///////////////////////////////////////////////////////////////////////////////////
// File     : sys_handler.c
// Date     : 01/04/2012
// Author   : alain greiner and joel porquet
// Copyright (c) UPMC-LIP6
///////////////////////////////////////////////////////////////////////////////////
// The sys_handler.c and sys_handler.h files are part of the GIET-VM nano-kernel.
// It define the syscall_vector[] (at the end of this file), as well as the 
// associated syscall handlers that are not related to peripherals.
// The syscall handlers for peripherals are defined in the drivers.c file.
///////////////////////////////////////////////////////////////////////////////////

#include <sys_handler.h>
#include <drivers.h>
#include <ctx_handler.h>
#include <common.h>
#include <giet_config.h>
#include <mapping_info.h>

////////////////////////////////////////////////////////////////////////////
//    Initialize the syscall vector with syscall handlers
////////////////////////////////////////////////////////////////////////////
const void * _syscall_vector[32] = {
    &_procid,              /* 0x00 */
    &_proctime,            /* 0x01 */
    &_tty_write,           /* 0x02 */
    &_tty_read,            /* 0x03 */
    &_timer_start,         /* 0x04 */
    &_timer_stop,          /* 0x05 */
    &_gcd_write,           /* 0x06 */
    &_gcd_read,            /* 0x07 */
    &_sys_ukn,             /* 0x08 */
    &_get_current_task_id, /* 0x09 */
    &_sys_ukn,             /* 0x0A */
    &_sys_ukn,             /* 0x0B */
    &_sys_ukn,             /* 0x0C */
    &_context_switch,      /* 0x0D */
    &_exit,                /* 0x0E */
    &_procs_number,        /* 0x0F */
    &_fb_sync_write,       /* 0x10 */
    &_fb_sync_read,        /* 0x11 */
    &_fb_write,            /* 0x12 */
    &_fb_read,             /* 0x13 */
    &_fb_completed,        /* 0x14 */
    &_ioc_write,           /* 0x15 */
    &_ioc_read,            /* 0x16 */
    &_ioc_completed,       /* 0x17 */
    &_sys_ukn,             /* 0x18 */
    &_sys_ukn,             /* 0x19 */
    &_vobj_get_vbase,      /* 0x1A */
    &_nic_write,           /* 0x1B */
    &_nic_read,            /* 0x1C */
    &_nic_completed,       /* 0x1D */
    &_sys_ukn,             /* 0x1E */
    &_sys_ukn,             /* 0x1F */
};

//////////////////////////////////////////////////////////////////////////////
// function executed in case of undefined syscall
//////////////////////////////////////////////////////////////////////////////
void _sys_ukn() {
    unsigned int epc;
    asm volatile("mfc0 %0, $14" : "=r" (epc));

    _puts("\n\n!!! Undefined System Call !!!\n");
    _puts("\nEPC = ");
    _putx(epc);
    _exit();
}


////////////////////////////////////////////////////////////////////////////
// _exit()
// Task suicide... after printing a death message.
////////////////////////////////////////////////////////////////////////////
void _exit() {
    unsigned int date = _proctime();
    unsigned int proc_id = _procid();
    unsigned int task_id = _get_current_task_id();

    // print death message
    _get_lock(&_tty_put_lock);
    _puts("\n[GIET] Exit task ");
    _putd(task_id);
    _puts(" on processor ");
    _putd(proc_id);
    _puts(" at cycle ");
    _putd(date);
    _puts("\n\n");
    _release_lock(&_tty_put_lock);

    // goes to sleeping state
    _set_context_slot( task_id, CTX_RUN_ID, 0);

    // deschedule
    _ctx_switch();
} 


//////////////////////////////////////////////////////////////////////////////
// _procid()
// Access CP0 and returns current processor's identifier.
// Max number or processors is 1024.
//////////////////////////////////////////////////////////////////////////////
unsigned int _procid() {
    unsigned int ret;
    asm volatile("mfc0 %0, $15, 1" : "=r" (ret));
    return (ret & 0xFFF);
}


//////////////////////////////////////////////////////////////////////////////
// _proctime()
// Access CP0 and returns current processor's elapsed clock cycles since boot.
//////////////////////////////////////////////////////////////////////////////
unsigned int _proctime() {
    unsigned int ret;
    asm volatile("mfc0 %0, $9" : "=r" (ret));
    return ret;
}


//////////////////////////////////////////////////////////////////////////////
// _procnumber()
// returns in buffer argument the number of processors in the cluster
// specified by the cluster_id argument.
//////////////////////////////////////////////////////////////////////////////
unsigned int _procs_number(unsigned int cluster_id, unsigned int * buffer) {
    mapping_header_t * header  = (mapping_header_t *) &seg_mapping_base;
    mapping_cluster_t * cluster = _get_cluster_base(header);

    if (cluster_id < header->clusters) {
        *buffer = cluster[cluster_id].procs;
        return 0;
    }
    else {
        return 1;
    }
}


int _get_vobj(char * vspace_name, char * vobj_name, unsigned int vobj_type, mapping_vobj_t ** res_vobj) {
    mapping_header_t * header = (mapping_header_t *) &seg_mapping_base;
    mapping_vspace_t * vspace = _get_vspace_base(header);
    mapping_vobj_t * vobj  = _get_vobj_base(header);

    unsigned int vspace_id;
    unsigned int vobj_id;

    // scan vspaces 
    for (vspace_id = 0; vspace_id < header->vspaces; vspace_id++) {
        if (_strncmp( vspace[vspace_id].name, vspace_name, 31) == 0) {
            // scan vobjs
            for (vobj_id = vspace[vspace_id].vobj_offset; 
                 vobj_id < (vspace[vspace_id].vobj_offset + vspace[vspace_id].vobjs); 
                 vobj_id++) {

                if (_strncmp(vobj[vobj_id].name, vobj_name, 31) == 0) {
                    if (vobj[vobj_id].type != vobj_type) {
                        _get_lock(&_tty_put_lock);
                        _puts("*** Error in _get_obj: wrong type\n");
                        _release_lock(&_tty_put_lock);
                        return -1; // wrong type
                    }
                    *res_vobj = &vobj[vobj_id];
                    return 0;
                }
            } 
        }
    } 
    _get_lock(&_tty_put_lock);
    _puts("*** Error in _get_obj: object not found\n");
    _release_lock(&_tty_put_lock);

    return -2; //not found 
}


/////////////////////////////////////////////////////////////////////////////
// _vobj_get_vbase()
// This function writes in vobj_vaddr the virtual base address of a vobj 
// identified by the (vspace_name / vobj_name ) couple.
// The vobj_type argument is here only for the purpose of checking .
// returns 0: success, else: failed.
/////////////////////////////////////////////////////////////////////////////
unsigned int _vobj_get_vbase(
        char * vspace_name,
        char * vobj_name,
        unsigned int vobj_type,
        unsigned int * vobj_vaddr) {
    mapping_vobj_t * res_vobj;
    unsigned int ret;
    if ((ret = _get_vobj(vspace_name, vobj_name, vobj_type, &res_vobj))) {
        return ret;
    }

    *vobj_vaddr = res_vobj->vaddr;
    return 0;
}


/////////////////////////////////////////////////////////////////////////////
// _vobj_get_length()
// This function writes in vobj_length the virtual base address of a vobj 
// identified by the (vspace_name / vobj_name ) couple.
// The vobj_type argument is here only for the purpose of checking .
// returns 0: success, else: failed.
/////////////////////////////////////////////////////////////////////////////
unsigned int _vobj_get_length(
        char * vspace_name, 
        char * vobj_name,
        unsigned int vobj_type, 
        unsigned int * vobj_length) {

    mapping_vobj_t * res_vobj;
    unsigned int ret;
    if ((ret = _get_vobj(vspace_name, vobj_name, vobj_type, &res_vobj))) {
        return ret;
    }

    *vobj_length = res_vobj->length;

    return 0;
}


////////////////////////////////////////////////////////////////
// _context_switch()
// This functions masks interruptions before calling _ctx_switch
// (They are usually masked when we receive a isr_switch interrupt
// because we execute isrs with interrupt masked)
////////////////////////////////////////////////////////////////
void _context_switch() {
    _it_mask();
    _ctx_switch();
    _it_restore();
}


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