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 *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 *to, struct _fpstate *to_fp,
  61                          struct pt_regs *regs)
  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 = REGS_SP(regs->regs.skas.regs);
  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 *) (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 *from,
 117                          int fpsize)
 118 {
 119         struct _fpstate *to_fp, *from_fp;
 120         unsigned long sigs;
 121         int err;
 122
 123         to_fp = to->fpstate;
 124         sigs = to->oldmask;
 125         err = copy_from_user(to, from, sizeof(*to));
 126         from_fp = to->fpstate;
 127         to->oldmask = sigs;
 128         to->fpstate = to_fp;
 129         if(to_fp != NULL)
 130                 err |= copy_from_user(to_fp, from_fp, fpsize);
 131         return(err);
 132 }
 133
 134 int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate *fp,
 135                        struct sigcontext *from, int fpsize)
 136 {
 137         struct _fpstate *to_fp, *from_fp;
 138         int err;
 139
 140         to_fp = (fp ? fp : (struct _fpstate *) (to + 1));
 141         from_fp = from->fpstate;
 142         err = copy_to_user(to, from, sizeof(*to));
 143         if(from_fp != NULL){
 144                 err |= copy_to_user(&to->fpstate, &to_fp, sizeof(to->fpstate));
 145                 err |= copy_to_user(to_fp, from_fp, fpsize);
 146         }
 147         return(err);
 148 }
 149 #endif
 150
 151 static int copy_sc_from_user(struct pt_regs *to, void __user *from)
 152 {
 153         int ret;
 154
 155         ret = CHOOSE_MODE(copy_sc_from_user_tt(UPT_SC(&to->regs), from,
 156                                                sizeof(struct _fpstate)),
 157                           copy_sc_from_user_skas(to, from));
 158         return(ret);
 159 }
 160
 161 static int copy_sc_to_user(struct sigcontext *to, struct _fpstate *fp,
 162                            struct pt_regs *from)
 163 {
 164         return(CHOOSE_MODE(copy_sc_to_user_tt(to, fp, UPT_SC(&from->regs),
 165                                               sizeof(*fp)),
 166                            copy_sc_to_user_skas(to, fp, from)));
 167 }
 168
 169 static int copy_ucontext_to_user(struct ucontext *uc, struct _fpstate *fp,
 170                                  sigset_t *set, unsigned long sp)
 171 {
 172         int err = 0;
 173
 174         err |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp);
 175         err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags);
 176         err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size);
 177         err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs);
 178         err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
 179         return(err);
 180 }
 181
 182 struct sigframe
 183 {
 184         char *pretcode;
 185         int sig;
 186         struct sigcontext sc;
 187         struct _fpstate fpstate;
 188         unsigned long extramask[_NSIG_WORDS-1];
 189         char retcode[8];
 190 };
 191
 192 struct rt_sigframe
 193 {
 194         char *pretcode;
 195         int sig;
 196         struct siginfo *pinfo;
 197         void *puc;
 198         struct siginfo info;
 199         struct ucontext uc;
 200         struct _fpstate fpstate;
 201         char retcode[8];
 202 };
 203
 204 int setup_signal_stack_sc(unsigned long stack_top, int sig,
 205                           struct k_sigaction *ka, struct pt_regs *regs,
 206                           sigset_t *mask)
 207 {
 208         struct sigframe __user *frame;
 209         void *restorer;
 210         int err = 0;
 211
 212         stack_top &= -8UL;
 213         frame = (struct sigframe *) stack_top - 1;
 214         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 215                 return 1;
 216
 217         restorer = (void *) frame->retcode;
 218         if(ka->sa.sa_flags & SA_RESTORER)
 219                 restorer = ka->sa.sa_restorer;
 220
 221         err |= __put_user(restorer, &frame->pretcode);
 222         err |= __put_user(sig, &frame->sig);
 223         err |= copy_sc_to_user(&frame->sc, NULL, regs);
 224         err |= __put_user(mask->sig[0], &frame->sc.oldmask);
 225         if (_NSIG_WORDS > 1)
 226                 err |= __copy_to_user(&frame->extramask, &mask->sig[1],
 227                                       sizeof(frame->extramask));
 228
 229         /*
 230          * This is popl %eax ; movl $,%eax ; int $0x80
 231          *
 232          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 233          * reasons and because gdb uses it as a signature to notice
 234          * signal handler stack frames.
 235          */
 236         err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
 237         err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
 238         err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
 239
 240         if(err)
 241                 return(err);
 242
 243         PT_REGS_SP(regs) = (unsigned long) frame;
 244         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 245         PT_REGS_EAX(regs) = (unsigned long) sig;
 246         PT_REGS_EDX(regs) = (unsigned long) 0;
 247         PT_REGS_ECX(regs) = (unsigned long) 0;
 248
 249         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 250                 ptrace_notify(SIGTRAP);
 251         return(0);
 252 }
 253
 254 int setup_signal_stack_si(unsigned long stack_top, int sig,
 255                           struct k_sigaction *ka, struct pt_regs *regs,
 256                           siginfo_t *info, sigset_t *mask)
 257 {
 258         struct rt_sigframe __user *frame;
 259         void *restorer;
 260         int err = 0;
 261
 262         stack_top &= -8UL;
 263         frame = (struct rt_sigframe *) stack_top - 1;
 264         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 265                 return 1;
 266
 267         restorer = (void *) frame->retcode;
 268         if(ka->sa.sa_flags & SA_RESTORER)
 269                 restorer = ka->sa.sa_restorer;
 270
 271         err |= __put_user(restorer, &frame->pretcode);
 272         err |= __put_user(sig, &frame->sig);
 273         err |= __put_user(&frame->info, &frame->pinfo);
 274         err |= __put_user(&frame->uc, &frame->puc);
 275         err |= copy_siginfo_to_user(&frame->info, info);
 276         err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
 277                                      PT_REGS_SP(regs));
 278
 279         /*
 280          * This is movl $,%eax ; int $0x80
 281          *
 282          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 283          * reasons and because gdb uses it as a signature to notice
 284          * signal handler stack frames.
 285          */
 286         err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
 287         err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
 288         err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
 289
 290         if(err)
 291                 return(err);
 292
 293         PT_REGS_SP(regs) = (unsigned long) frame;
 294         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 295         PT_REGS_EAX(regs) = (unsigned long) sig;
 296         PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 297         PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 298
 299         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 300                 ptrace_notify(SIGTRAP);
 301         return(0);
 302 }
 303
 304 long sys_sigreturn(struct pt_regs regs)
 305 {
 306         unsigned long sp = PT_REGS_SP(&current->thread.regs);
 307         struct sigframe __user *frame = (struct sigframe *)(sp - 8);
 308         sigset_t set;
 309         struct sigcontext __user *sc = &frame->sc;
 310         unsigned long __user *oldmask = &sc->oldmask;
 311         unsigned long __user *extramask = frame->extramask;
 312         int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
 313
 314         if(copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) ||
 315            copy_from_user(&set.sig[1], extramask, sig_size))
 316                 goto segfault;
 317
 318         sigdelsetmask(&set, ~_BLOCKABLE);
 319
 320         spin_lock_irq(&current->sighand->siglock);
 321         current->blocked = set;
 322         recalc_sigpending();
 323         spin_unlock_irq(&current->sighand->siglock);
 324
 325         if(copy_sc_from_user(&current->thread.regs, sc))
 326                 goto segfault;
 327
 328         /* Avoid ERESTART handling */
 329         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 330         return(PT_REGS_SYSCALL_RET(&current->thread.regs));
 331
 332  segfault:
 333         force_sig(SIGSEGV, current);
 334         return 0;
 335 }
 336
 337 long sys_rt_sigreturn(struct pt_regs regs)
 338 {
 339         unsigned long __user sp = PT_REGS_SP(&current->thread.regs);
 340         struct rt_sigframe __user *frame = (struct rt_sigframe *) (sp - 4);
 341         sigset_t set;
 342         struct ucontext __user *uc = &frame->uc;
 343         int sig_size = _NSIG_WORDS * sizeof(unsigned long);
 344
 345         if(copy_from_user(&set, &uc->uc_sigmask, sig_size))
 346                 goto segfault;
 347
 348         sigdelsetmask(&set, ~_BLOCKABLE);
 349
 350         spin_lock_irq(&current->sighand->siglock);
 351         current->blocked = set;
 352         recalc_sigpending();
 353         spin_unlock_irq(&current->sighand->siglock);
 354
 355         if(copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
 356                 goto segfault;
 357
 358         /* Avoid ERESTART handling */
 359         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 360         return(PT_REGS_SYSCALL_RET(&current->thread.regs));
 361
 362  segfault:
 363         force_sig(SIGSEGV, current);
 364         return 0;
 365 }
 366
 367 /*
 368  * Overrides for Emacs so that we follow Linus's tabbing style.
 369  * Emacs will notice this stuff at the end of the file and automatically
 370  * adjust the settings for this buffer only.  This must remain at the end
 371  * of the file.
 372  * ---------------------------------------------------------------------------
 373  * Local variables:
 374  * c-file-style: "linux"
 375  * End:
 376  */