arch/sh/kernel/ptrace_32.c

   1 /*
   2  * SuperH process tracing
   3  *
   4  * Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
   5  * Copyright (C) 2002 - 2008  Paul Mundt
   6  *
   7  * Audit support by Yuichi Nakamura <ynakam@hitachisoft.jp>
   8  *
   9  * This file is subject to the terms and conditions of the GNU General Public
  10  * License.  See the file "COPYING" in the main directory of this archive
  11  * for more details.
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/mm.h>
  16 #include <linux/smp.h>
  17 #include <linux/errno.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/user.h>
  20 #include <linux/slab.h>
  21 #include <linux/security.h>
  22 #include <linux/signal.h>
  23 #include <linux/io.h>
  24 #include <linux/audit.h>
  25 #include <linux/seccomp.h>
  26 #include <linux/tracehook.h>
  27 #include <linux/elf.h>
  28 #include <linux/regset.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/pgtable.h>
  31 #include <asm/system.h>
  32 #include <asm/processor.h>
  33 #include <asm/mmu_context.h>
  34 #include <asm/syscalls.h>
  35
  36 /*
  37  * This routine will get a word off of the process kernel stack.
  38  */
  39 static inline int get_stack_long(struct task_struct *task, int offset)
  40 {
  41         unsigned char *stack;
  42
  43         stack = (unsigned char *)task_pt_regs(task);
  44         stack += offset;
  45         return (*((int *)stack));
  46 }
  47
  48 /*
  49  * This routine will put a word on the process kernel stack.
  50  */
  51 static inline int put_stack_long(struct task_struct *task, int offset,
  52                                  unsigned long data)
  53 {
  54         unsigned char *stack;
  55
  56         stack = (unsigned char *)task_pt_regs(task);
  57         stack += offset;
  58         *(unsigned long *) stack = data;
  59         return 0;
  60 }
  61
  62 void user_enable_single_step(struct task_struct *child)
  63 {
  64         /* Next scheduling will set up UBC */
  65         if (child->thread.ubc_pc == 0)
  66                 ubc_usercnt += 1;
  67
  68         child->thread.ubc_pc = get_stack_long(child,
  69                                 offsetof(struct pt_regs, pc));
  70
  71         set_tsk_thread_flag(child, TIF_SINGLESTEP);
  72 }
  73
  74 void user_disable_single_step(struct task_struct *child)
  75 {
  76         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
  77
  78         /*
  79          * Ensure the UBC is not programmed at the next context switch.
  80          *
  81          * Normally this is not needed but there are sequences such as
  82          * singlestep, signal delivery, and continue that leave the
  83          * ubc_pc non-zero leading to spurious SIGTRAPs.
  84          */
  85         if (child->thread.ubc_pc != 0) {
  86                 ubc_usercnt -= 1;
  87                 child->thread.ubc_pc = 0;
  88         }
  89 }
  90
  91 /*
  92  * Called by kernel/ptrace.c when detaching..
  93  *
  94  * Make sure single step bits etc are not set.
  95  */
  96 void ptrace_disable(struct task_struct *child)
  97 {
  98         user_disable_single_step(child);
  99 }
 100
 101 static int genregs_get(struct task_struct *target,
 102                        const struct user_regset *regset,
 103                        unsigned int pos, unsigned int count,
 104                        void *kbuf, void __user *ubuf)
 105 {
 106         const struct pt_regs *regs = task_pt_regs(target);
 107         int ret;
 108
 109         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 110                                   regs->regs,
 111                                   0, 16 * sizeof(unsigned long));
 112         if (!ret)
 113                 /* PC, PR, SR, GBR, MACH, MACL, TRA */
 114                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 115                                           &regs->pc,
 116                                           offsetof(struct pt_regs, pc),
 117                                           sizeof(struct pt_regs));
 118         if (!ret)
 119                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 120                                                sizeof(struct pt_regs), -1);
 121
 122         return ret;
 123 }
 124
 125 static int genregs_set(struct task_struct *target,
 126                        const struct user_regset *regset,
 127                        unsigned int pos, unsigned int count,
 128                        const void *kbuf, const void __user *ubuf)
 129 {
 130         struct pt_regs *regs = task_pt_regs(target);
 131         int ret;
 132
 133         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 134                                  regs->regs,
 135                                  0, 16 * sizeof(unsigned long));
 136         if (!ret && count > 0)
 137                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 138                                          &regs->pc,
 139                                          offsetof(struct pt_regs, pc),
 140                                          sizeof(struct pt_regs));
 141         if (!ret)
 142                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 143                                                 sizeof(struct pt_regs), -1);
 144
 145         return ret;
 146 }
 147
 148 /*
 149  * These are our native regset flavours.
 150  */
 151 enum sh_regset {
 152         REGSET_GENERAL,
 153 };
 154
 155 static const struct user_regset sh_regsets[] = {
 156         /*
 157          * Format is:
 158          *      R0 --> R15
 159          *      PC, PR, SR, GBR, MACH, MACL, TRA
 160          */
 161         [REGSET_GENERAL] = {
 162                 .core_note_type = NT_PRSTATUS,
 163                 .n              = ELF_NGREG,
 164                 .size           = sizeof(long),
 165                 .align          = sizeof(long),
 166                 .get            = genregs_get,
 167                 .set            = genregs_set,
 168         },
 169 };
 170
 171 static const struct user_regset_view user_sh_native_view = {
 172         .name           = "sh",
 173         .e_machine      = EM_SH,
 174         .regsets        = sh_regsets,
 175         .n              = ARRAY_SIZE(sh_regsets),
 176 };
 177
 178 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 179 {
 180         struct user * dummy = NULL;
 181         unsigned long __user *datap = (unsigned long __user *)data;
 182         int ret;
 183
 184         switch (request) {
 185         /* read the word at location addr in the USER area. */
 186         case PTRACE_PEEKUSR: {
 187                 unsigned long tmp;
 188
 189                 ret = -EIO;
 190                 if ((addr & 3) || addr < 0 ||
 191                     addr > sizeof(struct user) - 3)
 192                         break;
 193
 194                 if (addr < sizeof(struct pt_regs))
 195                         tmp = get_stack_long(child, addr);
 196                 else if (addr >= (long) &dummy->fpu &&
 197                          addr < (long) &dummy->u_fpvalid) {
 198                         if (!tsk_used_math(child)) {
 199                                 if (addr == (long)&dummy->fpu.fpscr)
 200                                         tmp = FPSCR_INIT;
 201                                 else
 202                                         tmp = 0;
 203                         } else
 204                                 tmp = ((long *)&child->thread.fpu)
 205                                         [(addr - (long)&dummy->fpu) >> 2];
 206                 } else if (addr == (long) &dummy->u_fpvalid)
 207                         tmp = !!tsk_used_math(child);
 208                 else
 209                         tmp = 0;
 210                 ret = put_user(tmp, datap);
 211                 break;
 212         }
 213
 214         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 215                 ret = -EIO;
 216                 if ((addr & 3) || addr < 0 ||
 217                     addr > sizeof(struct user) - 3)
 218                         break;
 219
 220                 if (addr < sizeof(struct pt_regs))
 221                         ret = put_stack_long(child, addr, data);
 222                 else if (addr >= (long) &dummy->fpu &&
 223                          addr < (long) &dummy->u_fpvalid) {
 224                         set_stopped_child_used_math(child);
 225                         ((long *)&child->thread.fpu)
 226                                 [(addr - (long)&dummy->fpu) >> 2] = data;
 227                         ret = 0;
 228                 } else if (addr == (long) &dummy->u_fpvalid) {
 229                         conditional_stopped_child_used_math(data, child);
 230                         ret = 0;
 231                 }
 232                 break;
 233
 234         case PTRACE_GETREGS:
 235                 return copy_regset_to_user(child, &user_sh_native_view,
 236                                            REGSET_GENERAL,
 237                                            0, sizeof(struct pt_regs),
 238                                            (void __user *)data);
 239         case PTRACE_SETREGS:
 240                 return copy_regset_from_user(child, &user_sh_native_view,
 241                                              REGSET_GENERAL,
 242                                              0, sizeof(struct pt_regs),
 243                                              (const void __user *)data);
 244 #ifdef CONFIG_SH_DSP
 245         case PTRACE_GETDSPREGS: {
 246                 unsigned long dp;
 247
 248                 ret = -EIO;
 249                 dp = ((unsigned long) child) + THREAD_SIZE -
 250                          sizeof(struct pt_dspregs);
 251                 if (*((int *) (dp - 4)) == SR_FD) {
 252                         copy_to_user((void *)addr, (void *) dp,
 253                                 sizeof(struct pt_dspregs));
 254                         ret = 0;
 255                 }
 256                 break;
 257         }
 258
 259         case PTRACE_SETDSPREGS: {
 260                 unsigned long dp;
 261
 262                 ret = -EIO;
 263                 dp = ((unsigned long) child) + THREAD_SIZE -
 264                          sizeof(struct pt_dspregs);
 265                 if (*((int *) (dp - 4)) == SR_FD) {
 266                         copy_from_user((void *) dp, (void *)addr,
 267                                 sizeof(struct pt_dspregs));
 268                         ret = 0;
 269                 }
 270                 break;
 271         }
 272 #endif
 273 #ifdef CONFIG_BINFMT_ELF_FDPIC
 274         case PTRACE_GETFDPIC: {
 275                 unsigned long tmp = 0;
 276
 277                 switch (addr) {
 278                 case PTRACE_GETFDPIC_EXEC:
 279                         tmp = child->mm->context.exec_fdpic_loadmap;
 280                         break;
 281                 case PTRACE_GETFDPIC_INTERP:
 282                         tmp = child->mm->context.interp_fdpic_loadmap;
 283                         break;
 284                 default:
 285                         break;
 286                 }
 287
 288                 ret = 0;
 289                 if (put_user(tmp, datap)) {
 290                         ret = -EFAULT;
 291                         break;
 292                 }
 293                 break;
 294         }
 295 #endif
 296         default:
 297                 ret = ptrace_request(child, request, addr, data);
 298                 break;
 299         }
 300
 301         return ret;
 302 }
 303
 304 static inline int audit_arch(void)
 305 {
 306         int arch = EM_SH;
 307
 308 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 309         arch |= __AUDIT_ARCH_LE;
 310 #endif
 311
 312         return arch;
 313 }
 314
 315 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 316 {
 317         long ret = 0;
 318
 319         secure_computing(regs->regs[0]);
 320
 321         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 322             tracehook_report_syscall_entry(regs))
 323                 /*
 324                  * Tracing decided this syscall should not happen.
 325                  * We'll return a bogus call number to get an ENOSYS
 326                  * error, but leave the original number in regs->regs[0].
 327                  */
 328                 ret = -1L;
 329
 330         if (unlikely(current->audit_context))
 331                 audit_syscall_entry(audit_arch(), regs->regs[3],
 332                                     regs->regs[4], regs->regs[5],
 333                                     regs->regs[6], regs->regs[7]);
 334
 335         return ret ?: regs->regs[0];
 336 }
 337
 338 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 339 {
 340         int step;
 341
 342         if (unlikely(current->audit_context))
 343                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[0]),
 344                                    regs->regs[0]);
 345
 346         step = test_thread_flag(TIF_SINGLESTEP);
 347         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 348                 tracehook_report_syscall_exit(regs, step);
 349 }