libata doc: "error : unterminated entity reference exceptions"
[usb.git] / arch / arm26 / kernel / ptrace.c
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1 /*
2 * linux/arch/arm26/kernel/ptrace.c
4 * By Ross Biro 1/23/92
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>
14 #include <linux/mm.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/signal.h>
22 #include <asm/uaccess.h>
23 #include <asm/pgtable.h>
24 #include <asm/system.h>
25 //#include <asm/processor.h>
27 #include "ptrace.h"
29 #define REG_PC 15
30 #define REG_PSR 15
32 * does not yet catch signals sent when the child dies.
33 * in exit.c or in signal.c.
37 * Breakpoint SWI instruction: SWI &9F0001
39 #define BREAKINST_ARM 0xef9f0001
42 * this routine will get a word off of the processes privileged stack.
43 * the offset is how far from the base addr as stored in the THREAD.
44 * this routine assumes that all the privileged stacks are in our
45 * data space.
47 static inline long get_user_reg(struct task_struct *task, int offset)
49 return task_pt_regs(task)->uregs[offset];
53 * this routine will put a word on the processes privileged stack.
54 * the offset is how far from the base addr as stored in the THREAD.
55 * this routine assumes that all the privileged stacks are in our
56 * data space.
58 static inline int
59 put_user_reg(struct task_struct *task, int offset, long data)
61 struct pt_regs newregs, *regs = task_pt_regs(task);
62 int ret = -EINVAL;
64 newregs = *regs;
65 newregs.uregs[offset] = data;
67 if (valid_user_regs(&newregs)) {
68 regs->uregs[offset] = data;
69 ret = 0;
72 return ret;
75 static inline int
76 read_u32(struct task_struct *task, unsigned long addr, u32 *res)
78 int ret;
80 ret = access_process_vm(task, addr, res, sizeof(*res), 0);
82 return ret == sizeof(*res) ? 0 : -EIO;
85 static inline int
86 read_instr(struct task_struct *task, unsigned long addr, u32 *res)
88 int ret;
89 u32 val;
90 ret = access_process_vm(task, addr & ~3, &val, sizeof(val), 0);
91 ret = ret == sizeof(val) ? 0 : -EIO;
92 *res = val;
93 return ret;
97 * Get value of register `rn' (in the instruction)
99 static unsigned long
100 ptrace_getrn(struct task_struct *child, unsigned long insn)
102 unsigned int reg = (insn >> 16) & 15;
103 unsigned long val;
105 val = get_user_reg(child, reg);
106 if (reg == 15)
107 val = pc_pointer(val + 8); //FIXME - correct for arm26?
109 return val;
113 * Get value of operand 2 (in an ALU instruction)
115 static unsigned long
116 ptrace_getaluop2(struct task_struct *child, unsigned long insn)
118 unsigned long val;
119 int shift;
120 int type;
122 if (insn & 1 << 25) {
123 val = insn & 255;
124 shift = (insn >> 8) & 15;
125 type = 3;
126 } else {
127 val = get_user_reg (child, insn & 15);
129 if (insn & (1 << 4))
130 shift = (int)get_user_reg (child, (insn >> 8) & 15);
131 else
132 shift = (insn >> 7) & 31;
134 type = (insn >> 5) & 3;
137 switch (type) {
138 case 0: val <<= shift; break;
139 case 1: val >>= shift; break;
140 case 2:
141 val = (((signed long)val) >> shift);
142 break;
143 case 3:
144 val = (val >> shift) | (val << (32 - shift));
145 break;
147 return val;
151 * Get value of operand 2 (in a LDR instruction)
153 static unsigned long
154 ptrace_getldrop2(struct task_struct *child, unsigned long insn)
156 unsigned long val;
157 int shift;
158 int type;
160 val = get_user_reg(child, insn & 15);
161 shift = (insn >> 7) & 31;
162 type = (insn >> 5) & 3;
164 switch (type) {
165 case 0: val <<= shift; break;
166 case 1: val >>= shift; break;
167 case 2:
168 val = (((signed long)val) >> shift);
169 break;
170 case 3:
171 val = (val >> shift) | (val << (32 - shift));
172 break;
174 return val;
177 #define OP_MASK 0x01e00000
178 #define OP_AND 0x00000000
179 #define OP_EOR 0x00200000
180 #define OP_SUB 0x00400000
181 #define OP_RSB 0x00600000
182 #define OP_ADD 0x00800000
183 #define OP_ADC 0x00a00000
184 #define OP_SBC 0x00c00000
185 #define OP_RSC 0x00e00000
186 #define OP_ORR 0x01800000
187 #define OP_MOV 0x01a00000
188 #define OP_BIC 0x01c00000
189 #define OP_MVN 0x01e00000
191 static unsigned long
192 get_branch_address(struct task_struct *child, unsigned long pc, unsigned long insn)
194 u32 alt = 0;
196 switch (insn & 0x0e000000) {
197 case 0x00000000:
198 case 0x02000000: {
200 * data processing
202 long aluop1, aluop2, ccbit;
204 if ((insn & 0xf000) != 0xf000)
205 break;
207 aluop1 = ptrace_getrn(child, insn);
208 aluop2 = ptrace_getaluop2(child, insn);
209 ccbit = get_user_reg(child, REG_PSR) & PSR_C_BIT ? 1 : 0;
211 switch (insn & OP_MASK) {
212 case OP_AND: alt = aluop1 & aluop2; break;
213 case OP_EOR: alt = aluop1 ^ aluop2; break;
214 case OP_SUB: alt = aluop1 - aluop2; break;
215 case OP_RSB: alt = aluop2 - aluop1; break;
216 case OP_ADD: alt = aluop1 + aluop2; break;
217 case OP_ADC: alt = aluop1 + aluop2 + ccbit; break;
218 case OP_SBC: alt = aluop1 - aluop2 + ccbit; break;
219 case OP_RSC: alt = aluop2 - aluop1 + ccbit; break;
220 case OP_ORR: alt = aluop1 | aluop2; break;
221 case OP_MOV: alt = aluop2; break;
222 case OP_BIC: alt = aluop1 & ~aluop2; break;
223 case OP_MVN: alt = ~aluop2; break;
225 break;
228 case 0x04000000:
229 case 0x06000000:
231 * ldr
233 if ((insn & 0x0010f000) == 0x0010f000) {
234 unsigned long base;
236 base = ptrace_getrn(child, insn);
237 if (insn & 1 << 24) {
238 long aluop2;
240 if (insn & 0x02000000)
241 aluop2 = ptrace_getldrop2(child, insn);
242 else
243 aluop2 = insn & 0xfff;
245 if (insn & 1 << 23)
246 base += aluop2;
247 else
248 base -= aluop2;
250 if (read_u32(child, base, &alt) == 0)
251 alt = pc_pointer(alt);
253 break;
255 case 0x08000000:
257 * ldm
259 if ((insn & 0x00108000) == 0x00108000) {
260 unsigned long base;
261 unsigned int nr_regs;
263 if (insn & (1 << 23)) {
264 nr_regs = hweight16(insn & 65535) << 2;
266 if (!(insn & (1 << 24)))
267 nr_regs -= 4;
268 } else {
269 if (insn & (1 << 24))
270 nr_regs = -4;
271 else
272 nr_regs = 0;
275 base = ptrace_getrn(child, insn);
277 if (read_u32(child, base + nr_regs, &alt) == 0)
278 alt = pc_pointer(alt);
279 break;
281 break;
283 case 0x0a000000: {
285 * bl or b
287 signed long displ;
288 /* It's a branch/branch link: instead of trying to
289 * figure out whether the branch will be taken or not,
290 * we'll put a breakpoint at both locations. This is
291 * simpler, more reliable, and probably not a whole lot
292 * slower than the alternative approach of emulating the
293 * branch.
295 displ = (insn & 0x00ffffff) << 8;
296 displ = (displ >> 6) + 8;
297 if (displ != 0 && displ != 4)
298 alt = pc + displ;
300 break;
303 return alt;
306 static int
307 swap_insn(struct task_struct *task, unsigned long addr,
308 void *old_insn, void *new_insn, int size)
310 int ret;
312 ret = access_process_vm(task, addr, old_insn, size, 0);
313 if (ret == size)
314 ret = access_process_vm(task, addr, new_insn, size, 1);
315 return ret;
318 static void
319 add_breakpoint(struct task_struct *task, struct debug_info *dbg, unsigned long addr)
321 int nr = dbg->nsaved;
323 if (nr < 2) {
324 u32 new_insn = BREAKINST_ARM;
325 int res;
327 res = swap_insn(task, addr, &dbg->bp[nr].insn, &new_insn, 4);
329 if (res == 4) {
330 dbg->bp[nr].address = addr;
331 dbg->nsaved += 1;
333 } else
334 printk(KERN_ERR "ptrace: too many breakpoints\n");
338 * Clear one breakpoint in the user program. We copy what the hardware
339 * does and use bit 0 of the address to indicate whether this is a Thumb
340 * breakpoint or an ARM breakpoint.
342 static void clear_breakpoint(struct task_struct *task, struct debug_entry *bp)
344 unsigned long addr = bp->address;
345 u32 old_insn;
346 int ret;
348 ret = swap_insn(task, addr & ~3, &old_insn,
349 &bp->insn, 4);
351 if (ret != 4 || old_insn != BREAKINST_ARM)
352 printk(KERN_ERR "%s:%d: corrupted ARM breakpoint at "
353 "0x%08lx (0x%08x)\n", task->comm, task->pid,
354 addr, old_insn);
357 void ptrace_set_bpt(struct task_struct *child)
359 struct pt_regs *regs;
360 unsigned long pc;
361 u32 insn;
362 int res;
364 regs = task_pt_regs(child);
365 pc = instruction_pointer(regs);
367 res = read_instr(child, pc, &insn);
368 if (!res) {
369 struct debug_info *dbg = &child->thread.debug;
370 unsigned long alt;
372 dbg->nsaved = 0;
374 alt = get_branch_address(child, pc, insn);
375 if (alt)
376 add_breakpoint(child, dbg, alt);
379 * Note that we ignore the result of setting the above
380 * breakpoint since it may fail. When it does, this is
381 * not so much an error, but a forewarning that we may
382 * be receiving a prefetch abort shortly.
384 * If we don't set this breakpoint here, then we can
385 * lose control of the thread during single stepping.
387 if (!alt || predicate(insn) != PREDICATE_ALWAYS)
388 add_breakpoint(child, dbg, pc + 4);
393 * Ensure no single-step breakpoint is pending. Returns non-zero
394 * value if child was being single-stepped.
396 void ptrace_cancel_bpt(struct task_struct *child)
398 int i, nsaved = child->thread.debug.nsaved;
400 child->thread.debug.nsaved = 0;
402 if (nsaved > 2) {
403 printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved);
404 nsaved = 2;
407 for (i = 0; i < nsaved; i++)
408 clear_breakpoint(child, &child->thread.debug.bp[i]);
412 * Called by kernel/ptrace.c when detaching..
414 * Make sure the single step bit is not set.
416 void ptrace_disable(struct task_struct *child)
418 child->ptrace &= ~PT_SINGLESTEP;
419 ptrace_cancel_bpt(child);
423 * Handle hitting a breakpoint.
425 void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
427 siginfo_t info;
430 * The PC is always left pointing at the next instruction. Fix this.
432 regs->ARM_pc -= 4;
434 if (tsk->thread.debug.nsaved == 0)
435 printk(KERN_ERR "ptrace: bogus breakpoint trap\n");
437 ptrace_cancel_bpt(tsk);
439 info.si_signo = SIGTRAP;
440 info.si_errno = 0;
441 info.si_code = TRAP_BRKPT;
442 info.si_addr = (void *)instruction_pointer(regs) - 4;
444 force_sig_info(SIGTRAP, &info, tsk);
448 * Read the word at offset "off" into the "struct user". We
449 * actually access the pt_regs stored on the kernel stack.
451 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
452 unsigned long *ret)
454 unsigned long tmp;
456 if (off & 3 || off >= sizeof(struct user))
457 return -EIO;
459 tmp = 0;
460 if (off < sizeof(struct pt_regs))
461 tmp = get_user_reg(tsk, off >> 2);
463 return put_user(tmp, ret);
467 * Write the word at offset "off" into "struct user". We
468 * actually access the pt_regs stored on the kernel stack.
470 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
471 unsigned long val)
473 if (off & 3 || off >= sizeof(struct user))
474 return -EIO;
476 if (off >= sizeof(struct pt_regs))
477 return 0;
479 return put_user_reg(tsk, off >> 2, val);
483 * Get all user integer registers.
485 static int ptrace_getregs(struct task_struct *tsk, void *uregs)
487 struct pt_regs *regs = task_pt_regs(tsk);
489 return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
493 * Set all user integer registers.
495 static int ptrace_setregs(struct task_struct *tsk, void *uregs)
497 struct pt_regs newregs;
498 int ret;
500 ret = -EFAULT;
501 if (copy_from_user(&newregs, uregs, sizeof(struct pt_regs)) == 0) {
502 struct pt_regs *regs = task_pt_regs(tsk);
504 ret = -EINVAL;
505 if (valid_user_regs(&newregs)) {
506 *regs = newregs;
507 ret = 0;
511 return ret;
515 * Get the child FPU state.
517 static int ptrace_getfpregs(struct task_struct *tsk, void *ufp)
519 return copy_to_user(ufp, &task_thread_info(tsk)->fpstate,
520 sizeof(struct user_fp)) ? -EFAULT : 0;
524 * Set the child FPU state.
526 static int ptrace_setfpregs(struct task_struct *tsk, void *ufp)
528 set_stopped_child_used_math(tsk);
529 return copy_from_user(&task_thread_info(tsk)->fpstate, ufp,
530 sizeof(struct user_fp)) ? -EFAULT : 0;
533 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
535 unsigned long tmp;
536 int ret;
538 switch (request) {
540 * read word at location "addr" in the child process.
542 case PTRACE_PEEKTEXT:
543 case PTRACE_PEEKDATA:
544 ret = access_process_vm(child, addr, &tmp,
545 sizeof(unsigned long), 0);
546 if (ret == sizeof(unsigned long))
547 ret = put_user(tmp, (unsigned long *) data);
548 else
549 ret = -EIO;
550 break;
552 case PTRACE_PEEKUSR:
553 ret = ptrace_read_user(child, addr, (unsigned long *)data);
554 break;
557 * write the word at location addr.
559 case PTRACE_POKETEXT:
560 case PTRACE_POKEDATA:
561 ret = access_process_vm(child, addr, &data,
562 sizeof(unsigned long), 1);
563 if (ret == sizeof(unsigned long))
564 ret = 0;
565 else
566 ret = -EIO;
567 break;
569 case PTRACE_POKEUSR:
570 ret = ptrace_write_user(child, addr, data);
571 break;
574 * continue/restart and stop at next (return from) syscall
576 case PTRACE_SYSCALL:
577 case PTRACE_CONT:
578 ret = -EIO;
579 if (!valid_signal(data))
580 break;
581 if (request == PTRACE_SYSCALL)
582 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
583 else
584 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
585 child->exit_code = data;
586 /* make sure single-step breakpoint is gone. */
587 child->ptrace &= ~PT_SINGLESTEP;
588 ptrace_cancel_bpt(child);
589 wake_up_process(child);
590 ret = 0;
591 break;
594 * make the child exit. Best I can do is send it a sigkill.
595 * perhaps it should be put in the status that it wants to
596 * exit.
598 case PTRACE_KILL:
599 /* make sure single-step breakpoint is gone. */
600 child->ptrace &= ~PT_SINGLESTEP;
601 ptrace_cancel_bpt(child);
602 if (child->exit_state != EXIT_ZOMBIE) {
603 child->exit_code = SIGKILL;
604 wake_up_process(child);
606 ret = 0;
607 break;
610 * execute single instruction.
612 case PTRACE_SINGLESTEP:
613 ret = -EIO;
614 if (!valid_signal(data))
615 break;
616 child->ptrace |= PT_SINGLESTEP;
617 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
618 child->exit_code = data;
619 /* give it a chance to run. */
620 wake_up_process(child);
621 ret = 0;
622 break;
624 case PTRACE_DETACH:
625 ret = ptrace_detach(child, data);
626 break;
628 case PTRACE_GETREGS:
629 ret = ptrace_getregs(child, (void *)data);
630 break;
632 case PTRACE_SETREGS:
633 ret = ptrace_setregs(child, (void *)data);
634 break;
636 case PTRACE_GETFPREGS:
637 ret = ptrace_getfpregs(child, (void *)data);
638 break;
640 case PTRACE_SETFPREGS:
641 ret = ptrace_setfpregs(child, (void *)data);
642 break;
644 default:
645 ret = ptrace_request(child, request, addr, data);
646 break;
649 return ret;
652 asmlinkage void syscall_trace(int why, struct pt_regs *regs)
654 unsigned long ip;
656 if (!test_thread_flag(TIF_SYSCALL_TRACE))
657 return;
658 if (!(current->ptrace & PT_PTRACED))
659 return;
662 * Save IP. IP is used to denote syscall entry/exit:
663 * IP = 0 -> entry, = 1 -> exit
665 ip = regs->ARM_ip;
666 regs->ARM_ip = why;
668 /* the 0x80 provides a way for the tracing parent to distinguish
669 between a syscall stop and SIGTRAP delivery */
670 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
671 ? 0x80 : 0));
673 * this isn't the same as continuing with a signal, but it will do
674 * for normal use. strace only continues with a signal if the
675 * stopping signal is not SIGTRAP. -brl
677 if (current->exit_code) {
678 send_sig(current->exit_code, current, 1);
679 current->exit_code = 0;
681 regs->ARM_ip = ip;