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/ptrace.h>
  29 #include <linux/unistd.h>
  30 #include <linux/uaccess.h>
  31
  32 #include <asm/cacheflush.h>
  33 #include <asm/syscalls.h>
  34 #include <asm/ucontext.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 static 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 static 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 static void __user *get_sigframe(struct k_sigaction *ka,
 122                         struct pt_regs *regs, 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 asmlinkage long
 138 score_sigaltstack(struct pt_regs *regs)
 139 {
 140         const stack_t __user *uss = (const stack_t __user *) regs->regs[4];
 141         stack_t __user *uoss = (stack_t __user *) regs->regs[5];
 142         unsigned long usp = regs->regs[0];
 143
 144         return do_sigaltstack(uss, uoss, usp);
 145 }
 146
 147 asmlinkage long
 148 score_rt_sigreturn(struct pt_regs *regs)
 149 {
 150         struct rt_sigframe __user *frame;
 151         sigset_t set;
 152         stack_t st;
 153         int sig;
 154
 155         frame = (struct rt_sigframe __user *) regs->regs[0];
 156         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 157                 goto badframe;
 158         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
 159                 goto badframe;
 160
 161         sigdelsetmask(&set, ~_BLOCKABLE);
 162         set_current_blocked(&set);
 163
 164         sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 165         if (sig < 0)
 166                 goto badframe;
 167         else if (sig)
 168                 force_sig(sig, current);
 169
 170         if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
 171                 goto badframe;
 172
 173         /* It is more difficult to avoid calling this function than to
 174            call it and ignore errors.  */
 175         do_sigaltstack((stack_t __user *)&st, NULL, regs->regs[0]);
 176
 177         __asm__ __volatile__(
 178                 "mv\tr0, %0\n\t"
 179                 "la\tr8, syscall_exit\n\t"
 180                 "br\tr8\n\t"
 181                 : : "r" (regs) : "r8");
 182
 183 badframe:
 184         force_sig(SIGSEGV, current);
 185
 186         return 0;
 187 }
 188
 189 static int setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
 190                 int signr, sigset_t *set, siginfo_t *info)
 191 {
 192         struct rt_sigframe __user *frame;
 193         int err = 0;
 194
 195         frame = get_sigframe(ka, regs, sizeof(*frame));
 196         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 197                 goto give_sigsegv;
 198
 199         /*
 200          * Set up the return code ...
 201          *
 202          *         li      v0, __NR_rt_sigreturn
 203          *         syscall
 204          */
 205         err |= __put_user(0x87788000 + __NR_rt_sigreturn*2,
 206                         frame->rs_code + 0);
 207         err |= __put_user(0x80008002, frame->rs_code + 1);
 208         flush_cache_sigtramp((unsigned long) frame->rs_code);
 209
 210         err |= copy_siginfo_to_user(&frame->rs_info, info);
 211         err |= __put_user(0, &frame->rs_uc.uc_flags);
 212         err |= __put_user(NULL, &frame->rs_uc.uc_link);
 213         err |= __put_user((void __user *)current->sas_ss_sp,
 214                                 &frame->rs_uc.uc_stack.ss_sp);
 215         err |= __put_user(sas_ss_flags(regs->regs[0]),
 216                                 &frame->rs_uc.uc_stack.ss_flags);
 217         err |= __put_user(current->sas_ss_size,
 218                                 &frame->rs_uc.uc_stack.ss_size);
 219         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 220         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 221
 222         if (err)
 223                 goto give_sigsegv;
 224
 225         regs->regs[0] = (unsigned long) frame;
 226         regs->regs[3] = (unsigned long) frame->rs_code;
 227         regs->regs[4] = signr;
 228         regs->regs[5] = (unsigned long) &frame->rs_info;
 229         regs->regs[6] = (unsigned long) &frame->rs_uc;
 230         regs->regs[29] = (unsigned long) ka->sa.sa_handler;
 231         regs->cp0_epc = (unsigned long) ka->sa.sa_handler;
 232
 233         return 0;
 234
 235 give_sigsegv:
 236         if (signr == SIGSEGV)
 237                 ka->sa.sa_handler = SIG_DFL;
 238         force_sig(SIGSEGV, current);
 239         return -EFAULT;
 240 }
 241
 242 static int handle_signal(unsigned long sig, siginfo_t *info,
 243         struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
 244 {
 245         int ret;
 246
 247         if (regs->is_syscall) {
 248                 switch (regs->regs[4]) {
 249                 case ERESTART_RESTARTBLOCK:
 250                 case ERESTARTNOHAND:
 251                         regs->regs[4] = EINTR;
 252                         break;
 253                 case ERESTARTSYS:
 254                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 255                                 regs->regs[4] = EINTR;
 256                                 break;
 257                         }
 258                 case ERESTARTNOINTR:
 259                         regs->regs[4] = regs->orig_r4;
 260                         regs->regs[7] = regs->orig_r7;
 261                         regs->cp0_epc -= 8;
 262                 }
 263
 264                 regs->is_syscall = 0;
 265         }
 266
 267         /*
 268          * Set up the stack frame
 269          */
 270         ret = setup_rt_frame(ka, regs, sig, oldset, info);
 271
 272         if (ret == 0)
 273                 block_sigmask(ka, sig);
 274
 275         return ret;
 276 }
 277
 278 static void do_signal(struct pt_regs *regs)
 279 {
 280         struct k_sigaction ka;
 281         sigset_t *oldset;
 282         siginfo_t info;
 283         int signr;
 284
 285         /*
 286          * We want the common case to go fast, which is why we may in certain
 287          * cases get here from kernel mode. Just return without doing anything
 288          * if so.
 289          */
 290         if (!user_mode(regs))
 291                 return;
 292
 293         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 294                 oldset = &current->saved_sigmask;
 295         else
 296                 oldset = &current->blocked;
 297
 298         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 299         if (signr > 0) {
 300                 /* Actually deliver the signal.  */
 301                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 302                         /*
 303                          * A signal was successfully delivered; the saved
 304                          * sigmask will have been stored in the signal frame,
 305                          * and will be restored by sigreturn, so we can simply
 306                          * clear the TIF_RESTORE_SIGMASK flag.
 307                          */
 308                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 309                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 310                 }
 311
 312                 return;
 313         }
 314
 315         if (regs->is_syscall) {
 316                 if (regs->regs[4] == ERESTARTNOHAND ||
 317                     regs->regs[4] == ERESTARTSYS ||
 318                     regs->regs[4] == ERESTARTNOINTR) {
 319                         regs->regs[4] = regs->orig_r4;
 320                         regs->regs[7] = regs->orig_r7;
 321                         regs->cp0_epc -= 8;
 322                 }
 323
 324                 if (regs->regs[4] == ERESTART_RESTARTBLOCK) {
 325                         regs->regs[27] = __NR_restart_syscall;
 326                         regs->regs[4] = regs->orig_r4;
 327                         regs->regs[7] = regs->orig_r7;
 328                         regs->cp0_epc -= 8;
 329                 }
 330
 331                 regs->is_syscall = 0;   /* Don't deal with this again.  */
 332         }
 333
 334         /*
 335          * If there's no signal to deliver, we just put the saved sigmask
 336          * back
 337          */
 338         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 339                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 340                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 341         }
 342 }
 343
 344 /*
 345  * notification of userspace execution resumption
 346  * - triggered by the TIF_WORK_MASK flags
 347  */
 348 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 349                                 __u32 thread_info_flags)
 350 {
 351         /* deal with pending signal delivery */
 352         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 353                 do_signal(regs);
 354 }