/* Copyright (C) 2005 David Decotigny
    Copyright (C) 2003 Thomas Petazzoni
 
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License
    as published by the Free Software Foundation; either version 2
    of the License, or (at your option) any later version.
    
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
    
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
    USA. 
 */
 
 
 /**
  * @file crt.c
  *
  * The C RunTime environment for the basic support of SOS C user
  * programs
  */
 
 #include <hwcore/swintr.h>
 #include <string.h>
 #include "crt.h"
 
 /**
  * Starter function !
  */
 void _start() __attribute__((noreturn));
 void _start()
 {
   /* This starter function expects a main() function somewhere */
   extern int main();
 
   /* Reset the bss section */
   extern char _bbss, _ebss;
   memset(& _bbss, 0x0, (& _ebss) - (& _bbss));
 
   _sos_exit(main());
 }
 
 
 /*
  * By convention, the USER SOS programs always pass 4 arguments to the
  * kernel syscall handler: in eax/../edx. For less arguments, the
  * unused registers are filled with 0s. For more arguments, the 4th
  * syscall parameter gives the address of the array containing the
  * remaining arguments. In any case, eax corresponds to the syscall
  * IDentifier.
  */
 
 
 inline
 int _sos_syscall3(int id,
                   unsigned int arg1,
                   unsigned int arg2,
                   unsigned int arg3)
 {
   int ret;
 
   asm volatile("movl %1,%%eax \n"
                "movl %2,%%ebx \n"
                "movl %3,%%ecx \n"
                "movl %4,%%edx \n"
                "int  %5\n"
                "movl %%eax, %0"
                :"=g"(ret)
                :"g"(id),"g"(arg1),"g"(arg2),"g"(arg3)
                 ,"i"(SOS_SWINTR_SOS_SYSCALL)
                :"eax","ebx","ecx","edx");
 
   return ret;
 }
 
 
 int _sos_syscall0(int id)
 {
   return _sos_syscall3(id, 0, 0, 0);
 }
 
 
 int _sos_syscall1(int id,
              unsigned int arg1)
 {
   return _sos_syscall3(id, arg1, 0, 0);
 }
 
 
 int _sos_syscall2(int id,
                   unsigned int arg1,
                   unsigned int arg2)
 {
   return _sos_syscall3(id, arg1, arg2, 0);
 }
 
 
 int _sos_syscall4(int id,
                   unsigned int arg1,
                   unsigned int arg2,
                   unsigned int arg3,
                   unsigned int arg4)
 {
   unsigned int args[] = { arg3, arg4 };
   return _sos_syscall3(id, arg1, arg2, (unsigned)args);
 }
 
 
 int _sos_syscall5(int id,
                   unsigned int arg1,
                   unsigned int arg2,
                   unsigned int arg3,
                   unsigned int arg4,
                   unsigned int arg5)
 {
   unsigned int args[] = { arg3, arg4, arg5 };
   return _sos_syscall3(id, arg1, arg2, (unsigned)args);
 }
 
 
 int _sos_syscall6(int id,
                   unsigned int arg1,
                   unsigned int arg2,
                   unsigned int arg3,
                   unsigned int arg4,
                   unsigned int arg5,
                   unsigned int arg6)
 {
   unsigned int args[] = { arg3, arg4, arg5, arg6 };
   return _sos_syscall3(id, arg1, arg2, (unsigned)args);
 }
 
 
 int _sos_syscall7(int id,
                   unsigned int arg1,
                   unsigned int arg2,
                   unsigned int arg3,
                   unsigned int arg4,
                   unsigned int arg5,
                   unsigned int arg6,
                   unsigned int arg7)
 {
   unsigned int args[] = { arg3, arg4, arg5, arg6, arg7 };
   return _sos_syscall3(id, arg1, arg2, (unsigned)args);
 }
 
 
 int _sos_syscall8(int id,
                   unsigned int arg1,
                   unsigned int arg2,
                   unsigned int arg3,
                   unsigned int arg4,
                   unsigned int arg5,
                   unsigned int arg6,
                   unsigned int arg7,
                   unsigned int arg8)
 {
   unsigned int args[] = { arg3, arg4, arg5, arg6, arg7, arg8 };
   return _sos_syscall3(id, arg1, arg2, (unsigned)args);
 }
 
 
 void _sos_exit(int status)
 {
   _sos_syscall1(SOS_SYSCALL_ID_EXIT, (unsigned)status);
   
   /* Never reached ! */
   for ( ; ; )
     ;
 }
 
 
 int _sos_bochs_write(const char * str, unsigned length)
 {
   return _sos_syscall2(SOS_SYSCALL_ID_BOCHS_WRITE,
                        (unsigned)str,
                        length);
 }
 
 
 int _sos_fork()
 {
   return _sos_syscall0(SOS_SYSCALL_ID_FORK);
 }
 
 
 int _sos_exec(const char * prog)
 {
   return _sos_syscall2(SOS_SYSCALL_ID_EXEC, (unsigned int)prog,
                        (unsigned int)strlen(prog));
 }
 
 
 int _sos_mmap(void ** ptr_hint_addr, size_t len, int prot, int flags,
               const char *resource_path, loff_t offset)
 {
   return _sos_syscall7(SOS_SYSCALL_ID_MMAP,
                        (unsigned int)ptr_hint_addr, len, prot, flags,
                        (unsigned int)resource_path,
                        /* offs64_hi */(offset >> 32),
                        /* offs64_lo */(offset & 0xffffffff));
 }
 
 
 int _sos_munmap(void * start, size_t length)
 {
   return _sos_syscall2(SOS_SYSCALL_ID_MUNMAP,
                        (unsigned int)start,
                        length);
 }
 
 
 int _sos_mprotect(const void *addr, size_t len, int prot)
 {
   return _sos_syscall3(SOS_SYSCALL_ID_MPROTECT,
                        (unsigned int)addr,
                        len,
                        (unsigned int)prot);
 }
 
 
 int _sos_mresize(void * old_addr, size_t old_len,
                  void * *new_addr, size_t new_len,
                  unsigned long flags)
 {
   return _sos_syscall5(SOS_SYSCALL_ID_MRESIZE,
                        (unsigned int)old_addr,
                        old_len,
                        (unsigned int)new_addr,
                        new_len,
                        flags);
 }
 
 
 /**
  * Helper function that represents the start routine of a new user
  * thread created from user space (syscall new_thread). It takes 2
  * arguments that are passsed in the eax/ebx registers (@see
  * cpu_ustate_init() in hwcore/cpu_context.c): the start function of
  * the new thread (eax), the argument passed to it (ebx).
  */
 static void thread_routine()
 {
   /* NOTE: variables as named registers is a gcc extension */
   register unsigned long int reg_arg1 asm("%eax");
   register unsigned long int reg_arg2 asm("%ebx");
 
   sos_thread_func_t * func = (sos_thread_func_t*)reg_arg1;
   unsigned long int arg = reg_arg2;
 
   func(arg);
   _sos_exit(0);
 }
 
 
 int _sos_new_thread(sos_thread_func_t *func,
                     void* arg,
                     size_t stack_size)
 {
   return _sos_syscall4(SOS_SYSCALL_ID_NEW_THREAD,
                        (unsigned)thread_routine,
                        (unsigned)func, (unsigned)arg,
                        stack_size);
 }
 
 
 int _sos_nanosleep(unsigned long int sec,
                    unsigned long int nanosec)
 {
   return _sos_syscall2(SOS_SYSCALL_ID_NANOSLEEP,
                        sec, nanosec);
 }
 
 
 void * _sos_brk(void * new_top_address)
 {
   return (void*)_sos_syscall1(SOS_SYSCALL_ID_BRK,
                               (unsigned)new_top_address);
 }