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syscall.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1995, 1996, 1997, 2000, 2001, 05 by Ralf Baechle
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 * Copyright (C) 2001 MIPS Technologies, Inc.
 */
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/linkage.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <linux/mman.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/syscalls.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/utsname.h>
#include <linux/unistd.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/ipc.h>
#include <linux/uaccess.h>

#include <asm/asm.h>
#include <asm/branch.h>
#include <asm/cachectl.h>
#include <asm/cacheflush.h>
#include <asm/asm-offsets.h>
#include <asm/signal.h>
#include <asm/sim.h>
#include <asm/shmparam.h>
#include <asm/sysmips.h>
#include <asm/uaccess.h>

/*
 * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
 * convention.  It returns results in registers $v0 / $v1 which means there
 * is no need for it to do verify the validity of a userspace pointer
 * argument.  Historically that used to be expensive in Linux.  These days
 * the performance advantage is negligible.
 */
asmlinkage int sysm_pipe(nabi_no_regargs volatile struct pt_regs regs)
{
      int fd[2];
      int error, res;

      error = do_pipe_flags(fd, 0);
      if (error) {
            res = error;
            goto out;
      }
      regs.regs[3] = fd[1];
      res = fd[0];
out:
      return res;
}

unsigned long shm_align_mask = PAGE_SIZE - 1;   /* Sane caches */

EXPORT_SYMBOL(shm_align_mask);

#define COLOUR_ALIGN(addr,pgoff)                      \
      ((((addr) + shm_align_mask) & ~shm_align_mask) +      \
       (((pgoff) << PAGE_SHIFT) & shm_align_mask))

unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
      unsigned long len, unsigned long pgoff, unsigned long flags)
{
      struct vm_area_struct * vmm;
      int do_color_align;
      unsigned long task_size;

      task_size = STACK_TOP;

      if (len > task_size)
            return -ENOMEM;

      if (flags & MAP_FIXED) {
            /* Even MAP_FIXED mappings must reside within task_size.  */
            if (task_size - len < addr)
                  return -EINVAL;

            /*
             * We do not accept a shared mapping if it would violate
             * cache aliasing constraints.
             */
            if ((flags & MAP_SHARED) && (addr & shm_align_mask))
                  return -EINVAL;
            return addr;
      }

      do_color_align = 0;
      if (filp || (flags & MAP_SHARED))
            do_color_align = 1;
      if (addr) {
            if (do_color_align)
                  addr = COLOUR_ALIGN(addr, pgoff);
            else
                  addr = PAGE_ALIGN(addr);
            vmm = find_vma(current->mm, addr);
            if (task_size - len >= addr &&
                (!vmm || addr + len <= vmm->vm_start))
                  return addr;
      }
      addr = TASK_UNMAPPED_BASE;
      if (do_color_align)
            addr = COLOUR_ALIGN(addr, pgoff);
      else
            addr = PAGE_ALIGN(addr);

      for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
            /* At this point:  (!vmm || addr < vmm->vm_end). */
            if (task_size - len < addr)
                  return -ENOMEM;
            if (!vmm || addr + len <= vmm->vm_start)
                  return addr;
            addr = vmm->vm_end;
            if (do_color_align)
                  addr = COLOUR_ALIGN(addr, pgoff);
      }
}

/* common code for old and new mmaps */
static inline unsigned long
do_mmap2(unsigned long addr, unsigned long len, unsigned long prot,
        unsigned long flags, unsigned long fd, unsigned long pgoff)
{
      unsigned long error = -EBADF;
      struct file * file = NULL;

      flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
      if (!(flags & MAP_ANONYMOUS)) {
            file = fget(fd);
            if (!file)
                  goto out;
      }

      down_write(&current->mm->mmap_sem);
      error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
      up_write(&current->mm->mmap_sem);

      if (file)
            fput(file);
out:
      return error;
}

SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
      unsigned long, prot, unsigned long, flags, unsigned long,
      fd, off_t, offset)
{
      unsigned long result;

      result = -EINVAL;
      if (offset & ~PAGE_MASK)
            goto out;

      result = do_mmap2(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);

out:
      return result;
}

SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
      unsigned long, prot, unsigned long, flags, unsigned long, fd,
      unsigned long, pgoff)
{
      if (pgoff & (~PAGE_MASK >> 12))
            return -EINVAL;

      return do_mmap2(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
}

save_static_function(sys_fork);
static int __used noinline
_sys_fork(nabi_no_regargs struct pt_regs regs)
{
      return do_fork(SIGCHLD, regs.regs[29], &regs, 0, NULL, NULL);
}

save_static_function(sys_clone);
static int __used noinline
_sys_clone(nabi_no_regargs struct pt_regs regs)
{
      unsigned long clone_flags;
      unsigned long newsp;
      int __user *parent_tidptr, *child_tidptr;

      clone_flags = regs.regs[4];
      newsp = regs.regs[5];
      if (!newsp)
            newsp = regs.regs[29];
      parent_tidptr = (int __user *) regs.regs[6];
#ifdef CONFIG_32BIT
      /* We need to fetch the fifth argument off the stack.  */
      child_tidptr = NULL;
      if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
            int __user *__user *usp = (int __user *__user *) regs.regs[29];
            if (regs.regs[2] == __NR_syscall) {
                  if (get_user (child_tidptr, &usp[5]))
                        return -EFAULT;
            }
            else if (get_user (child_tidptr, &usp[4]))
                  return -EFAULT;
      }
#else
      child_tidptr = (int __user *) regs.regs[8];
#endif
      return do_fork(clone_flags, newsp, &regs, 0,
                     parent_tidptr, child_tidptr);
}

/*
 * sys_execve() executes a new program.
 */
asmlinkage int sys_execve(nabi_no_regargs struct pt_regs regs)
{
      int error;
      char * filename;

      filename = getname((char __user *) (long)regs.regs[4]);
      error = PTR_ERR(filename);
      if (IS_ERR(filename))
            goto out;
      error = do_execve(filename, (char __user *__user *) (long)regs.regs[5],
                        (char __user *__user *) (long)regs.regs[6], &regs);
      putname(filename);

out:
      return error;
}

/*
 * Compacrapability ...
 */
SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
{
      if (name && !copy_to_user(name, utsname(), sizeof (*name)))
            return 0;
      return -EFAULT;
}

/*
 * Compacrapability ...
 */
SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
{
      int error;

      if (!name)
            return -EFAULT;
      if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
            return -EFAULT;

      error = __copy_to_user(&name->sysname, &utsname()->sysname,
                         __OLD_UTS_LEN);
      error -= __put_user(0, name->sysname + __OLD_UTS_LEN);
      error -= __copy_to_user(&name->nodename, &utsname()->nodename,
                        __OLD_UTS_LEN);
      error -= __put_user(0, name->nodename + __OLD_UTS_LEN);
      error -= __copy_to_user(&name->release, &utsname()->release,
                        __OLD_UTS_LEN);
      error -= __put_user(0, name->release + __OLD_UTS_LEN);
      error -= __copy_to_user(&name->version, &utsname()->version,
                        __OLD_UTS_LEN);
      error -= __put_user(0, name->version + __OLD_UTS_LEN);
      error -= __copy_to_user(&name->machine, &utsname()->machine,
                        __OLD_UTS_LEN);
      error = __put_user(0, name->machine + __OLD_UTS_LEN);
      error = error ? -EFAULT : 0;

      return error;
}

SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
{
      struct thread_info *ti = task_thread_info(current);

      ti->tp_value = addr;
      if (cpu_has_userlocal)
            write_c0_userlocal(addr);

      return 0;
}

static inline int mips_atomic_set(struct pt_regs *regs,
      unsigned long addr, unsigned long new)
{
      unsigned long old, tmp;
      unsigned int err;

      if (unlikely(addr & 3))
            return -EINVAL;

      if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
            return -EINVAL;

      if (cpu_has_llsc && R10000_LLSC_WAR) {
            __asm__ __volatile__ (
            "     .set  mips3                         \n"
            "     li    %[err], 0                     \n"
            "1:   ll    %[old], (%[addr])             \n"
            "     move  %[tmp], %[new]                      \n"
            "2:   sc    %[tmp], (%[addr])             \n"
            "     beqzl %[tmp], 1b                    \n"
            "3:                                       \n"
            "     .section .fixup,\"ax\"                    \n"
            "4:   li    %[err], %[efault]             \n"
            "     j     3b                            \n"
            "     .previous                           \n"
            "     .section __ex_table,\"a\"                 \n"
            "     "STR(PTR)"  1b, 4b                        \n"
            "     "STR(PTR)"  2b, 4b                        \n"
            "     .previous                           \n"
            "     .set  mips0                         \n"
            : [old] "=&r" (old),
              [err] "=&r" (err),
              [tmp] "=&r" (tmp)
            : [addr] "r" (addr),
              [new] "r" (new),
              [efault] "i" (-EFAULT)
            : "memory");
      } else if (cpu_has_llsc) {
            __asm__ __volatile__ (
            "     .set  mips3                         \n"
            "     li    %[err], 0                     \n"
            "1:   ll    %[old], (%[addr])             \n"
            "     move  %[tmp], %[new]                      \n"
            "2:   sc    %[tmp], (%[addr])             \n"
            "     bnez  %[tmp], 4f                    \n"
            "3:                                       \n"
            "     .subsection 2                             \n"
            "4:   b     1b                            \n"
            "     .previous                           \n"
            "                                         \n"
            "     .section .fixup,\"ax\"                    \n"
            "5:   li    %[err], %[efault]             \n"
            "     j     3b                            \n"
            "     .previous                           \n"
            "     .section __ex_table,\"a\"                 \n"
            "     "STR(PTR)"  1b, 5b                        \n"
            "     "STR(PTR)"  2b, 5b                        \n"
            "     .previous                           \n"
            "     .set  mips0                         \n"
            : [old] "=&r" (old),
              [err] "=&r" (err),
              [tmp] "=&r" (tmp)
            : [addr] "r" (addr),
              [new] "r" (new),
              [efault] "i" (-EFAULT)
            : "memory");
      } else {
            do {
                  preempt_disable();
                  ll_bit = 1;
                  ll_task = current;
                  preempt_enable();

                  err = __get_user(old, (unsigned int *) addr);
                  err |= __put_user(new, (unsigned int *) addr);
                  if (err)
                        break;
                  rmb();
            } while (!ll_bit);
      }

      if (unlikely(err))
            return err;

      regs->regs[2] = old;
      regs->regs[7] = 0;      /* No error */

      /*
       * Don't let your children do this ...
       */
      __asm__ __volatile__(
      "     move  $29, %0                                   \n"
      "     j     syscall_exit                              \n"
      : /* no outputs */
      : "r" (regs));

      /* unreached.  Honestly.  */
      while (1);
}

save_static_function(sys_sysmips);
static int __used noinline
_sys_sysmips(nabi_no_regargs struct pt_regs regs)
{
      long cmd, arg1, arg2, arg3;

      cmd = regs.regs[4];
      arg1 = regs.regs[5];
      arg2 = regs.regs[6];
      arg3 = regs.regs[7];

      switch (cmd) {
      case MIPS_ATOMIC_SET:
            return mips_atomic_set(&regs, arg1, arg2);

      case MIPS_FIXADE:
            if (arg1 & ~3)
                  return -EINVAL;

            if (arg1 & 1)
                  set_thread_flag(TIF_FIXADE);
            else
                  clear_thread_flag(TIF_FIXADE);
            if (arg1 & 2)
                  set_thread_flag(TIF_LOGADE);
            else
                  clear_thread_flag(TIF_FIXADE);

            return 0;

      case FLUSH_CACHE:
            __flush_cache_all();
            return 0;
      }

      return -EINVAL;
}

/*
 * sys_ipc() is the de-multiplexer for the SysV IPC calls..
 *
 * This is really horribly ugly.
 */
SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, int, second,
      unsigned long, third, void __user *, ptr, long, fifth)
{
      int version, ret;

      version = call >> 16; /* hack for backward compatibility */
      call &= 0xffff;

      switch (call) {
      case SEMOP:
            return sys_semtimedop(first, (struct sembuf __user *)ptr,
                                  second, NULL);
      case SEMTIMEDOP:
            return sys_semtimedop(first, (struct sembuf __user *)ptr,
                              second,
                              (const struct timespec __user *)fifth);
      case SEMGET:
            return sys_semget(first, second, third);
      case SEMCTL: {
            union semun fourth;
            if (!ptr)
                  return -EINVAL;
            if (get_user(fourth.__pad, (void __user *__user *) ptr))
                  return -EFAULT;
            return sys_semctl(first, second, third, fourth);
      }

      case MSGSND:
            return sys_msgsnd(first, (struct msgbuf __user *) ptr,
                          second, third);
      case MSGRCV:
            switch (version) {
            case 0: {
                  struct ipc_kludge tmp;
                  if (!ptr)
                        return -EINVAL;

                  if (copy_from_user(&tmp,
                                 (struct ipc_kludge __user *) ptr,
                                 sizeof(tmp)))
                        return -EFAULT;
                  return sys_msgrcv(first, tmp.msgp, second,
                                tmp.msgtyp, third);
            }
            default:
                  return sys_msgrcv(first,
                                (struct msgbuf __user *) ptr,
                                second, fifth, third);
            }
      case MSGGET:
            return sys_msgget((key_t) first, second);
      case MSGCTL:
            return sys_msgctl(first, second,
                          (struct msqid_ds __user *) ptr);

      case SHMAT:
            switch (version) {
            default: {
                  unsigned long raddr;
                  ret = do_shmat(first, (char __user *) ptr, second,
                               &raddr);
                  if (ret)
                        return ret;
                  return put_user(raddr, (unsigned long __user *) third);
            }
            case 1:     /* iBCS2 emulator entry point */
                  if (!segment_eq(get_fs(), get_ds()))
                        return -EINVAL;
                  return do_shmat(first, (char __user *) ptr, second,
                                (unsigned long *) third);
            }
      case SHMDT:
            return sys_shmdt((char __user *)ptr);
      case SHMGET:
            return sys_shmget(first, second, third);
      case SHMCTL:
            return sys_shmctl(first, second,
                          (struct shmid_ds __user *) ptr);
      default:
            return -ENOSYS;
      }
}

/*
 * No implemented yet ...
 */
SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
{
      return -ENOSYS;
}

/*
 * If we ever come here the user sp is bad.  Zap the process right away.
 * Due to the bad stack signaling wouldn't work.
 */
asmlinkage void bad_stack(void)
{
      do_exit(SIGSEGV);
}

/*
 * Do a system call from kernel instead of calling sys_execve so we
 * end up with proper pt_regs.
 */
int kernel_execve(const char *filename, char *const argv[], char *const envp[])
{
      register unsigned long __a0 asm("$4") = (unsigned long) filename;
      register unsigned long __a1 asm("$5") = (unsigned long) argv;
      register unsigned long __a2 asm("$6") = (unsigned long) envp;
      register unsigned long __a3 asm("$7");
      unsigned long __v0;

      __asm__ volatile ("                             \n"
      "     .set  noreorder                     \n"
      "     li    $2, %5            # __NR_execve           \n"
      "     syscall                                   \n"
      "     move  %0, $2                              \n"
      "     .set  reorder                             \n"
      : "=&r" (__v0), "=r" (__a3)
      : "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
      : "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
        "memory");

      if (__a3 == 0)
            return __v0;

      return -__v0;
}

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