arch/um/sys-x86_64/signal.c

   1 /*
   2  * Copyright (C) 2003 PathScale, Inc.
   3  * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   4  * Licensed under the GPL
   5  */
   6
   7 #include <linux/personality.h>
   8 #include <linux/ptrace.h>
   9 #include <linux/kernel.h>
  10 #include <asm/unistd.h>
  11 #include <asm/uaccess.h>
  12 #include <asm/ucontext.h>
  13 #include "frame_kern.h"
  14 #include "skas.h"
  15
  16 void copy_sc(struct uml_pt_regs *regs, void *from)
  17 {
  18         struct sigcontext *sc = from;
  19
  20 #define GETREG(regs, regno, sc, regname)                                \
  21         (regs)->gp[(regno) / sizeof(unsigned long)] = (sc)->regname
  22
  23         GETREG(regs, R8, sc, r8);
  24         GETREG(regs, R9, sc, r9);
  25         GETREG(regs, R10, sc, r10);
  26         GETREG(regs, R11, sc, r11);
  27         GETREG(regs, R12, sc, r12);
  28         GETREG(regs, R13, sc, r13);
  29         GETREG(regs, R14, sc, r14);
  30         GETREG(regs, R15, sc, r15);
  31         GETREG(regs, RDI, sc, di);
  32         GETREG(regs, RSI, sc, si);
  33         GETREG(regs, RBP, sc, bp);
  34         GETREG(regs, RBX, sc, bx);
  35         GETREG(regs, RDX, sc, dx);
  36         GETREG(regs, RAX, sc, ax);
  37         GETREG(regs, RCX, sc, cx);
  38         GETREG(regs, RSP, sc, sp);
  39         GETREG(regs, RIP, sc, ip);
  40         GETREG(regs, EFLAGS, sc, flags);
  41         GETREG(regs, CS, sc, cs);
  42
  43 #undef GETREG
  44 }
  45
  46 static int copy_sc_from_user(struct pt_regs *regs,
  47                              struct sigcontext __user *from,
  48                              struct _fpstate __user *fpp)
  49 {
  50         struct user_i387_struct fp;
  51         int err = 0;
  52
  53 #define GETREG(regs, regno, sc, regname)                                \
  54         __get_user((regs)->regs.gp[(regno) / sizeof(unsigned long)],    \
  55                    &(sc)->regname)
  56
  57         err |= GETREG(regs, R8, from, r8);
  58         err |= GETREG(regs, R9, from, r9);
  59         err |= GETREG(regs, R10, from, r10);
  60         err |= GETREG(regs, R11, from, r11);
  61         err |= GETREG(regs, R12, from, r12);
  62         err |= GETREG(regs, R13, from, r13);
  63         err |= GETREG(regs, R14, from, r14);
  64         err |= GETREG(regs, R15, from, r15);
  65         err |= GETREG(regs, RDI, from, di);
  66         err |= GETREG(regs, RSI, from, si);
  67         err |= GETREG(regs, RBP, from, bp);
  68         err |= GETREG(regs, RBX, from, bx);
  69         err |= GETREG(regs, RDX, from, dx);
  70         err |= GETREG(regs, RAX, from, ax);
  71         err |= GETREG(regs, RCX, from, cx);
  72         err |= GETREG(regs, RSP, from, sp);
  73         err |= GETREG(regs, RIP, from, ip);
  74         err |= GETREG(regs, EFLAGS, from, flags);
  75         err |= GETREG(regs, CS, from, cs);
  76         if (err)
  77                 return 1;
  78
  79 #undef GETREG
  80
  81         err = copy_from_user(&fp, fpp, sizeof(struct user_i387_struct));
  82         if (err)
  83                 return 1;
  84
  85         err = restore_fp_registers(userspace_pid[current_thread_info()->cpu],
  86                                    (unsigned long *) &fp);
  87         if (err < 0) {
  88                 printk(KERN_ERR "copy_sc_from_user - "
  89                        "restore_fp_registers failed, errno = %d\n",
  90                        -err);
  91                 return 1;
  92         }
  93
  94         return 0;
  95 }
  96
  97 static int copy_sc_to_user(struct sigcontext __user *to,
  98                            struct _fpstate __user *to_fp, struct pt_regs *regs,
  99                            unsigned long mask, unsigned long sp)
 100 {
 101         struct faultinfo * fi = &current->thread.arch.faultinfo;
 102         struct user_i387_struct fp;
 103         int err = 0;
 104
 105         err |= __put_user(0, &to->gs);
 106         err |= __put_user(0, &to->fs);
 107
 108 #define PUTREG(regs, regno, sc, regname)                                \
 109         __put_user((regs)->regs.gp[(regno) / sizeof(unsigned long)],    \
 110                    &(sc)->regname)
 111
 112         err |= PUTREG(regs, RDI, to, di);
 113         err |= PUTREG(regs, RSI, to, si);
 114         err |= PUTREG(regs, RBP, to, bp);
 115         /*
 116          * Must use original RSP, which is passed in, rather than what's in
 117          * the pt_regs, because that's already been updated to point at the
 118          * signal frame.
 119          */
 120         err |= __put_user(sp, &to->sp);
 121         err |= PUTREG(regs, RBX, to, bx);
 122         err |= PUTREG(regs, RDX, to, dx);
 123         err |= PUTREG(regs, RCX, to, cx);
 124         err |= PUTREG(regs, RAX, to, ax);
 125         err |= PUTREG(regs, R8, to, r8);
 126         err |= PUTREG(regs, R9, to, r9);
 127         err |= PUTREG(regs, R10, to, r10);
 128         err |= PUTREG(regs, R11, to, r11);
 129         err |= PUTREG(regs, R12, to, r12);
 130         err |= PUTREG(regs, R13, to, r13);
 131         err |= PUTREG(regs, R14, to, r14);
 132         err |= PUTREG(regs, R15, to, r15);
 133         err |= PUTREG(regs, CS, to, cs); /* XXX x86_64 doesn't do this */
 134
 135         err |= __put_user(fi->cr2, &to->cr2);
 136         err |= __put_user(fi->error_code, &to->err);
 137         err |= __put_user(fi->trap_no, &to->trapno);
 138
 139         err |= PUTREG(regs, RIP, to, ip);
 140         err |= PUTREG(regs, EFLAGS, to, flags);
 141 #undef PUTREG
 142
 143         err |= __put_user(mask, &to->oldmask);
 144         if (err)
 145                 return 1;
 146
 147         err = save_fp_registers(userspace_pid[current_thread_info()->cpu],
 148                                 (unsigned long *) &fp);
 149         if (err < 0) {
 150                 printk(KERN_ERR "copy_sc_from_user - restore_fp_registers "
 151                        "failed, errno = %d\n", -err);
 152                 return 1;
 153         }
 154
 155         if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct)))
 156                 return 1;
 157
 158         return err;
 159 }
 160
 161 struct rt_sigframe
 162 {
 163         char __user *pretcode;
 164         struct ucontext uc;
 165         struct siginfo info;
 166         struct _fpstate fpstate;
 167 };
 168
 169 int setup_signal_stack_si(unsigned long stack_top, int sig,
 170                           struct k_sigaction *ka, struct pt_regs * regs,
 171                           siginfo_t *info, sigset_t *set)
 172 {
 173         struct rt_sigframe __user *frame;
 174         unsigned long save_sp = PT_REGS_RSP(regs);
 175         int err = 0;
 176         struct task_struct *me = current;
 177
 178         frame = (struct rt_sigframe __user *)
 179                 round_down(stack_top - sizeof(struct rt_sigframe), 16);
 180         /* Subtract 128 for a red zone and 8 for proper alignment */
 181         frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
 182
 183         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 184                 goto out;
 185
 186         if (ka->sa.sa_flags & SA_SIGINFO) {
 187                 err |= copy_siginfo_to_user(&frame->info, info);
 188                 if (err)
 189                         goto out;
 190         }
 191
 192         /*
 193          * Update SP now because the page fault handler refuses to extend
 194          * the stack if the faulting address is too far below the current
 195          * SP, which frame now certainly is.  If there's an error, the original
 196          * value is restored on the way out.
 197          * When writing the sigcontext to the stack, we have to write the
 198          * original value, so that's passed to copy_sc_to_user, which does
 199          * the right thing with it.
 200          */
 201         PT_REGS_RSP(regs) = (unsigned long) frame;
 202
 203         /* Create the ucontext.  */
 204         err |= __put_user(0, &frame->uc.uc_flags);
 205         err |= __put_user(0, &frame->uc.uc_link);
 206         err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 207         err |= __put_user(sas_ss_flags(save_sp),
 208                           &frame->uc.uc_stack.ss_flags);
 209         err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
 210         err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs,
 211                                set->sig[0], save_sp);
 212         err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate);
 213         if (sizeof(*set) == 16) {
 214                 __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
 215                 __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
 216         }
 217         else
 218                 err |= __copy_to_user(&frame->uc.uc_sigmask, set,
 219                                       sizeof(*set));
 220
 221         /*
 222          * Set up to return from userspace.  If provided, use a stub
 223          * already in userspace.
 224          */
 225         /* x86-64 should always use SA_RESTORER. */
 226         if (ka->sa.sa_flags & SA_RESTORER)
 227                 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
 228         else
 229                 /* could use a vstub here */
 230                 goto restore_sp;
 231
 232         if (err)
 233                 goto restore_sp;
 234
 235         /* Set up registers for signal handler */
 236         {
 237                 struct exec_domain *ed = current_thread_info()->exec_domain;
 238                 if (unlikely(ed && ed->signal_invmap && sig < 32))
 239                         sig = ed->signal_invmap[sig];
 240         }
 241
 242         PT_REGS_RDI(regs) = sig;
 243         /* In case the signal handler was declared without prototypes */
 244         PT_REGS_RAX(regs) = 0;
 245
 246         /*
 247          * This also works for non SA_SIGINFO handlers because they expect the
 248          * next argument after the signal number on the stack.
 249          */
 250         PT_REGS_RSI(regs) = (unsigned long) &frame->info;
 251         PT_REGS_RDX(regs) = (unsigned long) &frame->uc;
 252         PT_REGS_RIP(regs) = (unsigned long) ka->sa.sa_handler;
 253  out:
 254         return err;
 255
 256 restore_sp:
 257         PT_REGS_RSP(regs) = save_sp;
 258         return err;
 259 }
 260
 261 long sys_rt_sigreturn(struct pt_regs *regs)
 262 {
 263         unsigned long sp = PT_REGS_SP(&current->thread.regs);
 264         struct rt_sigframe __user *frame =
 265                 (struct rt_sigframe __user *)(sp - 8);
 266         struct ucontext __user *uc = &frame->uc;
 267         sigset_t set;
 268
 269         if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
 270                 goto segfault;
 271
 272         sigdelsetmask(&set, ~_BLOCKABLE);
 273         set_current_blocked(&set);
 274
 275         if (copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext,
 276                               &frame->fpstate))
 277                 goto segfault;
 278
 279         /* Avoid ERESTART handling */
 280         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 281         return PT_REGS_SYSCALL_RET(&current->thread.regs);
 282
 283  segfault:
 284         force_sig(SIGSEGV, current);
 285         return 0;
 286 }