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
  31 /*
  32  * does not yet catch signals sent when the child dies.
  33  * in exit.c or in signal.c.
  34  */
  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         struct pt_regs *regs = task_pt_regs(child);
  65         long pc;
  66
  67         pc = get_stack_long(child, (long)&regs->pc);
  68
  69         /* Next scheduling will set up UBC */
  70         if (child->thread.ubc_pc == 0)
  71                 ubc_usercnt += 1;
  72
  73         child->thread.ubc_pc = pc;
  74
  75         set_tsk_thread_flag(child, TIF_SINGLESTEP);
  76 }
  77
  78 void user_disable_single_step(struct task_struct *child)
  79 {
  80         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
  81
  82         /*
  83          * Ensure the UBC is not programmed at the next context switch.
  84          *
  85          * Normally this is not needed but there are sequences such as
  86          * singlestep, signal delivery, and continue that leave the
  87          * ubc_pc non-zero leading to spurious SIGTRAPs.
  88          */
  89         if (child->thread.ubc_pc != 0) {
  90                 ubc_usercnt -= 1;
  91                 child->thread.ubc_pc = 0;
  92         }
  93 }
  94
  95 /*
  96  * Called by kernel/ptrace.c when detaching..
  97  *
  98  * Make sure single step bits etc are not set.
  99  */
 100 void ptrace_disable(struct task_struct *child)
 101 {
 102         user_disable_single_step(child);
 103 }
 104
 105 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 106 {
 107         struct user * dummy = NULL;
 108         int ret;
 109
 110         switch (request) {
 111         /* read the word at location addr in the USER area. */
 112         case PTRACE_PEEKUSR: {
 113                 unsigned long tmp;
 114
 115                 ret = -EIO;
 116                 if ((addr & 3) || addr < 0 ||
 117                     addr > sizeof(struct user) - 3)
 118                         break;
 119
 120                 if (addr < sizeof(struct pt_regs))
 121                         tmp = get_stack_long(child, addr);
 122                 else if (addr >= (long) &dummy->fpu &&
 123                          addr < (long) &dummy->u_fpvalid) {
 124                         if (!tsk_used_math(child)) {
 125                                 if (addr == (long)&dummy->fpu.fpscr)
 126                                         tmp = FPSCR_INIT;
 127                                 else
 128                                         tmp = 0;
 129                         } else
 130                                 tmp = ((long *)&child->thread.fpu)
 131                                         [(addr - (long)&dummy->fpu) >> 2];
 132                 } else if (addr == (long) &dummy->u_fpvalid)
 133                         tmp = !!tsk_used_math(child);
 134                 else
 135                         tmp = 0;
 136                 ret = put_user(tmp, (unsigned long __user *)data);
 137                 break;
 138         }
 139
 140         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 141                 ret = -EIO;
 142                 if ((addr & 3) || addr < 0 ||
 143                     addr > sizeof(struct user) - 3)
 144                         break;
 145
 146                 if (addr < sizeof(struct pt_regs))
 147                         ret = put_stack_long(child, addr, data);
 148                 else if (addr >= (long) &dummy->fpu &&
 149                          addr < (long) &dummy->u_fpvalid) {
 150                         set_stopped_child_used_math(child);
 151                         ((long *)&child->thread.fpu)
 152                                 [(addr - (long)&dummy->fpu) >> 2] = data;
 153                         ret = 0;
 154                 } else if (addr == (long) &dummy->u_fpvalid) {
 155                         conditional_stopped_child_used_math(data, child);
 156                         ret = 0;
 157                 }
 158                 break;
 159
 160 #ifdef CONFIG_SH_DSP
 161         case PTRACE_GETDSPREGS: {
 162                 unsigned long dp;
 163
 164                 ret = -EIO;
 165                 dp = ((unsigned long) child) + THREAD_SIZE -
 166                          sizeof(struct pt_dspregs);
 167                 if (*((int *) (dp - 4)) == SR_FD) {
 168                         copy_to_user((void *)addr, (void *) dp,
 169                                 sizeof(struct pt_dspregs));
 170                         ret = 0;
 171                 }
 172                 break;
 173         }
 174
 175         case PTRACE_SETDSPREGS: {
 176                 unsigned long dp;
 177
 178                 ret = -EIO;
 179                 dp = ((unsigned long) child) + THREAD_SIZE -
 180                          sizeof(struct pt_dspregs);
 181                 if (*((int *) (dp - 4)) == SR_FD) {
 182                         copy_from_user((void *) dp, (void *)addr,
 183                                 sizeof(struct pt_dspregs));
 184                         ret = 0;
 185                 }
 186                 break;
 187         }
 188 #endif
 189 #ifdef CONFIG_BINFMT_ELF_FDPIC
 190         case PTRACE_GETFDPIC: {
 191                 unsigned long tmp = 0;
 192
 193                 switch (addr) {
 194                 case PTRACE_GETFDPIC_EXEC:
 195                         tmp = child->mm->context.exec_fdpic_loadmap;
 196                         break;
 197                 case PTRACE_GETFDPIC_INTERP:
 198                         tmp = child->mm->context.interp_fdpic_loadmap;
 199                         break;
 200                 default:
 201                         break;
 202                 }
 203
 204                 ret = 0;
 205                 if (put_user(tmp, (unsigned long *) data)) {
 206                         ret = -EFAULT;
 207                         break;
 208                 }
 209                 break;
 210         }
 211 #endif
 212         default:
 213                 ret = ptrace_request(child, request, addr, data);
 214                 break;
 215         }
 216
 217         return ret;
 218 }
 219
 220 static inline int audit_arch(void)
 221 {
 222         int arch = EM_SH;
 223
 224 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 225         arch |= __AUDIT_ARCH_LE;
 226 #endif
 227
 228         return arch;
 229 }
 230
 231 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 232 {
 233         long ret = 0;
 234
 235         secure_computing(regs->regs[0]);
 236
 237         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 238             tracehook_report_syscall_entry(regs))
 239                 /*
 240                  * Tracing decided this syscall should not happen.
 241                  * We'll return a bogus call number to get an ENOSYS
 242                  * error, but leave the original number in regs->regs[0].
 243                  */
 244                 ret = -1L;
 245
 246         if (unlikely(current->audit_context))
 247                 audit_syscall_entry(audit_arch(), regs->regs[3],
 248                                     regs->regs[4], regs->regs[5],
 249                                     regs->regs[6], regs->regs[7]);
 250
 251         return ret ?: regs->regs[0];
 252 }
 253
 254 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 255 {
 256         int step;
 257
 258         if (unlikely(current->audit_context))
 259                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[0]),
 260                                    regs->regs[0]);
 261
 262         step = test_thread_flag(TIF_SINGLESTEP);
 263         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 264                 tracehook_report_syscall_exit(regs, step);
 265 }