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 #include <linux/tracehook.h>
  32
  33 #include <asm/cacheflush.h>
  34 #include <asm/syscalls.h>
  35 #include <asm/ucontext.h>
  36
  37 struct rt_sigframe {
  38         u32 rs_ass[4];          /* argument save space */
  39         u32 rs_code[2];         /* signal trampoline */
  40         struct siginfo rs_info;
  41         struct ucontext rs_uc;
  42 };
  43
  44 static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
  45 {
  46         int err = 0;
  47         unsigned long reg;
  48
  49         reg = regs->cp0_epc; err |= __put_user(reg, &sc->sc_pc);
  50         err |= __put_user(regs->cp0_psr, &sc->sc_psr);
  51         err |= __put_user(regs->cp0_condition, &sc->sc_condition);
  52
  53
  54 #define save_gp_reg(i) {                                \
  55         reg = regs->regs[i];                            \
  56         err |= __put_user(reg, &sc->sc_regs[i]);        \
  57 } while (0)
  58         save_gp_reg(0); save_gp_reg(1); save_gp_reg(2);
  59         save_gp_reg(3); save_gp_reg(4); save_gp_reg(5);
  60         save_gp_reg(6); save_gp_reg(7); save_gp_reg(8);
  61         save_gp_reg(9); save_gp_reg(10); save_gp_reg(11);
  62         save_gp_reg(12); save_gp_reg(13); save_gp_reg(14);
  63         save_gp_reg(15); save_gp_reg(16); save_gp_reg(17);
  64         save_gp_reg(18); save_gp_reg(19); save_gp_reg(20);
  65         save_gp_reg(21); save_gp_reg(22); save_gp_reg(23);
  66         save_gp_reg(24); save_gp_reg(25); save_gp_reg(26);
  67         save_gp_reg(27); save_gp_reg(28); save_gp_reg(29);
  68 #undef save_gp_reg
  69
  70         reg = regs->ceh; err |= __put_user(reg, &sc->sc_mdceh);
  71         reg = regs->cel; err |= __put_user(reg, &sc->sc_mdcel);
  72         err |= __put_user(regs->cp0_ecr, &sc->sc_ecr);
  73         err |= __put_user(regs->cp0_ema, &sc->sc_ema);
  74
  75         return err;
  76 }
  77
  78 static int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
  79 {
  80         int err = 0;
  81         u32 reg;
  82
  83         err |= __get_user(regs->cp0_epc, &sc->sc_pc);
  84         err |= __get_user(regs->cp0_condition, &sc->sc_condition);
  85
  86         err |= __get_user(reg, &sc->sc_mdceh);
  87         regs->ceh = (int) reg;
  88         err |= __get_user(reg, &sc->sc_mdcel);
  89         regs->cel = (int) reg;
  90
  91         err |= __get_user(reg, &sc->sc_psr);
  92         regs->cp0_psr = (int) reg;
  93         err |= __get_user(reg, &sc->sc_ecr);
  94         regs->cp0_ecr = (int) reg;
  95         err |= __get_user(reg, &sc->sc_ema);
  96         regs->cp0_ema = (int) reg;
  97
  98 #define restore_gp_reg(i) do {                          \
  99         err |= __get_user(reg, &sc->sc_regs[i]);        \
 100         regs->regs[i] = reg;                            \
 101 } while (0)
 102         restore_gp_reg(0); restore_gp_reg(1); restore_gp_reg(2);
 103         restore_gp_reg(3); restore_gp_reg(4); restore_gp_reg(5);
 104         restore_gp_reg(6); restore_gp_reg(7); restore_gp_reg(8);
 105         restore_gp_reg(9); restore_gp_reg(10); restore_gp_reg(11);
 106         restore_gp_reg(12); restore_gp_reg(13); restore_gp_reg(14);
 107         restore_gp_reg(15); restore_gp_reg(16); restore_gp_reg(17);
 108         restore_gp_reg(18); restore_gp_reg(19); restore_gp_reg(20);
 109         restore_gp_reg(21); restore_gp_reg(22); restore_gp_reg(23);
 110         restore_gp_reg(24); restore_gp_reg(25); restore_gp_reg(26);
 111         restore_gp_reg(27); restore_gp_reg(28); restore_gp_reg(29);
 112 #undef restore_gp_reg
 113
 114         return err;
 115 }
 116
 117 /*
 118  * Determine which stack to use..
 119  */
 120 static void __user *get_sigframe(struct k_sigaction *ka,
 121                         struct pt_regs *regs, size_t frame_size)
 122 {
 123         unsigned long sp;
 124
 125         /* Default to using normal stack */
 126         sp = regs->regs[0];
 127         sp -= 32;
 128
 129         /* This is the X/Open sanctioned signal stack switching.  */
 130         if ((ka->sa.sa_flags & SA_ONSTACK) && (!on_sig_stack(sp)))
 131                 sp = current->sas_ss_sp + current->sas_ss_size;
 132
 133         return (void __user*)((sp - frame_size) & ~7);
 134 }
 135
 136 asmlinkage long
 137 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 asmlinkage long
 147 score_rt_sigreturn(struct pt_regs *regs)
 148 {
 149         struct rt_sigframe __user *frame;
 150         sigset_t set;
 151         stack_t st;
 152         int sig;
 153
 154         /* Always make any pending restarted system calls return -EINTR */
 155         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 156
 157         frame = (struct rt_sigframe __user *) regs->regs[0];
 158         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 159                 goto badframe;
 160         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
 161                 goto badframe;
 162
 163         set_current_blocked(&set);
 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         return 0;
 188 }
 189
 190 static int setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
 191                 int signr, sigset_t *set, siginfo_t *info)
 192 {
 193         struct rt_sigframe __user *frame;
 194         int err = 0;
 195
 196         frame = get_sigframe(ka, regs, sizeof(*frame));
 197         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 198                 goto give_sigsegv;
 199
 200         /*
 201          * Set up the return code ...
 202          *
 203          *         li      v0, __NR_rt_sigreturn
 204          *         syscall
 205          */
 206         err |= __put_user(0x87788000 + __NR_rt_sigreturn*2,
 207                         frame->rs_code + 0);
 208         err |= __put_user(0x80008002, frame->rs_code + 1);
 209         flush_cache_sigtramp((unsigned long) frame->rs_code);
 210
 211         err |= copy_siginfo_to_user(&frame->rs_info, info);
 212         err |= __put_user(0, &frame->rs_uc.uc_flags);
 213         err |= __put_user(NULL, &frame->rs_uc.uc_link);
 214         err |= __put_user((void __user *)current->sas_ss_sp,
 215                                 &frame->rs_uc.uc_stack.ss_sp);
 216         err |= __put_user(sas_ss_flags(regs->regs[0]),
 217                                 &frame->rs_uc.uc_stack.ss_flags);
 218         err |= __put_user(current->sas_ss_size,
 219                                 &frame->rs_uc.uc_stack.ss_size);
 220         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 221         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 222
 223         if (err)
 224                 goto give_sigsegv;
 225
 226         regs->regs[0] = (unsigned long) frame;
 227         regs->regs[3] = (unsigned long) frame->rs_code;
 228         regs->regs[4] = signr;
 229         regs->regs[5] = (unsigned long) &frame->rs_info;
 230         regs->regs[6] = (unsigned long) &frame->rs_uc;
 231         regs->regs[29] = (unsigned long) ka->sa.sa_handler;
 232         regs->cp0_epc = (unsigned long) ka->sa.sa_handler;
 233
 234         return 0;
 235
 236 give_sigsegv:
 237         force_sigsegv(signr, current);
 238         return -EFAULT;
 239 }
 240
 241 static void handle_signal(unsigned long sig, siginfo_t *info,
 242         struct k_sigaction *ka, struct pt_regs *regs)
 243 {
 244         if (regs->is_syscall) {
 245                 switch (regs->regs[4]) {
 246                 case ERESTART_RESTARTBLOCK:
 247                 case ERESTARTNOHAND:
 248                         regs->regs[4] = EINTR;
 249                         break;
 250                 case ERESTARTSYS:
 251                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 252                                 regs->regs[4] = EINTR;
 253                                 break;
 254                         }
 255                 case ERESTARTNOINTR:
 256                         regs->regs[4] = regs->orig_r4;
 257                         regs->regs[7] = regs->orig_r7;
 258                         regs->cp0_epc -= 8;
 259                 }
 260
 261                 regs->is_syscall = 0;
 262         }
 263
 264         /*
 265          * Set up the stack frame
 266          */
 267         if (setup_rt_frame(ka, regs, sig, sigmask_to_save(), info) < 0)
 268                 return;
 269
 270         signal_delivered(sig, info, ka, regs, 0);
 271 }
 272
 273 static void do_signal(struct pt_regs *regs)
 274 {
 275         struct k_sigaction ka;
 276         siginfo_t info;
 277         int signr;
 278
 279         /*
 280          * We want the common case to go fast, which is why we may in certain
 281          * cases get here from kernel mode. Just return without doing anything
 282          * if so.
 283          */
 284         if (!user_mode(regs))
 285                 return;
 286
 287         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 288         if (signr > 0) {
 289                 /* Actually deliver the signal.  */
 290                 handle_signal(signr, &info, &ka, regs);
 291                 return;
 292         }
 293
 294         if (regs->is_syscall) {
 295                 if (regs->regs[4] == ERESTARTNOHAND ||
 296                     regs->regs[4] == ERESTARTSYS ||
 297                     regs->regs[4] == ERESTARTNOINTR) {
 298                         regs->regs[4] = regs->orig_r4;
 299                         regs->regs[7] = regs->orig_r7;
 300                         regs->cp0_epc -= 8;
 301                 }
 302
 303                 if (regs->regs[4] == ERESTART_RESTARTBLOCK) {
 304                         regs->regs[27] = __NR_restart_syscall;
 305                         regs->regs[4] = regs->orig_r4;
 306                         regs->regs[7] = regs->orig_r7;
 307                         regs->cp0_epc -= 8;
 308                 }
 309
 310                 regs->is_syscall = 0;   /* Don't deal with this again.  */
 311         }
 312
 313         /*
 314          * If there's no signal to deliver, we just put the saved sigmask
 315          * back
 316          */
 317         restore_saved_sigmask();
 318 }
 319
 320 /*
 321  * notification of userspace execution resumption
 322  * - triggered by the TIF_WORK_MASK flags
 323  */
 324 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 325                                 __u32 thread_info_flags)
 326 {
 327         /* deal with pending signal delivery */
 328         if (thread_info_flags & _TIF_SIGPENDING)
 329                 do_signal(regs);
 330         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 331                 clear_thread_flag(TIF_NOTIFY_RESUME);
 332                 tracehook_notify_resume(regs);
 333         }
 334 }