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