arch/openrisc/kernel/ptrace.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * OpenRISC ptrace.c
   4  *
   5  * Linux architectural port borrowing liberally from similar works of
   6  * others.  All original copyrights apply as per the original source
   7  * declaration.
   8  *
   9  * Modifications for the OpenRISC architecture:
  10  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  11  * Copyright (C) 2005 Gyorgy Jeney <nog@bsemi.com>
  12  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/sched.h>
  17 #include <linux/sched/task_stack.h>
  18 #include <linux/string.h>
  19
  20 #include <linux/mm.h>
  21 #include <linux/errno.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/audit.h>
  24 #include <linux/regset.h>
  25 #include <linux/tracehook.h>
  26 #include <linux/elf.h>
  27
  28 #include <asm/thread_info.h>
  29 #include <asm/page.h>
  30 #include <asm/pgtable.h>
  31
  32 /*
  33  * Copy the thread state to a regset that can be interpreted by userspace.
  34  *
  35  * It doesn't matter what our internal pt_regs structure looks like.  The
  36  * important thing is that we export a consistent view of the thread state
  37  * to userspace.  As such, we need to make sure that the regset remains
  38  * ABI compatible as defined by the struct user_regs_struct:
  39  *
  40  * (Each item is a 32-bit word)
  41  * r0 = 0 (exported for clarity)
  42  * 31 GPRS r1-r31
  43  * PC (Program counter)
  44  * SR (Supervision register)
  45  */
  46 static int genregs_get(struct task_struct *target,
  47                        const struct user_regset *regset,
  48                        unsigned int pos, unsigned int count,
  49                        void *kbuf, void __user * ubuf)
  50 {
  51         const struct pt_regs *regs = task_pt_regs(target);
  52         int ret;
  53
  54         /* r0 */
  55         ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf, 0, 4);
  56
  57         if (!ret)
  58                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  59                                           regs->gpr+1, 4, 4*32);
  60         if (!ret)
  61                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  62                                   &regs->pc, 4*32, 4*33);
  63         if (!ret)
  64                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  65                                           &regs->sr, 4*33, 4*34);
  66         if (!ret)
  67                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
  68                                                4*34, -1);
  69
  70         return ret;
  71 }
  72
  73 /*
  74  * Set the thread state from a regset passed in via ptrace
  75  */
  76 static int genregs_set(struct task_struct *target,
  77                        const struct user_regset *regset,
  78                        unsigned int pos, unsigned int count,
  79                        const void *kbuf, const void __user * ubuf)
  80 {
  81         struct pt_regs *regs = task_pt_regs(target);
  82         int ret;
  83
  84         /* ignore r0 */
  85         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, 4);
  86         /* r1 - r31 */
  87         if (!ret)
  88                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  89                                          regs->gpr+1, 4, 4*32);
  90         /* PC */
  91         if (!ret)
  92                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  93                                  &regs->pc, 4*32, 4*33);
  94         /*
  95          * Skip SR and padding... userspace isn't allowed to changes bits in
  96          * the Supervision register
  97          */
  98         if (!ret)
  99                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 100                                                 4*33, -1);
 101
 102         return ret;
 103 }
 104
 105 /*
 106  * Define the register sets available on OpenRISC under Linux
 107  */
 108 enum or1k_regset {
 109         REGSET_GENERAL,
 110 };
 111
 112 static const struct user_regset or1k_regsets[] = {
 113         [REGSET_GENERAL] = {
 114                             .core_note_type = NT_PRSTATUS,
 115                             .n = ELF_NGREG,
 116                             .size = sizeof(long),
 117                             .align = sizeof(long),
 118                             .get = genregs_get,
 119                             .set = genregs_set,
 120                             },
 121 };
 122
 123 static const struct user_regset_view user_or1k_native_view = {
 124         .name = "or1k",
 125         .e_machine = EM_OPENRISC,
 126         .regsets = or1k_regsets,
 127         .n = ARRAY_SIZE(or1k_regsets),
 128 };
 129
 130 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 131 {
 132         return &user_or1k_native_view;
 133 }
 134
 135 /*
 136  * does not yet catch signals sent when the child dies.
 137  * in exit.c or in signal.c.
 138  */
 139
 140
 141 /*
 142  * Called by kernel/ptrace.c when detaching..
 143  *
 144  * Make sure the single step bit is not set.
 145  */
 146 void ptrace_disable(struct task_struct *child)
 147 {
 148         pr_debug("ptrace_disable(): TODO\n");
 149
 150         user_disable_single_step(child);
 151         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 152 }
 153
 154 long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
 155                  unsigned long data)
 156 {
 157         int ret;
 158
 159         switch (request) {
 160         default:
 161                 ret = ptrace_request(child, request, addr, data);
 162                 break;
 163         }
 164
 165         return ret;
 166 }
 167
 168 /*
 169  * Notification of system call entry/exit
 170  * - triggered by current->work.syscall_trace
 171  */
 172 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 173 {
 174         long ret = 0;
 175
 176         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 177             tracehook_report_syscall_entry(regs))
 178                 /*
 179                  * Tracing decided this syscall should not happen.
 180                  * We'll return a bogus call number to get an ENOSYS
 181                  * error, but leave the original number in <something>.
 182                  */
 183                 ret = -1L;
 184
 185         audit_syscall_entry(regs->gpr[11], regs->gpr[3], regs->gpr[4],
 186                             regs->gpr[5], regs->gpr[6]);
 187
 188         return ret ? : regs->gpr[11];
 189 }
 190
 191 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 192 {
 193         int step;
 194
 195         audit_syscall_exit(regs);
 196
 197         step = test_thread_flag(TIF_SINGLESTEP);
 198         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 199                 tracehook_report_syscall_exit(regs, step);
 200 }