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