2 * linux/arch/arm26/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/signal.h>
23 #include <asm/uaccess.h>
24 #include <asm/pgtable.h>
25 #include <asm/system.h>
26 //#include <asm/processor.h>
33 * does not yet catch signals sent when the child dies.
34 * in exit.c or in signal.c.
38 * Breakpoint SWI instruction: SWI &9F0001
40 #define BREAKINST_ARM 0xef9f0001
43 * this routine will get a word off of the processes privileged stack.
44 * the offset is how far from the base addr as stored in the THREAD.
45 * this routine assumes that all the privileged stacks are in our
48 static inline long get_user_reg(struct task_struct
*task
, int offset
)
50 return task_pt_regs(task
)->uregs
[offset
];
54 * this routine will put a word on the processes privileged stack.
55 * the offset is how far from the base addr as stored in the THREAD.
56 * this routine assumes that all the privileged stacks are in our
60 put_user_reg(struct task_struct
*task
, int offset
, long data
)
62 struct pt_regs newregs
, *regs
= task_pt_regs(task
);
66 newregs
.uregs
[offset
] = data
;
68 if (valid_user_regs(&newregs
)) {
69 regs
->uregs
[offset
] = data
;
77 read_u32(struct task_struct
*task
, unsigned long addr
, u32
*res
)
81 ret
= access_process_vm(task
, addr
, res
, sizeof(*res
), 0);
83 return ret
== sizeof(*res
) ? 0 : -EIO
;
87 read_instr(struct task_struct
*task
, unsigned long addr
, u32
*res
)
91 ret
= access_process_vm(task
, addr
& ~3, &val
, sizeof(val
), 0);
92 ret
= ret
== sizeof(val
) ? 0 : -EIO
;
98 * Get value of register `rn' (in the instruction)
101 ptrace_getrn(struct task_struct
*child
, unsigned long insn
)
103 unsigned int reg
= (insn
>> 16) & 15;
106 val
= get_user_reg(child
, reg
);
108 val
= pc_pointer(val
+ 8); //FIXME - correct for arm26?
114 * Get value of operand 2 (in an ALU instruction)
117 ptrace_getaluop2(struct task_struct
*child
, unsigned long insn
)
123 if (insn
& 1 << 25) {
125 shift
= (insn
>> 8) & 15;
128 val
= get_user_reg (child
, insn
& 15);
131 shift
= (int)get_user_reg (child
, (insn
>> 8) & 15);
133 shift
= (insn
>> 7) & 31;
135 type
= (insn
>> 5) & 3;
139 case 0: val
<<= shift
; break;
140 case 1: val
>>= shift
; break;
142 val
= (((signed long)val
) >> shift
);
145 val
= (val
>> shift
) | (val
<< (32 - shift
));
152 * Get value of operand 2 (in a LDR instruction)
155 ptrace_getldrop2(struct task_struct
*child
, unsigned long insn
)
161 val
= get_user_reg(child
, insn
& 15);
162 shift
= (insn
>> 7) & 31;
163 type
= (insn
>> 5) & 3;
166 case 0: val
<<= shift
; break;
167 case 1: val
>>= shift
; break;
169 val
= (((signed long)val
) >> shift
);
172 val
= (val
>> shift
) | (val
<< (32 - shift
));
178 #define OP_MASK 0x01e00000
179 #define OP_AND 0x00000000
180 #define OP_EOR 0x00200000
181 #define OP_SUB 0x00400000
182 #define OP_RSB 0x00600000
183 #define OP_ADD 0x00800000
184 #define OP_ADC 0x00a00000
185 #define OP_SBC 0x00c00000
186 #define OP_RSC 0x00e00000
187 #define OP_ORR 0x01800000
188 #define OP_MOV 0x01a00000
189 #define OP_BIC 0x01c00000
190 #define OP_MVN 0x01e00000
193 get_branch_address(struct task_struct
*child
, unsigned long pc
, unsigned long insn
)
197 switch (insn
& 0x0e000000) {
203 long aluop1
, aluop2
, ccbit
;
205 if ((insn
& 0xf000) != 0xf000)
208 aluop1
= ptrace_getrn(child
, insn
);
209 aluop2
= ptrace_getaluop2(child
, insn
);
210 ccbit
= get_user_reg(child
, REG_PSR
) & PSR_C_BIT
? 1 : 0;
212 switch (insn
& OP_MASK
) {
213 case OP_AND
: alt
= aluop1
& aluop2
; break;
214 case OP_EOR
: alt
= aluop1
^ aluop2
; break;
215 case OP_SUB
: alt
= aluop1
- aluop2
; break;
216 case OP_RSB
: alt
= aluop2
- aluop1
; break;
217 case OP_ADD
: alt
= aluop1
+ aluop2
; break;
218 case OP_ADC
: alt
= aluop1
+ aluop2
+ ccbit
; break;
219 case OP_SBC
: alt
= aluop1
- aluop2
+ ccbit
; break;
220 case OP_RSC
: alt
= aluop2
- aluop1
+ ccbit
; break;
221 case OP_ORR
: alt
= aluop1
| aluop2
; break;
222 case OP_MOV
: alt
= aluop2
; break;
223 case OP_BIC
: alt
= aluop1
& ~aluop2
; break;
224 case OP_MVN
: alt
= ~aluop2
; break;
234 if ((insn
& 0x0010f000) == 0x0010f000) {
237 base
= ptrace_getrn(child
, insn
);
238 if (insn
& 1 << 24) {
241 if (insn
& 0x02000000)
242 aluop2
= ptrace_getldrop2(child
, insn
);
244 aluop2
= insn
& 0xfff;
251 if (read_u32(child
, base
, &alt
) == 0)
252 alt
= pc_pointer(alt
);
260 if ((insn
& 0x00108000) == 0x00108000) {
262 unsigned int nr_regs
;
264 if (insn
& (1 << 23)) {
265 nr_regs
= hweight16(insn
& 65535) << 2;
267 if (!(insn
& (1 << 24)))
270 if (insn
& (1 << 24))
276 base
= ptrace_getrn(child
, insn
);
278 if (read_u32(child
, base
+ nr_regs
, &alt
) == 0)
279 alt
= pc_pointer(alt
);
289 /* It's a branch/branch link: instead of trying to
290 * figure out whether the branch will be taken or not,
291 * we'll put a breakpoint at both locations. This is
292 * simpler, more reliable, and probably not a whole lot
293 * slower than the alternative approach of emulating the
296 displ
= (insn
& 0x00ffffff) << 8;
297 displ
= (displ
>> 6) + 8;
298 if (displ
!= 0 && displ
!= 4)
308 swap_insn(struct task_struct
*task
, unsigned long addr
,
309 void *old_insn
, void *new_insn
, int size
)
313 ret
= access_process_vm(task
, addr
, old_insn
, size
, 0);
315 ret
= access_process_vm(task
, addr
, new_insn
, size
, 1);
320 add_breakpoint(struct task_struct
*task
, struct debug_info
*dbg
, unsigned long addr
)
322 int nr
= dbg
->nsaved
;
325 u32 new_insn
= BREAKINST_ARM
;
328 res
= swap_insn(task
, addr
, &dbg
->bp
[nr
].insn
, &new_insn
, 4);
331 dbg
->bp
[nr
].address
= addr
;
335 printk(KERN_ERR
"ptrace: too many breakpoints\n");
339 * Clear one breakpoint in the user program. We copy what the hardware
340 * does and use bit 0 of the address to indicate whether this is a Thumb
341 * breakpoint or an ARM breakpoint.
343 static void clear_breakpoint(struct task_struct
*task
, struct debug_entry
*bp
)
345 unsigned long addr
= bp
->address
;
349 ret
= swap_insn(task
, addr
& ~3, &old_insn
,
352 if (ret
!= 4 || old_insn
!= BREAKINST_ARM
)
353 printk(KERN_ERR
"%s:%d: corrupted ARM breakpoint at "
354 "0x%08lx (0x%08x)\n", task
->comm
, task
->pid
,
358 void ptrace_set_bpt(struct task_struct
*child
)
360 struct pt_regs
*regs
;
365 regs
= task_pt_regs(child
);
366 pc
= instruction_pointer(regs
);
368 res
= read_instr(child
, pc
, &insn
);
370 struct debug_info
*dbg
= &child
->thread
.debug
;
375 alt
= get_branch_address(child
, pc
, insn
);
377 add_breakpoint(child
, dbg
, alt
);
380 * Note that we ignore the result of setting the above
381 * breakpoint since it may fail. When it does, this is
382 * not so much an error, but a forewarning that we may
383 * be receiving a prefetch abort shortly.
385 * If we don't set this breakpoint here, then we can
386 * lose control of the thread during single stepping.
388 if (!alt
|| predicate(insn
) != PREDICATE_ALWAYS
)
389 add_breakpoint(child
, dbg
, pc
+ 4);
394 * Ensure no single-step breakpoint is pending. Returns non-zero
395 * value if child was being single-stepped.
397 void ptrace_cancel_bpt(struct task_struct
*child
)
399 int i
, nsaved
= child
->thread
.debug
.nsaved
;
401 child
->thread
.debug
.nsaved
= 0;
404 printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved
);
408 for (i
= 0; i
< nsaved
; i
++)
409 clear_breakpoint(child
, &child
->thread
.debug
.bp
[i
]);
413 * Called by kernel/ptrace.c when detaching..
415 * Make sure the single step bit is not set.
417 void ptrace_disable(struct task_struct
*child
)
419 child
->ptrace
&= ~PT_SINGLESTEP
;
420 ptrace_cancel_bpt(child
);
424 * Handle hitting a breakpoint.
426 void ptrace_break(struct task_struct
*tsk
, struct pt_regs
*regs
)
431 * The PC is always left pointing at the next instruction. Fix this.
435 if (tsk
->thread
.debug
.nsaved
== 0)
436 printk(KERN_ERR
"ptrace: bogus breakpoint trap\n");
438 ptrace_cancel_bpt(tsk
);
440 info
.si_signo
= SIGTRAP
;
442 info
.si_code
= TRAP_BRKPT
;
443 info
.si_addr
= (void *)instruction_pointer(regs
) - 4;
445 force_sig_info(SIGTRAP
, &info
, tsk
);
449 * Read the word at offset "off" into the "struct user". We
450 * actually access the pt_regs stored on the kernel stack.
452 static int ptrace_read_user(struct task_struct
*tsk
, unsigned long off
,
457 if (off
& 3 || off
>= sizeof(struct user
))
461 if (off
< sizeof(struct pt_regs
))
462 tmp
= get_user_reg(tsk
, off
>> 2);
464 return put_user(tmp
, ret
);
468 * Write the word at offset "off" into "struct user". We
469 * actually access the pt_regs stored on the kernel stack.
471 static int ptrace_write_user(struct task_struct
*tsk
, unsigned long off
,
474 if (off
& 3 || off
>= sizeof(struct user
))
477 if (off
>= sizeof(struct pt_regs
))
480 return put_user_reg(tsk
, off
>> 2, val
);
484 * Get all user integer registers.
486 static int ptrace_getregs(struct task_struct
*tsk
, void *uregs
)
488 struct pt_regs
*regs
= task_pt_regs(tsk
);
490 return copy_to_user(uregs
, regs
, sizeof(struct pt_regs
)) ? -EFAULT
: 0;
494 * Set all user integer registers.
496 static int ptrace_setregs(struct task_struct
*tsk
, void *uregs
)
498 struct pt_regs newregs
;
502 if (copy_from_user(&newregs
, uregs
, sizeof(struct pt_regs
)) == 0) {
503 struct pt_regs
*regs
= task_pt_regs(tsk
);
506 if (valid_user_regs(&newregs
)) {
516 * Get the child FPU state.
518 static int ptrace_getfpregs(struct task_struct
*tsk
, void *ufp
)
520 return copy_to_user(ufp
, &task_thread_info(tsk
)->fpstate
,
521 sizeof(struct user_fp
)) ? -EFAULT
: 0;
525 * Set the child FPU state.
527 static int ptrace_setfpregs(struct task_struct
*tsk
, void *ufp
)
529 set_stopped_child_used_math(tsk
);
530 return copy_from_user(&task_thread_info(tsk
)->fpstate
, ufp
,
531 sizeof(struct user_fp
)) ? -EFAULT
: 0;
534 long arch_ptrace(struct task_struct
*child
, long request
, long addr
, long data
)
541 * read word at location "addr" in the child process.
543 case PTRACE_PEEKTEXT
:
544 case PTRACE_PEEKDATA
:
545 ret
= access_process_vm(child
, addr
, &tmp
,
546 sizeof(unsigned long), 0);
547 if (ret
== sizeof(unsigned long))
548 ret
= put_user(tmp
, (unsigned long *) data
);
554 ret
= ptrace_read_user(child
, addr
, (unsigned long *)data
);
558 * write the word at location addr.
560 case PTRACE_POKETEXT
:
561 case PTRACE_POKEDATA
:
562 ret
= access_process_vm(child
, addr
, &data
,
563 sizeof(unsigned long), 1);
564 if (ret
== sizeof(unsigned long))
571 ret
= ptrace_write_user(child
, addr
, data
);
575 * continue/restart and stop at next (return from) syscall
580 if (!valid_signal(data
))
582 if (request
== PTRACE_SYSCALL
)
583 set_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
585 clear_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
586 child
->exit_code
= data
;
587 /* make sure single-step breakpoint is gone. */
588 child
->ptrace
&= ~PT_SINGLESTEP
;
589 ptrace_cancel_bpt(child
);
590 wake_up_process(child
);
595 * make the child exit. Best I can do is send it a sigkill.
596 * perhaps it should be put in the status that it wants to
600 /* make sure single-step breakpoint is gone. */
601 child
->ptrace
&= ~PT_SINGLESTEP
;
602 ptrace_cancel_bpt(child
);
603 if (child
->exit_state
!= EXIT_ZOMBIE
) {
604 child
->exit_code
= SIGKILL
;
605 wake_up_process(child
);
611 * execute single instruction.
613 case PTRACE_SINGLESTEP
:
615 if (!valid_signal(data
))
617 child
->ptrace
|= PT_SINGLESTEP
;
618 clear_tsk_thread_flag(child
, TIF_SYSCALL_TRACE
);
619 child
->exit_code
= data
;
620 /* give it a chance to run. */
621 wake_up_process(child
);
626 ret
= ptrace_detach(child
, data
);
630 ret
= ptrace_getregs(child
, (void *)data
);
634 ret
= ptrace_setregs(child
, (void *)data
);
637 case PTRACE_GETFPREGS
:
638 ret
= ptrace_getfpregs(child
, (void *)data
);
641 case PTRACE_SETFPREGS
:
642 ret
= ptrace_setfpregs(child
, (void *)data
);
646 ret
= ptrace_request(child
, request
, addr
, data
);
653 asmlinkage
void syscall_trace(int why
, struct pt_regs
*regs
)
657 if (!test_thread_flag(TIF_SYSCALL_TRACE
))
659 if (!(current
->ptrace
& PT_PTRACED
))
663 * Save IP. IP is used to denote syscall entry/exit:
664 * IP = 0 -> entry, = 1 -> exit
669 /* the 0x80 provides a way for the tracing parent to distinguish
670 between a syscall stop and SIGTRAP delivery */
671 ptrace_notify(SIGTRAP
| ((current
->ptrace
& PT_TRACESYSGOOD
)
674 * this isn't the same as continuing with a signal, but it will do
675 * for normal use. strace only continues with a signal if the
676 * stopping signal is not SIGTRAP. -brl
678 if (current
->exit_code
) {
679 send_sig(current
->exit_code
, current
, 1);
680 current
->exit_code
= 0;