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sys_sh.c

/*
 * linux/arch/sh/kernel/sys_sh.c
 *
 * This file contains various random system calls that
 * have a non-standard calling sequence on the Linux/SuperH
 * platform.
 *
 * Taken from i386 version.
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/stat.h>
#include <linux/syscalls.h>
#include <linux/mman.h>
#include <linux/file.h>
#include <linux/utsname.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/ipc.h>
#include <asm/cacheflush.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>

/*
 * sys_pipe() is the normal C calling standard for creating
 * a pipe. It's not the way Unix traditionally does this, though.
 */
asmlinkage int sys_pipe(unsigned long r4, unsigned long r5,
      unsigned long r6, unsigned long r7,
      struct pt_regs __regs)
{
      struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
      int fd[2];
      int error;

      error = do_pipe(fd);
      if (!error) {
            regs->regs[1] = fd[1];
            return fd[0];
      }
      return error;
}

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

EXPORT_SYMBOL(shm_align_mask);

#ifdef CONFIG_MMU
/*
 * To avoid cache aliases, we map the shared page with same color.
 */
#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 mm_struct *mm = current->mm;
      struct vm_area_struct *vma;
      unsigned long start_addr;
      int do_colour_align;

      if (flags & MAP_FIXED) {
            /* 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;
      }

      if (unlikely(len > TASK_SIZE))
            return -ENOMEM;

      do_colour_align = 0;
      if (filp || (flags & MAP_SHARED))
            do_colour_align = 1;

      if (addr) {
            if (do_colour_align)
                  addr = COLOUR_ALIGN(addr, pgoff);
            else
                  addr = PAGE_ALIGN(addr);

            vma = find_vma(mm, addr);
            if (TASK_SIZE - len >= addr &&
                (!vma || addr + len <= vma->vm_start))
                  return addr;
      }

      if (len > mm->cached_hole_size) {
            start_addr = addr = mm->free_area_cache;
      } else {
              mm->cached_hole_size = 0;
            start_addr = addr = TASK_UNMAPPED_BASE;
      }

full_search:
      if (do_colour_align)
            addr = COLOUR_ALIGN(addr, pgoff);
      else
            addr = PAGE_ALIGN(mm->free_area_cache);

      for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
            /* At this point:  (!vma || addr < vma->vm_end). */
            if (unlikely(TASK_SIZE - len < addr)) {
                  /*
                   * Start a new search - just in case we missed
                   * some holes.
                   */
                  if (start_addr != TASK_UNMAPPED_BASE) {
                        start_addr = addr = TASK_UNMAPPED_BASE;
                        mm->cached_hole_size = 0;
                        goto full_search;
                  }
                  return -ENOMEM;
            }
            if (likely(!vma || addr + len <= vma->vm_start)) {
                  /*
                   * Remember the place where we stopped the search:
                   */
                  mm->free_area_cache = addr + len;
                  return addr;
            }
            if (addr + mm->cached_hole_size < vma->vm_start)
                    mm->cached_hole_size = vma->vm_start - addr;

            addr = vma->vm_end;
            if (do_colour_align)
                  addr = COLOUR_ALIGN(addr, pgoff);
      }
}
#endif /* CONFIG_MMU */

static inline long
do_mmap2(unsigned long addr, unsigned long len, unsigned long prot, 
       unsigned long flags, int fd, unsigned long pgoff)
{
      int 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;
}

asmlinkage int old_mmap(unsigned long addr, unsigned long len,
      unsigned long prot, unsigned long flags,
      int fd, unsigned long off)
{
      if (off & ~PAGE_MASK)
            return -EINVAL;
      return do_mmap2(addr, len, prot, flags, fd, off>>PAGE_SHIFT);
}

asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
      unsigned long prot, unsigned long flags,
      unsigned long fd, unsigned long pgoff)
{
      return do_mmap2(addr, len, prot, flags, fd, pgoff);
}

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

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

      if (call <= SEMCTL)
            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 *) ptr))
                        return -EFAULT;
                  return sys_semctl (first, second, third, fourth);
                  }
            default:
                  return -EINVAL;
            }

      if (call <= MSGCTL) 
            switch (call) {
            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);
            default:
                  return -EINVAL;
            }
      if (call <= SHMCTL) 
            switch (call) {
            case SHMAT:
                  switch (version) {
                  default: {
                        ulong raddr;
                        ret = do_shmat (first, (char __user *) ptr,
                                     second, &raddr);
                        if (ret)
                              return ret;
                        return put_user (raddr, (ulong __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, (ulong *) 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 -EINVAL;
            }
      
      return -EINVAL;
}

asmlinkage int sys_uname(struct old_utsname * name)
{
      int err;
      if (!name)
            return -EFAULT;
      down_read(&uts_sem);
      err = copy_to_user(name, utsname(), sizeof (*name));
      up_read(&uts_sem);
      return err?-EFAULT:0;
}

asmlinkage ssize_t sys_pread_wrapper(unsigned int fd, char * buf,
                       size_t count, long dummy, loff_t pos)
{
      return sys_pread64(fd, buf, count, pos);
}

asmlinkage ssize_t sys_pwrite_wrapper(unsigned int fd, const char * buf,
                        size_t count, long dummy, loff_t pos)
{
      return sys_pwrite64(fd, buf, count, pos);
}

asmlinkage int sys_fadvise64_64_wrapper(int fd, u32 offset0, u32 offset1,
                        u32 len0, u32 len1, int advice)
{
#ifdef  __LITTLE_ENDIAN__
      return sys_fadvise64_64(fd, (u64)offset1 << 32 | offset0,
                        (u64)len1 << 32 | len0, advice);
#else
      return sys_fadvise64_64(fd, (u64)offset0 << 32 | offset1,
                        (u64)len0 << 32 | len1, advice);
#endif
}

#if defined(CONFIG_CPU_SH2) || defined(CONFIG_CPU_SH2A)
#define SYSCALL_ARG3    "trapa #0x23"
#else
#define SYSCALL_ARG3    "trapa #0x13"
#endif

/*
 * 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 long __sc0 __asm__ ("r3") = __NR_execve;
      register long __sc4 __asm__ ("r4") = (long) filename;
      register long __sc5 __asm__ ("r5") = (long) argv;
      register long __sc6 __asm__ ("r6") = (long) envp;
      __asm__ __volatile__ (SYSCALL_ARG3 : "=z" (__sc0)     
                  : "0" (__sc0), "r" (__sc4), "r" (__sc5), "r" (__sc6)
                  : "memory");
      return __sc0;
}

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