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 err;
  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         /* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */
 223         stack_top = ((stack_top + 4) & -16UL) - 4;
 224         frame = (struct sigframe __user *) stack_top - 1;
 225         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 226                 return 1;
 227
 228         restorer = frame->retcode;
 229         if(ka->sa.sa_flags & SA_RESTORER)
 230                 restorer = ka->sa.sa_restorer;
 231
 232         /* Update SP now because the page fault handler refuses to extend
 233          * the stack if the faulting address is too far below the current
 234          * SP, which frame now certainly is.  If there's an error, the original
 235          * value is restored on the way out.
 236          * When writing the sigcontext to the stack, we have to write the
 237          * original value, so that's passed to copy_sc_to_user, which does
 238          * the right thing with it.
 239          */
 240         PT_REGS_SP(regs) = (unsigned long) frame;
 241
 242         err |= __put_user(restorer, &frame->pretcode);
 243         err |= __put_user(sig, &frame->sig);
 244         err |= copy_sc_to_user(&frame->sc, NULL, regs, save_sp);
 245         err |= __put_user(mask->sig[0], &frame->sc.oldmask);
 246         if (_NSIG_WORDS > 1)
 247                 err |= __copy_to_user(&frame->extramask, &mask->sig[1],
 248                                       sizeof(frame->extramask));
 249
 250         /*
 251          * This is popl %eax ; movl $,%eax ; int $0x80
 252          *
 253          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 254          * reasons and because gdb uses it as a signature to notice
 255          * signal handler stack frames.
 256          */
 257         err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
 258         err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
 259         err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
 260
 261         if(err)
 262                 goto err;
 263
 264         PT_REGS_SP(regs) = (unsigned long) frame;
 265         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 266         PT_REGS_EAX(regs) = (unsigned long) sig;
 267         PT_REGS_EDX(regs) = (unsigned long) 0;
 268         PT_REGS_ECX(regs) = (unsigned long) 0;
 269
 270         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 271                 ptrace_notify(SIGTRAP);
 272         return 0;
 273
 274 err:
 275         PT_REGS_SP(regs) = save_sp;
 276         return err;
 277 }
 278
 279 int setup_signal_stack_si(unsigned long stack_top, int sig,
 280                           struct k_sigaction *ka, struct pt_regs *regs,
 281                           siginfo_t *info, sigset_t *mask)
 282 {
 283         struct rt_sigframe __user *frame;
 284         void __user *restorer;
 285         unsigned long save_sp = PT_REGS_SP(regs);
 286         int err = 0;
 287
 288         stack_top &= -8UL;
 289         frame = (struct rt_sigframe __user *) stack_top - 1;
 290         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 291                 return 1;
 292
 293         restorer = frame->retcode;
 294         if(ka->sa.sa_flags & SA_RESTORER)
 295                 restorer = ka->sa.sa_restorer;
 296
 297         /* See comment above about why this is here */
 298         PT_REGS_SP(regs) = (unsigned long) frame;
 299
 300         err |= __put_user(restorer, &frame->pretcode);
 301         err |= __put_user(sig, &frame->sig);
 302         err |= __put_user(&frame->info, &frame->pinfo);
 303         err |= __put_user(&frame->uc, &frame->puc);
 304         err |= copy_siginfo_to_user(&frame->info, info);
 305         err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
 306                                      save_sp);
 307
 308         /*
 309          * This is movl $,%eax ; int $0x80
 310          *
 311          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 312          * reasons and because gdb uses it as a signature to notice
 313          * signal handler stack frames.
 314          */
 315         err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
 316         err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
 317         err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
 318
 319         if(err)
 320                 goto err;
 321
 322         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 323         PT_REGS_EAX(regs) = (unsigned long) sig;
 324         PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 325         PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 326
 327         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 328                 ptrace_notify(SIGTRAP);
 329         return 0;
 330
 331 err:
 332         PT_REGS_SP(regs) = save_sp;
 333         return err;
 334 }
 335
 336 long sys_sigreturn(struct pt_regs regs)
 337 {
 338         unsigned long sp = PT_REGS_SP(&current->thread.regs);
 339         struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
 340         sigset_t set;
 341         struct sigcontext __user *sc = &frame->sc;
 342         unsigned long __user *oldmask = &sc->oldmask;
 343         unsigned long __user *extramask = frame->extramask;
 344         int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
 345
 346         if(copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) ||
 347            copy_from_user(&set.sig[1], extramask, sig_size))
 348                 goto segfault;
 349
 350         sigdelsetmask(&set, ~_BLOCKABLE);
 351
 352         spin_lock_irq(&current->sighand->siglock);
 353         current->blocked = set;
 354         recalc_sigpending();
 355         spin_unlock_irq(&current->sighand->siglock);
 356
 357         if(copy_sc_from_user(&current->thread.regs, sc))
 358                 goto segfault;
 359
 360         /* Avoid ERESTART handling */
 361         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 362         return PT_REGS_SYSCALL_RET(&current->thread.regs);
 363
 364  segfault:
 365         force_sig(SIGSEGV, current);
 366         return 0;
 367 }
 368
 369 long sys_rt_sigreturn(struct pt_regs regs)
 370 {
 371         unsigned long sp = PT_REGS_SP(&current->thread.regs);
 372         struct rt_sigframe __user *frame = (struct rt_sigframe __user *) (sp - 4);
 373         sigset_t set;
 374         struct ucontext __user *uc = &frame->uc;
 375         int sig_size = _NSIG_WORDS * sizeof(unsigned long);
 376
 377         if(copy_from_user(&set, &uc->uc_sigmask, sig_size))
 378                 goto segfault;
 379
 380         sigdelsetmask(&set, ~_BLOCKABLE);
 381
 382         spin_lock_irq(&current->sighand->siglock);
 383         current->blocked = set;
 384         recalc_sigpending();
 385         spin_unlock_irq(&current->sighand->siglock);
 386
 387         if(copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
 388                 goto segfault;
 389
 390         /* Avoid ERESTART handling */
 391         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 392         return PT_REGS_SYSCALL_RET(&current->thread.regs);
 393
 394  segfault:
 395         force_sig(SIGSEGV, current);
 396         return 0;
 397 }