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>
26 #include <linux/audit.h>
27 #include <linux/tracehook.h>
28 #include <linux/unistd.h>
30 #include <asm/pgtable.h>
31 #include <asm/traps.h>
36 * does not yet catch signals sent when the child dies.
37 * in exit.c or in signal.c.
42 * Breakpoint SWI instruction: SWI &9F0001
44 #define BREAKINST_ARM 0xef9f0001
45 #define BREAKINST_THUMB 0xdf00 /* fill this in later */
48 * New breakpoints - use an undefined instruction. The ARM architecture
49 * reference manual guarantees that the following instruction space
50 * will produce an undefined instruction exception on all CPUs:
52 * ARM: xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
53 * Thumb: 1101 1110 xxxx xxxx
55 #define BREAKINST_ARM 0xe7f001f0
56 #define BREAKINST_THUMB 0xde01
59 struct pt_regs_offset {
64 #define REG_OFFSET_NAME(r) \
65 {.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
66 #define REG_OFFSET_END {.name = NULL, .offset = 0}
68 static const struct pt_regs_offset regoffset_table[] = {
85 REG_OFFSET_NAME(cpsr),
86 REG_OFFSET_NAME(ORIG_r0),
91 * regs_query_register_offset() - query register offset from its name
92 * @name: the name of a register
94 * regs_query_register_offset() returns the offset of a register in struct
95 * pt_regs from its name. If the name is invalid, this returns -EINVAL;
97 int regs_query_register_offset(const char *name)
99 const struct pt_regs_offset *roff;
100 for (roff = regoffset_table; roff->name != NULL; roff++)
101 if (!strcmp(roff->name, name))
107 * regs_query_register_name() - query register name from its offset
108 * @offset: the offset of a register in struct pt_regs.
110 * regs_query_register_name() returns the name of a register from its
111 * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
113 const char *regs_query_register_name(unsigned int offset)
115 const struct pt_regs_offset *roff;
116 for (roff = regoffset_table; roff->name != NULL; roff++)
117 if (roff->offset == offset)
123 * regs_within_kernel_stack() - check the address in the stack
124 * @regs: pt_regs which contains kernel stack pointer.
125 * @addr: address which is checked.
127 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
128 * If @addr is within the kernel stack, it returns true. If not, returns false.
130 bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
132 return ((addr & ~(THREAD_SIZE - 1)) ==
133 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
137 * regs_get_kernel_stack_nth() - get Nth entry of the stack
138 * @regs: pt_regs which contains kernel stack pointer.
139 * @n: stack entry number.
141 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
142 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
145 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
147 unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
149 if (regs_within_kernel_stack(regs, (unsigned long)addr))
156 * this routine will get a word off of the processes privileged stack.
157 * the offset is how far from the base addr as stored in the THREAD.
158 * this routine assumes that all the privileged stacks are in our
161 static inline long get_user_reg(struct task_struct *task, int offset)
163 return task_pt_regs(task)->uregs[offset];
167 * this routine will put a word on the processes privileged stack.
168 * the offset is how far from the base addr as stored in the THREAD.
169 * this routine assumes that all the privileged stacks are in our
173 put_user_reg(struct task_struct *task, int offset, long data)
175 struct pt_regs newregs, *regs = task_pt_regs(task);
179 newregs.uregs[offset] = data;
181 if (valid_user_regs(&newregs)) {
182 regs->uregs[offset] = data;
190 * Called by kernel/ptrace.c when detaching..
192 void ptrace_disable(struct task_struct *child)
198 * Handle hitting a breakpoint.
200 void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
204 info.si_signo = SIGTRAP;
206 info.si_code = TRAP_BRKPT;
207 info.si_addr = (void __user *)instruction_pointer(regs);
209 force_sig_info(SIGTRAP, &info, tsk);
212 static int break_trap(struct pt_regs *regs, unsigned int instr)
214 ptrace_break(current, regs);
218 static struct undef_hook arm_break_hook = {
219 .instr_mask = 0x0fffffff,
220 .instr_val = 0x07f001f0,
221 .cpsr_mask = PSR_T_BIT,
226 static struct undef_hook thumb_break_hook = {
227 .instr_mask = 0xffff,
229 .cpsr_mask = PSR_T_BIT,
230 .cpsr_val = PSR_T_BIT,
234 static struct undef_hook thumb2_break_hook = {
235 .instr_mask = 0xffffffff,
236 .instr_val = 0xf7f0a000,
237 .cpsr_mask = PSR_T_BIT,
238 .cpsr_val = PSR_T_BIT,
242 static int __init ptrace_break_init(void)
244 register_undef_hook(&arm_break_hook);
245 register_undef_hook(&thumb_break_hook);
246 register_undef_hook(&thumb2_break_hook);
250 core_initcall(ptrace_break_init);
253 * Read the word at offset "off" into the "struct user". We
254 * actually access the pt_regs stored on the kernel stack.
256 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
257 unsigned long __user *ret)
265 if (off == PT_TEXT_ADDR)
266 tmp = tsk->mm->start_code;
267 else if (off == PT_DATA_ADDR)
268 tmp = tsk->mm->start_data;
269 else if (off == PT_TEXT_END_ADDR)
270 tmp = tsk->mm->end_code;
271 else if (off < sizeof(struct pt_regs))
272 tmp = get_user_reg(tsk, off >> 2);
273 else if (off >= sizeof(struct user))
276 return put_user(tmp, ret);
280 * Write the word at offset "off" into "struct user". We
281 * actually access the pt_regs stored on the kernel stack.
283 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
286 if (off & 3 || off >= sizeof(struct user))
289 if (off >= sizeof(struct pt_regs))
292 return put_user_reg(tsk, off >> 2, val);
298 * Get the child iWMMXt state.
300 static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
302 struct thread_info *thread = task_thread_info(tsk);
304 if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
306 iwmmxt_task_disable(thread); /* force it to ram */
307 return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
312 * Set the child iWMMXt state.
314 static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
316 struct thread_info *thread = task_thread_info(tsk);
318 if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
320 iwmmxt_task_release(thread); /* force a reload */
321 return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
329 * Get the child Crunch state.
331 static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
333 struct thread_info *thread = task_thread_info(tsk);
335 crunch_task_disable(thread); /* force it to ram */
336 return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
341 * Set the child Crunch state.
343 static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
345 struct thread_info *thread = task_thread_info(tsk);
347 crunch_task_release(thread); /* force a reload */
348 return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
353 #ifdef CONFIG_HAVE_HW_BREAKPOINT
355 * Convert a virtual register number into an index for a thread_info
356 * breakpoint array. Breakpoints are identified using positive numbers
357 * whilst watchpoints are negative. The registers are laid out as pairs
358 * of (address, control), each pair mapping to a unique hw_breakpoint struct.
359 * Register 0 is reserved for describing resource information.
361 static int ptrace_hbp_num_to_idx(long num)
364 num = (ARM_MAX_BRP << 1) - num;
365 return (num - 1) >> 1;
369 * Returns the virtual register number for the address of the
370 * breakpoint at index idx.
372 static long ptrace_hbp_idx_to_num(int idx)
374 long mid = ARM_MAX_BRP << 1;
375 long num = (idx << 1) + 1;
376 return num > mid ? mid - num : num;
380 * Handle hitting a HW-breakpoint.
382 static void ptrace_hbptriggered(struct perf_event *bp,
383 struct perf_sample_data *data,
384 struct pt_regs *regs)
386 struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
391 for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
392 if (current->thread.debug.hbp[i] == bp)
395 num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
397 info.si_signo = SIGTRAP;
398 info.si_errno = (int)num;
399 info.si_code = TRAP_HWBKPT;
400 info.si_addr = (void __user *)(bkpt->trigger);
402 force_sig_info(SIGTRAP, &info, current);
406 * Set ptrace breakpoint pointers to zero for this task.
407 * This is required in order to prevent child processes from unregistering
408 * breakpoints held by their parent.
410 void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
412 memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
416 * Unregister breakpoints from this task and reset the pointers in
419 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
422 struct thread_struct *t = &tsk->thread;
424 for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
425 if (t->debug.hbp[i]) {
426 unregister_hw_breakpoint(t->debug.hbp[i]);
427 t->debug.hbp[i] = NULL;
432 static u32 ptrace_get_hbp_resource_info(void)
434 u8 num_brps, num_wrps, debug_arch, wp_len;
437 num_brps = hw_breakpoint_slots(TYPE_INST);
438 num_wrps = hw_breakpoint_slots(TYPE_DATA);
439 debug_arch = arch_get_debug_arch();
440 wp_len = arch_get_max_wp_len();
453 static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
455 struct perf_event_attr attr;
457 ptrace_breakpoint_init(&attr);
459 /* Initialise fields to sane defaults. */
461 attr.bp_len = HW_BREAKPOINT_LEN_4;
465 return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
469 static int ptrace_gethbpregs(struct task_struct *tsk, long num,
470 unsigned long __user *data)
474 struct perf_event *bp;
475 struct arch_hw_breakpoint_ctrl arch_ctrl;
478 reg = ptrace_get_hbp_resource_info();
480 idx = ptrace_hbp_num_to_idx(num);
481 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
486 bp = tsk->thread.debug.hbp[idx];
492 arch_ctrl = counter_arch_bp(bp)->ctrl;
495 * Fix up the len because we may have adjusted it
496 * to compensate for an unaligned address.
498 while (!(arch_ctrl.len & 0x1))
502 reg = bp->attr.bp_addr;
504 reg = encode_ctrl_reg(arch_ctrl);
508 if (put_user(reg, data))
515 static int ptrace_sethbpregs(struct task_struct *tsk, long num,
516 unsigned long __user *data)
518 int idx, gen_len, gen_type, implied_type, ret = 0;
520 struct perf_event *bp;
521 struct arch_hw_breakpoint_ctrl ctrl;
522 struct perf_event_attr attr;
527 implied_type = HW_BREAKPOINT_RW;
529 implied_type = HW_BREAKPOINT_X;
531 idx = ptrace_hbp_num_to_idx(num);
532 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
537 if (get_user(user_val, data)) {
542 bp = tsk->thread.debug.hbp[idx];
544 bp = ptrace_hbp_create(tsk, implied_type);
549 tsk->thread.debug.hbp[idx] = bp;
556 attr.bp_addr = user_val;
559 decode_ctrl_reg(user_val, &ctrl);
560 ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
564 if ((gen_type & implied_type) != gen_type) {
569 attr.bp_len = gen_len;
570 attr.bp_type = gen_type;
571 attr.disabled = !ctrl.enabled;
574 ret = modify_user_hw_breakpoint(bp, &attr);
580 /* regset get/set implementations */
582 static int gpr_get(struct task_struct *target,
583 const struct user_regset *regset,
584 unsigned int pos, unsigned int count,
585 void *kbuf, void __user *ubuf)
587 struct pt_regs *regs = task_pt_regs(target);
589 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
594 static int gpr_set(struct task_struct *target,
595 const struct user_regset *regset,
596 unsigned int pos, unsigned int count,
597 const void *kbuf, const void __user *ubuf)
600 struct pt_regs newregs;
602 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
608 if (!valid_user_regs(&newregs))
611 *task_pt_regs(target) = newregs;
615 static int fpa_get(struct task_struct *target,
616 const struct user_regset *regset,
617 unsigned int pos, unsigned int count,
618 void *kbuf, void __user *ubuf)
620 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
621 &task_thread_info(target)->fpstate,
622 0, sizeof(struct user_fp));
625 static int fpa_set(struct task_struct *target,
626 const struct user_regset *regset,
627 unsigned int pos, unsigned int count,
628 const void *kbuf, const void __user *ubuf)
630 struct thread_info *thread = task_thread_info(target);
632 thread->used_cp[1] = thread->used_cp[2] = 1;
634 return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
636 0, sizeof(struct user_fp));
641 * VFP register get/set implementations.
643 * With respect to the kernel, struct user_fp is divided into three chunks:
644 * 16 or 32 real VFP registers (d0-d15 or d0-31)
645 * These are transferred to/from the real registers in the task's
646 * vfp_hard_struct. The number of registers depends on the kernel
649 * 16 or 0 fake VFP registers (d16-d31 or empty)
650 * i.e., the user_vfp structure has space for 32 registers even if
651 * the kernel doesn't have them all.
653 * vfp_get() reads this chunk as zero where applicable
654 * vfp_set() ignores this chunk
656 * 1 word for the FPSCR
658 * The bounds-checking logic built into user_regset_copyout and friends
659 * means that we can make a simple sequence of calls to map the relevant data
660 * to/from the specified slice of the user regset structure.
662 static int vfp_get(struct task_struct *target,
663 const struct user_regset *regset,
664 unsigned int pos, unsigned int count,
665 void *kbuf, void __user *ubuf)
668 struct thread_info *thread = task_thread_info(target);
669 struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
670 const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
671 const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
673 vfp_sync_hwstate(thread);
675 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
678 user_fpregs_offset + sizeof(vfp->fpregs));
682 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
683 user_fpregs_offset + sizeof(vfp->fpregs),
688 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
691 user_fpscr_offset + sizeof(vfp->fpscr));
695 * For vfp_set() a read-modify-write is done on the VFP registers,
696 * in order to avoid writing back a half-modified set of registers on
699 static int vfp_set(struct task_struct *target,
700 const struct user_regset *regset,
701 unsigned int pos, unsigned int count,
702 const void *kbuf, const void __user *ubuf)
705 struct thread_info *thread = task_thread_info(target);
706 struct vfp_hard_struct new_vfp;
707 const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
708 const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
710 vfp_sync_hwstate(thread);
711 new_vfp = thread->vfpstate.hard;
713 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
716 user_fpregs_offset + sizeof(new_vfp.fpregs));
720 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
721 user_fpregs_offset + sizeof(new_vfp.fpregs),
726 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
729 user_fpscr_offset + sizeof(new_vfp.fpscr));
733 vfp_flush_hwstate(thread);
734 thread->vfpstate.hard = new_vfp;
738 #endif /* CONFIG_VFP */
748 static const struct user_regset arm_regsets[] = {
750 .core_note_type = NT_PRSTATUS,
753 .align = sizeof(u32),
759 * For the FPA regs in fpstate, the real fields are a mixture
760 * of sizes, so pretend that the registers are word-sized:
762 .core_note_type = NT_PRFPREG,
763 .n = sizeof(struct user_fp) / sizeof(u32),
765 .align = sizeof(u32),
772 * Pretend that the VFP regs are word-sized, since the FPSCR is
773 * a single word dangling at the end of struct user_vfp:
775 .core_note_type = NT_ARM_VFP,
776 .n = ARM_VFPREGS_SIZE / sizeof(u32),
778 .align = sizeof(u32),
782 #endif /* CONFIG_VFP */
785 static const struct user_regset_view user_arm_view = {
786 .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
787 .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
790 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
792 return &user_arm_view;
795 long arch_ptrace(struct task_struct *child, long request,
796 unsigned long addr, unsigned long data)
799 unsigned long __user *datap = (unsigned long __user *) data;
803 ret = ptrace_read_user(child, addr, datap);
807 ret = ptrace_write_user(child, addr, data);
811 ret = copy_regset_to_user(child,
812 &user_arm_view, REGSET_GPR,
813 0, sizeof(struct pt_regs),
818 ret = copy_regset_from_user(child,
819 &user_arm_view, REGSET_GPR,
820 0, sizeof(struct pt_regs),
824 case PTRACE_GETFPREGS:
825 ret = copy_regset_to_user(child,
826 &user_arm_view, REGSET_FPR,
827 0, sizeof(union fp_state),
831 case PTRACE_SETFPREGS:
832 ret = copy_regset_from_user(child,
833 &user_arm_view, REGSET_FPR,
834 0, sizeof(union fp_state),
839 case PTRACE_GETWMMXREGS:
840 ret = ptrace_getwmmxregs(child, datap);
843 case PTRACE_SETWMMXREGS:
844 ret = ptrace_setwmmxregs(child, datap);
848 case PTRACE_GET_THREAD_AREA:
849 ret = put_user(task_thread_info(child)->tp_value,
853 case PTRACE_SET_SYSCALL:
854 task_thread_info(child)->syscall = data;
859 case PTRACE_GETCRUNCHREGS:
860 ret = ptrace_getcrunchregs(child, datap);
863 case PTRACE_SETCRUNCHREGS:
864 ret = ptrace_setcrunchregs(child, datap);
869 case PTRACE_GETVFPREGS:
870 ret = copy_regset_to_user(child,
871 &user_arm_view, REGSET_VFP,
876 case PTRACE_SETVFPREGS:
877 ret = copy_regset_from_user(child,
878 &user_arm_view, REGSET_VFP,
884 #ifdef CONFIG_HAVE_HW_BREAKPOINT
885 case PTRACE_GETHBPREGS:
886 if (ptrace_get_breakpoints(child) < 0)
889 ret = ptrace_gethbpregs(child, addr,
890 (unsigned long __user *)data);
891 ptrace_put_breakpoints(child);
893 case PTRACE_SETHBPREGS:
894 if (ptrace_get_breakpoints(child) < 0)
897 ret = ptrace_sethbpregs(child, addr,
898 (unsigned long __user *)data);
899 ptrace_put_breakpoints(child);
904 ret = ptrace_request(child, request, addr, data);
911 asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
916 audit_syscall_exit(regs);
918 audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0,
919 regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
921 if (why == 0 && test_and_clear_thread_flag(TIF_SYSCALL_RESTARTSYS))
922 scno = __NR_restart_syscall - __NR_SYSCALL_BASE;
923 if (!test_thread_flag(TIF_SYSCALL_TRACE))
926 current_thread_info()->syscall = scno;
929 * IP is used to denote syscall entry/exit:
930 * IP = 0 -> entry, =1 -> exit
936 tracehook_report_syscall_exit(regs, 0);
937 else if (tracehook_report_syscall_entry(regs))
938 current_thread_info()->syscall = -1;
942 return current_thread_info()->syscall;