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
  37 /*
  38  * Copy the thread state to a regset that can be interpreted by userspace.
  39  *
  40  * It doesn't matter what our internal pt_regs structure looks like.  The
  41  * important thing is that we export a consistent view of the thread state
  42  * to userspace.  As such, we need to make sure that the regset remains
  43  * ABI compatible as defined by the struct user_regs_struct:
  44  *
  45  * (Each item is a 32-bit word)
  46  * r0 = 0 (exported for clarity)
  47  * 31 GPRS r1-r31
  48  * PC (Program counter)
  49  * SR (Supervision register)
  50  */
  51 static int genregs_get(struct task_struct *target,
  52                        const struct user_regset *regset,
  53                        unsigned int pos, unsigned int count,
  54                        void *kbuf, void __user * ubuf)
  55 {
  56         const struct pt_regs *regs = task_pt_regs(target);
  57         int ret;
  58
  59         /* r0 */
  60         ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf, 0, 4);
  61
  62         if (!ret)
  63                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  64                                           regs->gpr+1, 4, 4*32);
  65         if (!ret)
  66                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  67                                   &regs->pc, 4*32, 4*33);
  68         if (!ret)
  69                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  70                                           &regs->sr, 4*33, 4*34);
  71         if (!ret)
  72                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
  73                                                4*34, -1);
  74
  75         return ret;
  76 }
  77
  78 /*
  79  * Set the thread state from a regset passed in via ptrace
  80  */
  81 static int genregs_set(struct task_struct *target,
  82                        const struct user_regset *regset,
  83                        unsigned int pos, unsigned int count,
  84                        const void *kbuf, const void __user * ubuf)
  85 {
  86         struct pt_regs *regs = task_pt_regs(target);
  87         int ret;
  88
  89         /* ignore r0 */
  90         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, 4);
  91         /* r1 - r31 */
  92         if (!ret)
  93                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  94                                          regs->gpr+1, 4, 4*32);
  95         /* PC */
  96         if (!ret)
  97                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  98                                  &regs->pc, 4*32, 4*33);
  99         /*
 100          * Skip SR and padding... userspace isn't allowed to changes bits in
 101          * the Supervision register
 102          */
 103         if (!ret)
 104                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 105                                                 4*33, -1);
 106
 107         return ret;
 108 }
 109
 110 /*
 111  * Define the register sets available on OpenRISC under Linux
 112  */
 113 enum or1k_regset {
 114         REGSET_GENERAL,
 115 };
 116
 117 static const struct user_regset or1k_regsets[] = {
 118         [REGSET_GENERAL] = {
 119                             .core_note_type = NT_PRSTATUS,
 120                             .n = ELF_NGREG,
 121                             .size = sizeof(long),
 122                             .align = sizeof(long),
 123                             .get = genregs_get,
 124                             .set = genregs_set,
 125                             },
 126 };
 127
 128 static const struct user_regset_view user_or1k_native_view = {
 129         .name = "or1k",
 130         .e_machine = EM_OPENRISC,
 131         .regsets = or1k_regsets,
 132         .n = ARRAY_SIZE(or1k_regsets),
 133 };
 134
 135 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 136 {
 137         return &user_or1k_native_view;
 138 }
 139
 140 /*
 141  * does not yet catch signals sent when the child dies.
 142  * in exit.c or in signal.c.
 143  */
 144
 145
 146 /*
 147  * Called by kernel/ptrace.c when detaching..
 148  *
 149  * Make sure the single step bit is not set.
 150  */
 151 void ptrace_disable(struct task_struct *child)
 152 {
 153         pr_debug("ptrace_disable(): TODO\n");
 154
 155         user_disable_single_step(child);
 156         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 157 }
 158
 159 long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
 160                  unsigned long data)
 161 {
 162         int ret;
 163
 164         switch (request) {
 165         default:
 166                 ret = ptrace_request(child, request, addr, data);
 167                 break;
 168         }
 169
 170         return ret;
 171 }
 172
 173 /*
 174  * Notification of system call entry/exit
 175  * - triggered by current->work.syscall_trace
 176  */
 177 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 178 {
 179         long ret = 0;
 180
 181         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 182             tracehook_report_syscall_entry(regs))
 183                 /*
 184                  * Tracing decided this syscall should not happen.
 185                  * We'll return a bogus call number to get an ENOSYS
 186                  * error, but leave the original number in <something>.
 187                  */
 188                 ret = -1L;
 189
 190         audit_syscall_entry(AUDIT_ARCH_OPENRISC, regs->gpr[11],
 191                             regs->gpr[3], regs->gpr[4],
 192                             regs->gpr[5], regs->gpr[6]);
 193
 194         return ret ? : regs->gpr[11];
 195 }
 196
 197 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 198 {
 199         int step;
 200
 201         audit_syscall_exit(regs);
 202
 203         step = test_thread_flag(TIF_SINGLESTEP);
 204         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 205                 tracehook_report_syscall_exit(regs, step);
 206 }