LXR linux/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/pgalloc.h>
  39#include <linux/syscalls.h>
  40#include <asm/cacheflush.h>
  41#include <asm/syscalls.h>
  42
  43/*
  44 * Do a signal return; undo the signal stack.
  45 */
  46struct sigframe {
  47        struct sigcontext sc;
  48        unsigned long extramask[_NSIG_WORDS-1];
  49        unsigned long tramp[2]; /* signal trampoline */
  50};
  51
  52struct rt_sigframe {
  53        struct siginfo info;
  54        struct ucontext uc;
  55        unsigned long tramp[2]; /* signal trampoline */
  56};
  57
  58static int restore_sigcontext(struct pt_regs *regs,
  59                                struct sigcontext __user *sc, int *rval_p)
  60{
  61        unsigned int err = 0;
  62
  63#define COPY(x)         {err |= __get_user(regs->x, &sc->regs.x); }
  64        COPY(r0);
  65        COPY(r1);
  66        COPY(r2);       COPY(r3);       COPY(r4);       COPY(r5);
  67        COPY(r6);       COPY(r7);       COPY(r8);       COPY(r9);
  68        COPY(r10);      COPY(r11);      COPY(r12);      COPY(r13);
  69        COPY(r14);      COPY(r15);      COPY(r16);      COPY(r17);
  70        COPY(r18);      COPY(r19);      COPY(r20);      COPY(r21);
  71        COPY(r22);      COPY(r23);      COPY(r24);      COPY(r25);
  72        COPY(r26);      COPY(r27);      COPY(r28);      COPY(r29);
  73        COPY(r30);      COPY(r31);
  74        COPY(pc);       COPY(ear);      COPY(esr);      COPY(fsr);
  75#undef COPY
  76
  77        *rval_p = regs->r3;
  78
  79        return err;
  80}
  81
  82asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
  83{
  84        struct rt_sigframe __user *frame =
  85                (struct rt_sigframe __user *)(regs->r1);
  86
  87        sigset_t set;
  88        int rval;
  89
  90        /* Always make any pending restarted system calls return -EINTR */
  91        current->restart_block.fn = do_no_restart_syscall;
  92
  93        if (!access_ok(frame, sizeof(*frame)))
  94                goto badframe;
  95
  96        if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
  97                goto badframe;
  98
  99        set_current_blocked(&set);
 100
 101        if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval))
 102                goto badframe;
 103
 104        if (restore_altstack(&frame->uc.uc_stack))
 105                goto badframe;
 106
 107        return rval;
 108
 109badframe:
 110        force_sig(SIGSEGV);
 111        return 0;
 112}
 113
 114/*
 115 * Set up a signal frame.
 116 */
 117
 118static int
 119setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 120                unsigned long mask)
 121{
 122        int err = 0;
 123
 124#define COPY(x)         {err |= __put_user(regs->x, &sc->regs.x); }
 125        COPY(r0);
 126        COPY(r1);
 127        COPY(r2);       COPY(r3);       COPY(r4);       COPY(r5);
 128        COPY(r6);       COPY(r7);       COPY(r8);       COPY(r9);
 129        COPY(r10);      COPY(r11);      COPY(r12);      COPY(r13);
 130        COPY(r14);      COPY(r15);      COPY(r16);      COPY(r17);
 131        COPY(r18);      COPY(r19);      COPY(r20);      COPY(r21);
 132        COPY(r22);      COPY(r23);      COPY(r24);      COPY(r25);
 133        COPY(r26);      COPY(r27);      COPY(r28);      COPY(r29);
 134        COPY(r30);      COPY(r31);
 135        COPY(pc);       COPY(ear);      COPY(esr);      COPY(fsr);
 136#undef COPY
 137
 138        err |= __put_user(mask, &sc->oldmask);
 139
 140        return err;
 141}
 142
 143/*
 144 * Determine which stack to use..
 145 */
 146static inline void __user *
 147get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size)
 148{
 149        /* Default to using normal stack */
 150        unsigned long sp = sigsp(regs->r1, ksig);
 151
 152        return (void __user *)((sp - frame_size) & -8UL);
 153}
 154
 155static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
 156                          struct pt_regs *regs)
 157{
 158        struct rt_sigframe __user *frame;
 159        int err = 0, sig = ksig->sig;
 160        unsigned long address = 0;
 161#ifdef CONFIG_MMU
 162        pmd_t *pmdp;
 163        pte_t *ptep;
 164#endif
 165
 166        frame = get_sigframe(ksig, regs, sizeof(*frame));
 167
 168        if (!access_ok(frame, sizeof(*frame)))
 169                return -EFAULT;
 170
 171        if (ksig->ka.sa.sa_flags & SA_SIGINFO)
 172                err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 173
 174        /* Create the ucontext. */
 175        err |= __put_user(0, &frame->uc.uc_flags);
 176        err |= __put_user(NULL, &frame->uc.uc_link);
 177        err |= __save_altstack(&frame->uc.uc_stack, regs->r1);
 178        err |= setup_sigcontext(&frame->uc.uc_mcontext,
 179                        regs, set->sig[0]);
 180        err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 181
 182        /* Set up to return from userspace. If provided, use a stub
 183         already in userspace. */
 184        /* minus 8 is offset to cater for "rtsd r15,8" */
 185        /* addi r12, r0, __NR_sigreturn */
 186        err |= __put_user(0x31800000 | __NR_rt_sigreturn ,
 187                        frame->tramp + 0);
 188        /* brki r14, 0x8 */
 189        err |= __put_user(0xb9cc0008, frame->tramp + 1);
 190
 191        /* Return from sighandler will jump to the tramp.
 192         Negative 8 offset because return is rtsd r15, 8 */
 193        regs->r15 = ((unsigned long)frame->tramp)-8;
 194
 195        address = ((unsigned long)frame->tramp);
 196#ifdef CONFIG_MMU
 197        pmdp = pmd_off(current->mm, address);
 198
 199        preempt_disable();
 200        ptep = pte_offset_map(pmdp, address);
 201        if (pte_present(*ptep)) {
 202                address = (unsigned long) page_address(pte_page(*ptep));
 203                /* MS: I need add offset in page */
 204                address += ((unsigned long)frame->tramp) & ~PAGE_MASK;
 205                /* MS address is virtual */
 206                address = __virt_to_phys(address);
 207                invalidate_icache_range(address, address + 8);
 208                flush_dcache_range(address, address + 8);
 209        }
 210        pte_unmap(ptep);
 211        preempt_enable();
 212#else
 213        flush_icache_range(address, address + 8);
 214        flush_dcache_range(address, address + 8);
 215#endif
 216        if (err)
 217                return -EFAULT;
 218
 219        /* Set up registers for signal handler */
 220        regs->r1 = (unsigned long) frame;
 221
 222        /* Signal handler args: */
 223        regs->r5 = sig; /* arg 0: signum */
 224        regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */
 225        regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */
 226        /* Offset to handle microblaze rtid r14, 0 */
 227        regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
 228
 229#ifdef DEBUG_SIG
 230        pr_info("SIG deliver (%s:%d): sp=%p pc=%08lx\n",
 231                current->comm, current->pid, frame, regs->pc);
 232#endif
 233
 234        return 0;
 235}
 236
 237/* Handle restarting system calls */
 238static inline void
 239handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
 240{
 241        switch (regs->r3) {
 242        case -ERESTART_RESTARTBLOCK:
 243        case -ERESTARTNOHAND:
 244                if (!has_handler)
 245                        goto do_restart;
 246                regs->r3 = -EINTR;
 247                break;
 248        case -ERESTARTSYS:
 249                if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
 250                        regs->r3 = -EINTR;
 251                        break;
 252        }
 253        /* fallthrough */
 254        case -ERESTARTNOINTR:
 255do_restart:
 256                /* offset of 4 bytes to re-execute trap (brki) instruction */
 257                regs->pc -= 4;
 258                break;
 259        }
 260}
 261
 262/*
 263 * OK, we're invoking a handler
 264 */
 265
 266static void
 267handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 268{
 269        sigset_t *oldset = sigmask_to_save();
 270        int ret;
 271
 272        /* Set up the stack frame */
 273        ret = setup_rt_frame(ksig, oldset, regs);
 274
 275        signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
 276}
 277
 278/*
 279 * Note that 'init' is a special process: it doesn't get signals it doesn't
 280 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 281 * mistake.
 282 *
 283 * Note that we go through the signals twice: once to check the signals that
 284 * the kernel can handle, and then we build all the user-level signal handling
 285 * stack-frames in one go after that.
 286 */
 287static void do_signal(struct pt_regs *regs, int in_syscall)
 288{
 289        struct ksignal ksig;
 290
 291#ifdef DEBUG_SIG
 292        pr_info("do signal: %p %d\n", regs, in_syscall);
 293        pr_info("do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
 294                        regs->r12, current_thread_info()->flags);
 295#endif
 296
 297        if (get_signal(&ksig)) {
 298                /* Whee! Actually deliver the signal. */
 299                if (in_syscall)
 300                        handle_restart(regs, &ksig.ka, 1);
 301                handle_signal(&ksig, regs);
 302                return;
 303        }
 304
 305        if (in_syscall)
 306                handle_restart(regs, NULL, 0);
 307
 308        /*
 309         * If there's no signal to deliver, we just put the saved sigmask
 310         * back.
 311         */
 312        restore_saved_sigmask();
 313}
 314
 315asmlinkage void do_notify_resume(struct pt_regs *regs, int in_syscall)
 316{
 317        if (test_thread_flag(TIF_SIGPENDING))
 318                do_signal(regs, in_syscall);
 319
 320        if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
 321                tracehook_notify_resume(regs);
 322}
 323