arch/score/kernel/signal.c

   1 /*
   2  * arch/score/kernel/signal.c
   3  *
   4  * Score Processor version.
   5  *
   6  * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
   7  *  Chen Liqin <liqin.chen@sunplusct.com>
   8  *  Lennox Wu <lennox.wu@sunplusct.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, see the file COPYING, or write
  22  * to the Free Software Foundation, Inc.,
  23  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  24  */
  25
  26 #include <linux/errno.h>
  27 #include <linux/signal.h>
  28 #include <linux/unistd.h>
  29 #include <linux/uaccess.h>
  30
  31 #include <asm/syscalls.h>
  32 #include <asm/ucontext.h>
  33
  34 #include <asm/cacheflush.h>
  35
  36 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  37
  38 struct rt_sigframe {
  39         u32 rs_ass[4];          /* argument save space */
  40         u32 rs_code[2];         /* signal trampoline */
  41         struct siginfo rs_info;
  42         struct ucontext rs_uc;
  43 };
  44
  45 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
  46 {
  47         int err = 0;
  48         unsigned long reg;
  49
  50         reg = regs->cp0_epc; err |= __put_user(reg, &sc->sc_pc);
  51         err |= __put_user(regs->cp0_psr, &sc->sc_psr);
  52         err |= __put_user(regs->cp0_condition, &sc->sc_condition);
  53
  54
  55 #define save_gp_reg(i) {                                \
  56         reg = regs->regs[i];                            \
  57         err |= __put_user(reg, &sc->sc_regs[i]);        \
  58 } while (0)
  59         save_gp_reg(0); save_gp_reg(1); save_gp_reg(2);
  60         save_gp_reg(3); save_gp_reg(4); save_gp_reg(5);
  61         save_gp_reg(6); save_gp_reg(7); save_gp_reg(8);
  62         save_gp_reg(9); save_gp_reg(10); save_gp_reg(11);
  63         save_gp_reg(12); save_gp_reg(13); save_gp_reg(14);
  64         save_gp_reg(15); save_gp_reg(16); save_gp_reg(17);
  65         save_gp_reg(18); save_gp_reg(19); save_gp_reg(20);
  66         save_gp_reg(21); save_gp_reg(22); save_gp_reg(23);
  67         save_gp_reg(24); save_gp_reg(25); save_gp_reg(26);
  68         save_gp_reg(27); save_gp_reg(28); save_gp_reg(29);
  69 #undef save_gp_reg
  70
  71         reg = regs->ceh; err |= __put_user(reg, &sc->sc_mdceh);
  72         reg = regs->cel; err |= __put_user(reg, &sc->sc_mdcel);
  73         err |= __put_user(regs->cp0_ecr, &sc->sc_ecr);
  74         err |= __put_user(regs->cp0_ema, &sc->sc_ema);
  75
  76         return err;
  77 }
  78
  79 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
  80 {
  81         int err = 0;
  82         u32 reg;
  83
  84         err |= __get_user(regs->cp0_epc, &sc->sc_pc);
  85         err |= __get_user(regs->cp0_condition, &sc->sc_condition);
  86
  87         err |= __get_user(reg, &sc->sc_mdceh);
  88         regs->ceh = (int) reg;
  89         err |= __get_user(reg, &sc->sc_mdcel);
  90         regs->cel = (int) reg;
  91
  92         err |= __get_user(reg, &sc->sc_psr);
  93         regs->cp0_psr = (int) reg;
  94         err |= __get_user(reg, &sc->sc_ecr);
  95         regs->cp0_ecr = (int) reg;
  96         err |= __get_user(reg, &sc->sc_ema);
  97         regs->cp0_ema = (int) reg;
  98
  99 #define restore_gp_reg(i) do {                          \
 100         err |= __get_user(reg, &sc->sc_regs[i]);        \
 101         regs->regs[i] = reg;                            \
 102 } while (0)
 103         restore_gp_reg(0); restore_gp_reg(1); restore_gp_reg(2);
 104         restore_gp_reg(3); restore_gp_reg(4); restore_gp_reg(5);
 105         restore_gp_reg(6); restore_gp_reg(7); restore_gp_reg(8);
 106         restore_gp_reg(9); restore_gp_reg(10); restore_gp_reg(11);
 107         restore_gp_reg(12); restore_gp_reg(13); restore_gp_reg(14);
 108         restore_gp_reg(15); restore_gp_reg(16); restore_gp_reg(17);
 109         restore_gp_reg(18); restore_gp_reg(19); restore_gp_reg(20);
 110         restore_gp_reg(21); restore_gp_reg(22); restore_gp_reg(23);
 111         restore_gp_reg(24); restore_gp_reg(25); restore_gp_reg(26);
 112         restore_gp_reg(27); restore_gp_reg(28); restore_gp_reg(29);
 113 #undef restore_gp_reg
 114
 115         return err;
 116 }
 117
 118 /*
 119  * Determine which stack to use..
 120  */
 121 void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 122                         size_t frame_size)
 123 {
 124         unsigned long sp;
 125
 126         /* Default to using normal stack */
 127         sp = regs->regs[0];
 128         sp -= 32;
 129
 130         /* This is the X/Open sanctioned signal stack switching.  */
 131         if ((ka->sa.sa_flags & SA_ONSTACK) && (!on_sig_stack(sp)))
 132                 sp = current->sas_ss_sp + current->sas_ss_size;
 133
 134         return (void __user*)((sp - frame_size) & ~7);
 135 }
 136
 137 int score_sigaltstack(struct pt_regs *regs)
 138 {
 139         const stack_t __user *uss = (const stack_t __user *) regs->regs[4];
 140         stack_t __user *uoss = (stack_t __user *) regs->regs[5];
 141         unsigned long usp = regs->regs[0];
 142
 143         return do_sigaltstack(uss, uoss, usp);
 144 }
 145
 146 void score_rt_sigreturn(struct pt_regs *regs)
 147 {
 148         struct rt_sigframe __user *frame;
 149         sigset_t set;
 150         stack_t st;
 151         int sig;
 152
 153         frame = (struct rt_sigframe __user *) regs->regs[0];
 154         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 155                 goto badframe;
 156         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
 157                 goto badframe;
 158
 159         sigdelsetmask(&set, ~_BLOCKABLE);
 160         spin_lock_irq(&current->sighand->siglock);
 161         current->blocked = set;
 162         recalc_sigpending();
 163         spin_unlock_irq(&current->sighand->siglock);
 164
 165         sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 166         if (sig < 0)
 167                 goto badframe;
 168         else if (sig)
 169                 force_sig(sig, current);
 170
 171         if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
 172                 goto badframe;
 173
 174         /* It is more difficult to avoid calling this function than to
 175            call it and ignore errors.  */
 176         do_sigaltstack((stack_t __user *)&st, NULL, regs->regs[0]);
 177
 178         __asm__ __volatile__(
 179                 "mv\tr0, %0\n\t"
 180                 "la\tr8, syscall_exit\n\t"
 181                 "br\tr8\n\t"
 182                 : : "r" (regs) : "r8");
 183
 184 badframe:
 185         force_sig(SIGSEGV, current);
 186 }
 187
 188 int setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
 189                 int signr, sigset_t *set, siginfo_t *info)
 190 {
 191         struct rt_sigframe __user *frame;
 192         int err = 0;
 193
 194         frame = get_sigframe(ka, regs, sizeof(*frame));
 195         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 196                 goto give_sigsegv;
 197
 198         /*
 199          * Set up the return code ...
 200          *
 201          *         li      v0, __NR_rt_sigreturn
 202          *         syscall
 203          */
 204         err |= __put_user(0x87788000 + __NR_rt_sigreturn*2,
 205                         frame->rs_code + 0);
 206         err |= __put_user(0x80008002, frame->rs_code + 1);
 207         flush_cache_sigtramp((unsigned long) frame->rs_code);
 208
 209         err |= copy_siginfo_to_user(&frame->rs_info, info);
 210         err |= __put_user(0, &frame->rs_uc.uc_flags);
 211         err |= __put_user(0, &frame->rs_uc.uc_link);
 212         err |= __put_user((void __user *)current->sas_ss_sp,
 213                                 &frame->rs_uc.uc_stack.ss_sp);
 214         err |= __put_user(sas_ss_flags(regs->regs[0]),
 215                                 &frame->rs_uc.uc_stack.ss_flags);
 216         err |= __put_user(current->sas_ss_size,
 217                                 &frame->rs_uc.uc_stack.ss_size);
 218         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 219         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 220
 221         if (err)
 222                 goto give_sigsegv;
 223
 224         regs->regs[0] = (unsigned long) frame;
 225         regs->regs[3] = (unsigned long) frame->rs_code;
 226         regs->regs[4] = signr;
 227         regs->regs[5] = (unsigned long) &frame->rs_info;
 228         regs->regs[6] = (unsigned long) &frame->rs_uc;
 229         regs->regs[29] = (unsigned long) ka->sa.sa_handler;
 230         regs->cp0_epc = (unsigned long) ka->sa.sa_handler;
 231
 232         return 0;
 233
 234 give_sigsegv:
 235         if (signr == SIGSEGV)
 236                 ka->sa.sa_handler = SIG_DFL;
 237         force_sig(SIGSEGV, current);
 238         return -EFAULT;
 239 }
 240
 241 int handle_signal(unsigned long sig, siginfo_t *info,
 242         struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
 243 {
 244         int ret;
 245
 246         if (regs->is_syscall) {
 247                 switch (regs->regs[4]) {
 248                 case ERESTART_RESTARTBLOCK:
 249                 case ERESTARTNOHAND:
 250                         regs->regs[4] = EINTR;
 251                         break;
 252                 case ERESTARTSYS:
 253                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 254                                 regs->regs[4] = EINTR;
 255                                 break;
 256                         }
 257                 case ERESTARTNOINTR:
 258                         regs->regs[4] = regs->orig_r4;
 259                         regs->regs[7] = regs->orig_r7;
 260                         regs->cp0_epc -= 8;
 261                 }
 262
 263                 regs->is_syscall = 0;
 264         }
 265
 266         /*
 267          * Set up the stack frame
 268          */
 269         ret = setup_rt_frame(ka, regs, sig, oldset, info);
 270
 271         spin_lock_irq(&current->sighand->siglock);
 272         sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
 273         if (!(ka->sa.sa_flags & SA_NODEFER))
 274                 sigaddset(&current->blocked, sig);
 275         recalc_sigpending();
 276         spin_unlock_irq(&current->sighand->siglock);
 277
 278         return ret;
 279 }
 280
 281 void do_signal(struct pt_regs *regs)
 282 {
 283         struct k_sigaction ka;
 284         sigset_t *oldset;
 285         siginfo_t info;
 286         int signr;
 287
 288         /*
 289          * We want the common case to go fast, which is why we may in certain
 290          * cases get here from kernel mode. Just return without doing anything
 291          * if so.
 292          */
 293         if (!user_mode(regs))
 294                 return;
 295
 296         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 297                 oldset = &current->saved_sigmask;
 298         else
 299                 oldset = &current->blocked;
 300
 301         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 302         if (signr > 0) {
 303                 /* Actually deliver the signal.  */
 304                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 305                         /*
 306                          * A signal was successfully delivered; the saved
 307                          * sigmask will have been stored in the signal frame,
 308                          * and will be restored by sigreturn, so we can simply
 309                          * clear the TIF_RESTORE_SIGMASK flag.
 310                          */
 311                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 312                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 313                 }
 314
 315                 return;
 316         }
 317
 318         if (regs->is_syscall) {
 319                 if (regs->regs[4] == ERESTARTNOHAND ||
 320                     regs->regs[4] == ERESTARTSYS ||
 321                     regs->regs[4] == ERESTARTNOINTR) {
 322                         regs->regs[4] = regs->orig_r4;
 323                         regs->regs[7] = regs->orig_r7;
 324                         regs->cp0_epc -= 8;
 325                 }
 326
 327                 if (regs->regs[4] == ERESTART_RESTARTBLOCK) {
 328                         regs->regs[27] = __NR_restart_syscall;
 329                         regs->regs[4] = regs->orig_r4;
 330                         regs->regs[7] = regs->orig_r7;
 331                         regs->cp0_epc -= 8;
 332                 }
 333
 334                 regs->is_syscall = 0;   /* Don't deal with this again.  */
 335         }
 336
 337         /*
 338          * If there's no signal to deliver, we just put the saved sigmask
 339          * back
 340          */
 341         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 342                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 343                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 344         }
 345 }
 346
 347 /*
 348  * notification of userspace execution resumption
 349  * - triggered by the TIF_WORK_MASK flags
 350  */
 351 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 352                                 __u32 thread_info_flags)
 353 {
 354         /* deal with pending signal delivery */
 355         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 356                 do_signal(regs);
 357 }