, void __user
*uregs
)
575 struct pt_regs newregs
;
579 if (copy_from_user(&newregs
, uregs
, sizeof(struct pt_regs
)) == 0) {
580 struct pt_regs
*regs
= get_user_regs(tsk
);
583 if (valid_user_regs(&newregs
)) {
593 * Get the child FPU state.
595 static int ptrace_getfpregs(struct task_struct
*tsk
, void __user
*ufp
)
597 return copy_to_user(ufp
, &tsk
->thread_info
->fpstate
,
598 sizeof(struct user_fp
)) ? -EFAULT
: 0;
602 * Set the child FPU state.
604 static int ptrace_setfpregs(struct task_struct
*tsk
, void __user
*ufp
)
606 struct thread_info
*thread
= tsk
->thread_info
;
607 thread
->used_cp
[1] = thread
->used_cp
[2] = 1;
608 return copy_from_user(&thread
->fpstate
, ufp
,
609 sizeof(struct user_fp
)) ? -EFAULT
: 0;
615 * Get the child iWMMXt state.
617 static int ptrace_getwmmxregs(struct task_struct
*tsk
, void __user
*ufp
)
619 struct thread_info
*thread
= tsk
->thread_info
;
620 void *ptr
= &thread
->fpstate
;
622 if (!test_ti_thread_flag(thread
, TIF_USING_IWMMXT
))
624 iwmmxt_task_disable(thread
); /* force it to ram */
625 /* The iWMMXt state is stored doubleword-aligned. */
626 if (((long) ptr
) & 4)
628 return copy_to_user(ufp
, ptr
, 0x98) ? -EFAULT
: 0;
632 * Set the child iWMMXt state.
634 static int ptrace_setwmmxregs(struct task_struct
*tsk
, void __user
*ufp
)
636 struct thread_info
*thread
= tsk
->thread_info
;
637 void *ptr
= &thread
->fpstate
;
639 if (!test_ti_thread_flag(thread
, TIF_USING_IWMMXT
))
641 iwmmxt_task_release(thread
); /* force a reload */
642 /* The iWMMXt state is stored doubleword-aligned. */
643 if (((long) ptr
) & 4)
645 return copy_from_user(ptr
, ufp
, 0x98) ? -EFAULT
: 0;
650 static int do_ptrace(int request
, struct task_struct
*child
, long addr
, long data
)
657 * read word at location "addr" in the child process.
659 case PTRACE_PEEKTEXT
:
660 case PTRACE_PEEKDATA
:
661 ret
= access_process_vm(child
, addr
, &tmp
,
662 sizeof(unsigned long), 0);
663 if (ret
== sizeof(unsigned long))
664 ret
= put_user(tmp
, (unsigned long __user
*) data
);
670 ret
= ptrace_read_user(child
, addr
, (unsigned long __user
*)data
);
674 * write the word at location addr.
676 case PTRACE_POKETEXT
:
677 case PTRACE_POKEDATA
:
678 ret
= access_process_vm(child
, addr
, &data
,
679 sizeof(unsigned long), 1);
680 if (ret
== sizeof(unsigned long))
687 ret
= ptrace_write_user(child
, addr
, data
);
691 * continue/restart and stop at next (return from) syscall
696 if ((unsigned long) data
> _NSIG
)
698 if (request
== PTRACE_SYSCALL
)
699 set_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
701 clear_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
702 child
->exit_code
= data
;
703 /* make sure single-step breakpoint is gone. */
704 child
->ptrace
&= ~PT_SINGLESTEP
;
705 ptrace_cancel_bpt(child
);
706 wake_up_process(child
);
711 * make the child exit. Best I can do is send it a sigkill.
712 * perhaps it should be put in the status that it wants to
716 /* make sure single-step breakpoint is gone. */
717 child
->ptrace
&= ~PT_SINGLESTEP
;
718 ptrace_cancel_bpt(child
);
719 if (child
->exit_state
!= EXIT_ZOMBIE
) {
720 child
->exit_code
= SIGKILL
;
721 wake_up_process(child
);
727 * execute single instruction.
729 case PTRACE_SINGLESTEP
:
731 if ((unsigned long) data
> _NSIG
)
733 child
->ptrace
|= PT_SINGLESTEP
;
734 clear_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
735 child
->exit_code
= data
;
736 /* give it a chance to run. */
737 wake_up_process(child
);
742 ret
= ptrace_detach(child
, data
);
746 ret
= ptrace_getregs(child
, (void __user
*)data
);
750 ret
= ptrace_setregs(child
, (void __user
*)data
);
753 case PTRACE_GETFPREGS
:
754 ret
= ptrace_getfpregs(child
, (void __user
*)data
);
757 case PTRACE_SETFPREGS
:
758 ret
= ptrace_setfpregs(child
, (void __user
*)data
);
762 case PTRACE_GETWMMXREGS
:
763 ret
= ptrace_getwmmxregs(child
, (void __user
*)data
);
766 case PTRACE_SETWMMXREGS
:
767 ret
= ptrace_setwmmxregs(child
, (void __user
*)data
);
771 case PTRACE_GET_THREAD_AREA
:
772 ret
= put_user(child
->thread_info
->tp_value
,
773 (unsigned long __user
*) data
);
777 ret
= ptrace_request(child
, request
, addr
, data
);
784 asmlinkage
int sys_ptrace(long request
, long pid
, long addr
, long data
)
786 struct task_struct
*child
;
791 if (request
== PTRACE_TRACEME
) {
792 /* are we already being traced? */
793 if (current
->ptrace
& PT_PTRACED
)
795 ret
= security_ptrace(current
->parent
, current
);
798 /* set the ptrace bit in the process flags. */
799 current
->ptrace
|= PT_PTRACED
;
804 read_lock(&tasklist_lock
);
805 child
= find_task_by_pid(pid
);
807 get_task_struct(child
);
808 read_unlock(&tasklist_lock
);
813 if (pid
== 1) /* you may not mess with init */
816 if (request
== PTRACE_ATTACH
) {
817 ret
= ptrace_attach(child
);
820 ret
= ptrace_check_attach(child
, request
== PTRACE_KILL
);
822 ret
= do_ptrace(request
, child
, addr
, data
);
825 put_task_struct(child
);
831 asmlinkage
void syscall_trace(int why
, struct pt_regs
*regs
)
835 if (!test_thread_flag(TIF_SYSCALL_TRACE
))
837 if (!(current
->ptrace
& PT_PTRACED
))
841 * Save IP. IP is used to denote syscall entry/exit:
842 * IP = 0 -> entry, = 1 -> exit
847 /* the 0x80 provides a way for the tracing parent to distinguish
848 between a syscall stop and SIGTRAP delivery */
849 ptrace_notify(SIGTRAP
| ((current
->ptrace
& PT_TRACESYSGOOD
)
852 * this isn't the same as continuing with a signal, but it will do
853 * for normal use. strace only continues with a signal if the
854 * stopping signal is not SIGTRAP. -brl
856 if (current
->exit_code
) {
857 send_sig(current
->exit_code
, current
, 1);
858 current
->exit_code
= 0;