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 <asm/unistd.h>
  10 #include <asm/uaccess.h>
  11 #include <asm/ucontext.h>
  12 #include "frame_kern.h"
  13 #include "skas.h"
  14
  15 void copy_sc(struct uml_pt_regs *regs, void *from)
  16 {
  17         struct sigcontext *sc = from;
  18
  19 #define GETREG(regs, regno, sc, regname)                                \
  20         (regs)->gp[(regno) / sizeof(unsigned long)] = (sc)->regname
  21
  22         GETREG(regs, R8, sc, r8);
  23         GETREG(regs, R9, sc, r9);
  24         GETREG(regs, R10, sc, r10);
  25         GETREG(regs, R11, sc, r11);
  26         GETREG(regs, R12, sc, r12);
  27         GETREG(regs, R13, sc, r13);
  28         GETREG(regs, R14, sc, r14);
  29         GETREG(regs, R15, sc, r15);
  30         GETREG(regs, RDI, sc, di);
  31         GETREG(regs, RSI, sc, si);
  32         GETREG(regs, RBP, sc, bp);
  33         GETREG(regs, RBX, sc, bx);
  34         GETREG(regs, RDX, sc, dx);
  35         GETREG(regs, RAX, sc, ax);
  36         GETREG(regs, RCX, sc, cx);
  37         GETREG(regs, RSP, sc, sp);
  38         GETREG(regs, RIP, sc, ip);
  39         GETREG(regs, EFLAGS, sc, flags);
  40         GETREG(regs, CS, sc, cs);
  41
  42 #undef GETREG
  43 }
  44
  45 static int copy_sc_from_user(struct pt_regs *regs,
  46                              struct sigcontext __user *from,
  47                              struct _fpstate __user *fpp)
  48 {
  49         struct user_i387_struct fp;
  50         int err = 0;
  51
  52 #define GETREG(regs, regno, sc, regname)                                \
  53         __get_user((regs)->regs.gp[(regno) / sizeof(unsigned long)],    \
  54                    &(sc)->regname)
  55
  56         err |= GETREG(regs, R8, from, r8);
  57         err |= GETREG(regs, R9, from, r9);
  58         err |= GETREG(regs, R10, from, r10);
  59         err |= GETREG(regs, R11, from, r11);
  60         err |= GETREG(regs, R12, from, r12);
  61         err |= GETREG(regs, R13, from, r13);
  62         err |= GETREG(regs, R14, from, r14);
  63         err |= GETREG(regs, R15, from, r15);
  64         err |= GETREG(regs, RDI, from, di);
  65         err |= GETREG(regs, RSI, from, si);
  66         err |= GETREG(regs, RBP, from, bp);
  67         err |= GETREG(regs, RBX, from, bx);
  68         err |= GETREG(regs, RDX, from, dx);
  69         err |= GETREG(regs, RAX, from, ax);
  70         err |= GETREG(regs, RCX, from, cx);
  71         err |= GETREG(regs, RSP, from, sp);
  72         err |= GETREG(regs, RIP, from, ip);
  73         err |= GETREG(regs, EFLAGS, from, flags);
  74         err |= GETREG(regs, CS, from, cs);
  75         if (err)
  76                 return 1;
  77
  78 #undef GETREG
  79
  80         err = copy_from_user(&fp, fpp, sizeof(struct user_i387_struct));
  81         if (err)
  82                 return 1;
  83
  84         err = restore_fp_registers(userspace_pid[current_thread_info()->cpu],
  85                                    (unsigned long *) &fp);
  86         if (err < 0) {
  87                 printk(KERN_ERR "copy_sc_from_user - "
  88                        "restore_fp_registers failed, errno = %d\n",
  89                        -err);
  90                 return 1;
  91         }
  92
  93         return 0;
  94 }
  95
  96 static int copy_sc_to_user(struct sigcontext __user *to,
  97                            struct _fpstate __user *to_fp, struct pt_regs *regs,
  98                            unsigned long mask, unsigned long sp)
  99 {
 100         struct faultinfo * fi = &current->thread.arch.faultinfo;
 101         struct user_i387_struct fp;
 102         int err = 0;
 103
 104         err |= __put_user(0, &to->gs);
 105         err |= __put_user(0, &to->fs);
 106
 107 #define PUTREG(regs, regno, sc, regname)                                \
 108         __put_user((regs)->regs.gp[(regno) / sizeof(unsigned long)],    \
 109                    &(sc)->regname)
 110
 111         err |= PUTREG(regs, RDI, to, di);
 112         err |= PUTREG(regs, RSI, to, si);
 113         err |= PUTREG(regs, RBP, to, bp);
 114         /*
 115          * Must use original RSP, which is passed in, rather than what's in
 116          * the pt_regs, because that's already been updated to point at the
 117          * signal frame.
 118          */
 119         err |= __put_user(sp, &to->sp);
 120         err |= PUTREG(regs, RBX, to, bx);
 121         err |= PUTREG(regs, RDX, to, dx);
 122         err |= PUTREG(regs, RCX, to, cx);
 123         err |= PUTREG(regs, RAX, to, ax);
 124         err |= PUTREG(regs, R8, to, r8);
 125         err |= PUTREG(regs, R9, to, r9);
 126         err |= PUTREG(regs, R10, to, r10);
 127         err |= PUTREG(regs, R11, to, r11);
 128         err |= PUTREG(regs, R12, to, r12);
 129         err |= PUTREG(regs, R13, to, r13);
 130         err |= PUTREG(regs, R14, to, r14);
 131         err |= PUTREG(regs, R15, to, r15);
 132         err |= PUTREG(regs, CS, to, cs); /* XXX x86_64 doesn't do this */
 133
 134         err |= __put_user(fi->cr2, &to->cr2);
 135         err |= __put_user(fi->error_code, &to->err);
 136         err |= __put_user(fi->trap_no, &to->trapno);
 137
 138         err |= PUTREG(regs, RIP, to, ip);
 139         err |= PUTREG(regs, EFLAGS, to, flags);
 140 #undef PUTREG
 141
 142         err |= __put_user(mask, &to->oldmask);
 143         if (err)
 144                 return 1;
 145
 146         err = save_fp_registers(userspace_pid[current_thread_info()->cpu],
 147                                 (unsigned long *) &fp);
 148         if (err < 0) {
 149                 printk(KERN_ERR "copy_sc_from_user - restore_fp_registers "
 150                        "failed, errno = %d\n", -err);
 151                 return 1;
 152         }
 153
 154         if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct)))
 155                 return 1;
 156
 157         return err;
 158 }
 159
 160 struct rt_sigframe
 161 {
 162         char __user *pretcode;
 163         struct ucontext uc;
 164         struct siginfo info;
 165         struct _fpstate fpstate;
 166 };
 167
 168 #define round_down(m, n) (((m) / (n)) * (n))
 169
 170 int setup_signal_stack_si(unsigned long stack_top, int sig,
 171                           struct k_sigaction *ka, struct pt_regs * regs,
 172                           siginfo_t *info, sigset_t *set)
 173 {
 174         struct rt_sigframe __user *frame;
 175         unsigned long save_sp = PT_REGS_RSP(regs);
 176         int err = 0;
 177         struct task_struct *me = current;
 178
 179         frame = (struct rt_sigframe __user *)
 180                 round_down(stack_top - sizeof(struct rt_sigframe), 16);
 181         /* Subtract 128 for a red zone and 8 for proper alignment */
 182         frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
 183
 184         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 185                 goto out;
 186
 187         if (ka->sa.sa_flags & SA_SIGINFO) {
 188                 err |= copy_siginfo_to_user(&frame->info, info);
 189                 if (err)
 190                         goto out;
 191         }
 192
 193         /*
 194          * Update SP now because the page fault handler refuses to extend
 195          * the stack if the faulting address is too far below the current
 196          * SP, which frame now certainly is.  If there's an error, the original
 197          * value is restored on the way out.
 198          * When writing the sigcontext to the stack, we have to write the
 199          * original value, so that's passed to copy_sc_to_user, which does
 200          * the right thing with it.
 201          */
 202         PT_REGS_RSP(regs) = (unsigned long) frame;
 203
 204         /* Create the ucontext.  */
 205         err |= __put_user(0, &frame->uc.uc_flags);
 206         err |= __put_user(0, &frame->uc.uc_link);
 207         err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 208         err |= __put_user(sas_ss_flags(save_sp),
 209                           &frame->uc.uc_stack.ss_flags);
 210         err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
 211         err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs,
 212                                set->sig[0], save_sp);
 213         err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate);
 214         if (sizeof(*set) == 16) {
 215                 __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
 216                 __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
 217         }
 218         else
 219                 err |= __copy_to_user(&frame->uc.uc_sigmask, set,
 220                                       sizeof(*set));
 221
 222         /*
 223          * Set up to return from userspace.  If provided, use a stub
 224          * already in userspace.
 225          */
 226         /* x86-64 should always use SA_RESTORER. */
 227         if (ka->sa.sa_flags & SA_RESTORER)
 228                 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
 229         else
 230                 /* could use a vstub here */
 231                 goto restore_sp;
 232
 233         if (err)
 234                 goto restore_sp;
 235
 236         /* Set up registers for signal handler */
 237         {
 238                 struct exec_domain *ed = current_thread_info()->exec_domain;
 239                 if (unlikely(ed && ed->signal_invmap && sig < 32))
 240                         sig = ed->signal_invmap[sig];
 241         }
 242
 243         PT_REGS_RDI(regs) = sig;
 244         /* In case the signal handler was declared without prototypes */
 245         PT_REGS_RAX(regs) = 0;
 246
 247         /*
 248          * This also works for non SA_SIGINFO handlers because they expect the
 249          * next argument after the signal number on the stack.
 250          */
 251         PT_REGS_RSI(regs) = (unsigned long) &frame->info;
 252         PT_REGS_RDX(regs) = (unsigned long) &frame->uc;
 253         PT_REGS_RIP(regs) = (unsigned long) ka->sa.sa_handler;
 254  out:
 255         return err;
 256
 257 restore_sp:
 258         PT_REGS_RSP(regs) = save_sp;
 259         return err;
 260 }
 261
 262 long sys_rt_sigreturn(struct pt_regs *regs)
 263 {
 264         unsigned long sp = PT_REGS_SP(&current->thread.regs);
 265         struct rt_sigframe __user *frame =
 266                 (struct rt_sigframe __user *)(sp - 8);
 267         struct ucontext __user *uc = &frame->uc;
 268         sigset_t set;
 269
 270         if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
 271                 goto segfault;
 272
 273         sigdelsetmask(&set, ~_BLOCKABLE);
 274
 275         spin_lock_irq(&current->sighand->siglock);
 276         current->blocked = set;
 277         recalc_sigpending();
 278         spin_unlock_irq(&current->sighand->siglock);
 279
 280         if (copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext,
 281                               &frame->fpstate))
 282                 goto segfault;
 283
 284         /* Avoid ERESTART handling */
 285         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
 286         return PT_REGS_SYSCALL_RET(&current->thread.regs);
 287
 288  segfault:
 289         force_sig(SIGSEGV, current);
 290         return 0;
 291 }