arch/microblaze/kernel/signal.c

   1 /*
   2  * Signal handling
   3  *
   4  * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
   5  * Copyright (C) 2008-2009 PetaLogix
   6  * Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au>
   7  * Copyright (C) 2001 NEC Corporation
   8  * Copyright (C) 2001 Miles Bader <miles@gnu.org>
   9  * Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima
  10  * Copyright (C) 1991,1992 Linus Torvalds
  11  *
  12  * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
  13  *
  14  * This file was was derived from the sh version, arch/sh/kernel/signal.c
  15  *
  16  * This file is subject to the terms and conditions of the GNU General
  17  * Public License. See the file COPYING in the main directory of this
  18  * archive for more details.
  19  */
  20
  21 #include <linux/sched.h>
  22 #include <linux/mm.h>
  23 #include <linux/smp.h>
  24 #include <linux/kernel.h>
  25 #include <linux/signal.h>
  26 #include <linux/errno.h>
  27 #include <linux/wait.h>
  28 #include <linux/ptrace.h>
  29 #include <linux/unistd.h>
  30 #include <linux/stddef.h>
  31 #include <linux/personality.h>
  32 #include <linux/percpu.h>
  33 #include <linux/linkage.h>
  34 #include <linux/tracehook.h>
  35 #include <asm/entry.h>
  36 #include <asm/ucontext.h>
  37 #include <linux/uaccess.h>
  38 #include <asm/pgtable.h>
  39 #include <asm/pgalloc.h>
  40 #include <linux/syscalls.h>
  41 #include <asm/cacheflush.h>
  42 #include <asm/syscalls.h>
  43
  44 asmlinkage long
  45 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
  46                 struct pt_regs *regs)
  47 {
  48         return do_sigaltstack(uss, uoss, regs->r1);
  49 }
  50
  51 /*
  52  * Do a signal return; undo the signal stack.
  53  */
  54 struct sigframe {
  55         struct sigcontext sc;
  56         unsigned long extramask[_NSIG_WORDS-1];
  57         unsigned long tramp[2]; /* signal trampoline */
  58 };
  59
  60 struct rt_sigframe {
  61         struct siginfo info;
  62         struct ucontext uc;
  63         unsigned long tramp[2]; /* signal trampoline */
  64 };
  65
  66 static int restore_sigcontext(struct pt_regs *regs,
  67                                 struct sigcontext __user *sc, int *rval_p)
  68 {
  69         unsigned int err = 0;
  70
  71 #define COPY(x)         {err |= __get_user(regs->x, &sc->regs.x); }
  72         COPY(r0);
  73         COPY(r1);
  74         COPY(r2);       COPY(r3);       COPY(r4);       COPY(r5);
  75         COPY(r6);       COPY(r7);       COPY(r8);       COPY(r9);
  76         COPY(r10);      COPY(r11);      COPY(r12);      COPY(r13);
  77         COPY(r14);      COPY(r15);      COPY(r16);      COPY(r17);
  78         COPY(r18);      COPY(r19);      COPY(r20);      COPY(r21);
  79         COPY(r22);      COPY(r23);      COPY(r24);      COPY(r25);
  80         COPY(r26);      COPY(r27);      COPY(r28);      COPY(r29);
  81         COPY(r30);      COPY(r31);
  82         COPY(pc);       COPY(ear);      COPY(esr);      COPY(fsr);
  83 #undef COPY
  84
  85         *rval_p = regs->r3;
  86
  87         return err;
  88 }
  89
  90 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
  91 {
  92         struct rt_sigframe __user *frame =
  93                 (struct rt_sigframe __user *)(regs->r1);
  94
  95         sigset_t set;
  96         int rval;
  97
  98         /* Always make any pending restarted system calls return -EINTR */
  99         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 100
 101         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 102                 goto badframe;
 103
 104         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 105                 goto badframe;
 106
 107         set_current_blocked(&set);
 108
 109         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval))
 110                 goto badframe;
 111
 112         /* It is more difficult to avoid calling this function than to
 113          call it and ignore errors. */
 114         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->r1))
 115                 goto badframe;
 116
 117         return rval;
 118
 119 badframe:
 120         force_sig(SIGSEGV, current);
 121         return 0;
 122 }
 123
 124 /*
 125  * Set up a signal frame.
 126  */
 127
 128 static int
 129 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 130                 unsigned long mask)
 131 {
 132         int err = 0;
 133
 134 #define COPY(x)         {err |= __put_user(regs->x, &sc->regs.x); }
 135         COPY(r0);
 136         COPY(r1);
 137         COPY(r2);       COPY(r3);       COPY(r4);       COPY(r5);
 138         COPY(r6);       COPY(r7);       COPY(r8);       COPY(r9);
 139         COPY(r10);      COPY(r11);      COPY(r12);      COPY(r13);
 140         COPY(r14);      COPY(r15);      COPY(r16);      COPY(r17);
 141         COPY(r18);      COPY(r19);      COPY(r20);      COPY(r21);
 142         COPY(r22);      COPY(r23);      COPY(r24);      COPY(r25);
 143         COPY(r26);      COPY(r27);      COPY(r28);      COPY(r29);
 144         COPY(r30);      COPY(r31);
 145         COPY(pc);       COPY(ear);      COPY(esr);      COPY(fsr);
 146 #undef COPY
 147
 148         err |= __put_user(mask, &sc->oldmask);
 149
 150         return err;
 151 }
 152
 153 /*
 154  * Determine which stack to use..
 155  */
 156 static inline void __user *
 157 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
 158 {
 159         /* Default to using normal stack */
 160         unsigned long sp = regs->r1;
 161
 162         if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && !on_sig_stack(sp))
 163                 sp = current->sas_ss_sp + current->sas_ss_size;
 164
 165         return (void __user *)((sp - frame_size) & -8UL);
 166 }
 167
 168 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 169                         sigset_t *set, struct pt_regs *regs)
 170 {
 171         struct rt_sigframe __user *frame;
 172         int err = 0;
 173         int signal;
 174         unsigned long address = 0;
 175 #ifdef CONFIG_MMU
 176         pmd_t *pmdp;
 177         pte_t *ptep;
 178 #endif
 179
 180         frame = get_sigframe(ka, regs, sizeof(*frame));
 181
 182         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 183                 goto give_sigsegv;
 184
 185         signal = current_thread_info()->exec_domain
 186                 && current_thread_info()->exec_domain->signal_invmap
 187                 && sig < 32
 188                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 189                 : sig;
 190
 191         if (info)
 192                 err |= copy_siginfo_to_user(&frame->info, info);
 193
 194         /* Create the ucontext. */
 195         err |= __put_user(0, &frame->uc.uc_flags);
 196         err |= __put_user(NULL, &frame->uc.uc_link);
 197         err |= __put_user((void __user *)current->sas_ss_sp,
 198                         &frame->uc.uc_stack.ss_sp);
 199         err |= __put_user(sas_ss_flags(regs->r1),
 200                         &frame->uc.uc_stack.ss_flags);
 201         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 202         err |= setup_sigcontext(&frame->uc.uc_mcontext,
 203                         regs, set->sig[0]);
 204         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 205
 206         /* Set up to return from userspace. If provided, use a stub
 207          already in userspace. */
 208         /* minus 8 is offset to cater for "rtsd r15,8" */
 209         /* addi r12, r0, __NR_sigreturn */
 210         err |= __put_user(0x31800000 | __NR_rt_sigreturn ,
 211                         frame->tramp + 0);
 212         /* brki r14, 0x8 */
 213         err |= __put_user(0xb9cc0008, frame->tramp + 1);
 214
 215         /* Return from sighandler will jump to the tramp.
 216          Negative 8 offset because return is rtsd r15, 8 */
 217         regs->r15 = ((unsigned long)frame->tramp)-8;
 218
 219         address = ((unsigned long)frame->tramp);
 220 #ifdef CONFIG_MMU
 221         pmdp = pmd_offset(pud_offset(
 222                         pgd_offset(current->mm, address),
 223                                         address), address);
 224
 225         preempt_disable();
 226         ptep = pte_offset_map(pmdp, address);
 227         if (pte_present(*ptep)) {
 228                 address = (unsigned long) page_address(pte_page(*ptep));
 229                 /* MS: I need add offset in page */
 230                 address += ((unsigned long)frame->tramp) & ~PAGE_MASK;
 231                 /* MS address is virtual */
 232                 address = virt_to_phys(address);
 233                 invalidate_icache_range(address, address + 8);
 234                 flush_dcache_range(address, address + 8);
 235         }
 236         pte_unmap(ptep);
 237         preempt_enable();
 238 #else
 239         flush_icache_range(address, address + 8);
 240         flush_dcache_range(address, address + 8);
 241 #endif
 242         if (err)
 243                 goto give_sigsegv;
 244
 245         /* Set up registers for signal handler */
 246         regs->r1 = (unsigned long) frame;
 247
 248         /* Signal handler args: */
 249         regs->r5 = signal; /* arg 0: signum */
 250         regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */
 251         regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */
 252         /* Offset to handle microblaze rtid r14, 0 */
 253         regs->pc = (unsigned long)ka->sa.sa_handler;
 254
 255         set_fs(USER_DS);
 256
 257         /* the tracer may want to single-step inside the handler */
 258         if (test_thread_flag(TIF_SINGLESTEP))
 259                 ptrace_notify(SIGTRAP);
 260
 261 #ifdef DEBUG_SIG
 262         printk(KERN_INFO "SIG deliver (%s:%d): sp=%p pc=%08lx\n",
 263                 current->comm, current->pid, frame, regs->pc);
 264 #endif
 265
 266         return 0;
 267
 268 give_sigsegv:
 269         force_sigsegv(sig, current);
 270         return -EFAULT;
 271 }
 272
 273 /* Handle restarting system calls */
 274 static inline void
 275 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
 276 {
 277         switch (regs->r3) {
 278         case -ERESTART_RESTARTBLOCK:
 279         case -ERESTARTNOHAND:
 280                 if (!has_handler)
 281                         goto do_restart;
 282                 regs->r3 = -EINTR;
 283                 break;
 284         case -ERESTARTSYS:
 285                 if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
 286                         regs->r3 = -EINTR;
 287                         break;
 288         }
 289         /* fallthrough */
 290         case -ERESTARTNOINTR:
 291 do_restart:
 292                 /* offset of 4 bytes to re-execute trap (brki) instruction */
 293 #ifndef CONFIG_MMU
 294                 regs->pc -= 4;
 295 #else
 296                 /* offset of 8 bytes required = 4 for rtbd
 297                    offset, plus 4 for size of
 298                         "brki r14,8"
 299                    instruction. */
 300                 regs->pc -= 8;
 301 #endif
 302                 break;
 303         }
 304 }
 305
 306 /*
 307  * OK, we're invoking a handler
 308  */
 309
 310 static void
 311 handle_signal(unsigned long sig, struct k_sigaction *ka,
 312                 siginfo_t *info, struct pt_regs *regs)
 313 {
 314         sigset_t *oldset = sigmask_to_save();
 315         int ret;
 316
 317         /* Set up the stack frame */
 318         if (ka->sa.sa_flags & SA_SIGINFO)
 319                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
 320         else
 321                 ret = setup_rt_frame(sig, ka, NULL, oldset, regs);
 322
 323         if (ret)
 324                 return;
 325
 326         signal_delivered(sig, info, ka, regs, 0);
 327 }
 328
 329 /*
 330  * Note that 'init' is a special process: it doesn't get signals it doesn't
 331  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 332  * mistake.
 333  *
 334  * Note that we go through the signals twice: once to check the signals that
 335  * the kernel can handle, and then we build all the user-level signal handling
 336  * stack-frames in one go after that.
 337  */
 338 static void do_signal(struct pt_regs *regs, int in_syscall)
 339 {
 340         siginfo_t info;
 341         int signr;
 342         struct k_sigaction ka;
 343 #ifdef DEBUG_SIG
 344         printk(KERN_INFO "do signal: %p %d\n", regs, in_syscall);
 345         printk(KERN_INFO "do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
 346                         regs->r12, current_thread_info()->flags);
 347 #endif
 348
 349         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 350         if (signr > 0) {
 351                 /* Whee! Actually deliver the signal. */
 352                 if (in_syscall)
 353                         handle_restart(regs, &ka, 1);
 354                 handle_signal(signr, &ka, &info, regs);
 355                 return;
 356         }
 357
 358         if (in_syscall)
 359                 handle_restart(regs, NULL, 0);
 360
 361         /*
 362          * If there's no signal to deliver, we just put the saved sigmask
 363          * back.
 364          */
 365         restore_saved_sigmask();
 366 }
 367
 368 void do_notify_resume(struct pt_regs *regs, int in_syscall)
 369 {
 370         /*
 371          * We want the common case to go fast, which
 372          * is why we may in certain cases get here from
 373          * kernel mode. Just return without doing anything
 374          * if so.
 375          */
 376         if (kernel_mode(regs))
 377                 return;
 378
 379         if (test_thread_flag(TIF_SIGPENDING))
 380                 do_signal(regs, in_syscall);
 381
 382         if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
 383                 tracehook_notify_resume(regs);
 384 }