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/pgtable.h>
  39#include <asm/pgalloc.h>
  40#include <linux/syscalls.h>
  41#include <asm/cacheflush.h>
  42#include <asm/syscalls.h>
  43
  44/*
  45 * Do a signal return; undo the signal stack.
  46 */
  47struct sigframe {
  48        struct sigcontext sc;
  49        unsigned long extramask[_NSIG_WORDS-1];
  50        unsigned long tramp[2]; /* signal trampoline */
  51};
  52
  53struct rt_sigframe {
  54        struct siginfo info;
  55        struct ucontext uc;
  56        unsigned long tramp[2]; /* signal trampoline */
  57};
  58
  59static int restore_sigcontext(struct pt_regs *regs,
  60                                struct sigcontext __user *sc, int *rval_p)
  61{
  62        unsigned int err = 0;
  63
  64#define COPY(x)         {err |= __get_user(regs->x, &sc->regs.x); }
  65        COPY(r0);
  66        COPY(r1);
  67        COPY(r2);       COPY(r3);       COPY(r4);       COPY(r5);
  68        COPY(r6);       COPY(r7);       COPY(r8);       COPY(r9);
  69        COPY(r10);      COPY(r11);      COPY(r12);      COPY(r13);
  70        COPY(r14);      COPY(r15);      COPY(r16);      COPY(r17);
  71        COPY(r18);      COPY(r19);      COPY(r20);      COPY(r21);
  72        COPY(r22);      COPY(r23);      COPY(r24);      COPY(r25);
  73        COPY(r26);      COPY(r27);      COPY(r28);      COPY(r29);
  74        COPY(r30);      COPY(r31);
  75        COPY(pc);       COPY(ear);      COPY(esr);      COPY(fsr);
  76#undef COPY
  77
  78        *rval_p = regs->r3;
  79
  80        return err;
  81}
  82
  83asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
  84{
  85        struct rt_sigframe __user *frame =
  86                (struct rt_sigframe __user *)(regs->r1);
  87
  88        sigset_t set;
  89        int rval;
  90
  91        /* Always make any pending restarted system calls return -EINTR */
  92        current->restart_block.fn = do_no_restart_syscall;
  93
  94        if (!access_ok(frame, sizeof(*frame)))
  95                goto badframe;
  96
  97        if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
  98                goto badframe;
  99
 100        set_current_blocked(&set);
 101
 102        if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval))
 103                goto badframe;
 104
 105        if (restore_altstack(&frame->uc.uc_stack))
 106                goto badframe;
 107
 108        return rval;
 109
 110badframe:
 111        force_sig(SIGSEGV);
 112        return 0;
 113}
 114
 115/*
 116 * Set up a signal frame.
 117 */
 118
 119static int
 120setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 121                unsigned long mask)
 122{
 123        int err = 0;
 124
 125#define COPY(x)         {err |= __put_user(regs->x, &sc->regs.x); }
 126        COPY(r0);
 127        COPY(r1);
 128        COPY(r2);       COPY(r3);       COPY(r4);       COPY(r5);
 129        COPY(r6);       COPY(r7);       COPY(r8);       COPY(r9);
 130        COPY(r10);      COPY(r11);      COPY(r12);      COPY(r13);
 131        COPY(r14);      COPY(r15);      COPY(r16);      COPY(r17);
 132        COPY(r18);      COPY(r19);      COPY(r20);      COPY(r21);
 133        COPY(r22);      COPY(r23);      COPY(r24);      COPY(r25);
 134        COPY(r26);      COPY(r27);      COPY(r28);      COPY(r29);
 135        COPY(r30);      COPY(r31);
 136        COPY(pc);       COPY(ear);      COPY(esr);      COPY(fsr);
 137#undef COPY
 138
 139        err |= __put_user(mask, &sc->oldmask);
 140
 141        return err;
 142}
 143
 144/*
 145 * Determine which stack to use..
 146 */
 147static inline void __user *
 148get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size)
 149{
 150        /* Default to using normal stack */
 151        unsigned long sp = sigsp(regs->r1, ksig);
 152
 153        return (void __user *)((sp - frame_size) & -8UL);
 154}
 155
 156static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
 157                          struct pt_regs *regs)
 158{
 159        struct rt_sigframe __user *frame;
 160        int err = 0, sig = ksig->sig;
 161        unsigned long address = 0;
 162#ifdef CONFIG_MMU
 163        pmd_t *pmdp;
 164        pte_t *ptep;
 165#endif
 166
 167        frame = get_sigframe(ksig, regs, sizeof(*frame));
 168
 169        if (!access_ok(frame, sizeof(*frame)))
 170                return -EFAULT;
 171
 172        if (ksig->ka.sa.sa_flags & SA_SIGINFO)
 173                err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 174
 175        /* Create the ucontext. */
 176        err |= __put_user(0, &frame->uc.uc_flags);
 177        err |= __put_user(NULL, &frame->uc.uc_link);
 178        err |= __save_altstack(&frame->uc.uc_stack, regs->r1);
 179        err |= setup_sigcontext(&frame->uc.uc_mcontext,
 180                        regs, set->sig[0]);
 181        err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 182
 183        /* Set up to return from userspace. If provided, use a stub
 184         already in userspace. */
 185        /* minus 8 is offset to cater for "rtsd r15,8" */
 186        /* addi r12, r0, __NR_sigreturn */
 187        err |= __put_user(0x31800000 | __NR_rt_sigreturn ,
 188                        frame->tramp + 0);
 189        /* brki r14, 0x8 */
 190        err |= __put_user(0xb9cc0008, frame->tramp + 1);
 191
 192        /* Return from sighandler will jump to the tramp.
 193         Negative 8 offset because return is rtsd r15, 8 */
 194        regs->r15 = ((unsigned long)frame->tramp)-8;
 195
 196        address = ((unsigned long)frame->tramp);
 197#ifdef CONFIG_MMU
 198        pmdp = pmd_offset(pud_offset(
 199                        pgd_offset(current->mm, address),
 200                                        address), address);
 201
 202        preempt_disable();
 203        ptep = pte_offset_map(pmdp, address);
 204        if (pte_present(*ptep)) {
 205                address = (unsigned long) page_address(pte_page(*ptep));
 206                /* MS: I need add offset in page */
 207                address += ((unsigned long)frame->tramp) & ~PAGE_MASK;
 208                /* MS address is virtual */
 209                address = __virt_to_phys(address);
 210                invalidate_icache_range(address, address + 8);
 211                flush_dcache_range(address, address + 8);
 212        }
 213        pte_unmap(ptep);
 214        preempt_enable();
 215#else
 216        flush_icache_range(address, address + 8);
 217        flush_dcache_range(address, address + 8);
 218#endif
 219        if (err)
 220                return -EFAULT;
 221
 222        /* Set up registers for signal handler */
 223        regs->r1 = (unsigned long) frame;
 224
 225        /* Signal handler args: */
 226        regs->r5 = sig; /* arg 0: signum */
 227        regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */
 228        regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */
 229        /* Offset to handle microblaze rtid r14, 0 */
 230        regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
 231
 232#ifdef DEBUG_SIG
 233        pr_info("SIG deliver (%s:%d): sp=%p pc=%08lx\n",
 234                current->comm, current->pid, frame, regs->pc);
 235#endif
 236
 237        return 0;
 238}
 239
 240/* Handle restarting system calls */
 241static inline void
 242handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
 243{
 244        switch (regs->r3) {
 245        case -ERESTART_RESTARTBLOCK:
 246        case -ERESTARTNOHAND:
 247                if (!has_handler)
 248                        goto do_restart;
 249                regs->r3 = -EINTR;
 250                break;
 251        case -ERESTARTSYS:
 252                if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
 253                        regs->r3 = -EINTR;
 254                        break;
 255        }
 256        /* fallthrough */
 257        case -ERESTARTNOINTR:
 258do_restart:
 259                /* offset of 4 bytes to re-execute trap (brki) instruction */
 260                regs->pc -= 4;
 261                break;
 262        }
 263}
 264
 265/*
 266 * OK, we're invoking a handler
 267 */
 268
 269static void
 270handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 271{
 272        sigset_t *oldset = sigmask_to_save();
 273        int ret;
 274
 275        /* Set up the stack frame */
 276        ret = setup_rt_frame(ksig, oldset, regs);
 277
 278        signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
 279}
 280
 281/*
 282 * Note that 'init' is a special process: it doesn't get signals it doesn't
 283 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 284 * mistake.
 285 *
 286 * Note that we go through the signals twice: once to check the signals that
 287 * the kernel can handle, and then we build all the user-level signal handling
 288 * stack-frames in one go after that.
 289 */
 290static void do_signal(struct pt_regs *regs, int in_syscall)
 291{
 292        struct ksignal ksig;
 293
 294#ifdef DEBUG_SIG
 295        pr_info("do signal: %p %d\n", regs, in_syscall);
 296        pr_info("do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
 297                        regs->r12, current_thread_info()->flags);
 298#endif
 299
 300        if (get_signal(&ksig)) {
 301                /* Whee! Actually deliver the signal. */
 302                if (in_syscall)
 303                        handle_restart(regs, &ksig.ka, 1);
 304                handle_signal(&ksig, regs);
 305                return;
 306        }
 307
 308        if (in_syscall)
 309                handle_restart(regs, NULL, 0);
 310
 311        /*
 312         * If there's no signal to deliver, we just put the saved sigmask
 313         * back.
 314         */
 315        restore_saved_sigmask();
 316}
 317
 318asmlinkage void do_notify_resume(struct pt_regs *regs, int in_syscall)
 319{
 320        if (test_thread_flag(TIF_SIGPENDING))
 321                do_signal(regs, in_syscall);
 322
 323        if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
 324                tracehook_notify_resume(regs);
 325}
 326