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/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/signal.h>
21 #include <asm/uaccess.h>
22 #include <asm/pgtable.h>
23 #include <asm/system.h>
24 //#include <asm/processor.h>
31 * does not yet catch signals sent when the child dies.
32 * in exit.c or in signal.c.
36 * Breakpoint SWI instruction: SWI &9F0001
38 #define BREAKINST_ARM 0xef9f0001
41 * this routine will get a word off of the processes privileged stack.
42 * the offset is how far from the base addr as stored in the THREAD.
43 * this routine assumes that all the privileged stacks are in our
46 static inline long get_user_reg(struct task_struct *task, int offset)
48 return task_pt_regs(task)->uregs[offset];
52 * this routine will put a word on the processes privileged stack.
53 * the offset is how far from the base addr as stored in the THREAD.
54 * this routine assumes that all the privileged stacks are in our
58 put_user_reg(struct task_struct *task, int offset, long data)
60 struct pt_regs newregs, *regs = task_pt_regs(task);
64 newregs.uregs[offset] = data;
66 if (valid_user_regs(&newregs)) {
67 regs->uregs[offset] = data;
75 read_u32(struct task_struct *task, unsigned long addr, u32 *res)
79 ret = access_process_vm(task, addr, res, sizeof(*res), 0);
81 return ret == sizeof(*res) ? 0 : -EIO;
85 read_instr(struct task_struct *task, unsigned long addr, u32 *res)
89 ret = access_process_vm(task, addr & ~3, &val, sizeof(val), 0);
90 ret = ret == sizeof(val) ? 0 : -EIO;
96 * Get value of register `rn' (in the instruction)
99 ptrace_getrn(struct task_struct *child, unsigned long insn)
101 unsigned int reg = (insn >> 16) & 15;
104 val = get_user_reg(child, reg);
106 val = pc_pointer(val + 8); //FIXME - correct for arm26?
112 * Get value of operand 2 (in an ALU instruction)
115 ptrace_getaluop2(struct task_struct *child, unsigned long insn)
121 if (insn & 1 << 25) {
123 shift = (insn >> 8) & 15;
126 val = get_user_reg (child, insn & 15);
129 shift = (int)get_user_reg (child, (insn >> 8) & 15);
131 shift = (insn >> 7) & 31;
133 type = (insn >> 5) & 3;
137 case 0: val <<= shift; break;
138 case 1: val >>= shift; break;
140 val = (((signed long)val) >> shift);
143 val = (val >> shift) | (val << (32 - shift));
150 * Get value of operand 2 (in a LDR instruction)
153 ptrace_getldrop2(struct task_struct *child, unsigned long insn)
159 val = get_user_reg(child, insn & 15);
160 shift = (insn >> 7) & 31;
161 type = (insn >> 5) & 3;
164 case 0: val <<= shift; break;
165 case 1: val >>= shift; break;
167 val = (((signed long)val) >> shift);
170 val = (val >> shift) | (val << (32 - shift));
176 #define OP_MASK 0x01e00000
177 #define OP_AND 0x00000000
178 #define OP_EOR 0x00200000
179 #define OP_SUB 0x00400000
180 #define OP_RSB 0x00600000
181 #define OP_ADD 0x00800000
182 #define OP_ADC 0x00a00000
183 #define OP_SBC 0x00c00000
184 #define OP_RSC 0x00e00000
185 #define OP_ORR 0x01800000
186 #define OP_MOV 0x01a00000
187 #define OP_BIC 0x01c00000
188 #define OP_MVN 0x01e00000
191 get_branch_address(struct task_struct *child, unsigned long pc, unsigned long insn)
195 switch (insn & 0x0e000000) {
201 long aluop1, aluop2, ccbit;
203 if ((insn & 0xf000) != 0xf000)
206 aluop1 = ptrace_getrn(child, insn);
207 aluop2 = ptrace_getaluop2(child, insn);
208 ccbit = get_user_reg(child, REG_PSR) & PSR_C_BIT ? 1 : 0;
210 switch (insn & OP_MASK) {
211 case OP_AND: alt = aluop1 & aluop2; break;
212 case OP_EOR: alt = aluop1 ^ aluop2; break;
213 case OP_SUB: alt = aluop1 - aluop2; break;
214 case OP_RSB: alt = aluop2 - aluop1; break;
215 case OP_ADD: alt = aluop1 + aluop2; break;
216 case OP_ADC: alt = aluop1 + aluop2 + ccbit; break;
217 case OP_SBC: alt = aluop1 - aluop2 + ccbit; break;
218 case OP_RSC: alt = aluop2 - aluop1 + ccbit; break;
219 case OP_ORR: alt = aluop1 | aluop2; break;
220 case OP_MOV: alt = aluop2; break;
221 case OP_BIC: alt = aluop1 & ~aluop2; break;
222 case OP_MVN: alt = ~aluop2; break;
232 if ((insn & 0x0010f000) == 0x0010f000) {
235 base = ptrace_getrn(child, insn);
236 if (insn & 1 << 24) {
239 if (insn & 0x02000000)
240 aluop2 = ptrace_getldrop2(child, insn);
242 aluop2 = insn & 0xfff;
249 if (read_u32(child, base, &alt) == 0)
250 alt = pc_pointer(alt);
258 if ((insn & 0x00108000) == 0x00108000) {
260 unsigned int nr_regs;
262 if (insn & (1 << 23)) {
263 nr_regs = hweight16(insn & 65535) << 2;
265 if (!(insn & (1 << 24)))
268 if (insn & (1 << 24))
274 base = ptrace_getrn(child, insn);
276 if (read_u32(child, base + nr_regs, &alt) == 0)
277 alt = pc_pointer(alt);
287 /* It's a branch/branch link: instead of trying to
288 * figure out whether the branch will be taken or not,
289 * we'll put a breakpoint at both locations. This is
290 * simpler, more reliable, and probably not a whole lot
291 * slower than the alternative approach of emulating the
294 displ = (insn & 0x00ffffff) << 8;
295 displ = (displ >> 6) + 8;
296 if (displ != 0 && displ != 4)
306 swap_insn(struct task_struct *task, unsigned long addr,
307 void *old_insn, void *new_insn, int size)
311 ret = access_process_vm(task, addr, old_insn, size, 0);
313 ret = access_process_vm(task, addr, new_insn, size, 1);
318 add_breakpoint(struct task_struct *task, struct debug_info *dbg, unsigned long addr)
320 int nr = dbg->nsaved;
323 u32 new_insn = BREAKINST_ARM;
326 res = swap_insn(task, addr, &dbg->bp[nr].insn, &new_insn, 4);
329 dbg->bp[nr].address = addr;
333 printk(KERN_ERR "ptrace: too many breakpoints\n");
337 * Clear one breakpoint in the user program. We copy what the hardware
338 * does and use bit 0 of the address to indicate whether this is a Thumb
339 * breakpoint or an ARM breakpoint.
341 static void clear_breakpoint(struct task_struct *task, struct debug_entry *bp)
343 unsigned long addr = bp->address;
347 ret = swap_insn(task, addr & ~3, &old_insn,
350 if (ret != 4 || old_insn != BREAKINST_ARM)
351 printk(KERN_ERR "%s:%d: corrupted ARM breakpoint at "
352 "0x%08lx (0x%08x)\n", task->comm, task->pid,
356 void ptrace_set_bpt(struct task_struct *child)
358 struct pt_regs *regs;
363 regs = task_pt_regs(child);
364 pc = instruction_pointer(regs);
366 res = read_instr(child, pc, &insn);
368 struct debug_info *dbg = &child->thread.debug;
373 alt = get_branch_address(child, pc, insn);
375 add_breakpoint(child, dbg, alt);
378 * Note that we ignore the result of setting the above
379 * breakpoint since it may fail. When it does, this is
380 * not so much an error, but a forewarning that we may
381 * be receiving a prefetch abort shortly.
383 * If we don't set this breakpoint here, then we can
384 * lose control of the thread during single stepping.
386 if (!alt || predicate(insn) != PREDICATE_ALWAYS)
387 add_breakpoint(child, dbg, pc + 4);
392 * Ensure no single-step breakpoint is pending. Returns non-zero
393 * value if child was being single-stepped.
395 void ptrace_cancel_bpt(struct task_struct *child)
397 int i, nsaved = child->thread.debug.nsaved;
399 child->thread.debug.nsaved = 0;
402 printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved);
406 for (i = 0; i < nsaved; i++)
407 clear_breakpoint(child, &child->thread.debug.bp[i]);
411 * Called by kernel/ptrace.c when detaching..
413 * Make sure the single step bit is not set.
415 void ptrace_disable(struct task_struct *child)
417 child->ptrace &= ~PT_SINGLESTEP;
418 ptrace_cancel_bpt(child);
422 * Handle hitting a breakpoint.
424 void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
429 * The PC is always left pointing at the next instruction. Fix this.
433 if (tsk->thread.debug.nsaved == 0)
434 printk(KERN_ERR "ptrace: bogus breakpoint trap\n");
436 ptrace_cancel_bpt(tsk);
438 info.si_signo = SIGTRAP;
440 info.si_code = TRAP_BRKPT;
441 info.si_addr = (void *)instruction_pointer(regs) - 4;
443 force_sig_info(SIGTRAP, &info, tsk);
447 * Read the word at offset "off" into the "struct user". We
448 * actually access the pt_regs stored on the kernel stack.
450 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
455 if (off & 3 || off >= sizeof(struct user))
459 if (off < sizeof(struct pt_regs))
460 tmp = get_user_reg(tsk, off >> 2);
462 return put_user(tmp, ret);
466 * Write the word at offset "off" into "struct user". We
467 * actually access the pt_regs stored on the kernel stack.
469 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
472 if (off & 3 || off >= sizeof(struct user))
475 if (off >= sizeof(struct pt_regs))
478 return put_user_reg(tsk, off >> 2, val);
482 * Get all user integer registers.
484 static int ptrace_getregs(struct task_struct *tsk, void *uregs)
486 struct pt_regs *regs = task_pt_regs(tsk);
488 return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
492 * Set all user integer registers.
494 static int ptrace_setregs(struct task_struct *tsk, void *uregs)
496 struct pt_regs newregs;
500 if (copy_from_user(&newregs, uregs, sizeof(struct pt_regs)) == 0) {
501 struct pt_regs *regs = task_pt_regs(tsk);
504 if (valid_user_regs(&newregs)) {
514 * Get the child FPU state.
516 static int ptrace_getfpregs(struct task_struct *tsk, void *ufp)
518 return copy_to_user(ufp, &task_thread_info(tsk)->fpstate,
519 sizeof(struct user_fp)) ? -EFAULT : 0;
523 * Set the child FPU state.
525 static int ptrace_setfpregs(struct task_struct *tsk, void *ufp)
527 set_stopped_child_used_math(tsk);
528 return copy_from_user(&task_thread_info(tsk)->fpstate, ufp,
529 sizeof(struct user_fp)) ? -EFAULT : 0;
532 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
538 * read word at location "addr" in the child process.
540 case PTRACE_PEEKTEXT:
541 case PTRACE_PEEKDATA:
542 ret = generic_ptrace_peekdata(child, addr, data);
546 ret = ptrace_read_user(child, addr, (unsigned long *)data);
550 * write the word at location addr.
552 case PTRACE_POKETEXT:
553 case PTRACE_POKEDATA:
554 ret = access_process_vm(child, addr, &data,
555 sizeof(unsigned long), 1);
556 if (ret == sizeof(unsigned long))
563 ret = ptrace_write_user(child, addr, data);
567 * continue/restart and stop at next (return from) syscall
572 if (!valid_signal(data))
574 if (request == PTRACE_SYSCALL)
575 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
577 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
578 child->exit_code = data;
579 /* make sure single-step breakpoint is gone. */
580 child->ptrace &= ~PT_SINGLESTEP;
581 ptrace_cancel_bpt(child);
582 wake_up_process(child);
587 * make the child exit. Best I can do is send it a sigkill.
588 * perhaps it should be put in the status that it wants to
592 /* make sure single-step breakpoint is gone. */
593 child->ptrace &= ~PT_SINGLESTEP;
594 ptrace_cancel_bpt(child);
595 if (child->exit_state != EXIT_ZOMBIE) {
596 child->exit_code = SIGKILL;
597 wake_up_process(child);
603 * execute single instruction.
605 case PTRACE_SINGLESTEP:
607 if (!valid_signal(data))
609 child->ptrace |= PT_SINGLESTEP;
610 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
611 child->exit_code = data;
612 /* give it a chance to run. */
613 wake_up_process(child);
618 ret = ptrace_detach(child, data);
622 ret = ptrace_getregs(child, (void *)data);
626 ret = ptrace_setregs(child, (void *)data);
629 case PTRACE_GETFPREGS:
630 ret = ptrace_getfpregs(child, (void *)data);
633 case PTRACE_SETFPREGS:
634 ret = ptrace_setfpregs(child, (void *)data);
638 ret = ptrace_request(child, request, addr, data);
645 asmlinkage void syscall_trace(int why, struct pt_regs *regs)
649 if (!test_thread_flag(TIF_SYSCALL_TRACE))
651 if (!(current->ptrace & PT_PTRACED))
655 * Save IP. IP is used to denote syscall entry/exit:
656 * IP = 0 -> entry, = 1 -> exit
661 /* the 0x80 provides a way for the tracing parent to distinguish
662 between a syscall stop and SIGTRAP delivery */
663 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
666 * this isn't the same as continuing with a signal, but it will do
667 * for normal use. strace only continues with a signal if the
668 * stopping signal is not SIGTRAP. -brl
670 if (current->exit_code) {
671 send_sig(current->exit_code, current, 1);
672 current->exit_code = 0;