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_rt_sigreturn(struct pt_regs *regs)
 138 {
 139         struct rt_sigframe __user *frame;
 140         sigset_t set;
 141         int sig;
 142
 143         /* Always make any pending restarted system calls return -EINTR */
 144         current->restart_block.fn = do_no_restart_syscall;
 145
 146         frame = (struct rt_sigframe __user *) regs->regs[0];
 147         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 148                 goto badframe;
 149         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
 150                 goto badframe;
 151
 152         set_current_blocked(&set);
 153
 154         sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 155         if (sig < 0)
 156                 goto badframe;
 157         else if (sig)
 158                 force_sig(sig, current);
 159
 160         if (restore_altstack(&frame->rs_uc.uc_stack))
 161                 goto badframe;
 162         regs->is_syscall = 0;
 163
 164         __asm__ __volatile__(
 165                 "mv\tr0, %0\n\t"
 166                 "la\tr8, syscall_exit\n\t"
 167                 "br\tr8\n\t"
 168                 : : "r" (regs) : "r8");
 169
 170 badframe:
 171         force_sig(SIGSEGV, current);
 172
 173         return 0;
 174 }
 175
 176 static int setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs,
 177                           sigset_t *set)
 178 {
 179         struct rt_sigframe __user *frame;
 180         int err = 0;
 181
 182         frame = get_sigframe(&ksig->ka, regs, sizeof(*frame));
 183         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 184                 return -EFAULT;
 185
 186         /*
 187          * Set up the return code ...
 188          *
 189          *         li      v0, __NR_rt_sigreturn
 190          *         syscall
 191          */
 192         err |= __put_user(0x87788000 + __NR_rt_sigreturn*2,
 193                         frame->rs_code + 0);
 194         err |= __put_user(0x80008002, frame->rs_code + 1);
 195         flush_cache_sigtramp((unsigned long) frame->rs_code);
 196
 197         err |= copy_siginfo_to_user(&frame->rs_info, &ksig->info);
 198         err |= __put_user(0, &frame->rs_uc.uc_flags);
 199         err |= __put_user(NULL, &frame->rs_uc.uc_link);
 200         err |= __save_altstack(&frame->rs_uc.uc_stack, regs->regs[0]);
 201         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 202         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 203
 204         if (err)
 205                 return -EFAULT;
 206
 207         regs->regs[0] = (unsigned long) frame;
 208         regs->regs[3] = (unsigned long) frame->rs_code;
 209         regs->regs[4] = ksig->sig;
 210         regs->regs[5] = (unsigned long) &frame->rs_info;
 211         regs->regs[6] = (unsigned long) &frame->rs_uc;
 212         regs->regs[29] = (unsigned long) ksig->ka.sa.sa_handler;
 213         regs->cp0_epc = (unsigned long) ksig->ka.sa.sa_handler;
 214
 215         return 0;
 216 }
 217
 218 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 219 {
 220         int ret;
 221
 222         if (regs->is_syscall) {
 223                 switch (regs->regs[4]) {
 224                 case ERESTART_RESTARTBLOCK:
 225                 case ERESTARTNOHAND:
 226                         regs->regs[4] = EINTR;
 227                         break;
 228                 case ERESTARTSYS:
 229                         if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
 230                                 regs->regs[4] = EINTR;
 231                                 break;
 232                         }
 233                 case ERESTARTNOINTR:
 234                         regs->regs[4] = regs->orig_r4;
 235                         regs->regs[7] = regs->orig_r7;
 236                         regs->cp0_epc -= 8;
 237                 }
 238
 239                 regs->is_syscall = 0;
 240         }
 241
 242         /*
 243          * Set up the stack frame
 244          */
 245         ret = setup_rt_frame(ksig, regs, sigmask_to_save());
 246
 247         signal_setup_done(ret, ksig, 0);
 248 }
 249
 250 static void do_signal(struct pt_regs *regs)
 251 {
 252         struct ksignal ksig;
 253
 254         /*
 255          * We want the common case to go fast, which is why we may in certain
 256          * cases get here from kernel mode. Just return without doing anything
 257          * if so.
 258          */
 259         if (!user_mode(regs))
 260                 return;
 261
 262         if (get_signal(&ksig)) {
 263                 /* Actually deliver the signal.  */
 264                 handle_signal(&ksig, regs);
 265                 return;
 266         }
 267
 268         if (regs->is_syscall) {
 269                 if (regs->regs[4] == ERESTARTNOHAND ||
 270                     regs->regs[4] == ERESTARTSYS ||
 271                     regs->regs[4] == ERESTARTNOINTR) {
 272                         regs->regs[4] = regs->orig_r4;
 273                         regs->regs[7] = regs->orig_r7;
 274                         regs->cp0_epc -= 8;
 275                 }
 276
 277                 if (regs->regs[4] == ERESTART_RESTARTBLOCK) {
 278                         regs->regs[27] = __NR_restart_syscall;
 279                         regs->regs[4] = regs->orig_r4;
 280                         regs->regs[7] = regs->orig_r7;
 281                         regs->cp0_epc -= 8;
 282                 }
 283
 284                 regs->is_syscall = 0;   /* Don't deal with this again.  */
 285         }
 286
 287         /*
 288          * If there's no signal to deliver, we just put the saved sigmask
 289          * back
 290          */
 291         restore_saved_sigmask();
 292 }
 293
 294 /*
 295  * notification of userspace execution resumption
 296  * - triggered by the TIF_WORK_MASK flags
 297  */
 298 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 299                                 __u32 thread_info_flags)
 300 {
 301         /* deal with pending signal delivery */
 302         if (thread_info_flags & _TIF_SIGPENDING)
 303                 do_signal(regs);
 304         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 305                 clear_thread_flag(TIF_NOTIFY_RESUME);
 306                 tracehook_notify_resume(regs);
 307         }
 308 }