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/signal.h>
14 #include <linux/sched/task_stack.h>
16 #include <linux/elf.h>
17 #include <linux/smp.h>
18 #include <linux/ptrace.h>
19 #include <linux/user.h>
20 #include <linux/security.h>
21 #include <linux/init.h>
22 #include <linux/signal.h>
23 #include <linux/uaccess.h>
24 #include <linux/perf_event.h>
25 #include <linux/hw_breakpoint.h>
26 #include <linux/regset.h>
27 #include <linux/audit.h>
28 #include <linux/tracehook.h>
29 #include <linux/unistd.h>
31 #include <asm/pgtable.h>
32 #include <asm/traps.h>
34 #define CREATE_TRACE_POINTS
35 #include <trace/events/syscalls.h>
40 * does not yet catch signals sent when the child dies.
41 * in exit.c or in signal.c.
46 * Breakpoint SWI instruction: SWI &9F0001
48 #define BREAKINST_ARM 0xef9f0001
49 #define BREAKINST_THUMB 0xdf00 /* fill this in later */
52 * New breakpoints - use an undefined instruction. The ARM architecture
53 * reference manual guarantees that the following instruction space
54 * will produce an undefined instruction exception on all CPUs:
56 * ARM: xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
57 * Thumb: 1101 1110 xxxx xxxx
59 #define BREAKINST_ARM 0xe7f001f0
60 #define BREAKINST_THUMB 0xde01
63 struct pt_regs_offset {
68 #define REG_OFFSET_NAME(r) \
69 {.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
70 #define REG_OFFSET_END {.name = NULL, .offset = 0}
72 static const struct pt_regs_offset regoffset_table[] = {
89 REG_OFFSET_NAME(cpsr),
90 REG_OFFSET_NAME(ORIG_r0),
95 * regs_query_register_offset() - query register offset from its name
96 * @name: the name of a register
98 * regs_query_register_offset() returns the offset of a register in struct
99 * pt_regs from its name. If the name is invalid, this returns -EINVAL;
101 int regs_query_register_offset(const char *name)
103 const struct pt_regs_offset *roff;
104 for (roff = regoffset_table; roff->name != NULL; roff++)
105 if (!strcmp(roff->name, name))
111 * regs_query_register_name() - query register name from its offset
112 * @offset: the offset of a register in struct pt_regs.
114 * regs_query_register_name() returns the name of a register from its
115 * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
117 const char *regs_query_register_name(unsigned int offset)
119 const struct pt_regs_offset *roff;
120 for (roff = regoffset_table; roff->name != NULL; roff++)
121 if (roff->offset == offset)
127 * regs_within_kernel_stack() - check the address in the stack
128 * @regs: pt_regs which contains kernel stack pointer.
129 * @addr: address which is checked.
131 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
132 * If @addr is within the kernel stack, it returns true. If not, returns false.
134 bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
136 return ((addr & ~(THREAD_SIZE - 1)) ==
137 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
141 * regs_get_kernel_stack_nth() - get Nth entry of the stack
142 * @regs: pt_regs which contains kernel stack pointer.
143 * @n: stack entry number.
145 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
146 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
149 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
151 unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
153 if (regs_within_kernel_stack(regs, (unsigned long)addr))
160 * this routine will get a word off of the processes privileged stack.
161 * the offset is how far from the base addr as stored in the THREAD.
162 * this routine assumes that all the privileged stacks are in our
165 static inline long get_user_reg(struct task_struct *task, int offset)
167 return task_pt_regs(task)->uregs[offset];
171 * this routine will put a word on the processes privileged stack.
172 * the offset is how far from the base addr as stored in the THREAD.
173 * this routine assumes that all the privileged stacks are in our
177 put_user_reg(struct task_struct *task, int offset, long data)
179 struct pt_regs newregs, *regs = task_pt_regs(task);
183 newregs.uregs[offset] = data;
185 if (valid_user_regs(&newregs)) {
186 regs->uregs[offset] = data;
194 * Called by kernel/ptrace.c when detaching..
196 void ptrace_disable(struct task_struct *child)
202 * Handle hitting a breakpoint.
204 void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
208 clear_siginfo(&info);
209 info.si_signo = SIGTRAP;
211 info.si_code = TRAP_BRKPT;
212 info.si_addr = (void __user *)instruction_pointer(regs);
214 force_sig_info(SIGTRAP, &info, tsk);
217 static int break_trap(struct pt_regs *regs, unsigned int instr)
219 ptrace_break(current, regs);
223 static struct undef_hook arm_break_hook = {
224 .instr_mask = 0x0fffffff,
225 .instr_val = 0x07f001f0,
226 .cpsr_mask = PSR_T_BIT,
231 static struct undef_hook thumb_break_hook = {
232 .instr_mask = 0xffffffff,
233 .instr_val = 0x0000de01,
234 .cpsr_mask = PSR_T_BIT,
235 .cpsr_val = PSR_T_BIT,
239 static struct undef_hook thumb2_break_hook = {
240 .instr_mask = 0xffffffff,
241 .instr_val = 0xf7f0a000,
242 .cpsr_mask = PSR_T_BIT,
243 .cpsr_val = PSR_T_BIT,
247 static int __init ptrace_break_init(void)
249 register_undef_hook(&arm_break_hook);
250 register_undef_hook(&thumb_break_hook);
251 register_undef_hook(&thumb2_break_hook);
255 core_initcall(ptrace_break_init);
258 * Read the word at offset "off" into the "struct user". We
259 * actually access the pt_regs stored on the kernel stack.
261 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
262 unsigned long __user *ret)
270 if (off == PT_TEXT_ADDR)
271 tmp = tsk->mm->start_code;
272 else if (off == PT_DATA_ADDR)
273 tmp = tsk->mm->start_data;
274 else if (off == PT_TEXT_END_ADDR)
275 tmp = tsk->mm->end_code;
276 else if (off < sizeof(struct pt_regs))
277 tmp = get_user_reg(tsk, off >> 2);
278 else if (off >= sizeof(struct user))
281 return put_user(tmp, ret);
285 * Write the word at offset "off" into "struct user". We
286 * actually access the pt_regs stored on the kernel stack.
288 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
291 if (off & 3 || off >= sizeof(struct user))
294 if (off >= sizeof(struct pt_regs))
297 return put_user_reg(tsk, off >> 2, val);
303 * Get the child iWMMXt state.
305 static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
307 struct thread_info *thread = task_thread_info(tsk);
309 if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
311 iwmmxt_task_disable(thread); /* force it to ram */
312 return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
317 * Set the child iWMMXt state.
319 static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
321 struct thread_info *thread = task_thread_info(tsk);
323 if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
325 iwmmxt_task_release(thread); /* force a reload */
326 return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
334 * Get the child Crunch state.
336 static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
338 struct thread_info *thread = task_thread_info(tsk);
340 crunch_task_disable(thread); /* force it to ram */
341 return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
346 * Set the child Crunch state.
348 static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
350 struct thread_info *thread = task_thread_info(tsk);
352 crunch_task_release(thread); /* force a reload */
353 return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
358 #ifdef CONFIG_HAVE_HW_BREAKPOINT
360 * Convert a virtual register number into an index for a thread_info
361 * breakpoint array. Breakpoints are identified using positive numbers
362 * whilst watchpoints are negative. The registers are laid out as pairs
363 * of (address, control), each pair mapping to a unique hw_breakpoint struct.
364 * Register 0 is reserved for describing resource information.
366 static int ptrace_hbp_num_to_idx(long num)
369 num = (ARM_MAX_BRP << 1) - num;
370 return (num - 1) >> 1;
374 * Returns the virtual register number for the address of the
375 * breakpoint at index idx.
377 static long ptrace_hbp_idx_to_num(int idx)
379 long mid = ARM_MAX_BRP << 1;
380 long num = (idx << 1) + 1;
381 return num > mid ? mid - num : num;
385 * Handle hitting a HW-breakpoint.
387 static void ptrace_hbptriggered(struct perf_event *bp,
388 struct perf_sample_data *data,
389 struct pt_regs *regs)
391 struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
395 for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
396 if (current->thread.debug.hbp[i] == bp)
399 num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
401 force_sig_ptrace_errno_trap((int)num, (void __user *)(bkpt->trigger));
405 * Set ptrace breakpoint pointers to zero for this task.
406 * This is required in order to prevent child processes from unregistering
407 * breakpoints held by their parent.
409 void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
411 memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
415 * Unregister breakpoints from this task and reset the pointers in
418 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
421 struct thread_struct *t = &tsk->thread;
423 for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
424 if (t->debug.hbp[i]) {
425 unregister_hw_breakpoint(t->debug.hbp[i]);
426 t->debug.hbp[i] = NULL;
431 static u32 ptrace_get_hbp_resource_info(void)
433 u8 num_brps, num_wrps, debug_arch, wp_len;
436 num_brps = hw_breakpoint_slots(TYPE_INST);
437 num_wrps = hw_breakpoint_slots(TYPE_DATA);
438 debug_arch = arch_get_debug_arch();
439 wp_len = arch_get_max_wp_len();
452 static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
454 struct perf_event_attr attr;
456 ptrace_breakpoint_init(&attr);
458 /* Initialise fields to sane defaults. */
460 attr.bp_len = HW_BREAKPOINT_LEN_4;
464 return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
468 static int ptrace_gethbpregs(struct task_struct *tsk, long num,
469 unsigned long __user *data)
473 struct perf_event *bp;
474 struct arch_hw_breakpoint_ctrl arch_ctrl;
477 reg = ptrace_get_hbp_resource_info();
479 idx = ptrace_hbp_num_to_idx(num);
480 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
485 bp = tsk->thread.debug.hbp[idx];
491 arch_ctrl = counter_arch_bp(bp)->ctrl;
494 * Fix up the len because we may have adjusted it
495 * to compensate for an unaligned address.
497 while (!(arch_ctrl.len & 0x1))
501 reg = bp->attr.bp_addr;
503 reg = encode_ctrl_reg(arch_ctrl);
507 if (put_user(reg, data))
514 static int ptrace_sethbpregs(struct task_struct *tsk, long num,
515 unsigned long __user *data)
517 int idx, gen_len, gen_type, implied_type, ret = 0;
519 struct perf_event *bp;
520 struct arch_hw_breakpoint_ctrl ctrl;
521 struct perf_event_attr attr;
526 implied_type = HW_BREAKPOINT_RW;
528 implied_type = HW_BREAKPOINT_X;
530 idx = ptrace_hbp_num_to_idx(num);
531 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
536 if (get_user(user_val, data)) {
541 bp = tsk->thread.debug.hbp[idx];
543 bp = ptrace_hbp_create(tsk, implied_type);
548 tsk->thread.debug.hbp[idx] = bp;
555 attr.bp_addr = user_val;
558 decode_ctrl_reg(user_val, &ctrl);
559 ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
563 if ((gen_type & implied_type) != gen_type) {
568 attr.bp_len = gen_len;
569 attr.bp_type = gen_type;
570 attr.disabled = !ctrl.enabled;
573 ret = modify_user_hw_breakpoint(bp, &attr);
579 /* regset get/set implementations */
581 static int gpr_get(struct task_struct *target,
582 const struct user_regset *regset,
583 unsigned int pos, unsigned int count,
584 void *kbuf, void __user *ubuf)
586 struct pt_regs *regs = task_pt_regs(target);
588 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
593 static int gpr_set(struct task_struct *target,
594 const struct user_regset *regset,
595 unsigned int pos, unsigned int count,
596 const void *kbuf, const void __user *ubuf)
599 struct pt_regs newregs = *task_pt_regs(target);
601 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
607 if (!valid_user_regs(&newregs))
610 *task_pt_regs(target) = newregs;
614 static int fpa_get(struct task_struct *target,
615 const struct user_regset *regset,
616 unsigned int pos, unsigned int count,
617 void *kbuf, void __user *ubuf)
619 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
620 &task_thread_info(target)->fpstate,
621 0, sizeof(struct user_fp));
624 static int fpa_set(struct task_struct *target,
625 const struct user_regset *regset,
626 unsigned int pos, unsigned int count,
627 const void *kbuf, const void __user *ubuf)
629 struct thread_info *thread = task_thread_info(target);
631 thread->used_cp[1] = thread->used_cp[2] = 1;
633 return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
635 0, sizeof(struct user_fp));
640 * VFP register get/set implementations.
642 * With respect to the kernel, struct user_fp is divided into three chunks:
643 * 16 or 32 real VFP registers (d0-d15 or d0-31)
644 * These are transferred to/from the real registers in the task's
645 * vfp_hard_struct. The number of registers depends on the kernel
648 * 16 or 0 fake VFP registers (d16-d31 or empty)
649 * i.e., the user_vfp structure has space for 32 registers even if
650 * the kernel doesn't have them all.
652 * vfp_get() reads this chunk as zero where applicable
653 * vfp_set() ignores this chunk
655 * 1 word for the FPSCR
657 * The bounds-checking logic built into user_regset_copyout and friends
658 * means that we can make a simple sequence of calls to map the relevant data
659 * to/from the specified slice of the user regset structure.
661 static int vfp_get(struct task_struct *target,
662 const struct user_regset *regset,
663 unsigned int pos, unsigned int count,
664 void *kbuf, void __user *ubuf)
667 struct thread_info *thread = task_thread_info(target);
668 struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
669 const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
670 const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
672 vfp_sync_hwstate(thread);
674 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
677 user_fpregs_offset + sizeof(vfp->fpregs));
681 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
682 user_fpregs_offset + sizeof(vfp->fpregs),
687 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
690 user_fpscr_offset + sizeof(vfp->fpscr));
694 * For vfp_set() a read-modify-write is done on the VFP registers,
695 * in order to avoid writing back a half-modified set of registers on
698 static int vfp_set(struct task_struct *target,
699 const struct user_regset *regset,
700 unsigned int pos, unsigned int count,
701 const void *kbuf, const void __user *ubuf)
704 struct thread_info *thread = task_thread_info(target);
705 struct vfp_hard_struct new_vfp;
706 const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
707 const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
709 vfp_sync_hwstate(thread);
710 new_vfp = thread->vfpstate.hard;
712 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
715 user_fpregs_offset + sizeof(new_vfp.fpregs));
719 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
720 user_fpregs_offset + sizeof(new_vfp.fpregs),
725 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
728 user_fpscr_offset + sizeof(new_vfp.fpscr));
732 thread->vfpstate.hard = new_vfp;
733 vfp_flush_hwstate(thread);
737 #endif /* CONFIG_VFP */
747 static const struct user_regset arm_regsets[] = {
749 .core_note_type = NT_PRSTATUS,
752 .align = sizeof(u32),
758 * For the FPA regs in fpstate, the real fields are a mixture
759 * of sizes, so pretend that the registers are word-sized:
761 .core_note_type = NT_PRFPREG,
762 .n = sizeof(struct user_fp) / sizeof(u32),
764 .align = sizeof(u32),
771 * Pretend that the VFP regs are word-sized, since the FPSCR is
772 * a single word dangling at the end of struct user_vfp:
774 .core_note_type = NT_ARM_VFP,
775 .n = ARM_VFPREGS_SIZE / sizeof(u32),
777 .align = sizeof(u32),
781 #endif /* CONFIG_VFP */
784 static const struct user_regset_view user_arm_view = {
785 .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
786 .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
789 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
791 return &user_arm_view;
794 long arch_ptrace(struct task_struct *child, long request,
795 unsigned long addr, unsigned long data)
798 unsigned long __user *datap = (unsigned long __user *) data;
802 ret = ptrace_read_user(child, addr, datap);
806 ret = ptrace_write_user(child, addr, data);
810 ret = copy_regset_to_user(child,
811 &user_arm_view, REGSET_GPR,
812 0, sizeof(struct pt_regs),
817 ret = copy_regset_from_user(child,
818 &user_arm_view, REGSET_GPR,
819 0, sizeof(struct pt_regs),
823 case PTRACE_GETFPREGS:
824 ret = copy_regset_to_user(child,
825 &user_arm_view, REGSET_FPR,
826 0, sizeof(union fp_state),
830 case PTRACE_SETFPREGS:
831 ret = copy_regset_from_user(child,
832 &user_arm_view, REGSET_FPR,
833 0, sizeof(union fp_state),
838 case PTRACE_GETWMMXREGS:
839 ret = ptrace_getwmmxregs(child, datap);
842 case PTRACE_SETWMMXREGS:
843 ret = ptrace_setwmmxregs(child, datap);
847 case PTRACE_GET_THREAD_AREA:
848 ret = put_user(task_thread_info(child)->tp_value[0],
852 case PTRACE_SET_SYSCALL:
853 task_thread_info(child)->syscall = data;
858 case PTRACE_GETCRUNCHREGS:
859 ret = ptrace_getcrunchregs(child, datap);
862 case PTRACE_SETCRUNCHREGS:
863 ret = ptrace_setcrunchregs(child, datap);
868 case PTRACE_GETVFPREGS:
869 ret = copy_regset_to_user(child,
870 &user_arm_view, REGSET_VFP,
875 case PTRACE_SETVFPREGS:
876 ret = copy_regset_from_user(child,
877 &user_arm_view, REGSET_VFP,
883 #ifdef CONFIG_HAVE_HW_BREAKPOINT
884 case PTRACE_GETHBPREGS:
885 ret = ptrace_gethbpregs(child, addr,
886 (unsigned long __user *)data);
888 case PTRACE_SETHBPREGS:
889 ret = ptrace_sethbpregs(child, addr,
890 (unsigned long __user *)data);
895 ret = ptrace_request(child, request, addr, data);
902 enum ptrace_syscall_dir {
903 PTRACE_SYSCALL_ENTER = 0,
907 static void tracehook_report_syscall(struct pt_regs *regs,
908 enum ptrace_syscall_dir dir)
913 * IP is used to denote syscall entry/exit:
914 * IP = 0 -> entry, =1 -> exit
919 if (dir == PTRACE_SYSCALL_EXIT)
920 tracehook_report_syscall_exit(regs, 0);
921 else if (tracehook_report_syscall_entry(regs))
922 current_thread_info()->syscall = -1;
927 asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
929 current_thread_info()->syscall = scno;
931 if (test_thread_flag(TIF_SYSCALL_TRACE))
932 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
934 /* Do seccomp after ptrace; syscall may have changed. */
935 #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
936 if (secure_computing(NULL) == -1)
939 /* XXX: remove this once OABI gets fixed */
940 secure_computing_strict(current_thread_info()->syscall);
943 /* Tracer or seccomp may have changed syscall. */
944 scno = current_thread_info()->syscall;
946 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
947 trace_sys_enter(regs, scno);
949 audit_syscall_entry(scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
955 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
958 * Audit the syscall before anything else, as a debugger may
959 * come in and change the current registers.
961 audit_syscall_exit(regs);
964 * Note that we haven't updated the ->syscall field for the
965 * current thread. This isn't a problem because it will have
966 * been set on syscall entry and there hasn't been an opportunity
967 * for a PTRACE_SET_SYSCALL since then.
969 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
970 trace_sys_exit(regs, regs_return_value(regs));
972 if (test_thread_flag(TIF_SYSCALL_TRACE))
973 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);