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 info.si_signo = SIGTRAP;
210 info.si_code = TRAP_BRKPT;
211 info.si_addr = (void __user *)instruction_pointer(regs);
213 force_sig_info(SIGTRAP, &info, tsk);
216 static int break_trap(struct pt_regs *regs, unsigned int instr)
218 ptrace_break(current, regs);
222 static struct undef_hook arm_break_hook = {
223 .instr_mask = 0x0fffffff,
224 .instr_val = 0x07f001f0,
225 .cpsr_mask = PSR_T_BIT,
230 static struct undef_hook thumb_break_hook = {
231 .instr_mask = 0xffff,
233 .cpsr_mask = PSR_T_BIT,
234 .cpsr_val = PSR_T_BIT,
238 static struct undef_hook thumb2_break_hook = {
239 .instr_mask = 0xffffffff,
240 .instr_val = 0xf7f0a000,
241 .cpsr_mask = PSR_T_BIT,
242 .cpsr_val = PSR_T_BIT,
246 static int __init ptrace_break_init(void)
248 register_undef_hook(&arm_break_hook);
249 register_undef_hook(&thumb_break_hook);
250 register_undef_hook(&thumb2_break_hook);
254 core_initcall(ptrace_break_init);
257 * Read the word at offset "off" into the "struct user". We
258 * actually access the pt_regs stored on the kernel stack.
260 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
261 unsigned long __user *ret)
269 if (off == PT_TEXT_ADDR)
270 tmp = tsk->mm->start_code;
271 else if (off == PT_DATA_ADDR)
272 tmp = tsk->mm->start_data;
273 else if (off == PT_TEXT_END_ADDR)
274 tmp = tsk->mm->end_code;
275 else if (off < sizeof(struct pt_regs))
276 tmp = get_user_reg(tsk, off >> 2);
277 else if (off >= sizeof(struct user))
280 return put_user(tmp, ret);
284 * Write the word at offset "off" into "struct user". We
285 * actually access the pt_regs stored on the kernel stack.
287 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
290 if (off & 3 || off >= sizeof(struct user))
293 if (off >= sizeof(struct pt_regs))
296 return put_user_reg(tsk, off >> 2, val);
302 * Get the child iWMMXt state.
304 static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
306 struct thread_info *thread = task_thread_info(tsk);
308 if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
310 iwmmxt_task_disable(thread); /* force it to ram */
311 return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
316 * Set the child iWMMXt state.
318 static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
320 struct thread_info *thread = task_thread_info(tsk);
322 if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
324 iwmmxt_task_release(thread); /* force a reload */
325 return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
333 * Get the child Crunch state.
335 static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
337 struct thread_info *thread = task_thread_info(tsk);
339 crunch_task_disable(thread); /* force it to ram */
340 return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
345 * Set the child Crunch state.
347 static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
349 struct thread_info *thread = task_thread_info(tsk);
351 crunch_task_release(thread); /* force a reload */
352 return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
357 #ifdef CONFIG_HAVE_HW_BREAKPOINT
359 * Convert a virtual register number into an index for a thread_info
360 * breakpoint array. Breakpoints are identified using positive numbers
361 * whilst watchpoints are negative. The registers are laid out as pairs
362 * of (address, control), each pair mapping to a unique hw_breakpoint struct.
363 * Register 0 is reserved for describing resource information.
365 static int ptrace_hbp_num_to_idx(long num)
368 num = (ARM_MAX_BRP << 1) - num;
369 return (num - 1) >> 1;
373 * Returns the virtual register number for the address of the
374 * breakpoint at index idx.
376 static long ptrace_hbp_idx_to_num(int idx)
378 long mid = ARM_MAX_BRP << 1;
379 long num = (idx << 1) + 1;
380 return num > mid ? mid - num : num;
384 * Handle hitting a HW-breakpoint.
386 static void ptrace_hbptriggered(struct perf_event *bp,
387 struct perf_sample_data *data,
388 struct pt_regs *regs)
390 struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
394 for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
395 if (current->thread.debug.hbp[i] == bp)
398 num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
400 force_sig_ptrace_errno_trap((int)num, (void __user *)(bkpt->trigger));
404 * Set ptrace breakpoint pointers to zero for this task.
405 * This is required in order to prevent child processes from unregistering
406 * breakpoints held by their parent.
408 void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
410 memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
414 * Unregister breakpoints from this task and reset the pointers in
417 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
420 struct thread_struct *t = &tsk->thread;
422 for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
423 if (t->debug.hbp[i]) {
424 unregister_hw_breakpoint(t->debug.hbp[i]);
425 t->debug.hbp[i] = NULL;
430 static u32 ptrace_get_hbp_resource_info(void)
432 u8 num_brps, num_wrps, debug_arch, wp_len;
435 num_brps = hw_breakpoint_slots(TYPE_INST);
436 num_wrps = hw_breakpoint_slots(TYPE_DATA);
437 debug_arch = arch_get_debug_arch();
438 wp_len = arch_get_max_wp_len();
451 static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
453 struct perf_event_attr attr;
455 ptrace_breakpoint_init(&attr);
457 /* Initialise fields to sane defaults. */
459 attr.bp_len = HW_BREAKPOINT_LEN_4;
463 return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
467 static int ptrace_gethbpregs(struct task_struct *tsk, long num,
468 unsigned long __user *data)
472 struct perf_event *bp;
473 struct arch_hw_breakpoint_ctrl arch_ctrl;
476 reg = ptrace_get_hbp_resource_info();
478 idx = ptrace_hbp_num_to_idx(num);
479 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
484 bp = tsk->thread.debug.hbp[idx];
490 arch_ctrl = counter_arch_bp(bp)->ctrl;
493 * Fix up the len because we may have adjusted it
494 * to compensate for an unaligned address.
496 while (!(arch_ctrl.len & 0x1))
500 reg = bp->attr.bp_addr;
502 reg = encode_ctrl_reg(arch_ctrl);
506 if (put_user(reg, data))
513 static int ptrace_sethbpregs(struct task_struct *tsk, long num,
514 unsigned long __user *data)
516 int idx, gen_len, gen_type, implied_type, ret = 0;
518 struct perf_event *bp;
519 struct arch_hw_breakpoint_ctrl ctrl;
520 struct perf_event_attr attr;
525 implied_type = HW_BREAKPOINT_RW;
527 implied_type = HW_BREAKPOINT_X;
529 idx = ptrace_hbp_num_to_idx(num);
530 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
535 if (get_user(user_val, data)) {
540 bp = tsk->thread.debug.hbp[idx];
542 bp = ptrace_hbp_create(tsk, implied_type);
547 tsk->thread.debug.hbp[idx] = bp;
554 attr.bp_addr = user_val;
557 decode_ctrl_reg(user_val, &ctrl);
558 ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
562 if ((gen_type & implied_type) != gen_type) {
567 attr.bp_len = gen_len;
568 attr.bp_type = gen_type;
569 attr.disabled = !ctrl.enabled;
572 ret = modify_user_hw_breakpoint(bp, &attr);
578 /* regset get/set implementations */
580 static int gpr_get(struct task_struct *target,
581 const struct user_regset *regset,
582 unsigned int pos, unsigned int count,
583 void *kbuf, void __user *ubuf)
585 struct pt_regs *regs = task_pt_regs(target);
587 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
592 static int gpr_set(struct task_struct *target,
593 const struct user_regset *regset,
594 unsigned int pos, unsigned int count,
595 const void *kbuf, const void __user *ubuf)
598 struct pt_regs newregs = *task_pt_regs(target);
600 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
606 if (!valid_user_regs(&newregs))
609 *task_pt_regs(target) = newregs;
613 static int fpa_get(struct task_struct *target,
614 const struct user_regset *regset,
615 unsigned int pos, unsigned int count,
616 void *kbuf, void __user *ubuf)
618 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
619 &task_thread_info(target)->fpstate,
620 0, sizeof(struct user_fp));
623 static int fpa_set(struct task_struct *target,
624 const struct user_regset *regset,
625 unsigned int pos, unsigned int count,
626 const void *kbuf, const void __user *ubuf)
628 struct thread_info *thread = task_thread_info(target);
630 thread->used_cp[1] = thread->used_cp[2] = 1;
632 return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
634 0, sizeof(struct user_fp));
639 * VFP register get/set implementations.
641 * With respect to the kernel, struct user_fp is divided into three chunks:
642 * 16 or 32 real VFP registers (d0-d15 or d0-31)
643 * These are transferred to/from the real registers in the task's
644 * vfp_hard_struct. The number of registers depends on the kernel
647 * 16 or 0 fake VFP registers (d16-d31 or empty)
648 * i.e., the user_vfp structure has space for 32 registers even if
649 * the kernel doesn't have them all.
651 * vfp_get() reads this chunk as zero where applicable
652 * vfp_set() ignores this chunk
654 * 1 word for the FPSCR
656 * The bounds-checking logic built into user_regset_copyout and friends
657 * means that we can make a simple sequence of calls to map the relevant data
658 * to/from the specified slice of the user regset structure.
660 static int vfp_get(struct task_struct *target,
661 const struct user_regset *regset,
662 unsigned int pos, unsigned int count,
663 void *kbuf, void __user *ubuf)
666 struct thread_info *thread = task_thread_info(target);
667 struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
668 const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
669 const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
671 vfp_sync_hwstate(thread);
673 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
676 user_fpregs_offset + sizeof(vfp->fpregs));
680 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
681 user_fpregs_offset + sizeof(vfp->fpregs),
686 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
689 user_fpscr_offset + sizeof(vfp->fpscr));
693 * For vfp_set() a read-modify-write is done on the VFP registers,
694 * in order to avoid writing back a half-modified set of registers on
697 static int vfp_set(struct task_struct *target,
698 const struct user_regset *regset,
699 unsigned int pos, unsigned int count,
700 const void *kbuf, const void __user *ubuf)
703 struct thread_info *thread = task_thread_info(target);
704 struct vfp_hard_struct new_vfp;
705 const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
706 const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
708 vfp_sync_hwstate(thread);
709 new_vfp = thread->vfpstate.hard;
711 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
714 user_fpregs_offset + sizeof(new_vfp.fpregs));
718 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
719 user_fpregs_offset + sizeof(new_vfp.fpregs),
724 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
727 user_fpscr_offset + sizeof(new_vfp.fpscr));
731 thread->vfpstate.hard = new_vfp;
732 vfp_flush_hwstate(thread);
736 #endif /* CONFIG_VFP */
746 static const struct user_regset arm_regsets[] = {
748 .core_note_type = NT_PRSTATUS,
751 .align = sizeof(u32),
757 * For the FPA regs in fpstate, the real fields are a mixture
758 * of sizes, so pretend that the registers are word-sized:
760 .core_note_type = NT_PRFPREG,
761 .n = sizeof(struct user_fp) / sizeof(u32),
763 .align = sizeof(u32),
770 * Pretend that the VFP regs are word-sized, since the FPSCR is
771 * a single word dangling at the end of struct user_vfp:
773 .core_note_type = NT_ARM_VFP,
774 .n = ARM_VFPREGS_SIZE / sizeof(u32),
776 .align = sizeof(u32),
780 #endif /* CONFIG_VFP */
783 static const struct user_regset_view user_arm_view = {
784 .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
785 .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
788 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
790 return &user_arm_view;
793 long arch_ptrace(struct task_struct *child, long request,
794 unsigned long addr, unsigned long data)
797 unsigned long __user *datap = (unsigned long __user *) data;
801 ret = ptrace_read_user(child, addr, datap);
805 ret = ptrace_write_user(child, addr, data);
809 ret = copy_regset_to_user(child,
810 &user_arm_view, REGSET_GPR,
811 0, sizeof(struct pt_regs),
816 ret = copy_regset_from_user(child,
817 &user_arm_view, REGSET_GPR,
818 0, sizeof(struct pt_regs),
822 case PTRACE_GETFPREGS:
823 ret = copy_regset_to_user(child,
824 &user_arm_view, REGSET_FPR,
825 0, sizeof(union fp_state),
829 case PTRACE_SETFPREGS:
830 ret = copy_regset_from_user(child,
831 &user_arm_view, REGSET_FPR,
832 0, sizeof(union fp_state),
837 case PTRACE_GETWMMXREGS:
838 ret = ptrace_getwmmxregs(child, datap);
841 case PTRACE_SETWMMXREGS:
842 ret = ptrace_setwmmxregs(child, datap);
846 case PTRACE_GET_THREAD_AREA:
847 ret = put_user(task_thread_info(child)->tp_value[0],
851 case PTRACE_SET_SYSCALL:
852 task_thread_info(child)->syscall = data;
857 case PTRACE_GETCRUNCHREGS:
858 ret = ptrace_getcrunchregs(child, datap);
861 case PTRACE_SETCRUNCHREGS:
862 ret = ptrace_setcrunchregs(child, datap);
867 case PTRACE_GETVFPREGS:
868 ret = copy_regset_to_user(child,
869 &user_arm_view, REGSET_VFP,
874 case PTRACE_SETVFPREGS:
875 ret = copy_regset_from_user(child,
876 &user_arm_view, REGSET_VFP,
882 #ifdef CONFIG_HAVE_HW_BREAKPOINT
883 case PTRACE_GETHBPREGS:
884 ret = ptrace_gethbpregs(child, addr,
885 (unsigned long __user *)data);
887 case PTRACE_SETHBPREGS:
888 ret = ptrace_sethbpregs(child, addr,
889 (unsigned long __user *)data);
894 ret = ptrace_request(child, request, addr, data);
901 enum ptrace_syscall_dir {
902 PTRACE_SYSCALL_ENTER = 0,
906 static void tracehook_report_syscall(struct pt_regs *regs,
907 enum ptrace_syscall_dir dir)
912 * IP is used to denote syscall entry/exit:
913 * IP = 0 -> entry, =1 -> exit
918 if (dir == PTRACE_SYSCALL_EXIT)
919 tracehook_report_syscall_exit(regs, 0);
920 else if (tracehook_report_syscall_entry(regs))
921 current_thread_info()->syscall = -1;
926 asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
928 current_thread_info()->syscall = scno;
930 if (test_thread_flag(TIF_SYSCALL_TRACE))
931 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
933 /* Do seccomp after ptrace; syscall may have changed. */
934 #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
935 if (secure_computing(NULL) == -1)
938 /* XXX: remove this once OABI gets fixed */
939 secure_computing_strict(current_thread_info()->syscall);
942 /* Tracer or seccomp may have changed syscall. */
943 scno = current_thread_info()->syscall;
945 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
946 trace_sys_enter(regs, scno);
948 audit_syscall_entry(scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
954 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
957 * Audit the syscall before anything else, as a debugger may
958 * come in and change the current registers.
960 audit_syscall_exit(regs);
963 * Note that we haven't updated the ->syscall field for the
964 * current thread. This isn't a problem because it will have
965 * been set on syscall entry and there hasn't been an opportunity
966 * for a PTRACE_SET_SYSCALL since then.
968 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
969 trace_sys_exit(regs, regs_return_value(regs));
971 if (test_thread_flag(TIF_SYSCALL_TRACE))
972 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);