SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 #include "skas.h"
  17
  18 void copy_sc(union uml_pt_regs *regs, void *from)
  19 {
  20         struct sigcontext *sc = from;
  21
  22         REGS_GS(regs->skas.regs) = sc->gs;
  23         REGS_FS(regs->skas.regs) = sc->fs;
  24         REGS_ES(regs->skas.regs) = sc->es;
  25         REGS_DS(regs->skas.regs) = sc->ds;
  26         REGS_EDI(regs->skas.regs) = sc->edi;
  27         REGS_ESI(regs->skas.regs) = sc->esi;
  28         REGS_EBP(regs->skas.regs) = sc->ebp;
  29         REGS_SP(regs->skas.regs) = sc->esp;
  30         REGS_EBX(regs->skas.regs) = sc->ebx;
  31         REGS_EDX(regs->skas.regs) = sc->edx;
  32         REGS_ECX(regs->skas.regs) = sc->ecx;
  33         REGS_EAX(regs->skas.regs) = sc->eax;
  34         REGS_IP(regs->skas.regs) = sc->eip;
  35         REGS_CS(regs->skas.regs) = sc->cs;
  36         REGS_EFLAGS(regs->skas.regs) = sc->eflags;
  37         REGS_SS(regs->skas.regs) = sc->ss;
  38 }
  39
  40 static int copy_sc_from_user_skas(struct pt_regs *regs,
  41                                   struct sigcontext __user *from)
  42 {
  43         struct sigcontext sc;
  44         unsigned long fpregs[HOST_FP_SIZE];
  45         int err;
  46
  47         err = copy_from_user(&sc, from, sizeof(sc));
  48         err |= copy_from_user(fpregs, sc.fpstate, sizeof(fpregs));
  49         if(err)
  50                 return err;
  51
  52         copy_sc(&regs->regs, &sc);
  53
  54         err = restore_fp_registers(userspace_pid[0], fpregs);
  55         if(err < 0) {
  56                 printk("copy_sc_from_user_skas - PTRACE_SETFPREGS failed, "
  57                        "errno = %d\n", -err);
  58                 return err;
  59         }
  60
  61         return 0;
  62 }
  63
  64 int copy_sc_to_user_skas(struct sigcontext __user *to, struct _fpstate __user *to_fp,
  65                          struct pt_regs *regs, unsigned long sp)
  66 {
  67         struct sigcontext sc;
  68         unsigned long fpregs[HOST_FP_SIZE];
  69         struct faultinfo * fi = &current->thread.arch.faultinfo;
  70         int err;
  71
  72         sc.gs = REGS_GS(regs->regs.skas.regs);
  73         sc.fs = REGS_FS(regs->regs.skas.regs);
  74         sc.es = REGS_ES(regs->regs.skas.regs);
  75         sc.ds = REGS_DS(regs->regs.skas.regs);
  76         sc.edi = REGS_EDI(regs->regs.skas.regs);
  77         sc.esi = REGS_ESI(regs->regs.skas.regs);
  78         sc.ebp = REGS_EBP(regs->regs.skas.regs);
  79         sc.esp = sp;
  80         sc.ebx = REGS_EBX(regs->regs.skas.regs);
  81         sc.edx = REGS_EDX(regs->regs.skas.regs);
  82         sc.ecx = REGS_ECX(regs->regs.skas.regs);
  83         sc.eax = REGS_EAX(regs->regs.skas.regs);
  84         sc.eip = REGS_IP(regs->regs.skas.regs);
  85         sc.cs = REGS_CS(regs->regs.skas.regs);
  86         sc.eflags = REGS_EFLAGS(regs->regs.skas.regs);
  87         sc.esp_at_signal = regs->regs.skas.regs[UESP];
  88         sc.ss = regs->regs.skas.regs[SS];
  89         sc.cr2 = fi->cr2;
  90         sc.err = fi->error_code;
  91         sc.trapno = fi->trap_no;
  92
  93         err = save_fp_registers(userspace_pid[0], fpregs);
  94         if(err < 0){
  95                 printk("copy_sc_to_user_skas - PTRACE_GETFPREGS failed, "
  96                        "errno = %d\n", err);
  97                 return 1;
  98         }
  99         to_fp = (to_fp ? to_fp : (struct _fpstate __user *) (to + 1));
 100         sc.fpstate = to_fp;
 101
 102         if(err)
 103                 return err;
 104
 105         return copy_to_user(to, &sc, sizeof(sc)) ||
 106                copy_to_user(to_fp, fpregs, sizeof(fpregs));
 107 }
 108
 109 static int copy_sc_from_user(struct pt_regs *to, void __user *from)
 110 {
 111         int ret;
 112
 113         ret = CHOOSE_MODE(copy_sc_from_user_tt(UPT_SC(&to->regs), from,
 114                                                sizeof(struct _fpstate)),
 115                           copy_sc_from_user_skas(to, from));
 116         return ret;
 117 }
 118
 119 static int copy_sc_to_user(struct sigcontext __user *to, struct _fpstate __user *fp,
 120                            struct pt_regs *from, unsigned long sp)
 121 {
 122         return CHOOSE_MODE(copy_sc_to_user_tt(to, fp, UPT_SC(&from->regs),
 123                                               sizeof(*fp), sp),
 124                            copy_sc_to_user_skas(to, fp, from, sp));
 125 }
 126
 127 static int copy_ucontext_to_user(struct ucontext __user *uc, struct _fpstate __user *fp,
 128                                  sigset_t *set, unsigned long sp)
 129 {
 130         int err = 0;
 131
 132         err |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp);
 133         err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags);
 134         err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size);
 135         err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, sp);
 136         err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
 137         return err;
 138 }
 139
 140 struct sigframe
 141 {
 142         char __user *pretcode;
 143         int sig;
 144         struct sigcontext sc;
 145         struct _fpstate fpstate;
 146         unsigned long extramask[_NSIG_WORDS-1];
 147         char retcode[8];
 148 };
 149
 150 struct rt_sigframe
 151 {
 152         char __user *pretcode;
 153         int sig;
 154         struct siginfo __user *pinfo;
 155         void __user *puc;
 156         struct siginfo info;
 157         struct ucontext uc;
 158         struct _fpstate fpstate;
 159         char retcode[8];
 160 };
 161
 162 int setup_signal_stack_sc(unsigned long stack_top, int sig,
 163                           struct k_sigaction *ka, struct pt_regs *regs,
 164                           sigset_t *mask)
 165 {
 166         struct sigframe __user *frame;
 167         void __user *restorer;
 168         unsigned long save_sp = PT_REGS_SP(regs);
 169         int err = 0;
 170
 171         /* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */
 172         stack_top = ((stack_top + 4) & -16UL) - 4;
 173         frame = (struct sigframe __user *) stack_top - 1;
 174         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 175                 return 1;
 176
 177         restorer = frame->retcode;
 178         if(ka->sa.sa_flags & SA_RESTORER)
 179                 restorer = ka->sa.sa_restorer;
 180
 181         /* Update SP now because the page fault handler refuses to extend
 182          * the stack if the faulting address is too far below the current
 183          * SP, which frame now certainly is.  If there's an error, the original
 184          * value is restored on the way out.
 185          * When writing the sigcontext to the stack, we have to write the
 186          * original value, so that's passed to copy_sc_to_user, which does
 187          * the right thing with it.
 188          */
 189         PT_REGS_SP(regs) = (unsigned long) frame;
 190
 191         err |= __put_user(restorer, &frame->pretcode);
 192         err |= __put_user(sig, &frame->sig);
 193         err |= copy_sc_to_user(&frame->sc, NULL, regs, save_sp);
 194         err |= __put_user(mask->sig[0], &frame->sc.oldmask);
 195         if (_NSIG_WORDS > 1)
 196                 err |= __copy_to_user(&frame->extramask, &mask->sig[1],
 197                                       sizeof(frame->extramask));
 198
 199         /*
 200          * This is popl %eax ; movl $,%eax ; int $0x80
 201          *
 202          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 203          * reasons and because gdb uses it as a signature to notice
 204          * signal handler stack frames.
 205          */
 206         err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
 207         err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
 208         err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
 209
 210         if(err)
 211                 goto err;
 212
 213         PT_REGS_SP(regs) = (unsigned long) frame;
 214         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 215         PT_REGS_EAX(regs) = (unsigned long) sig;
 216         PT_REGS_EDX(regs) = (unsigned long) 0;
 217         PT_REGS_ECX(regs) = (unsigned long) 0;
 218
 219         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 220                 ptrace_notify(SIGTRAP);
 221         return 0;
 222
 223 err:
 224         PT_REGS_SP(regs) = save_sp;
 225         return err;
 226 }
 227
 228 int setup_signal_stack_si(unsigned long stack_top, int sig,
 229                           struct k_sigaction *ka, struct pt_regs *regs,
 230                           siginfo_t *info, sigset_t *mask)
 231 {
 232         struct rt_sigframe __user *frame;
 233         void __user *restorer;
 234         unsigned long save_sp = PT_REGS_SP(regs);
 235         int err = 0;
 236
 237         stack_top &= -8UL;
 238         frame = (struct rt_sigframe __user *) stack_top - 1;
 239         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 240                 return 1;
 241
 242         restorer = frame->retcode;
 243         if(ka->sa.sa_flags & SA_RESTORER)
 244                 restorer = ka->sa.sa_restorer;
 245
 246         /* See comment above about why this is here */
 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 |= __put_user(&frame->info, &frame->pinfo);
 252         err |= __put_user(&frame->uc, &frame->puc);
 253         err |= copy_siginfo_to_user(&frame->info, info);
 254         err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
 255                                      save_sp);
 256
 257         /*
 258          * This is 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(0xb8, (char __user *)(frame->retcode+0));
 265         err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
 266         err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
 267
 268         if(err)
 269                 goto err;
 270
 271         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 272         PT_REGS_EAX(regs) = (unsigned long) sig;
 273         PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 274         PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 275
 276         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 277                 ptrace_notify(SIGTRAP);
 278         return 0;
 279
 280 err:
 281         PT_REGS_SP(regs) = save_sp;
 282         return err;
 283 }
 284
 285 long sys_sigreturn(struct pt_regs regs)
 286 {
 287         unsigned long sp = PT_REGS_SP(&current->thread.regs);
 288         struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
 289         sigset_t set;
 290         struct sigcontext __user *sc = &frame->sc;
 291         unsigned long __user *oldmask = &sc->oldmask;
 292         unsigned long __user *extramask = frame->extramask;
 293         int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
 294
 295         if(copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) ||
 296            copy_from_user(&set.sig[1], extramask, sig_size))
 297                 goto segfault;
 298
 299         sigdelsetmask(&set, ~_BLOCKABLE);
 300
 301         spin_lock_irq(&current->sighand->siglock);
 302         current->blocked = set;
 303         recalc_sigpending();
 304         spin_unlock_irq(&current->sighand->siglock);
 305
 306         if(copy_sc_from_user(&current->thread.regs, sc))
 307                 goto segfault;
 308
 309         /* Avoid ERESTART handling */
 310         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 311         return PT_REGS_SYSCALL_RET(&current->thread.regs);
 312
 313  segfault:
 314         force_sig(SIGSEGV, current);
 315         return 0;
 316 }
 317
 318 long sys_rt_sigreturn(struct pt_regs regs)
 319 {
 320         unsigned long sp = PT_REGS_SP(&current->thread.regs);
 321         struct rt_sigframe __user *frame = (struct rt_sigframe __user *) (sp - 4);
 322         sigset_t set;
 323         struct ucontext __user *uc = &frame->uc;
 324         int sig_size = _NSIG_WORDS * sizeof(unsigned long);
 325
 326         if(copy_from_user(&set, &uc->uc_sigmask, sig_size))
 327                 goto segfault;
 328
 329         sigdelsetmask(&set, ~_BLOCKABLE);
 330
 331         spin_lock_irq(&current->sighand->siglock);
 332         current->blocked = set;
 333         recalc_sigpending();
 334         spin_unlock_irq(&current->sighand->siglock);
 335
 336         if(copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
 337                 goto segfault;
 338
 339         /* Avoid ERESTART handling */
 340         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 341         return PT_REGS_SYSCALL_RET(&current->thread.regs);
 342
 343  segfault:
 344         force_sig(SIGSEGV, current);
 345         return 0;
 346 }