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   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         regs->regs.skas.fault_addr = sc.cr2;
  51         regs->regs.skas.fault_type = FAULT_WRITE(sc.err);
  52         regs->regs.skas.trap_type = sc.trapno;
  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(1);
  59         }
  60
  61         return(0);
  62 }
  63
  64 int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp,
  65                          struct pt_regs *regs, unsigned long fault_addr,
  66                          int fault_type)
  67 {
  68         struct sigcontext sc;
  69         unsigned long fpregs[HOST_FP_SIZE];
  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 = REGS_SP(regs->regs.skas.regs);
  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 = fault_addr;
  90         sc.err = TO_SC_ERR(fault_type);
  91         sc.trapno = regs->regs.skas.trap_type;
  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 *) (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 #endif
 109
 110 #ifdef CONFIG_MODE_TT
 111
 112 /* These copy a sigcontext to/from userspace.  They copy the fpstate pointer,
 113  * blowing away the old, good one.  So, that value is saved, and then restored
 114  * after the sigcontext copy.  In copy_from, the variable holding the saved
 115  * fpstate pointer, and the sigcontext that it should be restored to are both
 116  * in the kernel, so we can just restore using an assignment.  In copy_to, the
 117  * saved pointer is in the kernel, but the sigcontext is in userspace, so we
 118  * copy_to_user it.
 119  */
 120 int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext *from,
 121                          int fpsize)
 122 {
 123         struct _fpstate *to_fp, *from_fp;
 124         unsigned long sigs;
 125         int err;
 126
 127         to_fp = to->fpstate;
 128         from_fp = from->fpstate;
 129         sigs = to->oldmask;
 130         err = copy_from_user(to, from, sizeof(*to));
 131         to->oldmask = sigs;
 132         to->fpstate = to_fp;
 133         if(to_fp != NULL)
 134                 err |= copy_from_user(to_fp, from_fp, fpsize);
 135         return(err);
 136 }
 137
 138 int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate *fp,
 139                        struct sigcontext *from, int fpsize)
 140 {
 141         struct _fpstate *to_fp, *from_fp;
 142         int err;
 143
 144         to_fp = (fp ? fp : (struct _fpstate *) (to + 1));
 145         from_fp = from->fpstate;
 146         err = copy_to_user(to, from, sizeof(*to));
 147         if(from_fp != NULL){
 148                 err |= copy_to_user(&to->fpstate, &to_fp, sizeof(to->fpstate));
 149                 err |= copy_to_user(to_fp, from_fp, fpsize);
 150         }
 151         return(err);
 152 }
 153 #endif
 154
 155 static int copy_sc_from_user(struct pt_regs *to, void __user *from)
 156 {
 157         int ret;
 158
 159         ret = CHOOSE_MODE(copy_sc_from_user_tt(UPT_SC(&to->regs), from,
 160                                                sizeof(struct _fpstate)),
 161                           copy_sc_from_user_skas(to, from));
 162         return(ret);
 163 }
 164
 165 static int copy_sc_to_user(struct sigcontext *to, struct _fpstate *fp,
 166                            struct pt_regs *from)
 167 {
 168         return(CHOOSE_MODE(copy_sc_to_user_tt(to, fp, UPT_SC(&from->regs),
 169                                               sizeof(*fp)),
 170                            copy_sc_to_user_skas(to, fp, from,
 171                                                 current->thread.cr2,
 172                                                 current->thread.err)));
 173 }
 174
 175 static int copy_ucontext_to_user(struct ucontext *uc, struct _fpstate *fp,
 176                                  sigset_t *set, unsigned long sp)
 177 {
 178         int err = 0;
 179
 180         err |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp);
 181         err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags);
 182         err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size);
 183         err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs);
 184         err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
 185         return(err);
 186 }
 187
 188 struct sigframe
 189 {
 190         char *pretcode;
 191         int sig;
 192         struct sigcontext sc;
 193         struct _fpstate fpstate;
 194         unsigned long extramask[_NSIG_WORDS-1];
 195         char retcode[8];
 196 };
 197
 198 struct rt_sigframe
 199 {
 200         char *pretcode;
 201         int sig;
 202         struct siginfo *pinfo;
 203         void *puc;
 204         struct siginfo info;
 205         struct ucontext uc;
 206         struct _fpstate fpstate;
 207         char retcode[8];
 208 };
 209
 210 int setup_signal_stack_sc(unsigned long stack_top, int sig,
 211                           struct k_sigaction *ka, struct pt_regs *regs,
 212                           sigset_t *mask)
 213 {
 214         struct sigframe __user *frame;
 215         void *restorer;
 216         int err = 0;
 217
 218         stack_top &= -8UL;
 219         frame = (struct sigframe *) stack_top - 1;
 220         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 221                 return 1;
 222
 223         restorer = (void *) frame->retcode;
 224         if(ka->sa.sa_flags & SA_RESTORER)
 225                 restorer = ka->sa.sa_restorer;
 226
 227         err |= __put_user(restorer, &frame->pretcode);
 228         err |= __put_user(sig, &frame->sig);
 229         err |= copy_sc_to_user(&frame->sc, NULL, regs);
 230         err |= __put_user(mask->sig[0], &frame->sc.oldmask);
 231         if (_NSIG_WORDS > 1)
 232                 err |= __copy_to_user(&frame->extramask, &mask->sig[1],
 233                                       sizeof(frame->extramask));
 234
 235         /*
 236          * This is popl %eax ; movl $,%eax ; int $0x80
 237          *
 238          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 239          * reasons and because gdb uses it as a signature to notice
 240          * signal handler stack frames.
 241          */
 242         err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
 243         err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
 244         err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
 245
 246         if(err)
 247                 return(err);
 248
 249         PT_REGS_SP(regs) = (unsigned long) frame;
 250         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 251         PT_REGS_EAX(regs) = (unsigned long) sig;
 252         PT_REGS_EDX(regs) = (unsigned long) 0;
 253         PT_REGS_ECX(regs) = (unsigned long) 0;
 254
 255         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 256                 ptrace_notify(SIGTRAP);
 257         return(0);
 258 }
 259
 260 int setup_signal_stack_si(unsigned long stack_top, int sig,
 261                           struct k_sigaction *ka, struct pt_regs *regs,
 262                           siginfo_t *info, sigset_t *mask)
 263 {
 264         struct rt_sigframe __user *frame;
 265         void *restorer;
 266         int err = 0;
 267
 268         stack_top &= -8UL;
 269         frame = (struct rt_sigframe *) stack_top - 1;
 270         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 271                 return 1;
 272
 273         restorer = (void *) frame->retcode;
 274         if(ka->sa.sa_flags & SA_RESTORER)
 275                 restorer = ka->sa.sa_restorer;
 276
 277         err |= __put_user(restorer, &frame->pretcode);
 278         err |= __put_user(sig, &frame->sig);
 279         err |= __put_user(&frame->info, &frame->pinfo);
 280         err |= __put_user(&frame->uc, &frame->puc);
 281         err |= copy_siginfo_to_user(&frame->info, info);
 282         err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
 283                                      PT_REGS_SP(regs));
 284
 285         /*
 286          * This is movl $,%eax ; int $0x80
 287          *
 288          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 289          * reasons and because gdb uses it as a signature to notice
 290          * signal handler stack frames.
 291          */
 292         err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
 293         err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
 294         err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
 295
 296         if(err)
 297                 return(err);
 298
 299         PT_REGS_SP(regs) = (unsigned long) frame;
 300         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
 301         PT_REGS_EAX(regs) = (unsigned long) sig;
 302         PT_REGS_EDX(regs) = (unsigned long) &frame->info;
 303         PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
 304
 305         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
 306                 ptrace_notify(SIGTRAP);
 307         return(0);
 308 }
 309
 310 long sys_sigreturn(struct pt_regs regs)
 311 {
 312         unsigned long sp = PT_REGS_SP(&current->thread.regs);
 313         struct sigframe __user *frame = (struct sigframe *)(sp - 8);
 314         sigset_t set;
 315         struct sigcontext __user *sc = &frame->sc;
 316         unsigned long __user *oldmask = &sc->oldmask;
 317         unsigned long __user *extramask = frame->extramask;
 318         int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
 319
 320         if(copy_from_user(&set.sig[0], oldmask, sizeof(&set.sig[0])) ||
 321            copy_from_user(&set.sig[1], extramask, sig_size))
 322                 goto segfault;
 323
 324         sigdelsetmask(&set, ~_BLOCKABLE);
 325
 326         spin_lock_irq(&current->sighand->siglock);
 327         current->blocked = set;
 328         recalc_sigpending();
 329         spin_unlock_irq(&current->sighand->siglock);
 330
 331         if(copy_sc_from_user(&current->thread.regs, sc))
 332                 goto segfault;
 333
 334         /* Avoid ERESTART handling */
 335         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 336         return(PT_REGS_SYSCALL_RET(&current->thread.regs));
 337
 338  segfault:
 339         force_sig(SIGSEGV, current);
 340         return 0;
 341 }
 342
 343 long sys_rt_sigreturn(struct pt_regs regs)
 344 {
 345         unsigned long __user sp = PT_REGS_SP(&current->thread.regs);
 346         struct rt_sigframe __user *frame = (struct rt_sigframe *) (sp - 4);
 347         sigset_t set;
 348         struct ucontext __user *uc = &frame->uc;
 349         int sig_size = _NSIG_WORDS * sizeof(unsigned long);
 350
 351         if(copy_from_user(&set, &uc->uc_sigmask, sig_size))
 352                 goto segfault;
 353
 354         sigdelsetmask(&set, ~_BLOCKABLE);
 355
 356         spin_lock_irq(&current->sighand->siglock);
 357         current->blocked = set;
 358         recalc_sigpending();
 359         spin_unlock_irq(&current->sighand->siglock);
 360
 361         if(copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
 362                 goto segfault;
 363
 364         /* Avoid ERESTART handling */
 365         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 366         return(PT_REGS_SYSCALL_RET(&current->thread.regs));
 367
 368  segfault:
 369         force_sig(SIGSEGV, current);
 370         return 0;
 371 }
 372
 373 /*
 374  * Overrides for Emacs so that we follow Linus's tabbing style.
 375  * Emacs will notice this stuff at the end of the file and automatically
 376  * adjust the settings for this buffer only.  This must remain at the end
 377  * of the file.
 378  * ---------------------------------------------------------------------------
 379  * Local variables:
 380  * c-file-style: "linux"
 381  * End:
 382  */