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/ptrace.h>
17 #include <linux/user.h>
18 #include <linux/security.h>
19 #include <linux/init.h>
20 #include <linux/signal.h>
22 #include <asm/uaccess.h>
23 #include <asm/pgtable.h>
24 #include <asm/system.h>
25 #include <asm/traps.h>
32 * does not yet catch signals sent when the child dies.
33 * in exit.c or in signal.c.
38 * Breakpoint SWI instruction: SWI &9F0001
40 #define BREAKINST_ARM 0xef9f0001
41 #define BREAKINST_THUMB 0xdf00 /* fill this in later */
44 * New breakpoints - use an undefined instruction. The ARM architecture
45 * reference manual guarantees that the following instruction space
46 * will produce an undefined instruction exception on all CPUs:
48 * ARM: xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
49 * Thumb: 1101 1110 xxxx xxxx
51 #define BREAKINST_ARM 0xe7f001f0
52 #define BREAKINST_THUMB 0xde01
56 * this routine will get a word off of the processes privileged stack.
57 * the offset is how far from the base addr as stored in the THREAD.
58 * this routine assumes that all the privileged stacks are in our
61 static inline long get_user_reg(struct task_struct
*task
, int offset
)
63 return task_pt_regs(task
)->uregs
[offset
];
67 * this routine will put a word on the processes privileged stack.
68 * the offset is how far from the base addr as stored in the THREAD.
69 * this routine assumes that all the privileged stacks are in our
73 put_user_reg(struct task_struct
*task
, int offset
, long data
)
75 struct pt_regs newregs
, *regs
= task_pt_regs(task
);
79 newregs
.uregs
[offset
] = data
;
81 if (valid_user_regs(&newregs
)) {
82 regs
->uregs
[offset
] = data
;
90 read_u32(struct task_struct
*task
, unsigned long addr
, u32
*res
)
94 ret
= access_process_vm(task
, addr
, res
, sizeof(*res
), 0);
96 return ret
== sizeof(*res
) ? 0 : -EIO
;
100 read_instr(struct task_struct
*task
, unsigned long addr
, u32
*res
)
106 ret
= access_process_vm(task
, addr
& ~1, &val
, sizeof(val
), 0);
107 ret
= ret
== sizeof(val
) ? 0 : -EIO
;
111 ret
= access_process_vm(task
, addr
& ~3, &val
, sizeof(val
), 0);
112 ret
= ret
== sizeof(val
) ? 0 : -EIO
;
119 * Get value of register `rn' (in the instruction)
122 ptrace_getrn(struct task_struct
*child
, unsigned long insn
)
124 unsigned int reg
= (insn
>> 16) & 15;
127 val
= get_user_reg(child
, reg
);
129 val
= pc_pointer(val
+ 8);
135 * Get value of operand 2 (in an ALU instruction)
138 ptrace_getaluop2(struct task_struct
*child
, unsigned long insn
)
144 if (insn
& 1 << 25) {
146 shift
= (insn
>> 8) & 15;
149 val
= get_user_reg (child
, insn
& 15);
152 shift
= (int)get_user_reg (child
, (insn
>> 8) & 15);
154 shift
= (insn
>> 7) & 31;
156 type
= (insn
>> 5) & 3;
160 case 0: val
<<= shift
; break;
161 case 1: val
>>= shift
; break;
163 val
= (((signed long)val
) >> shift
);
166 val
= (val
>> shift
) | (val
<< (32 - shift
));
173 * Get value of operand 2 (in a LDR instruction)
176 ptrace_getldrop2(struct task_struct
*child
, unsigned long insn
)
182 val
= get_user_reg(child
, insn
& 15);
183 shift
= (insn
>> 7) & 31;
184 type
= (insn
>> 5) & 3;
187 case 0: val
<<= shift
; break;
188 case 1: val
>>= shift
; break;
190 val
= (((signed long)val
) >> shift
);
193 val
= (val
>> shift
) | (val
<< (32 - shift
));
199 #define OP_MASK 0x01e00000
200 #define OP_AND 0x00000000
201 #define OP_EOR 0x00200000
202 #define OP_SUB 0x00400000
203 #define OP_RSB 0x00600000
204 #define OP_ADD 0x00800000
205 #define OP_ADC 0x00a00000
206 #define OP_SBC 0x00c00000
207 #define OP_RSC 0x00e00000
208 #define OP_ORR 0x01800000
209 #define OP_MOV 0x01a00000
210 #define OP_BIC 0x01c00000
211 #define OP_MVN 0x01e00000
214 get_branch_address(struct task_struct
*child
, unsigned long pc
, unsigned long insn
)
218 switch (insn
& 0x0e000000) {
224 long aluop1
, aluop2
, ccbit
;
226 if ((insn
& 0x0fffffd0) == 0x012fff10) {
230 alt
= get_user_reg(child
, insn
& 15);
235 if ((insn
& 0xf000) != 0xf000)
238 aluop1
= ptrace_getrn(child
, insn
);
239 aluop2
= ptrace_getaluop2(child
, insn
);
240 ccbit
= get_user_reg(child
, REG_PSR
) & PSR_C_BIT
? 1 : 0;
242 switch (insn
& OP_MASK
) {
243 case OP_AND
: alt
= aluop1
& aluop2
; break;
244 case OP_EOR
: alt
= aluop1
^ aluop2
; break;
245 case OP_SUB
: alt
= aluop1
- aluop2
; break;
246 case OP_RSB
: alt
= aluop2
- aluop1
; break;
247 case OP_ADD
: alt
= aluop1
+ aluop2
; break;
248 case OP_ADC
: alt
= aluop1
+ aluop2
+ ccbit
; break;
249 case OP_SBC
: alt
= aluop1
- aluop2
+ ccbit
; break;
250 case OP_RSC
: alt
= aluop2
- aluop1
+ ccbit
; break;
251 case OP_ORR
: alt
= aluop1
| aluop2
; break;
252 case OP_MOV
: alt
= aluop2
; break;
253 case OP_BIC
: alt
= aluop1
& ~aluop2
; break;
254 case OP_MVN
: alt
= ~aluop2
; break;
264 if ((insn
& 0x0010f000) == 0x0010f000) {
267 base
= ptrace_getrn(child
, insn
);
268 if (insn
& 1 << 24) {
271 if (insn
& 0x02000000)
272 aluop2
= ptrace_getldrop2(child
, insn
);
274 aluop2
= insn
& 0xfff;
281 if (read_u32(child
, base
, &alt
) == 0)
282 alt
= pc_pointer(alt
);
290 if ((insn
& 0x00108000) == 0x00108000) {
292 unsigned int nr_regs
;
294 if (insn
& (1 << 23)) {
295 nr_regs
= hweight16(insn
& 65535) << 2;
297 if (!(insn
& (1 << 24)))
300 if (insn
& (1 << 24))
306 base
= ptrace_getrn(child
, insn
);
308 if (read_u32(child
, base
+ nr_regs
, &alt
) == 0)
309 alt
= pc_pointer(alt
);
319 /* It's a branch/branch link: instead of trying to
320 * figure out whether the branch will be taken or not,
321 * we'll put a breakpoint at both locations. This is
322 * simpler, more reliable, and probably not a whole lot
323 * slower than the alternative approach of emulating the
326 displ
= (insn
& 0x00ffffff) << 8;
327 displ
= (displ
>> 6) + 8;
328 if (displ
!= 0 && displ
!= 4)
338 swap_insn(struct task_struct
*task
, unsigned long addr
,
339 void *old_insn
, void *new_insn
, int size
)
343 ret
= access_process_vm(task
, addr
, old_insn
, size
, 0);
345 ret
= access_process_vm(task
, addr
, new_insn
, size
, 1);
350 add_breakpoint(struct task_struct
*task
, struct debug_info
*dbg
, unsigned long addr
)
352 int nr
= dbg
->nsaved
;
355 u32 new_insn
= BREAKINST_ARM
;
358 res
= swap_insn(task
, addr
, &dbg
->bp
[nr
].insn
, &new_insn
, 4);
361 dbg
->bp
[nr
].address
= addr
;
365 printk(KERN_ERR
"ptrace: too many breakpoints\n");
369 * Clear one breakpoint in the user program. We copy what the hardware
370 * does and use bit 0 of the address to indicate whether this is a Thumb
371 * breakpoint or an ARM breakpoint.
373 static void clear_breakpoint(struct task_struct
*task
, struct debug_entry
*bp
)
375 unsigned long addr
= bp
->address
;
376 union debug_insn old_insn
;
380 ret
= swap_insn(task
, addr
& ~1, &old_insn
.thumb
,
383 if (ret
!= 2 || old_insn
.thumb
!= BREAKINST_THUMB
)
384 printk(KERN_ERR
"%s:%d: corrupted Thumb breakpoint at "
385 "0x%08lx (0x%04x)\n", task
->comm
, task
->pid
,
386 addr
, old_insn
.thumb
);
388 ret
= swap_insn(task
, addr
& ~3, &old_insn
.arm
,
391 if (ret
!= 4 || old_insn
.arm
!= BREAKINST_ARM
)
392 printk(KERN_ERR
"%s:%d: corrupted ARM breakpoint at "
393 "0x%08lx (0x%08x)\n", task
->comm
, task
->pid
,
398 void ptrace_set_bpt(struct task_struct
*child
)
400 struct pt_regs
*regs
;
405 regs
= task_pt_regs(child
);
406 pc
= instruction_pointer(regs
);
408 if (thumb_mode(regs
)) {
409 printk(KERN_WARNING
"ptrace: can't handle thumb mode\n");
413 res
= read_instr(child
, pc
, &insn
);
415 struct debug_info
*dbg
= &child
->thread
.debug
;
420 alt
= get_branch_address(child
, pc
, insn
);
422 add_breakpoint(child
, dbg
, alt
);
425 * Note that we ignore the result of setting the above
426 * breakpoint since it may fail. When it does, this is
427 * not so much an error, but a forewarning that we may
428 * be receiving a prefetch abort shortly.
430 * If we don't set this breakpoint here, then we can
431 * lose control of the thread during single stepping.
433 if (!alt
|| predicate(insn
) != PREDICATE_ALWAYS
)
434 add_breakpoint(child
, dbg
, pc
+ 4);
439 * Ensure no single-step breakpoint is pending. Returns non-zero
440 * value if child was being single-stepped.
442 void ptrace_cancel_bpt(struct task_struct
*child
)
444 int i
, nsaved
= child
->thread
.debug
.nsaved
;
446 child
->thread
.debug
.nsaved
= 0;
449 printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved
);
453 for (i
= 0; i
< nsaved
; i
++)
454 clear_breakpoint(child
, &child
->thread
.debug
.bp
[i
]);
458 * Called by kernel/ptrace.c when detaching..
460 void ptrace_disable(struct task_struct
*child
)
462 single_step_disable(child
);
466 * Handle hitting a breakpoint.
468 void ptrace_break(struct task_struct
*tsk
, struct pt_regs
*regs
)
472 ptrace_cancel_bpt(tsk
);
474 info
.si_signo
= SIGTRAP
;
476 info
.si_code
= TRAP_BRKPT
;
477 info
.si_addr
= (void __user
*)instruction_pointer(regs
);
479 force_sig_info(SIGTRAP
, &info
, tsk
);
482 static int break_trap(struct pt_regs
*regs
, unsigned int instr
)
484 ptrace_break(current
, regs
);
488 static struct undef_hook arm_break_hook
= {
489 .instr_mask
= 0x0fffffff,
490 .instr_val
= 0x07f001f0,
491 .cpsr_mask
= PSR_T_BIT
,
496 static struct undef_hook thumb_break_hook
= {
497 .instr_mask
= 0xffff,
499 .cpsr_mask
= PSR_T_BIT
,
500 .cpsr_val
= PSR_T_BIT
,
504 static int __init
ptrace_break_init(void)
506 register_undef_hook(&arm_break_hook
);
507 register_undef_hook(&thumb_break_hook
);
511 core_initcall(ptrace_break_init
);
514 * Read the word at offset "off" into the "struct user". We
515 * actually access the pt_regs stored on the kernel stack.
517 static int ptrace_read_user(struct task_struct
*tsk
, unsigned long off
,
518 unsigned long __user
*ret
)
522 if (off
& 3 || off
>= sizeof(struct user
))
526 if (off
< sizeof(struct pt_regs
))
527 tmp
= get_user_reg(tsk
, off
>> 2);
529 return put_user(tmp
, ret
);
533 * Write the word at offset "off" into "struct user". We
534 * actually access the pt_regs stored on the kernel stack.
536 static int ptrace_write_user(struct task_struct
*tsk
, unsigned long off
,
539 if (off
& 3 || off
>= sizeof(struct user
))
542 if (off
>= sizeof(struct pt_regs
))
545 return put_user_reg(tsk
, off
>> 2, val
);
549 * Get all user integer registers.
551 static int ptrace_getregs(struct task_struct
*tsk
, void __user
*uregs
)
553 struct pt_regs
*regs
= task_pt_regs(tsk
);
555 return copy_to_user(uregs
, regs
, sizeof(struct pt_regs
)) ? -EFAULT
: 0;
559 * Set all user integer registers.
561 static int ptrace_setregs(struct task_struct
*tsk
, void __user
*uregs
)
563 struct pt_regs newregs
;
567 if (copy_from_user(&newregs
, uregs
, sizeof(struct pt_regs
)) == 0) {
568 struct pt_regs
*regs
= task_pt_regs(tsk
);
571 if (valid_user_regs(&newregs
)) {
581 * Get the child FPU state.
583 static int ptrace_getfpregs(struct task_struct
*tsk
, void __user
*ufp
)
585 return copy_to_user(ufp
, &task_thread_info(tsk
)->fpstate
,
586 sizeof(struct user_fp
)) ? -EFAULT
: 0;
590 * Set the child FPU state.
592 static int ptrace_setfpregs(struct task_struct
*tsk
, void __user
*ufp
)
594 struct thread_info
*thread
= task_thread_info(tsk
);
595 thread
->used_cp
[1] = thread
->used_cp
[2] = 1;
596 return copy_from_user(&thread
->fpstate
, ufp
,
597 sizeof(struct user_fp
)) ? -EFAULT
: 0;
603 * Get the child iWMMXt state.
605 static int ptrace_getwmmxregs(struct task_struct
*tsk
, void __user
*ufp
)
607 struct thread_info
*thread
= task_thread_info(tsk
);
609 if (!test_ti_thread_flag(thread
, TIF_USING_IWMMXT
))
611 iwmmxt_task_disable(thread
); /* force it to ram */
612 return copy_to_user(ufp
, &thread
->fpstate
.iwmmxt
, IWMMXT_SIZE
)
617 * Set the child iWMMXt state.
619 static int ptrace_setwmmxregs(struct task_struct
*tsk
, void __user
*ufp
)
621 struct thread_info
*thread
= task_thread_info(tsk
);
623 if (!test_ti_thread_flag(thread
, TIF_USING_IWMMXT
))
625 iwmmxt_task_release(thread
); /* force a reload */
626 return copy_from_user(&thread
->fpstate
.iwmmxt
, ufp
, IWMMXT_SIZE
)
634 * Get the child Crunch state.
636 static int ptrace_getcrunchregs(struct task_struct
*tsk
, void __user
*ufp
)
638 struct thread_info
*thread
= task_thread_info(tsk
);
640 crunch_task_disable(thread
); /* force it to ram */
641 return copy_to_user(ufp
, &thread
->crunchstate
, CRUNCH_SIZE
)
646 * Set the child Crunch state.
648 static int ptrace_setcrunchregs(struct task_struct
*tsk
, void __user
*ufp
)
650 struct thread_info
*thread
= task_thread_info(tsk
);
652 crunch_task_release(thread
); /* force a reload */
653 return copy_from_user(&thread
->crunchstate
, ufp
, CRUNCH_SIZE
)
658 long arch_ptrace(struct task_struct
*child
, long request
, long addr
, long data
)
664 * read word at location "addr" in the child process.
666 case PTRACE_PEEKTEXT
:
667 case PTRACE_PEEKDATA
:
668 ret
= generic_ptrace_peekdata(child
, addr
, data
);
672 ret
= ptrace_read_user(child
, addr
, (unsigned long __user
*)data
);
676 * write the word at location addr.
678 case PTRACE_POKETEXT
:
679 case PTRACE_POKEDATA
:
680 ret
= generic_ptrace_pokedata(child
, addr
, data
);
684 ret
= ptrace_write_user(child
, addr
, data
);
688 * continue/restart and stop at next (return from) syscall
693 if (!valid_signal(data
))
695 if (request
== PTRACE_SYSCALL
)
696 set_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
698 clear_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
699 child
->exit_code
= data
;
700 single_step_disable(child
);
701 wake_up_process(child
);
706 * make the child exit. Best I can do is send it a sigkill.
707 * perhaps it should be put in the status that it wants to
711 single_step_disable(child
);
712 if (child
->exit_state
!= EXIT_ZOMBIE
) {
713 child
->exit_code
= SIGKILL
;
714 wake_up_process(child
);
720 * execute single instruction.
722 case PTRACE_SINGLESTEP
:
724 if (!valid_signal(data
))
726 single_step_enable(child
);
727 clear_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
728 child
->exit_code
= data
;
729 /* give it a chance to run. */
730 wake_up_process(child
);
735 ret
= ptrace_detach(child
, data
);
739 ret
= ptrace_getregs(child
, (void __user
*)data
);
743 ret
= ptrace_setregs(child
, (void __user
*)data
);
746 case PTRACE_GETFPREGS
:
747 ret
= ptrace_getfpregs(child
, (void __user
*)data
);
750 case PTRACE_SETFPREGS
:
751 ret
= ptrace_setfpregs(child
, (void __user
*)data
);
755 case PTRACE_GETWMMXREGS
:
756 ret
= ptrace_getwmmxregs(child
, (void __user
*)data
);
759 case PTRACE_SETWMMXREGS
:
760 ret
= ptrace_setwmmxregs(child
, (void __user
*)data
);
764 case PTRACE_GET_THREAD_AREA
:
765 ret
= put_user(task_thread_info(child
)->tp_value
,
766 (unsigned long __user
*) data
);
769 case PTRACE_SET_SYSCALL
:
770 task_thread_info(child
)->syscall
= data
;
775 case PTRACE_GETCRUNCHREGS
:
776 ret
= ptrace_getcrunchregs(child
, (void __user
*)data
);
779 case PTRACE_SETCRUNCHREGS
:
780 ret
= ptrace_setcrunchregs(child
, (void __user
*)data
);
785 ret
= ptrace_request(child
, request
, addr
, data
);
792 asmlinkage
int syscall_trace(int why
, struct pt_regs
*regs
, int scno
)
796 if (!test_thread_flag(TIF_SYSCALL_TRACE
))
798 if (!(current
->ptrace
& PT_PTRACED
))
802 * Save IP. IP is used to denote syscall entry/exit:
803 * IP = 0 -> entry, = 1 -> exit
808 current_thread_info()->syscall
= scno
;
810 /* the 0x80 provides a way for the tracing parent to distinguish
811 between a syscall stop and SIGTRAP delivery */
812 ptrace_notify(SIGTRAP
| ((current
->ptrace
& PT_TRACESYSGOOD
)
815 * this isn't the same as continuing with a signal, but it will do
816 * for normal use. strace only continues with a signal if the
817 * stopping signal is not SIGTRAP. -brl
819 if (current
->exit_code
) {
820 send_sig(current
->exit_code
, current
, 1);
821 current
->exit_code
= 0;
825 return current_thread_info()->syscall
;