arch/openrisc/kernel/ptrace.c

   1 /*
   2  * OpenRISC ptrace.c
   3  *
   4  * Linux architectural port borrowing liberally from similar works of
   5  * others.  All original copyrights apply as per the original source
   6  * declaration.
   7  *
   8  * Modifications for the OpenRISC architecture:
   9  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  10  * Copyright (C) 2005 Gyorgy Jeney <nog@bsemi.com>
  11  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  12  *
  13  *      This program is free software; you can redistribute it and/or
  14  *      modify it under the terms of the GNU General Public License
  15  *      as published by the Free Software Foundation; either version
  16  *      2 of the License, or (at your option) any later version.
  17  */
  18
  19 #include <stddef.h>
  20 #include <linux/kernel.h>
  21 #include <linux/sched.h>
  22 #include <linux/string.h>
  23
  24 #include <linux/mm.h>
  25 #include <linux/errno.h>
  26 #include <linux/ptrace.h>
  27 #include <linux/audit.h>
  28 #include <linux/regset.h>
  29 #include <linux/tracehook.h>
  30 #include <linux/elf.h>
  31
  32 #include <asm/thread_info.h>
  33 #include <asm/segment.h>
  34 #include <asm/page.h>
  35 #include <asm/pgtable.h>
  36 #include <asm/system.h>
  37
  38 /*
  39  * Copy the thread state to a regset that can be interpreted by userspace.
  40  *
  41  * It doesn't matter what our internal pt_regs structure looks like.  The
  42  * important thing is that we export a consistent view of the thread state
  43  * to userspace.  As such, we need to make sure that the regset remains
  44  * ABI compatible as defined by the struct user_regs_struct:
  45  *
  46  * (Each item is a 32-bit word)
  47  * r0 = 0 (exported for clarity)
  48  * 31 GPRS r1-r31
  49  * PC (Program counter)
  50  * SR (Supervision register)
  51  */
  52 static int genregs_get(struct task_struct *target,
  53                        const struct user_regset *regset,
  54                        unsigned int pos, unsigned int count,
  55                        void *kbuf, void __user * ubuf)
  56 {
  57         const struct pt_regs *regs = task_pt_regs(target);
  58         int ret;
  59
  60         /* r0 */
  61         ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf, 0, 4);
  62
  63         if (!ret)
  64                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  65                                           regs->gpr+1, 4, 4*32);
  66         if (!ret)
  67                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  68                                   &regs->pc, 4*32, 4*33);
  69         if (!ret)
  70                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  71                                           &regs->sr, 4*33, 4*34);
  72         if (!ret)
  73                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
  74                                                4*34, -1);
  75
  76         return ret;
  77 }
  78
  79 /*
  80  * Set the thread state from a regset passed in via ptrace
  81  */
  82 static int genregs_set(struct task_struct *target,
  83                        const struct user_regset *regset,
  84                        unsigned int pos, unsigned int count,
  85                        const void *kbuf, const void __user * ubuf)
  86 {
  87         struct pt_regs *regs = task_pt_regs(target);
  88         int ret;
  89
  90         /* ignore r0 */
  91         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, 4);
  92         /* r1 - r31 */
  93         if (!ret)
  94                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  95                                          regs->gpr+1, 4, 4*32);
  96         /* PC */
  97         if (!ret)
  98                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  99                                  &regs->pc, 4*32, 4*33);
 100         /*
 101          * Skip SR and padding... userspace isn't allowed to changes bits in
 102          * the Supervision register
 103          */
 104         if (!ret)
 105                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 106                                                 4*33, -1);
 107
 108         return ret;
 109 }
 110
 111 /*
 112  * Define the register sets available on OpenRISC under Linux
 113  */
 114 enum or1k_regset {
 115         REGSET_GENERAL,
 116 };
 117
 118 static const struct user_regset or1k_regsets[] = {
 119         [REGSET_GENERAL] = {
 120                             .core_note_type = NT_PRSTATUS,
 121                             .n = ELF_NGREG,
 122                             .size = sizeof(long),
 123                             .align = sizeof(long),
 124                             .get = genregs_get,
 125                             .set = genregs_set,
 126                             },
 127 };
 128
 129 static const struct user_regset_view user_or1k_native_view = {
 130         .name = "or1k",
 131         .e_machine = EM_OPENRISC,
 132         .regsets = or1k_regsets,
 133         .n = ARRAY_SIZE(or1k_regsets),
 134 };
 135
 136 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 137 {
 138         return &user_or1k_native_view;
 139 }
 140
 141 /*
 142  * does not yet catch signals sent when the child dies.
 143  * in exit.c or in signal.c.
 144  */
 145
 146
 147 /*
 148  * Called by kernel/ptrace.c when detaching..
 149  *
 150  * Make sure the single step bit is not set.
 151  */
 152 void ptrace_disable(struct task_struct *child)
 153 {
 154         pr_debug("ptrace_disable(): TODO\n");
 155
 156         user_disable_single_step(child);
 157         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 158 }
 159
 160 long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
 161                  unsigned long data)
 162 {
 163         int ret;
 164
 165         switch (request) {
 166         default:
 167                 ret = ptrace_request(child, request, addr, data);
 168                 break;
 169         }
 170
 171         return ret;
 172 }
 173
 174 /*
 175  * Notification of system call entry/exit
 176  * - triggered by current->work.syscall_trace
 177  */
 178 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 179 {
 180         long ret = 0;
 181
 182         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 183             tracehook_report_syscall_entry(regs))
 184                 /*
 185                  * Tracing decided this syscall should not happen.
 186                  * We'll return a bogus call number to get an ENOSYS
 187                  * error, but leave the original number in <something>.
 188                  */
 189                 ret = -1L;
 190
 191         /* Are these regs right??? */
 192         if (unlikely(current->audit_context))
 193                 audit_syscall_entry(audit_arch(), regs->syscallno,
 194                                     regs->gpr[3], regs->gpr[4],
 195                                     regs->gpr[5], regs->gpr[6]);
 196
 197         return ret ? : regs->syscallno;
 198 }
 199
 200 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 201 {
 202         int step;
 203
 204         if (unlikely(current->audit_context))
 205                 audit_syscall_exit(AUDITSC_RESULT(regs->gpr[11]),
 206                                    regs->gpr[11]);
 207
 208         step = test_thread_flag(TIF_SINGLESTEP);
 209         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 210                 tracehook_report_syscall_exit(regs, step);
 211 }