LXR linux/arch/avr32/kernel/signal.c

   1/*
   2 * Copyright (C) 2004-2006 Atmel Corporation
   3 *
   4 * Based on linux/arch/sh/kernel/signal.c
   5 *  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
   6 *  Copyright (C) 1991, 1992  Linus Torvalds
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License version 2 as
  10 * published by the Free Software Foundation.
  11 */
  12
  13#include <linux/sched.h>
  14#include <linux/mm.h>
  15#include <linux/errno.h>
  16#include <linux/ptrace.h>
  17#include <linux/unistd.h>
  18#include <linux/freezer.h>
  19#include <linux/tracehook.h>
  20
  21#include <asm/uaccess.h>
  22#include <asm/ucontext.h>
  23#include <asm/syscalls.h>
  24
  25#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  26
  27asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
  28                               struct pt_regs *regs)
  29{
  30        return do_sigaltstack(uss, uoss, regs->sp);
  31}
  32
  33struct rt_sigframe
  34{
  35        struct siginfo info;
  36        struct ucontext uc;
  37        unsigned long retcode;
  38};
  39
  40static int
  41restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
  42{
  43        int err = 0;
  44
  45#define COPY(x)         err |= __get_user(regs->x, &sc->x)
  46        COPY(sr);
  47        COPY(pc);
  48        COPY(lr);
  49        COPY(sp);
  50        COPY(r12);
  51        COPY(r11);
  52        COPY(r10);
  53        COPY(r9);
  54        COPY(r8);
  55        COPY(r7);
  56        COPY(r6);
  57        COPY(r5);
  58        COPY(r4);
  59        COPY(r3);
  60        COPY(r2);
  61        COPY(r1);
  62        COPY(r0);
  63#undef  COPY
  64
  65        /*
  66         * Don't allow anyone to pretend they're running in supervisor
  67         * mode or something...
  68         */
  69        err |= !valid_user_regs(regs);
  70
  71        return err;
  72}
  73
  74
  75asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
  76{
  77        struct rt_sigframe __user *frame;
  78        sigset_t set;
  79
  80        frame = (struct rt_sigframe __user *)regs->sp;
  81        pr_debug("SIG return: frame = %p\n", frame);
  82
  83        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  84                goto badframe;
  85
  86        if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
  87                goto badframe;
  88
  89        sigdelsetmask(&set, ~_BLOCKABLE);
  90        spin_lock_irq(&current->sighand->siglock);
  91        current->blocked = set;
  92        recalc_sigpending();
  93        spin_unlock_irq(&current->sighand->siglock);
  94
  95        if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
  96                goto badframe;
  97
  98        if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
  99                goto badframe;
 100
 101        pr_debug("Context restored: pc = %08lx, lr = %08lx, sp = %08lx\n",
 102                 regs->pc, regs->lr, regs->sp);
 103
 104        return regs->r12;
 105
 106badframe:
 107        force_sig(SIGSEGV, current);
 108        return 0;
 109}
 110
 111static int
 112setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
 113{
 114        int err = 0;
 115
 116#define COPY(x)         err |= __put_user(regs->x, &sc->x)
 117        COPY(sr);
 118        COPY(pc);
 119        COPY(lr);
 120        COPY(sp);
 121        COPY(r12);
 122        COPY(r11);
 123        COPY(r10);
 124        COPY(r9);
 125        COPY(r8);
 126        COPY(r7);
 127        COPY(r6);
 128        COPY(r5);
 129        COPY(r4);
 130        COPY(r3);
 131        COPY(r2);
 132        COPY(r1);
 133        COPY(r0);
 134#undef  COPY
 135
 136        return err;
 137}
 138
 139static inline void __user *
 140get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
 141{
 142        unsigned long sp = regs->sp;
 143
 144        if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
 145                sp = current->sas_ss_sp + current->sas_ss_size;
 146
 147        return (void __user *)((sp - framesize) & ~3);
 148}
 149
 150static int
 151setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 152               sigset_t *set, struct pt_regs *regs)
 153{
 154        struct rt_sigframe __user *frame;
 155        int err = 0;
 156
 157        frame = get_sigframe(ka, regs, sizeof(*frame));
 158        err = -EFAULT;
 159        if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 160                goto out;
 161
 162        /*
 163         * Set up the return code:
 164         *
 165         *      mov     r8, __NR_rt_sigreturn
 166         *      scall
 167         *
 168         * Note: This will blow up since we're using a non-executable
 169         * stack. Better use SA_RESTORER.
 170         */
 171#if __NR_rt_sigreturn > 127
 172# error __NR_rt_sigreturn must be < 127 to fit in a short mov
 173#endif
 174        err = __put_user(0x3008d733 | (__NR_rt_sigreturn << 20),
 175                         &frame->retcode);
 176
 177        err |= copy_siginfo_to_user(&frame->info, info);
 178
 179        /* Set up the ucontext */
 180        err |= __put_user(0, &frame->uc.uc_flags);
 181        err |= __put_user(NULL, &frame->uc.uc_link);
 182        err |= __put_user((void __user *)current->sas_ss_sp,
 183                          &frame->uc.uc_stack.ss_sp);
 184        err |= __put_user(sas_ss_flags(regs->sp),
 185                          &frame->uc.uc_stack.ss_flags);
 186        err |= __put_user(current->sas_ss_size,
 187                          &frame->uc.uc_stack.ss_size);
 188        err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
 189        err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 190
 191        if (err)
 192                goto out;
 193
 194        regs->r12 = sig;
 195        regs->r11 = (unsigned long) &frame->info;
 196        regs->r10 = (unsigned long) &frame->uc;
 197        regs->sp = (unsigned long) frame;
 198        if (ka->sa.sa_flags & SA_RESTORER)
 199                regs->lr = (unsigned long)ka->sa.sa_restorer;
 200        else {
 201                printk(KERN_NOTICE "[%s:%d] did not set SA_RESTORER\n",
 202                       current->comm, current->pid);
 203                regs->lr = (unsigned long) &frame->retcode;
 204        }
 205
 206        pr_debug("SIG deliver [%s:%d]: sig=%d sp=0x%lx pc=0x%lx->0x%p lr=0x%lx\n",
 207                 current->comm, current->pid, sig, regs->sp,
 208                 regs->pc, ka->sa.sa_handler, regs->lr);
 209
 210        regs->pc = (unsigned long) ka->sa.sa_handler;
 211
 212out:
 213        return err;
 214}
 215
 216static inline void setup_syscall_restart(struct pt_regs *regs)
 217{
 218        if (regs->r12 == -ERESTART_RESTARTBLOCK)
 219                regs->r8 = __NR_restart_syscall;
 220        else
 221                regs->r12 = regs->r12_orig;
 222        regs->pc -= 2;
 223}
 224
 225static inline void
 226handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
 227              sigset_t *oldset, struct pt_regs *regs, int syscall)
 228{
 229        int ret;
 230
 231        /*
 232         * Set up the stack frame
 233         */
 234        ret = setup_rt_frame(sig, ka, info, oldset, regs);
 235
 236        /*
 237         * Check that the resulting registers are sane
 238         */
 239        ret |= !valid_user_regs(regs);
 240
 241        /*
 242         * Block the signal if we were unsuccessful.
 243         */
 244        if (ret != 0 || !(ka->sa.sa_flags & SA_NODEFER)) {
 245                spin_lock_irq(&current->sighand->siglock);
 246                sigorsets(&current->blocked, &current->blocked,
 247                          &ka->sa.sa_mask);
 248                sigaddset(&current->blocked, sig);
 249                recalc_sigpending();
 250                spin_unlock_irq(&current->sighand->siglock);
 251        }
 252
 253        if (ret == 0)
 254                return;
 255
 256        force_sigsegv(sig, current);
 257}
 258
 259/*
 260 * Note that 'init' is a special process: it doesn't get signals it
 261 * doesn't want to handle. Thus you cannot kill init even with a
 262 * SIGKILL even by mistake.
 263 */
 264int do_signal(struct pt_regs *regs, sigset_t *oldset, int syscall)
 265{
 266        siginfo_t info;
 267        int signr;
 268        struct k_sigaction ka;
 269
 270        /*
 271         * We want the common case to go fast, which is why we may in
 272         * certain cases get here from kernel mode. Just return
 273         * without doing anything if so.
 274         */
 275        if (!user_mode(regs))
 276                return 0;
 277
 278        if (test_thread_flag(TIF_RESTORE_SIGMASK))
 279                oldset = &current->saved_sigmask;
 280        else if (!oldset)
 281                oldset = &current->blocked;
 282
 283        signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 284        if (syscall) {
 285                switch (regs->r12) {
 286                case -ERESTART_RESTARTBLOCK:
 287                case -ERESTARTNOHAND:
 288                        if (signr > 0) {
 289                                regs->r12 = -EINTR;
 290                                break;
 291                        }
 292                        /* fall through */
 293                case -ERESTARTSYS:
 294                        if (signr > 0 && !(ka.sa.sa_flags & SA_RESTART)) {
 295                                regs->r12 = -EINTR;
 296                                break;
 297                        }
 298                        /* fall through */
 299                case -ERESTARTNOINTR:
 300                        setup_syscall_restart(regs);
 301                }
 302        }
 303
 304        if (signr == 0) {
 305                /* No signal to deliver -- put the saved sigmask back */
 306                if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 307                        clear_thread_flag(TIF_RESTORE_SIGMASK);
 308                        sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 309                }
 310                return 0;
 311        }
 312
 313        handle_signal(signr, &ka, &info, oldset, regs, syscall);
 314        return 1;
 315}
 316
 317asmlinkage void do_notify_resume(struct pt_regs *regs, struct thread_info *ti)
 318{
 319        int syscall = 0;
 320
 321        if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR)
 322                syscall = 1;
 323
 324        if (ti->flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 325                do_signal(regs, &current->blocked, syscall);
 326
 327        if (ti->flags & _TIF_NOTIFY_RESUME) {
 328                clear_thread_flag(TIF_NOTIFY_RESUME);
 329                tracehook_notify_resume(regs);
 330                if (current->replacement_session_keyring)
 331                        key_replace_session_keyring();
 332        }
 333}
 334