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/elf.h>
16 #include <linux/smp.h>
17 #include <linux/ptrace.h>
18 #include <linux/user.h>
19 #include <linux/security.h>
20 #include <linux/init.h>
21 #include <linux/signal.h>
22 #include <linux/uaccess.h>
23 #include <linux/perf_event.h>
24 #include <linux/hw_breakpoint.h>
25 #include <linux/regset.h>
27 #include <asm/pgtable.h>
28 #include <asm/system.h>
29 #include <asm/traps.h>
34 * does not yet catch signals sent when the child dies.
35 * in exit.c or in signal.c.
40 * Breakpoint SWI instruction: SWI &9F0001
42 #define BREAKINST_ARM 0xef9f0001
43 #define BREAKINST_THUMB 0xdf00 /* fill this in later */
46 * New breakpoints - use an undefined instruction. The ARM architecture
47 * reference manual guarantees that the following instruction space
48 * will produce an undefined instruction exception on all CPUs:
50 * ARM: xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
51 * Thumb: 1101 1110 xxxx xxxx
53 #define BREAKINST_ARM 0xe7f001f0
54 #define BREAKINST_THUMB 0xde01
57 struct pt_regs_offset {
62 #define REG_OFFSET_NAME(r) \
63 {.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
64 #define REG_OFFSET_END {.name = NULL, .offset = 0}
66 static const struct pt_regs_offset regoffset_table[] = {
83 REG_OFFSET_NAME(cpsr),
84 REG_OFFSET_NAME(ORIG_r0),
89 * regs_query_register_offset() - query register offset from its name
90 * @name: the name of a register
92 * regs_query_register_offset() returns the offset of a register in struct
93 * pt_regs from its name. If the name is invalid, this returns -EINVAL;
95 int regs_query_register_offset(const char *name)
97 const struct pt_regs_offset *roff;
98 for (roff = regoffset_table; roff->name != NULL; roff++)
99 if (!strcmp(roff->name, name))
105 * regs_query_register_name() - query register name from its offset
106 * @offset: the offset of a register in struct pt_regs.
108 * regs_query_register_name() returns the name of a register from its
109 * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
111 const char *regs_query_register_name(unsigned int offset)
113 const struct pt_regs_offset *roff;
114 for (roff = regoffset_table; roff->name != NULL; roff++)
115 if (roff->offset == offset)
121 * regs_within_kernel_stack() - check the address in the stack
122 * @regs: pt_regs which contains kernel stack pointer.
123 * @addr: address which is checked.
125 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
126 * If @addr is within the kernel stack, it returns true. If not, returns false.
128 bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
130 return ((addr & ~(THREAD_SIZE - 1)) ==
131 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
135 * regs_get_kernel_stack_nth() - get Nth entry of the stack
136 * @regs: pt_regs which contains kernel stack pointer.
137 * @n: stack entry number.
139 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
140 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
143 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
145 unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
147 if (regs_within_kernel_stack(regs, (unsigned long)addr))
154 * this routine will get a word off of the processes privileged stack.
155 * the offset is how far from the base addr as stored in the THREAD.
156 * this routine assumes that all the privileged stacks are in our
159 static inline long get_user_reg(struct task_struct *task, int offset)
161 return task_pt_regs(task)->uregs[offset];
165 * this routine will put a word on the processes privileged stack.
166 * the offset is how far from the base addr as stored in the THREAD.
167 * this routine assumes that all the privileged stacks are in our
171 put_user_reg(struct task_struct *task, int offset, long data)
173 struct pt_regs newregs, *regs = task_pt_regs(task);
177 newregs.uregs[offset] = data;
179 if (valid_user_regs(&newregs)) {
180 regs->uregs[offset] = data;
188 * Called by kernel/ptrace.c when detaching..
190 void ptrace_disable(struct task_struct *child)
196 * Handle hitting a breakpoint.
198 void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
202 info.si_signo = SIGTRAP;
204 info.si_code = TRAP_BRKPT;
205 info.si_addr = (void __user *)instruction_pointer(regs);
207 force_sig_info(SIGTRAP, &info, tsk);
210 static int break_trap(struct pt_regs *regs, unsigned int instr)
212 ptrace_break(current, regs);
216 static struct undef_hook arm_break_hook = {
217 .instr_mask = 0x0fffffff,
218 .instr_val = 0x07f001f0,
219 .cpsr_mask = PSR_T_BIT,
224 static struct undef_hook thumb_break_hook = {
225 .instr_mask = 0xffff,
227 .cpsr_mask = PSR_T_BIT,
228 .cpsr_val = PSR_T_BIT,
232 static struct undef_hook thumb2_break_hook = {
233 .instr_mask = 0xffffffff,
234 .instr_val = 0xf7f0a000,
235 .cpsr_mask = PSR_T_BIT,
236 .cpsr_val = PSR_T_BIT,
240 static int __init ptrace_break_init(void)
242 register_undef_hook(&arm_break_hook);
243 register_undef_hook(&thumb_break_hook);
244 register_undef_hook(&thumb2_break_hook);
248 core_initcall(ptrace_break_init);
251 * Read the word at offset "off" into the "struct user". We
252 * actually access the pt_regs stored on the kernel stack.
254 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
255 unsigned long __user *ret)
259 if (off & 3 || off >= sizeof(struct user))
263 if (off == PT_TEXT_ADDR)
264 tmp = tsk->mm->start_code;
265 else if (off == PT_DATA_ADDR)
266 tmp = tsk->mm->start_data;
267 else if (off == PT_TEXT_END_ADDR)
268 tmp = tsk->mm->end_code;
269 else if (off < sizeof(struct pt_regs))
270 tmp = get_user_reg(tsk, off >> 2);
272 return put_user(tmp, ret);
276 * Write the word at offset "off" into "struct user". We
277 * actually access the pt_regs stored on the kernel stack.
279 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
282 if (off & 3 || off >= sizeof(struct user))
285 if (off >= sizeof(struct pt_regs))
288 return put_user_reg(tsk, off >> 2, val);
294 * Get the child iWMMXt state.
296 static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
298 struct thread_info *thread = task_thread_info(tsk);
300 if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
302 iwmmxt_task_disable(thread); /* force it to ram */
303 return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
308 * Set the child iWMMXt state.
310 static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
312 struct thread_info *thread = task_thread_info(tsk);
314 if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
316 iwmmxt_task_release(thread); /* force a reload */
317 return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
325 * Get the child Crunch state.
327 static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
329 struct thread_info *thread = task_thread_info(tsk);
331 crunch_task_disable(thread); /* force it to ram */
332 return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
337 * Set the child Crunch state.
339 static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
341 struct thread_info *thread = task_thread_info(tsk);
343 crunch_task_release(thread); /* force a reload */
344 return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
349 #ifdef CONFIG_HAVE_HW_BREAKPOINT
351 * Convert a virtual register number into an index for a thread_info
352 * breakpoint array. Breakpoints are identified using positive numbers
353 * whilst watchpoints are negative. The registers are laid out as pairs
354 * of (address, control), each pair mapping to a unique hw_breakpoint struct.
355 * Register 0 is reserved for describing resource information.
357 static int ptrace_hbp_num_to_idx(long num)
360 num = (ARM_MAX_BRP << 1) - num;
361 return (num - 1) >> 1;
365 * Returns the virtual register number for the address of the
366 * breakpoint at index idx.
368 static long ptrace_hbp_idx_to_num(int idx)
370 long mid = ARM_MAX_BRP << 1;
371 long num = (idx << 1) + 1;
372 return num > mid ? mid - num : num;
376 * Handle hitting a HW-breakpoint.
378 static void ptrace_hbptriggered(struct perf_event *bp,
379 struct perf_sample_data *data,
380 struct pt_regs *regs)
382 struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
387 for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
388 if (current->thread.debug.hbp[i] == bp)
391 num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
393 info.si_signo = SIGTRAP;
394 info.si_errno = (int)num;
395 info.si_code = TRAP_HWBKPT;
396 info.si_addr = (void __user *)(bkpt->trigger);
398 force_sig_info(SIGTRAP, &info, current);
402 * Set ptrace breakpoint pointers to zero for this task.
403 * This is required in order to prevent child processes from unregistering
404 * breakpoints held by their parent.
406 void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
408 memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
412 * Unregister breakpoints from this task and reset the pointers in
415 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
418 struct thread_struct *t = &tsk->thread;
420 for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
421 if (t->debug.hbp[i]) {
422 unregister_hw_breakpoint(t->debug.hbp[i]);
423 t->debug.hbp[i] = NULL;
428 static u32 ptrace_get_hbp_resource_info(void)
430 u8 num_brps, num_wrps, debug_arch, wp_len;
433 num_brps = hw_breakpoint_slots(TYPE_INST);
434 num_wrps = hw_breakpoint_slots(TYPE_DATA);
435 debug_arch = arch_get_debug_arch();
436 wp_len = arch_get_max_wp_len();
449 static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
451 struct perf_event_attr attr;
453 ptrace_breakpoint_init(&attr);
455 /* Initialise fields to sane defaults. */
457 attr.bp_len = HW_BREAKPOINT_LEN_4;
461 return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
465 static int ptrace_gethbpregs(struct task_struct *tsk, long num,
466 unsigned long __user *data)
470 struct perf_event *bp;
471 struct arch_hw_breakpoint_ctrl arch_ctrl;
474 reg = ptrace_get_hbp_resource_info();
476 idx = ptrace_hbp_num_to_idx(num);
477 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
482 bp = tsk->thread.debug.hbp[idx];
488 arch_ctrl = counter_arch_bp(bp)->ctrl;
491 * Fix up the len because we may have adjusted it
492 * to compensate for an unaligned address.
494 while (!(arch_ctrl.len & 0x1))
498 reg = bp->attr.bp_addr;
500 reg = encode_ctrl_reg(arch_ctrl);
504 if (put_user(reg, data))
511 static int ptrace_sethbpregs(struct task_struct *tsk, long num,
512 unsigned long __user *data)
514 int idx, gen_len, gen_type, implied_type, ret = 0;
516 struct perf_event *bp;
517 struct arch_hw_breakpoint_ctrl ctrl;
518 struct perf_event_attr attr;
523 implied_type = HW_BREAKPOINT_RW;
525 implied_type = HW_BREAKPOINT_X;
527 idx = ptrace_hbp_num_to_idx(num);
528 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
533 if (get_user(user_val, data)) {
538 bp = tsk->thread.debug.hbp[idx];
540 bp = ptrace_hbp_create(tsk, implied_type);
545 tsk->thread.debug.hbp[idx] = bp;
552 attr.bp_addr = user_val;
555 decode_ctrl_reg(user_val, &ctrl);
556 ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
560 if ((gen_type & implied_type) != gen_type) {
565 attr.bp_len = gen_len;
566 attr.bp_type = gen_type;
567 attr.disabled = !ctrl.enabled;
570 ret = modify_user_hw_breakpoint(bp, &attr);
576 /* regset get/set implementations */
578 static int gpr_get(struct task_struct *target,
579 const struct user_regset *regset,
580 unsigned int pos, unsigned int count,
581 void *kbuf, void __user *ubuf)
583 struct pt_regs *regs = task_pt_regs(target);
585 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
590 static int gpr_set(struct task_struct *target,
591 const struct user_regset *regset,
592 unsigned int pos, unsigned int count,
593 const void *kbuf, const void __user *ubuf)
596 struct pt_regs newregs;
598 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
604 if (!valid_user_regs(&newregs))
607 *task_pt_regs(target) = newregs;
611 static int fpa_get(struct task_struct *target,
612 const struct user_regset *regset,
613 unsigned int pos, unsigned int count,
614 void *kbuf, void __user *ubuf)
616 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
617 &task_thread_info(target)->fpstate,
618 0, sizeof(struct user_fp));
621 static int fpa_set(struct task_struct *target,
622 const struct user_regset *regset,
623 unsigned int pos, unsigned int count,
624 const void *kbuf, const void __user *ubuf)
626 struct thread_info *thread = task_thread_info(target);
628 thread->used_cp[1] = thread->used_cp[2] = 1;
630 return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
632 0, sizeof(struct user_fp));
637 * VFP register get/set implementations.
639 * With respect to the kernel, struct user_fp is divided into three chunks:
640 * 16 or 32 real VFP registers (d0-d15 or d0-31)
641 * These are transferred to/from the real registers in the task's
642 * vfp_hard_struct. The number of registers depends on the kernel
645 * 16 or 0 fake VFP registers (d16-d31 or empty)
646 * i.e., the user_vfp structure has space for 32 registers even if
647 * the kernel doesn't have them all.
649 * vfp_get() reads this chunk as zero where applicable
650 * vfp_set() ignores this chunk
652 * 1 word for the FPSCR
654 * The bounds-checking logic built into user_regset_copyout and friends
655 * means that we can make a simple sequence of calls to map the relevant data
656 * to/from the specified slice of the user regset structure.
658 static int vfp_get(struct task_struct *target,
659 const struct user_regset *regset,
660 unsigned int pos, unsigned int count,
661 void *kbuf, void __user *ubuf)
664 struct thread_info *thread = task_thread_info(target);
665 struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
666 const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
667 const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
669 vfp_sync_hwstate(thread);
671 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
674 user_fpregs_offset + sizeof(vfp->fpregs));
678 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
679 user_fpregs_offset + sizeof(vfp->fpregs),
684 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
687 user_fpscr_offset + sizeof(vfp->fpscr));
691 * For vfp_set() a read-modify-write is done on the VFP registers,
692 * in order to avoid writing back a half-modified set of registers on
695 static int vfp_set(struct task_struct *target,
696 const struct user_regset *regset,
697 unsigned int pos, unsigned int count,
698 const void *kbuf, const void __user *ubuf)
701 struct thread_info *thread = task_thread_info(target);
702 struct vfp_hard_struct new_vfp = thread->vfpstate.hard;
703 const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
704 const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
706 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
709 user_fpregs_offset + sizeof(new_vfp.fpregs));
713 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
714 user_fpregs_offset + sizeof(new_vfp.fpregs),
719 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
722 user_fpscr_offset + sizeof(new_vfp.fpscr));
726 vfp_sync_hwstate(thread);
727 thread->vfpstate.hard = new_vfp;
728 vfp_flush_hwstate(thread);
732 #endif /* CONFIG_VFP */
742 static const struct user_regset arm_regsets[] = {
744 .core_note_type = NT_PRSTATUS,
747 .align = sizeof(u32),
753 * For the FPA regs in fpstate, the real fields are a mixture
754 * of sizes, so pretend that the registers are word-sized:
756 .core_note_type = NT_PRFPREG,
757 .n = sizeof(struct user_fp) / sizeof(u32),
759 .align = sizeof(u32),
766 * Pretend that the VFP regs are word-sized, since the FPSCR is
767 * a single word dangling at the end of struct user_vfp:
769 .core_note_type = NT_ARM_VFP,
770 .n = ARM_VFPREGS_SIZE / sizeof(u32),
772 .align = sizeof(u32),
776 #endif /* CONFIG_VFP */
779 static const struct user_regset_view user_arm_view = {
780 .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
781 .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
784 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
786 return &user_arm_view;
789 long arch_ptrace(struct task_struct *child, long request,
790 unsigned long addr, unsigned long data)
793 unsigned long __user *datap = (unsigned long __user *) data;
797 ret = ptrace_read_user(child, addr, datap);
801 ret = ptrace_write_user(child, addr, data);
805 ret = copy_regset_to_user(child,
806 &user_arm_view, REGSET_GPR,
807 0, sizeof(struct pt_regs),
812 ret = copy_regset_from_user(child,
813 &user_arm_view, REGSET_GPR,
814 0, sizeof(struct pt_regs),
818 case PTRACE_GETFPREGS:
819 ret = copy_regset_to_user(child,
820 &user_arm_view, REGSET_FPR,
821 0, sizeof(union fp_state),
825 case PTRACE_SETFPREGS:
826 ret = copy_regset_from_user(child,
827 &user_arm_view, REGSET_FPR,
828 0, sizeof(union fp_state),
833 case PTRACE_GETWMMXREGS:
834 ret = ptrace_getwmmxregs(child, datap);
837 case PTRACE_SETWMMXREGS:
838 ret = ptrace_setwmmxregs(child, datap);
842 case PTRACE_GET_THREAD_AREA:
843 ret = put_user(task_thread_info(child)->tp_value,
847 case PTRACE_SET_SYSCALL:
848 task_thread_info(child)->syscall = data;
853 case PTRACE_GETCRUNCHREGS:
854 ret = ptrace_getcrunchregs(child, datap);
857 case PTRACE_SETCRUNCHREGS:
858 ret = ptrace_setcrunchregs(child, datap);
863 case PTRACE_GETVFPREGS:
864 ret = copy_regset_to_user(child,
865 &user_arm_view, REGSET_VFP,
870 case PTRACE_SETVFPREGS:
871 ret = copy_regset_from_user(child,
872 &user_arm_view, REGSET_VFP,
878 #ifdef CONFIG_HAVE_HW_BREAKPOINT
879 case PTRACE_GETHBPREGS:
880 if (ptrace_get_breakpoints(child) < 0)
883 ret = ptrace_gethbpregs(child, addr,
884 (unsigned long __user *)data);
885 ptrace_put_breakpoints(child);
887 case PTRACE_SETHBPREGS:
888 if (ptrace_get_breakpoints(child) < 0)
891 ret = ptrace_sethbpregs(child, addr,
892 (unsigned long __user *)data);
893 ptrace_put_breakpoints(child);
898 ret = ptrace_request(child, request, addr, data);
905 asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
909 if (!test_thread_flag(TIF_SYSCALL_TRACE))
911 if (!(current->ptrace & PT_PTRACED))
915 * Save IP. IP is used to denote syscall entry/exit:
916 * IP = 0 -> entry, = 1 -> exit
921 current_thread_info()->syscall = scno;
923 /* the 0x80 provides a way for the tracing parent to distinguish
924 between a syscall stop and SIGTRAP delivery */
925 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
928 * this isn't the same as continuing with a signal, but it will do
929 * for normal use. strace only continues with a signal if the
930 * stopping signal is not SIGTRAP. -brl
932 if (current->exit_code) {
933 send_sig(current->exit_code, current, 1);
934 current->exit_code = 0;
938 return current_thread_info()->syscall;