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 void copy_sc(union uml_pt_regs *regs, void *from)
  22 {
  23         struct sigcontext *sc = from;
  24
  25         REGS_GS(regs->skas.regs) = sc->gs;
  26         REGS_FS(regs->skas.regs) = sc->fs;
  27         REGS_ES(regs->skas.regs) = sc->es;
  28         REGS_DS(regs->skas.regs) = sc->ds;
  29         REGS_EDI(regs->skas.regs) = sc->edi;
  30         REGS_ESI(regs->skas.regs) = sc->esi;
  31         REGS_EBP(regs->skas.regs) = sc->ebp;
  32         REGS_SP(regs->skas.regs) = sc->esp;
  33         REGS_EBX(regs->skas.regs) = sc->ebx;
  34         REGS_EDX(regs->skas.regs) = sc->edx;
  35         REGS_ECX(regs->skas.regs) = sc->ecx;
  36         REGS_EAX(regs->skas.regs) = sc->eax;
  37         REGS_IP(regs->skas.regs) = sc->eip;
  38         REGS_CS(regs->skas.regs) = sc->cs;
  39         REGS_EFLAGS(regs->skas.regs) = sc->eflags;
  40         REGS_SS(regs->skas.regs) = sc->ss;
  41 }
  42
  43 static int copy_sc_from_user_skas(struct pt_regs *regs,
  44                                   struct sigcontext __user *from)
  45 {
  46         struct sigcontext sc;
  47         unsigned long fpregs[HOST_FP_SIZE];
  48         int err;
  49
  50         err = copy_from_user(&sc, from, sizeof(sc));
  51         err |= copy_from_user(fpregs, sc.fpstate, sizeof(fpregs));
  52         if(err)
  53                 return err;
  54
  55         copy_sc(&regs->regs, &sc);
  56
  57         err = restore_fp_registers(userspace_pid[0], fpregs);
  58         if(err < 0) {
  59                 printk("copy_sc_from_user_skas - PTRACE_SETFPREGS failed, "
  60                        "errno = %d\n", -err);
  61                 return err;
  62         }
  63
  64         return 0;
  65 }
  66
  67 int copy_sc_to_user_skas(struct sigcontext __user *to, struct _fpstate __user *to_fp,
  68                          struct pt_regs *regs, unsigned long sp)
  69 {
  70         struct sigcontext sc;
  71         unsigned long fpregs[HOST_FP_SIZE];
  72         struct faultinfo * fi = &current->thread.arch.faultinfo;
  73         int err;
  74
  75         sc.gs = REGS_GS(regs->regs.skas.regs);
  76         sc.fs = REGS_FS(regs->regs.skas.regs);
  77         sc.es = REGS_ES(regs->regs.skas.regs);
  78         sc.ds = REGS_DS(regs->regs.skas.regs);
  79         sc.edi = REGS_EDI(regs->regs.skas.regs);
  80         sc.esi = REGS_ESI(regs->regs.skas.regs);
  81         sc.ebp = REGS_EBP(regs->regs.skas.regs);
  82         sc.esp = sp;
  83         sc.ebx = REGS_EBX(regs->regs.skas.regs);
  84         sc.edx = REGS_EDX(regs->regs.skas.regs);
  85         sc.ecx = REGS_ECX(regs->regs.skas.regs);
  86         sc.eax = REGS_EAX(regs->regs.skas.regs);
  87         sc.eip = REGS_IP(regs->regs.skas.regs);
  88         sc.cs = REGS_CS(regs->regs.skas.regs);
  89         sc.eflags = REGS_EFLAGS(regs->regs.skas.regs);
  90         sc.esp_at_signal = regs->regs.skas.regs[UESP];
  91         sc.ss = regs->regs.skas.regs[SS];
  92         sc.cr2 = fi->cr2;
  93         sc.err = fi->error_code;
  94         sc.trapno = fi->trap_no;
  95
  96         err = save_fp_registers(userspace_pid[0], fpregs);
  97         if(err < 0){
  98                 printk("copy_sc_to_user_skas - PTRACE_GETFPREGS failed, "
  99                        "errno = %d\n", err);
 100                 return 1;
 101         }
 102         to_fp = (to_fp ? to_fp : (struct _fpstate __user *) (to + 1));
 103         sc.fpstate = to_fp;
 104
 105         if(err)
 106                 return err;
 107
 108         return copy_to_user(to, &sc, sizeof(sc)) ||
 109                copy_to_user(to_fp, fpregs, sizeof(fpregs));
 110 }
 111 #endif
 112
 113 #ifdef CONFIG_MODE_TT
 114
 115 /* These copy a sigcontext to/from userspace.  They copy the fpstate pointer,
 116  * blowing away the old, good one.  So, that value is saved, and then restored
 117  * after the sigcontext copy.  In copy_from, the variable holding the saved
 118  * fpstate pointer, and the sigcontext that it should be restored to are both
 119  * in the kernel, so we can just restore using an assignment.  In copy_to, the
 120  * saved pointer is in the kernel, but the sigcontext is in userspace, so we
 121  * copy_to_user it.
 122  */
 123 int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext __user *from,
 124                          int fpsize)
 125 {
 126         struct _fpstate *to_fp;
 127         struct _fpstate __user *from_fp;
 128         unsigned long sigs;
 129         int err;
 130
 131         to_fp = to->fpstate;
 132         sigs = to->oldmask;
 133         err = copy_from_user(to, from, sizeof(*to));
 134         from_fp = to->fpstate;
 135         to->oldmask = sigs;
 136         to->fpstate = to_fp;
 137         if(to_fp != NULL)
 138                 err |= copy_from_user(to_fp, from_fp, fpsize);
 139         return err;
 140 }
 141
 142 int copy_sc_to_user_tt(struct sigcontext __user *to, struct _fpstate __user *fp,
 143                        struct sigcontext *from, int fpsize, unsigned long sp)
 144 {
 145         struct _fpstate __user *to_fp;
 146         struct _fpstate *from_fp;
 147         int err;
 148
 149         to_fp = (fp ? fp : (struct _fpstate __user *) (to + 1));
 150         from_fp = from->fpstate;
 151         err = copy_to_user(to, from, sizeof(*to));
 152
 153         /* The SP in the sigcontext is the updated one for the signal
 154          * delivery.  The sp passed in is the original, and this needs
 155          * to be restored, so we stick it in separately.
 156          */
 157         err |= copy_to_user(&SC_SP(to), &sp, sizeof(sp));
 158
 159         if(from_fp != NULL){
 160                 err |= copy_to_user(&to->fpstate, &to_fp, sizeof(to->fpstate));
 161                 err |= copy_to_user(to_fp, from_fp, fpsize);
 162         }
 163         return err;
 164 }
 165 #endif
 166
 167 static int copy_sc_from_user(struct pt_regs *to, void __user *from)
 168 {
 169         int ret;
 170
 171         ret = CHOOSE_MODE(copy_sc_from_user_tt(UPT_SC(&to->regs), from,
 172                                                sizeof(struct _fpstate)),
 173                           copy_sc_from_user_skas(to, from));
 174         return ret;
 175 }
 176
 177 static int copy_sc_to_user(struct sigcontext __user *to, struct _fpstate __user *fp,
 178                            struct pt_regs *from, unsigned long sp)
 179 {
 180         return CHOOSE_MODE(copy_sc_to_user_tt(to, fp, UPT_SC(&from->regs),
 181                                               sizeof(*fp), sp),
 182                            copy_sc_to_user_skas(to, fp, from, sp));
 183 }
 184
 185 static int copy_ucontext_to_user(struct ucontext __user *uc, struct _fpstate __user *fp,
 186                                  sigset_t *set, unsigned long sp)
 187 {
 188         int err = 0;
 189
 190         err |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp);
 191         err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags);
 192         err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size);
 193         err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, sp);
 194         err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
 195         return err;
 196 }
 197
 198 struct sigframe
 199 {
 200         char __user *pretcode;
 201         int sig;
 202         struct sigcontext sc;
 203         struct _fpstate fpstate;
 204         unsigned long extramask[_NSIG_WORDS-1];
 205         char retcode[8];
 206 };
 207
 208 struct rt_sigframe
 209 {
 210         char __user *pretcode;
 211         int sig;
 212         struct siginfo __user *pinfo;
 213         void __user *puc;
 214         struct siginfo info;
 215         struct ucontext uc;
 216         struct _fpstate fpstate;
 217         char retcode[8];
 218 };
 219
 220 int setup_signal_stack_sc(unsigned long stack_top, int sig,
 221                           struct k_sigaction *ka, struct pt_regs *regs,
 222                           sigset_t *mask)
 223 {
 224         struct sigframe __user *frame;
 225         void __user *restorer;
 226         unsigned long save_sp = PT_REGS_SP(regs);
 227         int err = 0;
 228
 229         /* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */
 230         stack_top = ((stack_top + 4) & -16UL) - 4;
 231         frame = (struct sigframe __user *) stack_top - 1;
 232         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 233                 return 1;
 234
 235         restorer = frame->retcode;
 236         if(ka->sa.sa_flags & SA_RESTORER)
 237                 restorer = ka->sa.sa_restorer;
 238
 239         /* Update SP now because the page fault handler refuses to extend
 240          * the stack if the faulting address is too far below the current
 241          * SP, which frame now certainly is.  If there's an error, the original
 242          * value is restored on the way out.
 243          * When writing the sigcontext to the stack, we have to write the
 244          * original value, so that's passed to copy_sc_to_user, which does
 245          * the right thing with it.
 246          */
 247         PT_REGS_SP(regs) = (unsigned long) frame;
 248
 249         err |= __put_user(restorer, &frame->pretcode);
 250         err |= __put_user(sig, &frame->sig);
 251         err |= copy_sc_to_user(&frame->sc, NULL, regs, save_sp);
 252         err |= __put_user(mask->sig[0], &frame->sc.oldmask);
 253         if (_NSIG_WORDS > 1)
 254                 err |= __copy_to_user(&frame->extramask, &mask->sig[1],
 255                                       sizeof(frame->extramask));
 256
 257         /*
 258          * This is popl %eax ; movl $,%eax ; int $0x80
 259          *
 260          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 261          * reasons and because gdb uses it as a signature to notice
 262          * signal handler stack frames.
 263          */
 264         err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
 265         err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
 266         err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
 267
 268         if(err)
 269                 goto err;
 270
 271         PT_REGS_SP(regs) = (unsigned long) frame;
 272         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 273         PT_REGS_EAX(regs) = (unsigned long) sig;
 274         PT_REGS_EDX(regs) = (unsigned long) 0;
 275         PT_REGS_ECX(regs) = (unsigned long) 0;
 276
 277         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 278                 ptrace_notify(SIGTRAP);
 279         return 0;
 280
 281 err:
 282         PT_REGS_SP(regs) = save_sp;
 283         return err;
 284 }
 285
 286 int setup_signal_stack_si(unsigned long stack_top, int sig,
 287                           struct k_sigaction *ka, struct pt_regs *regs,
 288                           siginfo_t *info, sigset_t *mask)
 289 {
 290         struct rt_sigframe __user *frame;
 291         void __user *restorer;
 292         unsigned long save_sp = PT_REGS_SP(regs);
 293         int err = 0;
 294
 295         stack_top &= -8UL;
 296         frame = (struct rt_sigframe __user *) stack_top - 1;
 297         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 298                 return 1;
 299
 300         restorer = frame->retcode;
 301         if(ka->sa.sa_flags & SA_RESTORER)
 302                 restorer = ka->sa.sa_restorer;
 303
 304         /* See comment above about why this is here */
 305         PT_REGS_SP(regs) = (unsigned long) frame;
 306
 307         err |= __put_user(restorer, &frame->pretcode);
 308         err |= __put_user(sig, &frame->sig);
 309         err |= __put_user(&frame->info, &frame->pinfo);
 310         err |= __put_user(&frame->uc, &frame->puc);
 311         err |= copy_siginfo_to_user(&frame->info, info);
 312         err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
 313                                      save_sp);
 314
 315         /*
 316          * This is movl $,%eax ; int $0x80
 317          *
 318          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 319          * reasons and because gdb uses it as a signature to notice
 320          * signal handler stack frames.
 321          */
 322         err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
 323         err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
 324         err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
 325
 326         if(err)
 327                 goto err;
 328
 329         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 330         PT_REGS_EAX(regs) = (unsigned long) sig;
 331         PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 332         PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 333
 334         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 335                 ptrace_notify(SIGTRAP);
 336         return 0;
 337
 338 err:
 339         PT_REGS_SP(regs) = save_sp;
 340         return err;
 341 }
 342
 343 long sys_sigreturn(struct pt_regs regs)
 344 {
 345         unsigned long sp = PT_REGS_SP(&current->thread.regs);
 346         struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
 347         sigset_t set;
 348         struct sigcontext __user *sc = &frame->sc;
 349         unsigned long __user *oldmask = &sc->oldmask;
 350         unsigned long __user *extramask = frame->extramask;
 351         int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
 352
 353         if(copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) ||
 354            copy_from_user(&set.sig[1], extramask, sig_size))
 355                 goto segfault;
 356
 357         sigdelsetmask(&set, ~_BLOCKABLE);
 358
 359         spin_lock_irq(&current->sighand->siglock);
 360         current->blocked = set;
 361         recalc_sigpending();
 362         spin_unlock_irq(&current->sighand->siglock);
 363
 364         if(copy_sc_from_user(&current->thread.regs, sc))
 365                 goto segfault;
 366
 367         /* Avoid ERESTART handling */
 368         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 369         return PT_REGS_SYSCALL_RET(&current->thread.regs);
 370
 371  segfault:
 372         force_sig(SIGSEGV, current);
 373         return 0;
 374 }
 375
 376 long sys_rt_sigreturn(struct pt_regs regs)
 377 {
 378         unsigned long sp = PT_REGS_SP(&current->thread.regs);
 379         struct rt_sigframe __user *frame = (struct rt_sigframe __user *) (sp - 4);
 380         sigset_t set;
 381         struct ucontext __user *uc = &frame->uc;
 382         int sig_size = _NSIG_WORDS * sizeof(unsigned long);
 383
 384         if(copy_from_user(&set, &uc->uc_sigmask, sig_size))
 385                 goto segfault;
 386
 387         sigdelsetmask(&set, ~_BLOCKABLE);
 388
 389         spin_lock_irq(&current->sighand->siglock);
 390         current->blocked = set;
 391         recalc_sigpending();
 392         spin_unlock_irq(&current->sighand->siglock);
 393
 394         if(copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
 395                 goto segfault;
 396
 397         /* Avoid ERESTART handling */
 398         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 399         return PT_REGS_SYSCALL_RET(&current->thread.regs);
 400
 401  segfault:
 402         force_sig(SIGSEGV, current);
 403         return 0;
 404 }