arch/sh/kernel/ptrace_32.c

   1 /*
   2  * linux/arch/sh/kernel/ptrace.c
   3  *
   4  * Original x86 implementation:
   5  *      By Ross Biro 1/23/92
   6  *      edited by Linus Torvalds
   7  *
   8  * SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
   9  * Audit support: Yuichi Nakamura <ynakam@hitachisoft.jp>
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/sched.h>
  13 #include <linux/mm.h>
  14 #include <linux/smp.h>
  15 #include <linux/errno.h>
  16 #include <linux/ptrace.h>
  17 #include <linux/user.h>
  18 #include <linux/slab.h>
  19 #include <linux/security.h>
  20 #include <linux/signal.h>
  21 #include <linux/io.h>
  22 #include <linux/audit.h>
  23 #include <linux/seccomp.h>
  24 #include <linux/tracehook.h>
  25 #include <asm/uaccess.h>
  26 #include <asm/pgtable.h>
  27 #include <asm/system.h>
  28 #include <asm/processor.h>
  29 #include <asm/mmu_context.h>
  30 #include <asm/syscalls.h>
  31
  32 /*
  33  * does not yet catch signals sent when the child dies.
  34  * in exit.c or in signal.c.
  35  */
  36
  37 /*
  38  * This routine will get a word off of the process kernel stack.
  39  */
  40 static inline int get_stack_long(struct task_struct *task, int offset)
  41 {
  42         unsigned char *stack;
  43
  44         stack = (unsigned char *)task_pt_regs(task);
  45         stack += offset;
  46         return (*((int *)stack));
  47 }
  48
  49 /*
  50  * This routine will put a word on the process kernel stack.
  51  */
  52 static inline int put_stack_long(struct task_struct *task, int offset,
  53                                  unsigned long data)
  54 {
  55         unsigned char *stack;
  56
  57         stack = (unsigned char *)task_pt_regs(task);
  58         stack += offset;
  59         *(unsigned long *) stack = data;
  60         return 0;
  61 }
  62
  63 void user_enable_single_step(struct task_struct *child)
  64 {
  65         struct pt_regs *regs = task_pt_regs(child);
  66         long pc;
  67
  68         pc = get_stack_long(child, (long)&regs->pc);
  69
  70         /* Next scheduling will set up UBC */
  71         if (child->thread.ubc_pc == 0)
  72                 ubc_usercnt += 1;
  73
  74         child->thread.ubc_pc = pc;
  75
  76         set_tsk_thread_flag(child, TIF_SINGLESTEP);
  77 }
  78
  79 void user_disable_single_step(struct task_struct *child)
  80 {
  81         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
  82
  83         /*
  84          * Ensure the UBC is not programmed at the next context switch.
  85          *
  86          * Normally this is not needed but there are sequences such as
  87          * singlestep, signal delivery, and continue that leave the
  88          * ubc_pc non-zero leading to spurious SIGTRAPs.
  89          */
  90         if (child->thread.ubc_pc != 0) {
  91                 ubc_usercnt -= 1;
  92                 child->thread.ubc_pc = 0;
  93         }
  94 }
  95
  96 /*
  97  * Called by kernel/ptrace.c when detaching..
  98  *
  99  * Make sure single step bits etc are not set.
 100  */
 101 void ptrace_disable(struct task_struct *child)
 102 {
 103         user_disable_single_step(child);
 104 }
 105
 106 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 107 {
 108         struct user * dummy = NULL;
 109         unsigned long __user *datap = (unsigned long __user *)data;
 110         int ret;
 111
 112         switch (request) {
 113         /* read the word at location addr in the USER area. */
 114         case PTRACE_PEEKUSR: {
 115                 unsigned long tmp;
 116
 117                 ret = -EIO;
 118                 if ((addr & 3) || addr < 0 ||
 119                     addr > sizeof(struct user) - 3)
 120                         break;
 121
 122                 if (addr < sizeof(struct pt_regs))
 123                         tmp = get_stack_long(child, addr);
 124                 else if (addr >= (long) &dummy->fpu &&
 125                          addr < (long) &dummy->u_fpvalid) {
 126                         if (!tsk_used_math(child)) {
 127                                 if (addr == (long)&dummy->fpu.fpscr)
 128                                         tmp = FPSCR_INIT;
 129                                 else
 130                                         tmp = 0;
 131                         } else
 132                                 tmp = ((long *)&child->thread.fpu)
 133                                         [(addr - (long)&dummy->fpu) >> 2];
 134                 } else if (addr == (long) &dummy->u_fpvalid)
 135                         tmp = !!tsk_used_math(child);
 136                 else
 137                         tmp = 0;
 138                 ret = put_user(tmp, datap);
 139                 break;
 140         }
 141
 142         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 143                 ret = -EIO;
 144                 if ((addr & 3) || addr < 0 ||
 145                     addr > sizeof(struct user) - 3)
 146                         break;
 147
 148                 if (addr < sizeof(struct pt_regs))
 149                         ret = put_stack_long(child, addr, data);
 150                 else if (addr >= (long) &dummy->fpu &&
 151                          addr < (long) &dummy->u_fpvalid) {
 152                         set_stopped_child_used_math(child);
 153                         ((long *)&child->thread.fpu)
 154                                 [(addr - (long)&dummy->fpu) >> 2] = data;
 155                         ret = 0;
 156                 } else if (addr == (long) &dummy->u_fpvalid) {
 157                         conditional_stopped_child_used_math(data, child);
 158                         ret = 0;
 159                 }
 160                 break;
 161
 162 #ifdef CONFIG_SH_DSP
 163         case PTRACE_GETDSPREGS: {
 164                 unsigned long dp;
 165
 166                 ret = -EIO;
 167                 dp = ((unsigned long) child) + THREAD_SIZE -
 168                          sizeof(struct pt_dspregs);
 169                 if (*((int *) (dp - 4)) == SR_FD) {
 170                         copy_to_user((void *)addr, (void *) dp,
 171                                 sizeof(struct pt_dspregs));
 172                         ret = 0;
 173                 }
 174                 break;
 175         }
 176
 177         case PTRACE_SETDSPREGS: {
 178                 unsigned long dp;
 179
 180                 ret = -EIO;
 181                 dp = ((unsigned long) child) + THREAD_SIZE -
 182                          sizeof(struct pt_dspregs);
 183                 if (*((int *) (dp - 4)) == SR_FD) {
 184                         copy_from_user((void *) dp, (void *)addr,
 185                                 sizeof(struct pt_dspregs));
 186                         ret = 0;
 187                 }
 188                 break;
 189         }
 190 #endif
 191 #ifdef CONFIG_BINFMT_ELF_FDPIC
 192         case PTRACE_GETFDPIC: {
 193                 unsigned long tmp = 0;
 194
 195                 switch (addr) {
 196                 case PTRACE_GETFDPIC_EXEC:
 197                         tmp = child->mm->context.exec_fdpic_loadmap;
 198                         break;
 199                 case PTRACE_GETFDPIC_INTERP:
 200                         tmp = child->mm->context.interp_fdpic_loadmap;
 201                         break;
 202                 default:
 203                         break;
 204                 }
 205
 206                 ret = 0;
 207                 if (put_user(tmp, datap)) {
 208                         ret = -EFAULT;
 209                         break;
 210                 }
 211                 break;
 212         }
 213 #endif
 214         default:
 215                 ret = ptrace_request(child, request, addr, data);
 216                 break;
 217         }
 218
 219         return ret;
 220 }
 221
 222 static inline int audit_arch(void)
 223 {
 224         int arch = EM_SH;
 225
 226 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 227         arch |= __AUDIT_ARCH_LE;
 228 #endif
 229
 230         return arch;
 231 }
 232
 233 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 234 {
 235         long ret = 0;
 236
 237         secure_computing(regs->regs[0]);
 238
 239         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 240             tracehook_report_syscall_entry(regs))
 241                 /*
 242                  * Tracing decided this syscall should not happen.
 243                  * We'll return a bogus call number to get an ENOSYS
 244                  * error, but leave the original number in regs->regs[0].
 245                  */
 246                 ret = -1L;
 247
 248         if (unlikely(current->audit_context))
 249                 audit_syscall_entry(audit_arch(), regs->regs[3],
 250                                     regs->regs[4], regs->regs[5],
 251                                     regs->regs[6], regs->regs[7]);
 252
 253         return ret ?: regs->regs[0];
 254 }
 255
 256 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 257 {
 258         int step;
 259
 260         if (unlikely(current->audit_context))
 261                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[0]),
 262                                    regs->regs[0]);
 263
 264         step = test_thread_flag(TIF_SINGLESTEP);
 265         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 266                 tracehook_report_syscall_exit(regs, step);
 267 }