arch/xtensa/kernel/syscalls.c

   1 /*
   2  * arch/xtensa/kernel/syscall.c
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  *
   8  * Copyright (C) 2001 - 2005 Tensilica Inc.
   9  * Copyright (C) 2000 Silicon Graphics, Inc.
  10  * Copyright (C) 1995 - 2000 by Ralf Baechle
  11  *
  12  * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
  13  * Marc Gauthier <marc@tensilica.com, marc@alumni.uwaterloo.ca>
  14  * Chris Zankel <chris@zankel.net>
  15  * Kevin Chea
  16  *
  17  */
  18
  19 #define DEBUG   0
  20
  21 #include <linux/linkage.h>
  22 #include <linux/mm.h>
  23 #include <linux/smp.h>
  24 #include <linux/smp_lock.h>
  25 #include <linux/mman.h>
  26 #include <linux/sched.h>
  27 #include <linux/file.h>
  28 #include <linux/slab.h>
  29 #include <linux/utsname.h>
  30 #include <linux/unistd.h>
  31 #include <linux/stringify.h>
  32 #include <linux/syscalls.h>
  33 #include <linux/sem.h>
  34 #include <linux/msg.h>
  35 #include <linux/shm.h>
  36 #include <linux/errno.h>
  37 #include <asm/ptrace.h>
  38 #include <asm/signal.h>
  39 #include <asm/uaccess.h>
  40 #include <asm/hardirq.h>
  41 #include <asm/mman.h>
  42 #include <asm/shmparam.h>
  43 #include <asm/page.h>
  44
  45 extern void do_syscall_trace(void);
  46 typedef int (*syscall_t)(void *a0,...);
  47 extern syscall_t sys_call_table[];
  48 extern unsigned char sys_narg_table[];
  49
  50 /*
  51  * sys_pipe() is the normal C calling standard for creating a pipe. It's not
  52  * the way unix traditional does this, though.
  53  */
  54
  55 int sys_pipe(int __user *userfds)
  56 {
  57         int fd[2];
  58         int error;
  59
  60         error = do_pipe(fd);
  61         if (!error) {
  62                 if (copy_to_user(userfds, fd, 2 * sizeof(int)))
  63                         error = -EFAULT;
  64         }
  65         return error;
  66 }
  67
  68 /*
  69  * Common code for old and new mmaps.
  70  */
  71 long sys_mmap(unsigned long addr, unsigned long len, unsigned long prot,
  72               unsigned long flags, unsigned long fd, unsigned long pgoff)
  73 {
  74         int error = -EBADF;
  75         struct file * file = NULL;
  76
  77         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
  78         if (!(flags & MAP_ANONYMOUS)) {
  79                 file = fget(fd);
  80                 if (!file)
  81                         goto out;
  82         }
  83
  84         down_write(&current->mm->mmap_sem);
  85         error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
  86         up_write(&current->mm->mmap_sem);
  87
  88         if (file)
  89                 fput(file);
  90 out:
  91         return error;
  92 }
  93
  94 int sys_clone(struct pt_regs *regs)
  95 {
  96         unsigned long clone_flags;
  97         unsigned long newsp;
  98         int __user *parent_tidptr, *child_tidptr;
  99         clone_flags = regs->areg[4];
 100         newsp = regs->areg[3];
 101         parent_tidptr = (int __user *)regs->areg[5];
 102         child_tidptr = (int __user *)regs->areg[6];
 103         if (!newsp)
 104                 newsp = regs->areg[1];
 105         return do_fork(clone_flags,newsp,regs,0,parent_tidptr,child_tidptr);
 106 }
 107
 108 /*
 109  * sys_execve() executes a new program.
 110  */
 111
 112 int sys_execve(struct pt_regs *regs)
 113 {
 114         int error;
 115         char * filename;
 116
 117         filename = getname((char *) (long)regs->areg[5]);
 118         error = PTR_ERR(filename);
 119         if (IS_ERR(filename))
 120                 goto out;
 121         error = do_execve(filename, (char **) (long)regs->areg[3],
 122                           (char **) (long)regs->areg[4], regs);
 123         putname(filename);
 124
 125 out:
 126         return error;
 127 }
 128
 129 int sys_uname(struct old_utsname * name)
 130 {
 131         if (name && !copy_to_user(name, &system_utsname, sizeof (*name)))
 132                 return 0;
 133         return -EFAULT;
 134 }
 135
 136 /*
 137  * Build the string table for the builtin "poor man's strace".
 138  */
 139
 140 #if DEBUG
 141 #define SYSCALL(fun, narg) #fun,
 142 static char *sfnames[] = {
 143 #include "syscalls.h"
 144 };
 145 #undef SYS
 146 #endif
 147
 148 void system_call (struct pt_regs *regs)
 149 {
 150         syscall_t syscall;
 151         unsigned long parm0, parm1, parm2, parm3, parm4, parm5;
 152         int nargs, res;
 153         unsigned int syscallnr;
 154         int ps;
 155
 156 #if DEBUG
 157         int i;
 158         unsigned long parms[6];
 159         char *sysname;
 160 #endif
 161
 162         regs->syscall = regs->areg[2];
 163
 164         do_syscall_trace();
 165
 166         /* Have to load after syscall_trace because strace
 167          * sometimes changes regs->syscall.
 168          */
 169         syscallnr = regs->syscall;
 170
 171         parm0 = parm1 = parm2 = parm3 = parm4 = parm5 = 0;
 172
 173         /* Restore interrupt level to syscall invoker's.
 174          * If this were in assembly, we wouldn't disable
 175          * interrupts in the first place:
 176          */
 177         local_save_flags (ps);
 178         local_irq_restore((ps & ~XCHAL_PS_INTLEVEL_MASK) |
 179                           (regs->ps & XCHAL_PS_INTLEVEL_MASK) );
 180
 181         if (syscallnr > __NR_Linux_syscalls) {
 182                 regs->areg[2] = -ENOSYS;
 183                 return;
 184         }
 185
 186         syscall = sys_call_table[syscallnr];
 187         nargs = sys_narg_table[syscallnr];
 188
 189         if (syscall == NULL) {
 190                 regs->areg[2] = -ENOSYS;
 191                 return;
 192         }
 193
 194         /* There shouldn't be more than six arguments in the table! */
 195
 196         if (nargs > 6)
 197                 panic("Internal error - too many syscall arguments (%d)!\n",
 198                       nargs);
 199
 200         /* Linux takes system-call arguments in registers.  The ABI
 201          * and Xtensa software conventions require the system-call
 202          * number in a2.  If an argument exists in a2, we move it to
 203          * the next available register.  Note that for improved
 204          * efficiency, we do NOT shift all parameters down one
 205          * register to maintain the original order.
 206          *
 207          * At best case (zero arguments), we just write the syscall
 208          * number to a2.  At worst case (1 to 6 arguments), we move
 209          * the argument in a2 to the next available register, then
 210          * write the syscall number to a2.
 211          *
 212          * For clarity, the following truth table enumerates all
 213          * possibilities.
 214          *
 215          * arguments    syscall number  arg0, arg1, arg2, arg3, arg4, arg5
 216          * ---------    --------------  ----------------------------------
 217          *      0             a2
 218          *      1             a2        a3
 219          *      2             a2        a4,   a3
 220          *      3             a2        a5,   a3,   a4
 221          *      4             a2        a6,   a3,   a4,   a5
 222          *      5             a2        a7,   a3,   a4,   a5,   a6
 223          *      6             a2        a8,   a3,   a4,   a5,   a6,   a7
 224          */
 225         if (nargs) {
 226                 parm0 = regs->areg[nargs+2];
 227                 parm1 = regs->areg[3];
 228                 parm2 = regs->areg[4];
 229                 parm3 = regs->areg[5];
 230                 parm4 = regs->areg[6];
 231                 parm5 = regs->areg[7];
 232         } else /* nargs == 0 */
 233                 parm0 = (unsigned long) regs;
 234
 235 #if DEBUG
 236         parms[0] = parm0;
 237         parms[1] = parm1;
 238         parms[2] = parm2;
 239         parms[3] = parm3;
 240         parms[4] = parm4;
 241         parms[5] = parm5;
 242
 243         sysname = sfnames[syscallnr];
 244         if (strncmp(sysname, "sys_", 4) == 0)
 245                 sysname = sysname + 4;
 246
 247         printk("\017SYSCALL:I:%x:%d:%s  %s(", regs->pc, current->pid,
 248                current->comm, sysname);
 249         for (i = 0; i < nargs; i++)
 250                 printk((i>0) ? ", %#lx" : "%#lx", parms[i]);
 251         printk(")\n");
 252 #endif
 253
 254         res = syscall((void *)parm0, parm1, parm2, parm3, parm4, parm5);
 255
 256 #if DEBUG
 257         printk("\017SYSCALL:O:%d:%s  %s(",current->pid, current->comm, sysname);
 258         for (i = 0; i < nargs; i++)
 259                 printk((i>0) ? ", %#lx" : "%#lx", parms[i]);
 260         if (res < 4096)
 261                 printk(") = %d\n", res);
 262         else
 263                 printk(") = %#x\n", res);
 264 #endif /* DEBUG */
 265
 266         regs->areg[2] = res;
 267         do_syscall_trace();
 268 }