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/config.h>
  22 #include <linux/linkage.h>
  23 #include <linux/mm.h>
  24 #include <linux/smp.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/mman.h>
  27 #include <linux/sched.h>
  28 #include <linux/file.h>
  29 #include <linux/slab.h>
  30 #include <linux/utsname.h>
  31 #include <linux/unistd.h>
  32 #include <linux/stringify.h>
  33 #include <linux/syscalls.h>
  34 #include <linux/sem.h>
  35 #include <linux/msg.h>
  36 #include <linux/shm.h>
  37 #include <linux/errno.h>
  38 #include <asm/ptrace.h>
  39 #include <asm/signal.h>
  40 #include <asm/uaccess.h>
  41 #include <asm/hardirq.h>
  42 #include <asm/mman.h>
  43 #include <asm/shmparam.h>
  44 #include <asm/page.h>
  45
  46 extern void do_syscall_trace(void);
  47 typedef int (*syscall_t)(void *a0,...);
  48 extern syscall_t sys_call_table[];
  49 extern unsigned char sys_narg_table[];
  50
  51 /*
  52  * sys_pipe() is the normal C calling standard for creating a pipe. It's not
  53  * the way unix traditional does this, though.
  54  */
  55
  56 int sys_pipe(int __user *userfds)
  57 {
  58         int fd[2];
  59         int error;
  60
  61         error = do_pipe(fd);
  62         if (!error) {
  63                 if (copy_to_user(userfds, fd, 2 * sizeof(int)))
  64                         error = -EFAULT;
  65         }
  66         return error;
  67 }
  68
  69 /*
  70  * Common code for old and new mmaps.
  71  */
  72 long sys_mmap(unsigned long addr, unsigned long len, unsigned long prot,
  73               unsigned long flags, unsigned long fd, unsigned long pgoff)
  74 {
  75         int error = -EBADF;
  76         struct file * file = NULL;
  77
  78         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
  79         if (!(flags & MAP_ANONYMOUS)) {
  80                 file = fget(fd);
  81                 if (!file)
  82                         goto out;
  83         }
  84
  85         down_write(&current->mm->mmap_sem);
  86         error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
  87         up_write(&current->mm->mmap_sem);
  88
  89         if (file)
  90                 fput(file);
  91 out:
  92         return error;
  93 }
  94
  95 int sys_clone(struct pt_regs *regs)
  96 {
  97         unsigned long clone_flags;
  98         unsigned long newsp;
  99         int __user *parent_tidptr, *child_tidptr;
 100         clone_flags = regs->areg[4];
 101         newsp = regs->areg[3];
 102         parent_tidptr = (int __user *)regs->areg[5];
 103         child_tidptr = (int __user *)regs->areg[6];
 104         if (!newsp)
 105                 newsp = regs->areg[1];
 106         return do_fork(clone_flags,newsp,regs,0,parent_tidptr,child_tidptr);
 107 }
 108
 109 /*
 110  * sys_execve() executes a new program.
 111  */
 112
 113 int sys_execve(struct pt_regs *regs)
 114 {
 115         int error;
 116         char * filename;
 117
 118         filename = getname((char *) (long)regs->areg[5]);
 119         error = PTR_ERR(filename);
 120         if (IS_ERR(filename))
 121                 goto out;
 122         error = do_execve(filename, (char **) (long)regs->areg[3],
 123                           (char **) (long)regs->areg[4], regs);
 124         putname(filename);
 125
 126 out:
 127         return error;
 128 }
 129
 130 int sys_uname(struct old_utsname * name)
 131 {
 132         if (name && !copy_to_user(name, &system_utsname, sizeof (*name)))
 133                 return 0;
 134         return -EFAULT;
 135 }
 136
 137 /*
 138  * Build the string table for the builtin "poor man's strace".
 139  */
 140
 141 #if DEBUG
 142 #define SYSCALL(fun, narg) #fun,
 143 static char *sfnames[] = {
 144 #include "syscalls.h"
 145 };
 146 #undef SYS
 147 #endif
 148
 149 void system_call (struct pt_regs *regs)
 150 {
 151         syscall_t syscall;
 152         unsigned long parm0, parm1, parm2, parm3, parm4, parm5;
 153         int nargs, res;
 154         unsigned int syscallnr;
 155         int ps;
 156
 157 #if DEBUG
 158         int i;
 159         unsigned long parms[6];
 160         char *sysname;
 161 #endif
 162
 163         regs->syscall = regs->areg[2];
 164
 165         do_syscall_trace();
 166
 167         /* Have to load after syscall_trace because strace
 168          * sometimes changes regs->syscall.
 169          */
 170         syscallnr = regs->syscall;
 171
 172         parm0 = parm1 = parm2 = parm3 = parm4 = parm5 = 0;
 173
 174         /* Restore interrupt level to syscall invoker's.
 175          * If this were in assembly, we wouldn't disable
 176          * interrupts in the first place:
 177          */
 178         local_save_flags (ps);
 179         local_irq_restore((ps & ~XCHAL_PS_INTLEVEL_MASK) |
 180                           (regs->ps & XCHAL_PS_INTLEVEL_MASK) );
 181
 182         if (syscallnr > __NR_Linux_syscalls) {
 183                 regs->areg[2] = -ENOSYS;
 184                 return;
 185         }
 186
 187         syscall = sys_call_table[syscallnr];
 188         nargs = sys_narg_table[syscallnr];
 189
 190         if (syscall == NULL) {
 191                 regs->areg[2] = -ENOSYS;
 192                 return;
 193         }
 194
 195         /* There shouldn't be more than six arguments in the table! */
 196
 197         if (nargs > 6)
 198                 panic("Internal error - too many syscall arguments (%d)!\n",
 199                       nargs);
 200
 201         /* Linux takes system-call arguments in registers.  The ABI
 202          * and Xtensa software conventions require the system-call
 203          * number in a2.  If an argument exists in a2, we move it to
 204          * the next available register.  Note that for improved
 205          * efficiency, we do NOT shift all parameters down one
 206          * register to maintain the original order.
 207          *
 208          * At best case (zero arguments), we just write the syscall
 209          * number to a2.  At worst case (1 to 6 arguments), we move
 210          * the argument in a2 to the next available register, then
 211          * write the syscall number to a2.
 212          *
 213          * For clarity, the following truth table enumerates all
 214          * possibilities.
 215          *
 216          * arguments    syscall number  arg0, arg1, arg2, arg3, arg4, arg5
 217          * ---------    --------------  ----------------------------------
 218          *      0             a2
 219          *      1             a2        a3
 220          *      2             a2        a4,   a3
 221          *      3             a2        a5,   a3,   a4
 222          *      4             a2        a6,   a3,   a4,   a5
 223          *      5             a2        a7,   a3,   a4,   a5,   a6
 224          *      6             a2        a8,   a3,   a4,   a5,   a6,   a7
 225          */
 226         if (nargs) {
 227                 parm0 = regs->areg[nargs+2];
 228                 parm1 = regs->areg[3];
 229                 parm2 = regs->areg[4];
 230                 parm3 = regs->areg[5];
 231                 parm4 = regs->areg[6];
 232                 parm5 = regs->areg[7];
 233         } else /* nargs == 0 */
 234                 parm0 = (unsigned long) regs;
 235
 236 #if DEBUG
 237         parms[0] = parm0;
 238         parms[1] = parm1;
 239         parms[2] = parm2;
 240         parms[3] = parm3;
 241         parms[4] = parm4;
 242         parms[5] = parm5;
 243
 244         sysname = sfnames[syscallnr];
 245         if (strncmp(sysname, "sys_", 4) == 0)
 246                 sysname = sysname + 4;
 247
 248         printk("\017SYSCALL:I:%x:%d:%s  %s(", regs->pc, current->pid,
 249                current->comm, sysname);
 250         for (i = 0; i < nargs; i++)
 251                 printk((i>0) ? ", %#lx" : "%#lx", parms[i]);
 252         printk(")\n");
 253 #endif
 254
 255         res = syscall((void *)parm0, parm1, parm2, parm3, parm4, parm5);
 256
 257 #if DEBUG
 258         printk("\017SYSCALL:O:%d:%s  %s(",current->pid, current->comm, sysname);
 259         for (i = 0; i < nargs; i++)
 260                 printk((i>0) ? ", %#lx" : "%#lx", parms[i]);
 261         if (res < 4096)
 262                 printk(") = %d\n", res);
 263         else
 264                 printk(") = %#x\n", res);
 265 #endif /* DEBUG */
 266
 267         regs->areg[2] = res;
 268         do_syscall_trace();
 269 }