arch/um/sys-i386/signal.c

   1 /*
   2  * Copyright (C) 2004 Jeff Dike (jdike@addtoit.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/signal.h"
   7 #include "linux/ptrace.h"
   8 #include "asm/current.h"
   9 #include "asm/ucontext.h"
  10 #include "asm/uaccess.h"
  11 #include "asm/unistd.h"
  12 #include "frame_kern.h"
  13 #include "sigcontext.h"
  14 #include "registers.h"
  15 #include "mode.h"
  16
  17 #ifdef CONFIG_MODE_SKAS
  18
  19 #include "skas.h"
  20
  21 static int copy_sc_from_user_skas(struct pt_regs *regs,
  22                                   struct sigcontext __user *from)
  23 {
  24         struct sigcontext sc;
  25         unsigned long fpregs[HOST_FP_SIZE];
  26         int err;
  27
  28         err = copy_from_user(&sc, from, sizeof(sc));
  29         err |= copy_from_user(fpregs, sc.fpstate, sizeof(fpregs));
  30         if(err)
  31                 return(err);
  32
  33         REGS_GS(regs->regs.skas.regs) = sc.gs;
  34         REGS_FS(regs->regs.skas.regs) = sc.fs;
  35         REGS_ES(regs->regs.skas.regs) = sc.es;
  36         REGS_DS(regs->regs.skas.regs) = sc.ds;
  37         REGS_EDI(regs->regs.skas.regs) = sc.edi;
  38         REGS_ESI(regs->regs.skas.regs) = sc.esi;
  39         REGS_EBP(regs->regs.skas.regs) = sc.ebp;
  40         REGS_SP(regs->regs.skas.regs) = sc.esp;
  41         REGS_EBX(regs->regs.skas.regs) = sc.ebx;
  42         REGS_EDX(regs->regs.skas.regs) = sc.edx;
  43         REGS_ECX(regs->regs.skas.regs) = sc.ecx;
  44         REGS_EAX(regs->regs.skas.regs) = sc.eax;
  45         REGS_IP(regs->regs.skas.regs) = sc.eip;
  46         REGS_CS(regs->regs.skas.regs) = sc.cs;
  47         REGS_EFLAGS(regs->regs.skas.regs) = sc.eflags;
  48         REGS_SS(regs->regs.skas.regs) = sc.ss;
  49
  50         err = restore_fp_registers(userspace_pid[0], fpregs);
  51         if(err < 0){
  52                 printk("copy_sc_from_user_skas - PTRACE_SETFPREGS failed, "
  53                        "errno = %d\n", err);
  54                 return(1);
  55         }
  56
  57         return(0);
  58 }
  59
  60 int copy_sc_to_user_skas(struct sigcontext __user *to, struct _fpstate __user *to_fp,
  61                          struct pt_regs *regs, unsigned long sp)
  62 {
  63         struct sigcontext sc;
  64         unsigned long fpregs[HOST_FP_SIZE];
  65         struct faultinfo * fi = &current->thread.arch.faultinfo;
  66         int err;
  67
  68         sc.gs = REGS_GS(regs->regs.skas.regs);
  69         sc.fs = REGS_FS(regs->regs.skas.regs);
  70         sc.es = REGS_ES(regs->regs.skas.regs);
  71         sc.ds = REGS_DS(regs->regs.skas.regs);
  72         sc.edi = REGS_EDI(regs->regs.skas.regs);
  73         sc.esi = REGS_ESI(regs->regs.skas.regs);
  74         sc.ebp = REGS_EBP(regs->regs.skas.regs);
  75         sc.esp = sp;
  76         sc.ebx = REGS_EBX(regs->regs.skas.regs);
  77         sc.edx = REGS_EDX(regs->regs.skas.regs);
  78         sc.ecx = REGS_ECX(regs->regs.skas.regs);
  79         sc.eax = REGS_EAX(regs->regs.skas.regs);
  80         sc.eip = REGS_IP(regs->regs.skas.regs);
  81         sc.cs = REGS_CS(regs->regs.skas.regs);
  82         sc.eflags = REGS_EFLAGS(regs->regs.skas.regs);
  83         sc.esp_at_signal = regs->regs.skas.regs[UESP];
  84         sc.ss = regs->regs.skas.regs[SS];
  85         sc.cr2 = fi->cr2;
  86         sc.err = fi->error_code;
  87         sc.trapno = fi->trap_no;
  88
  89         err = save_fp_registers(userspace_pid[0], fpregs);
  90         if(err < 0){
  91                 printk("copy_sc_to_user_skas - PTRACE_GETFPREGS failed, "
  92                        "errno = %d\n", err);
  93                 return(1);
  94         }
  95         to_fp = (to_fp ? to_fp : (struct _fpstate __user *) (to + 1));
  96         sc.fpstate = to_fp;
  97
  98         if(err)
  99                 return(err);
 100
 101         return(copy_to_user(to, &sc, sizeof(sc)) ||
 102                copy_to_user(to_fp, fpregs, sizeof(fpregs)));
 103 }
 104 #endif
 105
 106 #ifdef CONFIG_MODE_TT
 107
 108 /* These copy a sigcontext to/from userspace.  They copy the fpstate pointer,
 109  * blowing away the old, good one.  So, that value is saved, and then restored
 110  * after the sigcontext copy.  In copy_from, the variable holding the saved
 111  * fpstate pointer, and the sigcontext that it should be restored to are both
 112  * in the kernel, so we can just restore using an assignment.  In copy_to, the
 113  * saved pointer is in the kernel, but the sigcontext is in userspace, so we
 114  * copy_to_user it.
 115  */
 116 int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext __user *from,
 117                          int fpsize)
 118 {
 119         struct _fpstate *to_fp;
 120         struct _fpstate __user *from_fp;
 121         unsigned long sigs;
 122         int err;
 123
 124         to_fp = to->fpstate;
 125         sigs = to->oldmask;
 126         err = copy_from_user(to, from, sizeof(*to));
 127         from_fp = to->fpstate;
 128         to->oldmask = sigs;
 129         to->fpstate = to_fp;
 130         if(to_fp != NULL)
 131                 err |= copy_from_user(to_fp, from_fp, fpsize);
 132         return(err);
 133 }
 134
 135 int copy_sc_to_user_tt(struct sigcontext __user *to, struct _fpstate __user *fp,
 136                        struct sigcontext *from, int fpsize, unsigned long sp)
 137 {
 138         struct _fpstate __user *to_fp;
 139         struct _fpstate *from_fp;
 140         int err;
 141
 142         to_fp = (fp ? fp : (struct _fpstate __user *) (to + 1));
 143         from_fp = from->fpstate;
 144         err = copy_to_user(to, from, sizeof(*to));
 145
 146         /* The SP in the sigcontext is the updated one for the signal
 147          * delivery.  The sp passed in is the original, and this needs
 148          * to be restored, so we stick it in separately.
 149          */
 150         err |= copy_to_user(&SC_SP(to), &sp, sizeof(sp));
 151
 152         if(from_fp != NULL){
 153                 err |= copy_to_user(&to->fpstate, &to_fp, sizeof(to->fpstate));
 154                 err |= copy_to_user(to_fp, from_fp, fpsize);
 155         }
 156         return err;
 157 }
 158 #endif
 159
 160 static int copy_sc_from_user(struct pt_regs *to, void __user *from)
 161 {
 162         int ret;
 163
 164         ret = CHOOSE_MODE(copy_sc_from_user_tt(UPT_SC(&to->regs), from,
 165                                                sizeof(struct _fpstate)),
 166                           copy_sc_from_user_skas(to, from));
 167         return(ret);
 168 }
 169
 170 static int copy_sc_to_user(struct sigcontext __user *to, struct _fpstate __user *fp,
 171                            struct pt_regs *from, unsigned long sp)
 172 {
 173         return(CHOOSE_MODE(copy_sc_to_user_tt(to, fp, UPT_SC(&from->regs),
 174                                               sizeof(*fp), sp),
 175                            copy_sc_to_user_skas(to, fp, from, sp)));
 176 }
 177
 178 static int copy_ucontext_to_user(struct ucontext __user *uc, struct _fpstate __user *fp,
 179                                  sigset_t *set, unsigned long sp)
 180 {
 181         int err = 0;
 182
 183         err |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp);
 184         err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags);
 185         err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size);
 186         err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, sp);
 187         err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
 188         return(err);
 189 }
 190
 191 struct sigframe
 192 {
 193         char __user *pretcode;
 194         int sig;
 195         struct sigcontext sc;
 196         struct _fpstate fpstate;
 197         unsigned long extramask[_NSIG_WORDS-1];
 198         char retcode[8];
 199 };
 200
 201 struct rt_sigframe
 202 {
 203         char __user *pretcode;
 204         int sig;
 205         struct siginfo __user *pinfo;
 206         void __user *puc;
 207         struct siginfo info;
 208         struct ucontext uc;
 209         struct _fpstate fpstate;
 210         char retcode[8];
 211 };
 212
 213 int setup_signal_stack_sc(unsigned long stack_top, int sig,
 214                           struct k_sigaction *ka, struct pt_regs *regs,
 215                           sigset_t *mask)
 216 {
 217         struct sigframe __user *frame;
 218         void __user *restorer;
 219         unsigned long save_sp = PT_REGS_SP(regs);
 220         int err = 0;
 221
 222         stack_top &= -8UL;
 223         frame = (struct sigframe __user *) stack_top - 1;
 224         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 225                 return 1;
 226
 227         restorer = frame->retcode;
 228         if(ka->sa.sa_flags & SA_RESTORER)
 229                 restorer = ka->sa.sa_restorer;
 230
 231         /* Update SP now because the page fault handler refuses to extend
 232          * the stack if the faulting address is too far below the current
 233          * SP, which frame now certainly is.  If there's an error, the original
 234          * value is restored on the way out.
 235          * When writing the sigcontext to the stack, we have to write the
 236          * original value, so that's passed to copy_sc_to_user, which does
 237          * the right thing with it.
 238          */
 239         PT_REGS_SP(regs) = (unsigned long) frame;
 240
 241         err |= __put_user(restorer, &frame->pretcode);
 242         err |= __put_user(sig, &frame->sig);
 243         err |= copy_sc_to_user(&frame->sc, NULL, regs, save_sp);
 244         err |= __put_user(mask->sig[0], &frame->sc.oldmask);
 245         if (_NSIG_WORDS > 1)
 246                 err |= __copy_to_user(&frame->extramask, &mask->sig[1],
 247                                       sizeof(frame->extramask));
 248
 249         /*
 250          * This is popl %eax ; movl $,%eax ; int $0x80
 251          *
 252          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 253          * reasons and because gdb uses it as a signature to notice
 254          * signal handler stack frames.
 255          */
 256         err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
 257         err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
 258         err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
 259
 260         if(err)
 261                 goto err;
 262
 263         PT_REGS_SP(regs) = (unsigned long) frame;
 264         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 265         PT_REGS_EAX(regs) = (unsigned long) sig;
 266         PT_REGS_EDX(regs) = (unsigned long) 0;
 267         PT_REGS_ECX(regs) = (unsigned long) 0;
 268
 269         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 270                 ptrace_notify(SIGTRAP);
 271         return 0;
 272
 273 err:
 274         PT_REGS_SP(regs) = save_sp;
 275         return err;
 276 }
 277
 278 int setup_signal_stack_si(unsigned long stack_top, int sig,
 279                           struct k_sigaction *ka, struct pt_regs *regs,
 280                           siginfo_t *info, sigset_t *mask)
 281 {
 282         struct rt_sigframe __user *frame;
 283         void __user *restorer;
 284         unsigned long save_sp = PT_REGS_SP(regs);
 285         int err = 0;
 286
 287         stack_top &= -8UL;
 288         frame = (struct rt_sigframe __user *) stack_top - 1;
 289         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 290                 return 1;
 291
 292         restorer = frame->retcode;
 293         if(ka->sa.sa_flags & SA_RESTORER)
 294                 restorer = ka->sa.sa_restorer;
 295
 296         /* See comment above about why this is here */
 297         PT_REGS_SP(regs) = (unsigned long) frame;
 298
 299         err |= __put_user(restorer, &frame->pretcode);
 300         err |= __put_user(sig, &frame->sig);
 301         err |= __put_user(&frame->info, &frame->pinfo);
 302         err |= __put_user(&frame->uc, &frame->puc);
 303         err |= copy_siginfo_to_user(&frame->info, info);
 304         err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
 305                                      save_sp);
 306
 307         /*
 308          * This is movl $,%eax ; int $0x80
 309          *
 310          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 311          * reasons and because gdb uses it as a signature to notice
 312          * signal handler stack frames.
 313          */
 314         err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
 315         err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
 316         err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
 317
 318         if(err)
 319                 goto err;
 320
 321         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 322         PT_REGS_EAX(regs) = (unsigned long) sig;
 323         PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 324         PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 325
 326         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 327                 ptrace_notify(SIGTRAP);
 328         return 0;
 329
 330 err:
 331         PT_REGS_SP(regs) = save_sp;
 332         return err;
 333 }
 334
 335 long sys_sigreturn(struct pt_regs regs)
 336 {
 337         unsigned long sp = PT_REGS_SP(&current->thread.regs);
 338         struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
 339         sigset_t set;
 340         struct sigcontext __user *sc = &frame->sc;
 341         unsigned long __user *oldmask = &sc->oldmask;
 342         unsigned long __user *extramask = frame->extramask;
 343         int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
 344
 345         if(copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) ||
 346            copy_from_user(&set.sig[1], extramask, sig_size))
 347                 goto segfault;
 348
 349         sigdelsetmask(&set, ~_BLOCKABLE);
 350
 351         spin_lock_irq(&current->sighand->siglock);
 352         current->blocked = set;
 353         recalc_sigpending();
 354         spin_unlock_irq(&current->sighand->siglock);
 355
 356         if(copy_sc_from_user(&current->thread.regs, sc))
 357                 goto segfault;
 358
 359         /* Avoid ERESTART handling */
 360         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 361         return(PT_REGS_SYSCALL_RET(&current->thread.regs));
 362
 363  segfault:
 364         force_sig(SIGSEGV, current);
 365         return 0;
 366 }
 367
 368 long sys_rt_sigreturn(struct pt_regs regs)
 369 {
 370         unsigned long sp = PT_REGS_SP(&current->thread.regs);
 371         struct rt_sigframe __user *frame = (struct rt_sigframe __user *) (sp - 4);
 372         sigset_t set;
 373         struct ucontext __user *uc = &frame->uc;
 374         int sig_size = _NSIG_WORDS * sizeof(unsigned long);
 375
 376         if(copy_from_user(&set, &uc->uc_sigmask, sig_size))
 377                 goto segfault;
 378
 379         sigdelsetmask(&set, ~_BLOCKABLE);
 380
 381         spin_lock_irq(&current->sighand->siglock);
 382         current->blocked = set;
 383         recalc_sigpending();
 384         spin_unlock_irq(&current->sighand->siglock);
 385
 386         if(copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
 387                 goto segfault;
 388
 389         /* Avoid ERESTART handling */
 390         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 391         return(PT_REGS_SYSCALL_RET(&current->thread.regs));
 392
 393  segfault:
 394         force_sig(SIGSEGV, current);
 395         return 0;
 396 }
 397
 398 /*
 399  * Overrides for Emacs so that we follow Linus's tabbing style.
 400  * Emacs will notice this stuff at the end of the file and automatically
 401  * adjust the settings for this buffer only.  This must remain at the end
 402  * of the file.
 403  * ---------------------------------------------------------------------------
 404  * Local variables:
 405  * c-file-style: "linux"
 406  * End:
 407  */