source: soft/giet_vm/boot/boot_init.c @ 193

//////////////////////////////////////////////////////////////////////////////////
// File     : boot_init.c
// Date     : 01/04/2012
// Author   : alain greiner
// Copyright (c) UPMC-LIP6
///////////////////////////////////////////////////////////////////////////////////
// The boot_init.c file is part of the GIET-VM nano-kernel.
// This code is executed in the boot phase by proc[0] to initialize the
//  peripherals and the kernel data structures:
// - pages tables for the various vspaces
// - shedulers for processors (including the tasks contexts and interrupt vectors)
//
// The GIET-VM uses the paged virtual memory and the MAPPING_INFO binary file
// to provides two services:
// 1) classical memory protection, when several independant applications compiled
//    in different virtual spaces are executing on the same hardware platform.
// 2) data placement in NUMA architectures, when we want to control the placement 
//    of the software objects (virtual segments) on the physical memory banks.
//
// The MAPPING_INFO binary data structure must be loaded in the the seg_boot_mapping 
// segment (at address seg_mapping_base).
// This MAPPING_INFO data structure defines both the hardware architecture
// and the mapping:
// - physical segmentation of the physical address space, 
// - number of virtual spaces (one multi-task application per vspace), 
// - static placement of tasks on the processors, 
// - static placement of virtual segments (vseg) in the physical segments (pseg).
// - static placement of virtual objects (vobj) on virtual segments (vseg).
//
// The page table are statically constructed in the boot phase, and they do not 
// change during execution. The GIET uses only 4 Kbytes pages.
// As most applications use only a limited number of segments, the number of PT2s 
// actually used by a given virtual space is generally smaller than 2048, and is
// computed using the length of the vobj and stored in the boot_max_pt2 global variable,
// which is a table indexed by the vspace_id.

// defined by the (GIET_NB_PT2_MAX) configuration parameter.
// The max number of virtual spaces (GIET_NB_VSPACE_MAX) is a configuration parameter.
//
// Each page table (one page table per virtual space) is monolithic, and
// contains one PT1 and (GIET_NB_PT2_MAX) PT2s. The PT1 is addressed using the ix1 field
// (11 bits) of the VPN, and the selected PT2 is addressed using the ix2 field (9 bits).
// - PT1[2048] : a first 8K aligned array of unsigned int, indexed by the (ix1) field of VPN. 
//   Each entry in the PT1 contains a 32 bits PTD. The MSB bit PTD[31] is 
//   the PTD valid bit, and LSB bits PTD[19:0] are the 20 MSB bits of the physical base
//   address of the selected PT2.
//   The PT1 contains 2048 PTD of 4 bytes => 8K bytes.
// - PT2[1024][GIET_NB_PT2_MAX] : an array of array of unsigned int. 
//   Each PT2[1024] must be 4K aligned,  and each entry in a PT2 contains two unsigned int: 
//   the first word contains the protection flags, and the second word contains the PPN.
//   Each PT2 contains 512 PTE2 of 8bytes => 4K bytes.
// The total size of a page table is finally = 8K + (GIET_NB_PT2_MAX)*4K bytes.
////////////////////////////////////////////////////////////////////////////////////

#include <common.h>
#include <mips32_registers.h>
#include <giet_config.h>
#include <mapping_info.h>
#include <mwmr_channel.h>
#include <barrier.h>
#include <irq_handler.h>
#include <ctx_handler.h>
#include <vm_handler.h>
#include <hwr_mapping.h>

#include <stdarg.h>

#if !defined(NB_CLUSTERS) 
# error The NB_CLUSTERS value must be defined in the 'giet_config.h' file !
#endif

#if !defined(NB_PROCS_MAX) 
# error The NB_PROCS_MAX value must be defined in the 'giet_config.h' file !
#endif

#if !defined(GIET_NB_VSPACE_MAX) 
# error The GIET_NB_VSPACE_MAX value must be defined in the 'giet_config.h' file !
#endif

////////////////////////////////////////////////////////////////////////////
//      Global variables for boot code
// As both the page tables and the schedulers are physically distributed,
// these global variables are just arrays of pointers. 
////////////////////////////////////////////////////////////////////////////

// Page table pointers array
page_table_t*           boot_ptabs_vaddr[GIET_NB_VSPACE_MAX];
page_table_t*           boot_ptabs_paddr[GIET_NB_VSPACE_MAX];

// Scheduler pointers array
static_scheduler_t*     boot_schedulers_paddr[NB_CLUSTERS * NB_PROCS_MAX];

// Next free PT2 index array
unsigned int            boot_next_free_pt2[GIET_NB_VSPACE_MAX] =
                             { [0 ... GIET_NB_VSPACE_MAX-1] = 0 };

// Max PT2 index 
unsigned int            boot_max_pt2[GIET_NB_VSPACE_MAX] =
                            { [0 ... GIET_NB_VSPACE_MAX-1] = 0 };


//////////////////////////////////////////////////////////////////////////////
// boot_procid() 
//////////////////////////////////////////////////////////////////////////////
inline unsigned int boot_procid()
{
    unsigned int ret;
    asm volatile("mfc0 %0, $15, 1" : "=r"(ret));
    return (ret & 0x3FF);
}
//////////////////////////////////////////////////////////////////////////////
// boot_proctime() 
//////////////////////////////////////////////////////////////////////////////
inline unsigned int boot_proctime()
{
    unsigned int ret;
    asm volatile("mfc0 %0, $9" : "=r"(ret));
    return ret;
}
//////////////////////////////////////////////////////////////////////////////
// boot_exit() 
//////////////////////////////////////////////////////////////////////////////
void boot_exit()
{
    while(1) asm volatile("nop");
}
//////////////////////////////////////////////////////////////////////////////
// boot_eret()
// The address of this function is used to initialise the return address (RA)
// in all task contexts (when the task has never been executed.
/////////////////////////////////"/////////////////////////////////////////////
void boot_eret()
{
    asm volatile("eret");
}
//////////////////////////////////////////////////////////////////////////////
// boot_scheduler_set_context()
// This function set a context slot in a scheduler, after a temporary
// desactivation of the DTLB (because we use the scheduler physical address).
// - gpid   : global processor/scheduler index
// - ltid   : local task index
// - slotid : context slot index
// - value  : value to be written 
//////////////////////////////////////////////////////////////////////////////
inline void boot_scheduler_set_context( unsigned int gpid, 
                                        unsigned int ltid, 
                                        unsigned int slotid,
                                        unsigned int value )
{
    // get scheduler physical address
    static_scheduler_t*     psched = boot_schedulers_paddr[gpid];
    
    // get slot physical address
    unsigned int*           pslot  = &(psched->context[ltid][slotid]);

    asm volatile ( "li      $26,    0xB     \n"
                   "mtc2    $26,    $1      \n"     /* desactivate DTLB */
                   "sw      %1,     0(%0)   \n"     /* *pslot <= value  */
                   "li      $26,    0xF     \n" 
                   "mtc2    $26,    $1      \n"     /* activate DTLB    */
                   : 
                   : "r"(pslot), "r"(value) 
                   : "$26" );
}
//////////////////////////////////////////////////////////////////////////////
// boot_scheduler_set_itvector()
// This function set an interrupt vector slot in a scheduler, after a temporary
// desactivation of the DTLB (because we use the scheduler physical address).
// - gpid   : global processor/scheduler index
// - slotid : context slot index
// - value  : value to be written 
//////////////////////////////////////////////////////////////////////////////
inline void boot_scheduler_set_itvector( unsigned int gpid, 
                                         unsigned int slotid,
                                         unsigned int value )
{
    // get scheduler physical address
    static_scheduler_t*     psched = boot_schedulers_paddr[gpid];
    
    // get slot physical address
    unsigned int*           pslot  = &(psched->interrupt_vector[slotid]);

    asm volatile ( "li      $26,    0xB     \n"
                   "mtc2    $26,    $1      \n"     /* desactivate DTLB */
                   "sw      %1,     0(%0)   \n"     /* *pslot <= value  */
                   "li      $26,    0xF     \n" 
                   "mtc2    $26,    $1      \n"     /* activate DTLB    */
                   : 
                   : "r"(pslot), "r"(value) 
                   : "$26" );
}
//////////////////////////////////////////////////////////////////////////////
// boot_scheduler_get_tasks()
// This function returns the "tasks" field of a scheduler, after temporary 
// desactivation of the DTLB (because we use the scheduler physical address).
// - gpid   : global processor/scheduler index
//////////////////////////////////////////////////////////////////////////////
inline unsigned int boot_scheduler_get_tasks( unsigned int gpid )
{
    unsigned int    ret; 

    // get scheduler physical address
    static_scheduler_t*     psched = boot_schedulers_paddr[gpid];
    
    // get tasks physical address
    unsigned int*           ptasks = &(psched->tasks);

    asm volatile ( "li      $26,    0xB     \n"
                   "mtc2    $26,    $1      \n"     /* desactivate DTLB */
                   "lw      %0,     0(%1)   \n"     /* ret <= *ptasks   */
                   "li      $26,    0xF     \n" 
                   "mtc2    $26,    $1      \n"     /* activate DTLB    */
                   : "=r"(ret)
                   : "r"(ptasks) 
                   : "$26" );
    return ret;
}
//////////////////////////////////////////////////////////////////////////////
// boot_scheduler_set_tasks()
// This function set the "tasks" field of a scheduler, after temporary 
// desactivation of the DTLB (because we use the scheduler physical address).
// - gpid   : global processor/scheduler index
// - value  : value to be written 
//////////////////////////////////////////////////////////////////////////////
inline void boot_scheduler_set_tasks( unsigned int gpid,
                                      unsigned int value )
{
    // get scheduler physical address
    static_scheduler_t*     psched = boot_schedulers_paddr[gpid];
    
    // get tasks physical address
    unsigned int*           ptasks = &(psched->tasks);

    asm volatile ( "li      $26,    0xB     \n"
                   "mtc2    $26,    $1      \n"     /* desactivate DTLB */
                   "sw      %1,     0(%0)   \n"     /* *ptasks <= value */
                   "li      $26,    0xF     \n" 
                   "mtc2    $26,    $1      \n"     /* activate DTLB    */
                   : 
                   : "r"(ptasks), "r"(value) 
                   : "$26" );
}
//////////////////////////////////////////////////////////////////////////////
// boot_scheduler_set_current()
// This function set the "current" field of a scheduler, after temporary 
// desactivation of the DTLB (because we use the scheduler physical address).
// - gpid   : global processor/scheduler index
// - value  : value to be written 
//////////////////////////////////////////////////////////////////////////////
inline void boot_scheduler_set_current( unsigned int gpid,
                                 unsigned int value )
{
    // get scheduler physical address
    static_scheduler_t*     psched = boot_schedulers_paddr[gpid];
    
    // get tasks physical address
    unsigned int*           pcur   = &(psched->current);

    asm volatile ( "li      $26,    0xB     \n"
                   "mtc2    $26,    $1      \n"     /* desactivate DTLB */
                   "sw      %1,     0(%0)   \n"     /* *pcur   <= value */
                   "li      $26,    0xF     \n" 
                   "mtc2    $26,    $1      \n"     /* activate DTLB    */
                   : 
                   : "r"(pcur), "r"(value) 
                   : "$26" );
}
//////////////////////////////////////////////////////////////////////////////
// boot_set_mmu_ptpr() 
// This function set a new value for the MMU PTPR register.
//////////////////////////////////////////////////////////////////////////////
inline void boot_set_mmu_ptpr( unsigned int val )
{
    asm volatile("mtc2  %0, $0" : : "r"(val) );
}

//////////////////////////////////////////////////////////////////////////////
// boot_set_mmu_mode() 
// This function set a new value for the MMU MODE register.
//////////////////////////////////////////////////////////////////////////////
inline void boot_set_mmu_mode( unsigned int val )
{
    asm volatile("mtc2  %0, $1" : : "r"(val) );
}
////////////////////////////////////////////////////////////////////////////
// boot_puts()
// (it uses TTY0)
////////////////////////////////////////////////////////////////////////////
void boot_puts(const char *buffer) 
{
    unsigned int* tty_address = (unsigned int*)&seg_tty_base;
    unsigned int n;

    for ( n=0; n<100; n++)
    {
        if (buffer[n] == 0) break;
        tty_address[0] = (unsigned int)buffer[n];
    }
    
} 
////////////////////////////////////////////////////////////////////////////
// boot_putw() 
// (it uses TTY0)
////////////////////////////////////////////////////////////////////////////
void boot_putw(unsigned int val)
{
    static const char   HexaTab[] = "0123456789ABCDEF";
    char                buf[11];
    unsigned int        c;

    buf[0]  = '0';
    buf[1]  = 'x';
    buf[10] = 0;

    for ( c = 0 ; c < 8 ; c++ )
    { 
        buf[9-c] = HexaTab[val&0xF];
        val = val >> 4;
    }
    boot_puts(buf);
}

/////////////////////////////////////////////////////////////////////////////
//  mapping_info data structure access functions
/////////////////////////////////////////////////////////////////////////////
inline mapping_cluster_t* boot_get_cluster_base( mapping_header_t* header )
{
    return   (mapping_cluster_t*) ((char*)header +
                                  MAPPING_HEADER_SIZE);
}
/////////////////////////////////////////////////////////////////////////////
inline mapping_pseg_t* boot_get_pseg_base( mapping_header_t* header )
{
    return   (mapping_pseg_t*)    ((char*)header +
                                  MAPPING_HEADER_SIZE +
                                  MAPPING_CLUSTER_SIZE*header->clusters);
}
/////////////////////////////////////////////////////////////////////////////
inline mapping_vspace_t* boot_get_vspace_base( mapping_header_t* header )
{
    return   (mapping_vspace_t*)  ((char*)header +
                                  MAPPING_HEADER_SIZE +
                                  MAPPING_CLUSTER_SIZE*header->clusters +
                                  MAPPING_PSEG_SIZE*header->psegs);
}
/////////////////////////////////////////////////////////////////////////////
inline mapping_vseg_t* boot_get_vseg_base( mapping_header_t* header )
{
    return   (mapping_vseg_t*)    ((char*)header +
                                  MAPPING_HEADER_SIZE +
                                  MAPPING_CLUSTER_SIZE*header->clusters +
                                  MAPPING_PSEG_SIZE*header->psegs +
                                  MAPPING_VSPACE_SIZE*header->vspaces);
}
/////////////////////////////////////////////////////////////////////////////
inline mapping_vobj_t* boot_get_vobj_base( mapping_header_t* header )
{
    return   (mapping_vobj_t*)   ((char*)header +
                                  MAPPING_HEADER_SIZE +
                                  MAPPING_CLUSTER_SIZE*header->clusters +
                                  MAPPING_PSEG_SIZE*header->psegs +
                                  MAPPING_VSPACE_SIZE*header->vspaces +
                                  MAPPING_VSEG_SIZE*header->vsegs );
}
/////////////////////////////////////////////////////////////////////////////
inline mapping_task_t* boot_get_task_base( mapping_header_t* header )
{
    return   (mapping_task_t*)    ((char*)header +
                                  MAPPING_HEADER_SIZE +
                                  MAPPING_CLUSTER_SIZE*header->clusters +
                                  MAPPING_PSEG_SIZE*header->psegs +
                                  MAPPING_VSPACE_SIZE*header->vspaces +
                                  MAPPING_VSEG_SIZE*header->vsegs +
                                  MAPPING_VOBJ_SIZE*header->vobjs );
}
/////////////////////////////////////////////////////////////////////////////
inline mapping_proc_t* boot_get_proc_base( mapping_header_t* header )
{
    return   (mapping_proc_t*)    ((char*)header +
                                  MAPPING_HEADER_SIZE +
                                  MAPPING_CLUSTER_SIZE*header->clusters +
                                  MAPPING_PSEG_SIZE*header->psegs +
                                  MAPPING_VSPACE_SIZE*header->vspaces +
                                  MAPPING_VSEG_SIZE*header->vsegs +
                                  MAPPING_VOBJ_SIZE*header->vobjs +
                                  MAPPING_TASK_SIZE*header->tasks );
}
/////////////////////////////////////////////////////////////////////////////
inline mapping_irq_t* boot_get_irq_base( mapping_header_t* header )
{
    return   (mapping_irq_t*)     ((char*)header +
                                  MAPPING_HEADER_SIZE +
                                  MAPPING_CLUSTER_SIZE*header->clusters +
                                  MAPPING_PSEG_SIZE*header->psegs +
                                  MAPPING_VSPACE_SIZE*header->vspaces +
                                  MAPPING_VSEG_SIZE*header->vsegs +
                                  MAPPING_VOBJ_SIZE*header->vobjs +
                                  MAPPING_TASK_SIZE*header->tasks +
                                  MAPPING_PROC_SIZE*header->procs );
}
/////////////////////////////////////////////////////////////////////////////
inline mapping_coproc_t* boot_get_coproc_base( mapping_header_t* header )
{
    return  (mapping_coproc_t*)   ((char*)header +
                                  MAPPING_HEADER_SIZE +
                                  MAPPING_CLUSTER_SIZE*header->clusters +
                                  MAPPING_PSEG_SIZE*header->psegs +
                                  MAPPING_VSPACE_SIZE*header->vspaces +
                                  MAPPING_VOBJ_SIZE*header->vobjs +
                                  MAPPING_VSEG_SIZE*header->vsegs +
                                  MAPPING_TASK_SIZE*header->tasks +
                                  MAPPING_PROC_SIZE*header->procs +
                                  MAPPING_IRQ_SIZE*header->irqs );
}
///////////////////////////////////////////////////////////////////////////////////
inline mapping_cp_port_t* boot_get_cp_port_base( mapping_header_t* header )
{
    return (mapping_cp_port_t*)   ((char*)header +
                                  MAPPING_HEADER_SIZE +
                                  MAPPING_CLUSTER_SIZE*header->clusters +
                                  MAPPING_PSEG_SIZE*header->psegs +
                                  MAPPING_VSPACE_SIZE*header->vspaces +
                                  MAPPING_VOBJ_SIZE*header->vobjs +
                                  MAPPING_VSEG_SIZE*header->vsegs +
                                  MAPPING_TASK_SIZE*header->tasks +
                                  MAPPING_PROC_SIZE*header->procs +
                                  MAPPING_IRQ_SIZE*header->irqs +
                                  MAPPING_COPROC_SIZE*header->coprocs );
}
///////////////////////////////////////////////////////////////////////////////////
inline mapping_periph_t* boot_get_periph_base( mapping_header_t* header )
{
    return (mapping_periph_t*)    ((char*)header +
                                  MAPPING_HEADER_SIZE +
                                  MAPPING_CLUSTER_SIZE*header->clusters +
                                  MAPPING_PSEG_SIZE*header->psegs +
                                  MAPPING_VSPACE_SIZE*header->vspaces +
                                  MAPPING_VOBJ_SIZE*header->vobjs +
                                  MAPPING_VSEG_SIZE*header->vsegs +
                                  MAPPING_TASK_SIZE*header->tasks +
                                  MAPPING_PROC_SIZE*header->procs +
                                  MAPPING_IRQ_SIZE*header->irqs +
                                  MAPPING_COPROC_SIZE*header->coprocs +
                                  MAPPING_CP_PORT_SIZE*header->cp_ports );
}

//////////////////////////////////////////////////////////////////////////////
//     boot_pseg_get() 
// This function returns the pointer on a physical segment
// identified  by the pseg index.
//////////////////////////////////////////////////////////////////////////////
mapping_pseg_t* boot_pseg_get( unsigned int seg_id)
{
    mapping_header_t* header = (mapping_header_t*)&seg_mapping_base;
    mapping_pseg_t*   pseg   = boot_get_pseg_base( header );

    // checking argument
    if ( seg_id >= header->psegs )
    {
        boot_puts("\n[BOOT ERROR] : seg_id argument too large\n");
        boot_puts("               in function boot_pseg_get()\n");
        boot_exit();
    }

    return &pseg[seg_id];                                    
} // end boot_pseg_get()

//////////////////////////////////////////////////////////////////////////////
// boot_add_pte() 
// This function registers a new PTE in the page table pointed
// by the vspace_id argument, and updates both PT1 and PT2.
// A new PT2 is used when required.
// As the set of PT2s is implemented as a fixed size array (no dynamic 
// allocation), this function checks a possible overflow of the PT2 array.
//
// The global parameter is a boolean indicating wether a global vseg is
// being mapped.
//////////////////////////////////////////////////////////////////////////////
void boot_add_pte( unsigned int    vspace_id,    
                   unsigned int    vpn,           
                   unsigned int    flags,
                   unsigned int    ppn )
{
    unsigned int    ix1;
    unsigned int    ix2;
    unsigned int    ptba;       // PT2 base address
    unsigned int    pt2_id;     // PT2 index
    unsigned int*   pt_flags;   // pointer on the pte_flags = &PT2[2*ix2]    
    unsigned int*   pt_ppn;     // pointer on the pte_ppn   = &PT2[2*ix2+1]  

    ix1 = vpn >> 9;             // 11 bits
    ix2 = vpn  & 0x1FF;         //  9 bits

    // check that the boot_max_pt2[vspace_id] has been set
    unsigned int max_pt2   = boot_max_pt2[vspace_id];

    if(max_pt2 == 0)
    {
        boot_puts("Unfound page table for vspace ");
        boot_putw(vspace_id);
        boot_puts("\n");
        boot_exit();
    }

    // get page table physical address
    page_table_t* pt = boot_ptabs_paddr[vspace_id];

    if ( (pt->pt1[ix1] & PTE_V) == 0 )   // set a new PTD in PT1 
    {
        pt2_id = boot_next_free_pt2[vspace_id];
        if ( pt2_id == max_pt2 )
        {
            boot_puts("\n[BOOT ERROR] in boot_add_pte() function\n");
            boot_puts("the length of the ptab vobj is too small\n"); 
            boot_exit();
        }
        else
        {
            ptba = (unsigned int)pt + PT1_SIZE + PT2_SIZE*pt2_id;
            pt->pt1[ix1] = PTE_V | PTE_T | (ptba >> 12);    
            boot_next_free_pt2[vspace_id] = pt2_id + 1;
        }
    }
    else
    {
        ptba = pt->pt1[ix1] << 12;
    }

    // set PTE2 after checking double mapping error
    pt_flags = (unsigned int*)(ptba + 8*ix2);
    pt_ppn   = (unsigned int*)(ptba + 8*ix2 + 4);

    if ( ( *pt_flags & PTE_V) != 0 )    // page already mapped
    {
        boot_puts("\n[BOOT ERROR] in boot_add_pte() function\n");
        boot_puts("page already mapped\n");
        boot_exit();
    }

    // set PTE2
    *pt_flags = flags;
    *pt_ppn   = ppn;

} // end boot_add_pte()
                
/////////////////////////////////////////////////////////////////////
// This function build the page table for a given vspace. 
// The physical base addresses for all vsegs (global and private)
// must have been previously computed.
// It initializes the MWMR channels.
/////////////////////////////////////////////////////////////////////
void boot_vspace_pt_build( unsigned int vspace_id )
{
    unsigned int    vseg_id;
    unsigned int    npages;
    unsigned int    ppn;
    unsigned int    vpn;
    unsigned int    flags;
    unsigned int    page_id;

    mapping_header_t*  header = (mapping_header_t*)&seg_mapping_base;  
    mapping_vspace_t*  vspace = boot_get_vspace_base( header );
    mapping_vseg_t*    vseg   = boot_get_vseg_base( header );
    
    // private segments
    for ( vseg_id = vspace[vspace_id].vseg_offset ; 
          vseg_id < (vspace[vspace_id].vseg_offset + vspace[vspace_id].vsegs) ; 
          vseg_id++ )
    {
        vpn       = vseg[vseg_id].vbase >> 12;
        ppn       = vseg[vseg_id].pbase >> 12;
        npages    = vseg[vseg_id].length >> 12;
        if ( (vseg[vseg_id].length & 0xFFF) != 0 ) npages++;

        flags = PTE_V;
        if ( vseg[vseg_id].mode & C_MODE_MASK )  flags = flags | PTE_C;
        if ( vseg[vseg_id].mode & X_MODE_MASK )  flags = flags | PTE_X;
        if ( vseg[vseg_id].mode & W_MODE_MASK )  flags = flags | PTE_W;
        if ( vseg[vseg_id].mode & U_MODE_MASK )  flags = flags | PTE_U;

#if BOOT_DEBUG_PT
boot_puts( vseg[vseg_id].name );
boot_puts(" : flags = ");
boot_putw( flags );
boot_puts(" / npages = ");
boot_putw( npages );
boot_puts(" / pbase = ");
boot_putw( vseg[vseg_id].pbase );
boot_puts("\n");
#endif        
        // loop on 4K pages
        for ( page_id = 0 ; page_id < npages ; page_id++ )
        {
            boot_add_pte( vspace_id,
                          vpn,
                          flags,
                          ppn );
            vpn++;
            ppn++;
        }
    }

    // global segments
    for ( vseg_id = 0 ; vseg_id < header->globals ; vseg_id++ )
    {
        vpn       = vseg[vseg_id].vbase >> 12;
        ppn       = vseg[vseg_id].pbase >> 12;
        npages    = vseg[vseg_id].length >> 12;
        if ( (vseg[vseg_id].length & 0xFFF) != 0 ) npages++;

        flags = PTE_V;
        if ( vseg[vseg_id].mode & C_MODE_MASK )  flags = flags | PTE_C;
        if ( vseg[vseg_id].mode & X_MODE_MASK )  flags = flags | PTE_X;
        if ( vseg[vseg_id].mode & W_MODE_MASK )  flags = flags | PTE_W;
        if ( vseg[vseg_id].mode & U_MODE_MASK )  flags = flags | PTE_U;

#if BOOT_DEBUG_PT
boot_puts( vseg[vseg_id].name );
boot_puts(" / flags = ");
boot_putw( flags );
boot_puts(" / npages = ");
boot_putw( npages );
boot_puts(" / pbase = ");
boot_putw( vseg[vseg_id].pbase );
boot_puts("\n");
#endif        
        // loop on 4K pages
        for ( page_id = 0 ; page_id < npages ; page_id++ )
        {
            boot_add_pte( vspace_id,
                          vpn,
                          flags,
                          ppn );
            vpn++;
            ppn++;
        }
    }

} // end boot_vspace_pt_build()

///////////////////////////////////////////////////////////////////////////
// Align the value "toAlign" to the required alignement indicated by
// alignPow2 ( the logarithme of 2 the alignement).
///////////////////////////////////////////////////////////////////////////
unsigned int align_to( unsigned int toAlign, 
                       unsigned int alignPow2)
{
    unsigned int    mask = (1 << alignPow2) - 1;
    return ((toAlign + mask ) & ~mask ); 
}

///////////////////////////////////////////////////////////////////////////
// This function compute the physical base address for a vseg
// as specified in the mapping info data structure.
// It updates the pbase and the length fields of the vseg.
// It updates the pbase and vbase fields of all vobjs in the vseg.
// It updates the next_base field of the pseg, and checks overflow.
// It updates the boot_ptabs_paddr[] and boot_ptabs_vaddr[] arrays. 
// It is a global vseg if vspace_id = (-1). 
///////////////////////////////////////////////////////////////////////////
void boot_vseg_map( mapping_vseg_t*     vseg, 
                    unsigned int        vspace_id ) 
{
    unsigned int        vobj_id;
    unsigned int        cur_vaddr;
    unsigned int        cur_paddr;
    mapping_header_t*   header = (mapping_header_t*)&seg_mapping_base;  
    mapping_vobj_t*     vobj   = boot_get_vobj_base( header );
 
    // get physical segment pointer
    mapping_pseg_t*  pseg = boot_pseg_get( vseg->psegid );

    // compute vseg physical base address
    if ( vseg->ident != 0 )            // identity mapping required
    {
         vseg->pbase = vseg->vbase;
    }
    else                                // unconstrained mapping
    {
        vseg->pbase = pseg->next_base;

        // test alignment constraint
        if ( vobj[vseg->vobj_offset].align )
        {
            vseg->pbase = align_to( vseg->pbase, vobj[vseg->vobj_offset].align );
        }
    }
    
    // loop on vobjs contained in vseg to :
    // (1) computes the length of the vseg,
    // (2) initialise the vaddr and paddr fields of all vobjs,
    // (3) initialise the page table pointers arrays 

    cur_vaddr = vseg->vbase;
    cur_paddr = vseg->pbase;

    for( vobj_id = vseg->vobj_offset; 
         vobj_id < (vseg->vobj_offset + vseg->vobjs); 
         vobj_id++)
    {
        if ( vobj[vobj_id].align )
        {
            cur_paddr = align_to(cur_paddr, vobj[vobj_id].align);
        }

        // set vaddr/paddr for current vobj
        vobj[vobj_id].vaddr = cur_vaddr;        
        vobj[vobj_id].paddr = cur_paddr;  
      
        // initialise boot_ptabs_vaddr[] if current vobj is a PTAB
        if ( vobj[vobj_id].type == VOBJ_TYPE_PTAB )
        {
            if(vspace_id == ((unsigned int) -1))    // global vseg
            {
                boot_puts( "\n[BOOT ERROR] in boot_vseg_map() function: " );
                boot_puts( "a PTAB vobj cannot be global" );
                boot_exit();
            }

            // we need at least one PT2 => ( boot_max_pt2[vspace_id] >= 1)
            if(vobj[vobj_id].length < (PT1_SIZE + PT2_SIZE) ) 
            {
                boot_puts( "\n[BOOT ERROR] in boot_vseg_map() function, " );
                boot_puts("PTAB too small, minumum size is: ");
                boot_putw( PT1_SIZE + PT2_SIZE);
                boot_exit();
            }

            // register both physical and virtual page table address
            boot_ptabs_vaddr[vspace_id] = (page_table_t*)vobj[vobj_id].vaddr;
            boot_ptabs_paddr[vspace_id] = (page_table_t*)vobj[vobj_id].paddr;

            /* computing the number of second level page */
            boot_max_pt2[vspace_id] = (vobj[vobj_id].length - PT1_SIZE) / PT2_SIZE;
        }

        // set next vaddr/paddr
        cur_vaddr += vobj[vobj_id].length;
        cur_paddr += vobj[vobj_id].length; 

    } // end for vobjs
    
    //set the vseg length
    vseg->length = align_to( (cur_paddr - vseg->pbase), 12);

    // checking pseg overflow
    if ( (vseg->pbase < pseg->base) || 
         ((vseg->pbase + vseg->length) > (pseg->base + pseg->length)) )
    {
        boot_puts("\n[BOOT ERROR] in boot_vseg_map() function\n");
        boot_puts("impossible mapping for virtual segment: ");
        boot_puts( vseg->name ); 
        boot_puts("\n"); 
        boot_puts("vseg pbase = ");
        boot_putw( vseg->pbase ); 
        boot_puts("\n"); 
        boot_puts("vseg length = ");
        boot_putw( vseg->length ); 
        boot_puts("\n"); 
        boot_puts("pseg pbase = ");
        boot_putw( pseg->base ); 
        boot_puts("\n"); 
        boot_puts("pseg length = ");
        boot_putw( pseg->length ); 
        boot_puts("\n"); 
        boot_exit();
    }

    // set the next_base field in vseg
    if ( vseg->ident == 0 )
        pseg->next_base = vseg->pbase + vseg->length;

#if BOOT_DEBUG_PT
boot_puts( vseg->name );
boot_puts(" : len = ");
boot_putw( vseg->length );
boot_puts(" / vbase = ");
boot_putw( vseg->vbase );
boot_puts(" / pbase = ");
boot_putw( vseg->pbase );
boot_puts("\n");
#endif  

} // end boot_vseg_map()

/////////////////////////////////////////////////////////////////////
// This function checks consistence beween the  mapping_info data 
// structure (soft), and the giet_config file (hard).
/////////////////////////////////////////////////////////////////////
void boot_check_mapping()
{
    mapping_header_t*   header  = (mapping_header_t*)&seg_mapping_base;  
    mapping_cluster_t*  cluster = boot_get_cluster_base( header ); 
    mapping_periph_t*   periph  = boot_get_periph_base( header );

    unsigned int periph_id;
    unsigned int cluster_id;
    unsigned int channels;

    // checking mapping availability
    if ( header->signature != IN_MAPPING_SIGNATURE )
    {
        boot_puts("\n[BOOT ERROR] Illegal mapping signature: ");
        boot_putw(header->signature);
        boot_puts("\n");
        boot_exit();
    }

    // checking NB_CLUSTERS
    if ( header->clusters != NB_CLUSTERS )
    {
        boot_puts("\n[BOOT ERROR] Incoherent NB_CLUSTERS");
        boot_puts("\n             - In giet_config,  value = ");
        boot_putw ( NB_CLUSTERS );
        boot_puts("\n             - In mapping_info, value = ");
        boot_putw ( header->clusters );
        boot_puts("\n");
        boot_exit();
    }

    // checking NB_PROC_MAX
    for ( cluster_id = 0 ; cluster_id < NB_CLUSTERS ; cluster_id++ )
    {
        if ( cluster[cluster_id].procs > NB_PROCS_MAX )
        {
            boot_puts("\n[BOOT ERROR] too much processors in cluster ");
            boot_putw( cluster_id );
            boot_puts("\n             - In giet_config, NB_PROCS_MAX = ");
            boot_putw ( NB_PROCS_MAX );
            boot_puts("\n             - In mapping_info, nprocs = ");
            boot_putw ( cluster[cluster_id].procs );
            boot_puts("\n");
            boot_exit();
        }
    }

    if ( header->clusters != NB_CLUSTERS )
    {
        boot_puts("\n[BOOT ERROR] Incoherent NB_CLUSTERS");
        boot_puts("\n             - In giet_config,  value = ");
        boot_putw ( NB_CLUSTERS );
        boot_puts("\n             - In mapping_info, value = ");
        boot_putw ( header->clusters );
        boot_puts("\n");
        boot_exit();
    }



    // checking number of virtual spaces
    if ( header->vspaces > GIET_NB_VSPACE_MAX )
    {
        boot_puts("\n[BOOT ERROR] : number of vspaces > GIET_NB_VSPACE_MAX\n");
        boot_puts("\n");
        boot_exit();
    }

    // checking TTY number
    cluster_id = header->tty_clusterid;
    for ( periph_id = cluster[cluster_id].periph_offset ;
          periph_id < cluster[cluster_id].periph_offset + cluster[cluster_id].periphs ;
          periph_id++ )
    {
        if ( periph[periph_id].type == PERIPH_TYPE_TTY ) 
        {
            channels = periph[periph_id].channels;
            break;
        }
                
    } 
    if ( channels > NB_TTYS )
    {
        boot_puts("\n[BOOT ERROR] Incoherent NB_TTYS");
        boot_puts("\n             - In giet_config,  value = ");
        boot_putw ( NB_TTYS );
        boot_puts("\n             - In mapping_info, value = ");
        boot_putw ( channels );
        boot_puts("\n");
        boot_exit();
    }

    // TODO same type of checking for TIMERS, DMAS, NIC channels

} // end boot_check_mapping()

/////////////////////////////////////////////////////////////////////
// This function initialises the physical pages table allocators 
// for all psegs (i.e. next_base field of the pseg). 
// In each cluster containing processors, it reserve space for the
// schedulers in the first RAM pseg found (4k bytes per processor). 
/////////////////////////////////////////////////////////////////////
void boot_psegs_init()
{
    mapping_header_t*   header  = (mapping_header_t*)&seg_mapping_base;  

    mapping_cluster_t*  cluster = boot_get_cluster_base( header ); 
    mapping_pseg_t*     pseg    = boot_get_pseg_base( header ); 

    unsigned int cluster_id;
    unsigned int pseg_id;
    unsigned int found;

#if BOOT_DEBUG_PT
boot_puts("\n[BOOT DEBUG] ****** psegs allocators nitialisation ******\n");
#endif

    for ( cluster_id = 0 ; cluster_id < header->clusters ; cluster_id++ )
    {
        if ( cluster[cluster_id].procs > NB_PROCS_MAX )
        {
            boot_puts("\n[BOOT ERROR] The number of processors in cluster ");
            boot_putw( cluster_id );
            boot_puts(" is larger than NB_PROCS_MAX \n");
            boot_exit();
        }

        found    = 0;

        for ( pseg_id = cluster[cluster_id].pseg_offset ;
              pseg_id < cluster[cluster_id].pseg_offset + cluster[cluster_id].psegs ;
              pseg_id++ )
        {
            unsigned int free = pseg[pseg_id].base;

            if ( (pseg[pseg_id].type == PSEG_TYPE_RAM) && (found == 0) )
            {
                free = free + (cluster[cluster_id].procs << 12);
                found = 1;
            }
            pseg[pseg_id].next_base = free;

#if BOOT_DEBUG_PT
boot_puts("cluster ");
boot_putw(cluster_id);
boot_puts(" / pseg ");
boot_puts(pseg[pseg_id].name);
boot_puts(" : next_base = ");
boot_putw(pseg[pseg_id].next_base);
boot_puts("\n");
#endif
        }
    }
} // end boot_pseg_init()

/////////////////////////////////////////////////////////////////////
// This function builds the page tables for all virtual spaces 
// defined in the mapping_info data structure.
// For each virtual space, it maps both the global vsegs 
// (replicated in all vspaces), and the private vsegs.
/////////////////////////////////////////////////////////////////////
void boot_pt_init()
{
    mapping_header_t*   header = (mapping_header_t*)&seg_mapping_base;  

    mapping_vspace_t*   vspace = boot_get_vspace_base( header );     
    mapping_vseg_t*     vseg   = boot_get_vseg_base( header );

    unsigned int        vspace_id;  
    unsigned int        vseg_id;

#if BOOT_DEBUG_PT
boot_puts("\n[BOOT DEBUG] ****** mapping global vsegs ******\n");
#endif
            
    // step 1 : first loop on virtual spaces to map global vsegs
    for ( vseg_id = 0 ; vseg_id < header->globals ; vseg_id++ )
    {
        boot_vseg_map( &vseg[vseg_id], ((unsigned int)(-1)) );
    }

    // step 2 : loop on virtual vspaces to map private vsegs
    for ( vspace_id = 0 ; vspace_id < header->vspaces ; vspace_id++ )
    {

#if BOOT_DEBUG_PT
boot_puts("\n[BOOT DEBUG] ****** mapping private vsegs in vspace ");
boot_puts(vspace[vspace_id].name);
boot_puts(" ******\n");
#endif
            
        for ( vseg_id = vspace[vspace_id].vseg_offset ; 
              vseg_id < (vspace[vspace_id].vseg_offset + vspace[vspace_id].vsegs) ; 
              vseg_id++ )
        {
            boot_vseg_map( &vseg[vseg_id], vspace_id ); 
        }
    } 

    // step 3 : loop on the vspaces to build the page tables
    for ( vspace_id = 0 ; vspace_id < header->vspaces ; vspace_id++ )
    {

#if BOOT_DEBUG_PT
boot_puts("\n[BOOT DEBUG] ****** building page table for vspace ");
boot_puts(vspace[vspace_id].name);
boot_puts(" ******\n");
#endif
            
        boot_vspace_pt_build( vspace_id );

#if BOOT_DEBUG_PT
boot_puts("\n>>> page table physical address = ");
boot_putw((unsigned int)boot_ptabs_paddr[vspace_id]);
boot_puts(", page table number of PT2 = ");
boot_putw((unsigned int)boot_max_pt2[vspace_id]);
boot_puts("\n");
#endif
    } 
} // end boot_pt_init()

///////////////////////////////////////////////////////////////////////////////
// This function initializes all private vobjs defined in the vspaces,
// such as mwmr channels, barriers and locks, because these vobjs 
// are not known, and not initialised by the compiler.
///////////////////////////////////////////////////////////////////////////////
void boot_vobjs_init()
{
    mapping_header_t*   header  = (mapping_header_t*)&seg_mapping_base;  
    mapping_vspace_t*   vspace  = boot_get_vspace_base( header );     
    mapping_vobj_t*     vobj    = boot_get_vobj_base( header );

    unsigned int        vspace_id;  
    unsigned int        vobj_id;

    // loop on the vspaces 
    for ( vspace_id = 0 ; vspace_id < header->vspaces ; vspace_id++ )
    {

#if BOOT_DEBUG_VOBJS
boot_puts("\n[BOOT DEBUG] ****** vobjs initialisation in vspace "); 
boot_puts(vspace[vspace_id].name);
boot_puts(" ******\n");
#endif
        // We must set the PTPR depending on the vspace, because the addresses 
        // of mwmmr channels, barriers and locks are defined in virtual space.
        boot_set_mmu_ptpr( (unsigned int)boot_ptabs_paddr[vspace_id] >> 13 );

        unsigned int ptab_found = 0;

        // loop on the vobjs
            for(vobj_id= vspace[vspace_id].vobj_offset; 
                        vobj_id < (vspace[vspace_id].vobj_offset+ vspace[vspace_id].vobjs);
                        vobj_id++)
            {
            switch( vobj[vobj_id].type )
            {
                case VOBJ_TYPE_MWMR:    // storage capacity is (vobj.length/4 - 5) words
                        {
                    mwmr_channel_t* mwmr = (mwmr_channel_t*)(vobj[vobj_id].vaddr);
                    mwmr->ptw   = 0;
                    mwmr->ptr   = 0;
                    mwmr->sts   = 0;
                    mwmr->width = vobj[vobj_id].init;
                    mwmr->depth = (vobj[vobj_id].length>>2) - 6;
                    mwmr->lock  = 0;
#if BOOT_DEBUG_VOBJS
boot_puts("MWMR    : ");
boot_puts( vobj[vobj_id].name);
boot_puts(" / depth = ");
boot_putw( mwmr->depth );
boot_puts(" / width = ");
boot_putw( mwmr->width );
boot_puts("\n");
#endif
                    break;
                }
                case VOBJ_TYPE_ELF:             // initialisation done by the loader 
                {
#if BOOT_DEBUG_VOBJS
boot_puts("ELF     : ");
boot_puts( vobj[vobj_id].name);
boot_puts(" / length = ");
boot_putw( vobj[vobj_id].length ); 
boot_puts("\n");
#endif
                    break;
                }
                case VOBJ_TYPE_BLOB:            // initialisation done by the loader 
                {
#if BOOT_DEBUG_VOBJS
boot_puts("BLOB     : ");
boot_puts( vobj[vobj_id].name);
boot_puts(" / length = ");
boot_putw( vobj[vobj_id].length ); 
boot_puts("\n");
#endif
                    break;
                }
                case VOBJ_TYPE_BARRIER: // init is the number of participants
                {
                    giet_barrier_t* barrier = (giet_barrier_t*)(vobj[vobj_id].vaddr);
                    barrier->count = 0;
                    barrier->init  = vobj[vobj_id].init;
#if BOOT_DEBUG_VOBJS
boot_puts("BARRIER : ");
boot_puts( vobj[vobj_id].name);
boot_puts(" / init_value = ");
boot_putw( barrier->init );
boot_puts("\n");
#endif
                    break;
                }
                case VOBJ_TYPE_LOCK:    // init is "not taken"
                {
                    unsigned int* lock = (unsigned int*)(vobj[vobj_id].vaddr);
                    *lock = 0;
#if BOOT_DEBUG_VOBJS
boot_puts("LOCK    : ");
boot_puts( vobj[vobj_id].name);
boot_puts("\n");
#endif
                    break;
                }
                case VOBJ_TYPE_BUFFER:  // nothing to initialise
                {
#if BOOT_DEBUG_VOBJS
boot_puts("BUFFER  : ");
boot_puts( vobj[vobj_id].name);
boot_puts(" / length = ");
boot_putw( vobj[vobj_id].length ); 
boot_puts("\n");
#endif
                    break;
                }
                case VOBJ_TYPE_PTAB:    // nothing to initialise
                {
                    ptab_found = 1;
#if BOOT_DEBUG_VOBJS
boot_puts("PTAB    : ");
boot_puts( vobj[vobj_id].name);
boot_puts(" / length = ");
boot_putw( vobj[vobj_id].length ); 
boot_puts("\n");
#endif
                    break;
                }
                default:
                {
                    boot_puts("\n[INIT ERROR] illegal vobj of name ");
                    boot_puts(vobj->name);
                    boot_puts(" / in vspace = ");
                    boot_puts(vobj->name);
                    boot_puts("\n ");
                    boot_exit();
                }
            } // end switch type
        } // end loop on vobjs
        if( ptab_found == 0 )
        {
            boot_puts("\n[INIT ERROR] Missing PTAB for vspace ");
            boot_putw( vspace_id );
            boot_exit();
        }
    } // end loop on vspaces
} // end boot_vobjs_init()

////////////////////////////////////////////////////////////////////////////////
// This function intializes the periherals and coprocessors, as specified
// tsuch as the IOB component
// (I/O bridge, containing the IOMMU, the IOC (external disk controller), 
// the NIC (external network controller), the FBDMA (frame buffer controller), 
////////////////////////////////////////////////////////////////////////////////
void boot_peripherals_init()
{
    mapping_header_t*   header  = (mapping_header_t*)&seg_mapping_base;  
    mapping_cluster_t*  cluster = boot_get_cluster_base( header );     
    mapping_periph_t*   periph  = boot_get_periph_base( header );
    mapping_pseg_t*     pseg    = boot_get_pseg_base( header );

    unsigned int        cluster_id;
    unsigned int        periph_id;  
    unsigned int        coproc_id;  
    unsigned int        channel_id;

    for ( cluster_id = 0 ; cluster_id < header->clusters ; cluster_id++ )
    {

#if BOOT_DEBUG_PERI
boot_puts("\n[BOOT DEBUG] ****** peripheral initialisation in cluster "); 
boot_putw( cluster_id );
boot_puts(" ******\n");
#endif

        for ( periph_id = cluster[cluster_id].periph_offset ;
              periph_id < cluster[cluster_id].periph_offset + cluster[cluster_id].periphs ;
              periph_id++ )
        {
            unsigned int    type      = periph[periph_id].type;
            unsigned int    channels  = periph[periph_id].channels;
            unsigned int    pseg_id   = periph[periph_id].psegid;

            unsigned int*   pseg_base = (unsigned int*)pseg[pseg_id].base;

            //////// vci_block_device component
            if      ( type == PERIPH_TYPE_IOC )
            {

                // activate interrupts
                pseg_base[BLOCK_DEVICE_IRQ_ENABLE] = 1; 

#if BOOT_DEBUG_PERI
boot_puts("- IOC initialised : ");
boot_putw( channels );
boot_puts(" channels\n");
#endif
            }

            //////// vci_multi_dma component
            else if ( type == PERIPH_TYPE_DMA )
            {
                for ( channel_id = 0 ; channel_id < channels ; channel_id++ )
                { 
                    // activate interrupts
                    pseg_base[DMA_IRQ_DISABLE + channel_id*DMA_SPAN] = 0;
                }

#if BOOT_DEBUG_PERI
boot_puts("- DMA initialised : ");
boot_putw( channels );
boot_puts(" channels\n");
#endif
            }

            //////// vci_multi_nic component
            else if ( type == PERIPH_TYPE_NIC  )
            {
                for ( channel_id = 0 ; channel_id < channels ; channel_id++ )
                { 
                // TODO
                }

#if BOOT_DEBUG_PERI
boot_puts("- NIC initialised : ");
boot_putw( channels );
boot_puts(" channels\n");
#endif
            }

            //////// vci_io_bridge component
            else if ( (type == PERIPH_TYPE_IOB) && GIET_IOMMU_ACTIVE )
            {
                // get the iommu page table physical address
                // TODO

                // define IPI address mapping the IOC interrupt 
                // TODO

                // set IOMMU page table address
                // pseg_base[IOB_IOMMU_PTPR] = ptab_pbase;    

                // activate IOMMU
                // pseg_base[IOB_IOMMU_ACTIVE] = 1;        

#if BOOT_DEBUG_PERI
boot_puts("- IOB initialised : ");
boot_putw( channels );
boot_puts(" channels\n");
#endif
            }

        } // end for periphs

        for ( coproc_id = cluster[cluster_id].coproc_offset ;
              coproc_id < cluster[cluster_id].coproc_offset + cluster[cluster_id].coprocs ;
              coproc_id++ )
        {
            // TODO
        } // end for coprocs

    } // end for clusters
} // end boot_peripherals_init()


///////////////////////////////////////////////////////////////////////////////
// This function initialises all processors schedulers.
// This is done by processor 0, and the MMU must be activated.
// It initialises the boot_schedulers_paddr[gpid] pointers array.
// Finally, it scan all tasks in all vspaces to initialise the tasks contexts, 
// as specified in the mapping_info data structure. 
// For each task, a TTY channel, a TIMER channel, a FBDMA channel, and a NIC
// channel can be allocated if required. 
///////////////////////////////////////////////////////////////////////////////
void boot_schedulers_init()
{
    mapping_header_t*   header  = (mapping_header_t*)&seg_mapping_base;  
    mapping_cluster_t*  cluster = boot_get_cluster_base( header );
    mapping_pseg_t*     pseg    = boot_get_pseg_base( header );
    mapping_vspace_t*   vspace  = boot_get_vspace_base( header );     
    mapping_task_t*     task    = boot_get_task_base( header );
    mapping_vobj_t*     vobj    = boot_get_vobj_base( header );
    mapping_proc_t*     proc    = boot_get_proc_base( header );
    mapping_irq_t*      irq     = boot_get_irq_base( header );

    unsigned int        alloc_tty_channel;                 // TTY channel allocator
    unsigned int        alloc_nic_channel;                 // NIC channel allocator
    unsigned int        alloc_fbdma_channel[NB_CLUSTERS];  // FBDMA channel allocators
    unsigned int        alloc_timer_channel[NB_CLUSTERS];  // user TIMER allocators

    unsigned int        cluster_id;                        // cluster global index 
    unsigned int        proc_id;                           // processor global index 
    unsigned int        irq_id;                            // irq global index 
    unsigned int        pseg_id;                           // pseg global index 
    unsigned int        vspace_id;                         // vspace global index 
    unsigned int        task_id;                           // task global index;

    // Step 0 : TTY, NIC, TIMERS and DMA channels allocators initialisation
    //          global_id = cluster_id*NB_*_MAX + loc_id
    //          - TTY[0] is reserved for the kernel
    //          - In all clusters the first NB_PROCS_MAX timers 
    //            are reserved for the kernel (context switch)

    alloc_tty_channel = 1; 
    alloc_nic_channel = 0;

    for ( cluster_id = 0 ; cluster_id < header->clusters ; cluster_id++ )
    {
        alloc_fbdma_channel[cluster_id] = 0;
        alloc_timer_channel[cluster_id] = NB_PROCS_MAX;
    }
                
    // Step 1 : loop on the clusters and on the processors 
    //          - initialise the boot_schedulers_paddr[] pointers array 
    //          - initialise the interrupt vectors for each processor.

    for ( cluster_id = 0 ; cluster_id < header->clusters ; cluster_id++ )
    {

#if BOOT_DEBUG_SCHED
boot_puts("\n[BOOT DEBUG] Initialise schedulers / IT vector in cluster ");
boot_putw( cluster_id );
boot_puts("\n");
#endif
        unsigned int found = 0;
        unsigned int pseg_pbase;           // pseg base address 
        unsigned int lpid;                 // processor local index

        // get the physical base address of the first PSEG_TYPE_RAM pseg in cluster
        for ( pseg_id = cluster[cluster_id].pseg_offset ; 
              pseg_id < cluster[cluster_id].pseg_offset + cluster[cluster_id].psegs ; 
              pseg_id++ )
        {
            if ( pseg[pseg_id].type == PSEG_TYPE_RAM ) 
            {
                pseg_pbase = pseg[pseg_id].base;
                found = 1;
                break;
            }
        }

        if ( (cluster[cluster_id].procs > 0) && (found == 0) )
        {
            boot_puts("\n[BOOT ERROR] Missing RAM pseg in cluster ");
            boot_putw( cluster_id );
            boot_puts("\n");
            boot_exit();
        }

        // 4 Kbytes per scheduler
        for ( lpid = 0 ; lpid < cluster[cluster_id].procs ; lpid++ )
        {
            boot_schedulers_paddr[cluster_id*NB_PROCS_MAX + lpid] =
                (static_scheduler_t*)( pseg_pbase + (lpid<<12) );
        }

        for ( proc_id = cluster[cluster_id].proc_offset ;
              proc_id < cluster[cluster_id].proc_offset + cluster[cluster_id].procs ;
              proc_id++ )
        {

#if BOOT_DEBUG_SCHED
boot_puts("\nProc ");
boot_putw( proc_id );
boot_puts(" : scheduler pbase = ");
boot_putw( pseg_pbase + (lpid<<12) );
boot_puts("\n");
#endif
            // initialise the interrupt_vector with ISR_DEFAULT
            unsigned int slot;
            for ( slot = 0 ; slot < 32 ; slot++) 
            {
                boot_scheduler_set_itvector( proc_id, slot, 0);
            }

            // scan the IRQs actually allocated to current processor
            for ( irq_id = proc[proc_id].irq_offset ;
                  irq_id < proc[proc_id].irq_offset + proc[proc_id].irqs ;
                  irq_id++ )
            {
                unsigned int type    = irq[irq_id].type;
                unsigned int icu_id  = irq[irq_id].icuid;
                unsigned int isr_id  = irq[irq_id].isr;
                unsigned int channel = irq[irq_id].channel;
                unsigned int value   = isr_id | (type<<8) | (channel<<16); 
                boot_scheduler_set_itvector( proc_id, icu_id, value );

#if BOOT_DEBUG_SCHED
boot_puts("- IRQ : icu = ");
boot_putw( icu_id );
boot_puts(" / type = ");
boot_putw( type );
boot_puts(" / isr = ");
boot_putw( isr_id );
boot_puts(" / channel = ");
boot_putw( channel );
boot_puts("\n");
#endif
            }
        } // end for procs
    } // end for clusters

    // Step 2 : loop on the vspaces and the tasks 
    //          to initialise the schedulers and the task contexts.

    for ( vspace_id = 0 ; vspace_id < header->vspaces ; vspace_id++ )
    {

#if BOOT_DEBUG_SCHED
boot_puts("\n[BOOT DEBUG] Initialise schedulers / task contexts for vspace ");
boot_puts(vspace[vspace_id].name);
boot_puts("\n");
#endif
        // We must set the PTPR depending on the vspace, because the start_vector 
        // and the stack address are defined in virtual space.
        boot_set_mmu_ptpr( (unsigned int)boot_ptabs_paddr[vspace_id] >> 13 );

        // loop on the tasks (task_id is the global index)
        for ( task_id = vspace[vspace_id].task_offset ; 
              task_id < (vspace[vspace_id].task_offset + vspace[vspace_id].tasks) ; 
              task_id++ )
        {
            // ra :  the return address is &boot_eret()
            unsigned int ra = (unsigned int)&boot_eret;

            // sr : value required before an eret instruction
            unsigned int sr = 0x0000FF13; 

            // ptpr : page table physical base address (shifted by 13 bits for ptpr)
            unsigned int ptpr = (unsigned int)boot_ptabs_paddr[vspace_id] >> 13;

            // ptab : page_table virtual base address (not a register)
            unsigned int ptab = (unsigned int)boot_ptabs_vaddr[vspace_id];

            // tty : terminal global index  
            unsigned int tty = 0xFFFFFFFF;
            if ( task[task_id].use_tty ) 
            {
                if ( alloc_tty_channel >= NB_TTYS )
                {
                    boot_puts("\n[BOOT ERROR] TTY index too large for task ");
                    boot_puts( task[task_id].name );
                    boot_puts(" in vspace ");
                    boot_puts( vspace[vspace_id].name );
                    boot_puts("\n");
                    boot_exit();
                }
                tty = alloc_tty_channel;
                alloc_tty_channel++;
            }

            // nic : NIC channel global index  
            unsigned int nic = 0xFFFFFFFF;
            if ( task[task_id].use_nic ) 
            {
                if ( alloc_nic_channel >= NB_NICS )
                {
                    boot_puts("\n[BOOT ERROR] NIC channel index too large for task ");
                    boot_puts( task[task_id].name );
                    boot_puts(" in vspace ");
                    boot_puts( vspace[vspace_id].name );
                    boot_puts("\n");
                    boot_exit();
                }
                nic = alloc_nic_channel;
                alloc_nic_channel++;
            }

            // timer : user TIMER local index 
            unsigned int timer = 0xFFFFFFFF;
            if ( task[task_id].use_timer ) 
            {
                unsigned int cluster_id = task[task_id].clusterid;
                if ( alloc_timer_channel[cluster_id] >= NB_TIMERS_MAX )
                {
                    boot_puts("\n[BOOT ERROR] local TIMER index too large for task ");
                    boot_puts( task[task_id].name );
                    boot_puts(" in vspace ");
                    boot_puts( vspace[vspace_id].name );
                    boot_puts("\n");
                    boot_exit();
                }
                timer = cluster_id*NB_TIMERS_MAX + alloc_timer_channel[cluster_id];
                alloc_timer_channel[cluster_id]++;
            }

            // fbdma : DMA local index  
            unsigned int fbdma = 0xFFFFFFFF;
            if ( task[task_id].use_fbdma ) 
            {
                unsigned int cluster_id = task[task_id].clusterid;
                if ( alloc_fbdma_channel[cluster_id] >= NB_DMAS_MAX )
                {
                    boot_puts("\n[BOOT ERROR] local FBDMA index too large for task ");
                    boot_puts( task[task_id].name );
                    boot_puts(" in vspace ");
                    boot_puts( vspace[vspace_id].name );
                    boot_puts("\n");
                    boot_exit();
                }
                fbdma = cluster_id*NB_DMAS_MAX + alloc_fbdma_channel[cluster_id];
                alloc_fbdma_channel[cluster_id]++;
            }

            // epc : Get the (virtual) base address of the start_vector containing
            // the start addresses for all tasks defined in the vspace.
            mapping_vobj_t* pvobj = &vobj[vspace[vspace_id].vobj_offset + 
                                          vspace[vspace_id].start_offset]; 
            unsigned int* start_vector_vbase = (unsigned int*)pvobj->vaddr;
            unsigned int epc = start_vector_vbase[task[task_id].startid];

            // sp :  Get the vobj containing the stack 
            unsigned int vobj_id = task[task_id].vobjlocid + vspace[vspace_id].vobj_offset;
            unsigned int sp = vobj[vobj_id].vaddr + vobj[vobj_id].length;

            // compute gpid = global processor index
            unsigned int gpid = task[task_id].clusterid*NB_PROCS_MAX + 
                                task[task_id].proclocid;

            // sched : scheduler physical address
            unsigned int sched = (unsigned int)boot_schedulers_paddr[gpid];

            // In the code below, we access the scheduler with specific access 
            // functions, because we only have the physical address of the scheduler, 
            // and these functions must temporary desactivate the DTLB...

            // get local task index in scheduler[gpid]
            unsigned int ltid = boot_scheduler_get_tasks( gpid );

            if ( ltid >= 15 )
            {
                boot_puts("\n[BOOT ERROR] : too much tasks allocated to processor ");
                boot_putw( gpid );
                boot_puts("\n");
                boot_exit();
            }

            // update the "tasks" field in scheduler[gpid]
            boot_scheduler_set_tasks( gpid, ltid + 1);

            // update the "current" field in scheduler[gpid]
            boot_scheduler_set_current( gpid, 0 );

            // initializes the task context in scheduler[gpid]
            boot_scheduler_set_context( gpid, ltid, CTX_SR_ID    , sr    );
            boot_scheduler_set_context( gpid, ltid, CTX_SP_ID    , sp    );
            boot_scheduler_set_context( gpid, ltid, CTX_RA_ID    , ra    );
            boot_scheduler_set_context( gpid, ltid, CTX_EPC_ID   , epc   );
            boot_scheduler_set_context( gpid, ltid, CTX_PTPR_ID  , ptpr  );
            boot_scheduler_set_context( gpid, ltid, CTX_TTY_ID   , tty   );
            boot_scheduler_set_context( gpid, ltid, CTX_TIMER_ID , timer );
            boot_scheduler_set_context( gpid, ltid, CTX_FBDMA_ID , fbdma );
            boot_scheduler_set_context( gpid, ltid, CTX_PTAB_ID  , ptab  );
            boot_scheduler_set_context( gpid, ltid, CTX_SCHED_ID , sched );
                                        
#if BOOT_DEBUG_SCHED
boot_puts("\nTask ");
boot_puts( task[task_id].name );
boot_puts(" allocated to processor ");
boot_putw( gpid );
boot_puts(" / ltid = ");
boot_putw( ltid );
boot_puts("\n");

boot_puts("  - SR          = ");
boot_putw( sr );
boot_puts("\n");

boot_puts("  - SP          = ");
boot_putw( sp );
boot_puts("\n");

boot_puts("  - RA          = ");
boot_putw( ra );
boot_puts("\n");

boot_puts("  - EPC         = ");
boot_putw( epc );
boot_puts("\n");

boot_puts("  - PTPR        = ");
boot_putw( ptpr<<13 );
boot_puts("\n");

boot_puts("  - TTY         = ");
boot_putw( tty );
boot_puts("\n");

boot_puts("  - TIMER       = ");
boot_putw( timer );
boot_puts("\n");

boot_puts("  - FBDMA       = ");
boot_putw( fbdma );
boot_puts("\n");

boot_puts("  - PTAB        = ");
boot_putw( ptab );
boot_puts("\n");

boot_puts("  - SCHED       = ");
boot_putw( sched );
boot_puts("\n");
#endif

        } // end loop on tasks
    } // end loop on vspaces
} // end boot_schedulers_init()

//////////////////////////////////////////////////////////////////////////////////
// This function is executed by P[0] to wakeup all processors.
//////////////////////////////////////////////////////////////////////////////////
void boot_start_all_procs()
{
    mapping_header_t*   header = (mapping_header_t*)&seg_mapping_base;  
    header->signature = OUT_MAPPING_SIGNATURE;
}

/////////////////////////////////////////////////////////////////////
// This function is the entry point of the initialisation procedure
/////////////////////////////////////////////////////////////////////
void boot_init()
{
    // mapping_info checking
    boot_check_mapping();

    boot_puts("\n[BOOT] Mapping check completed at cycle ");
    boot_putw( boot_proctime() );
    boot_puts("\n");

    // pseg allocators initialisation 
    boot_psegs_init();

    boot_puts("\n[BOOT] Pseg allocators initialisation completed at cycle ");
    boot_putw( boot_proctime() );
    boot_puts("\n");

    // peripherals initialisation
    boot_peripherals_init();

    boot_puts("\n[BOOT] Peripherals initialisation completed at cycle ");
    boot_putw( boot_proctime() );
    boot_puts("\n");

    // page table building
    boot_pt_init();

    boot_puts("\n[BOOT] Page Tables initialisation completed at cycle ");
    boot_putw( boot_proctime() );
    boot_puts("\n");

    // mmu activation
    boot_set_mmu_ptpr( (unsigned int)boot_ptabs_paddr[0] >> 13 );
    boot_set_mmu_mode( 0xF );

    boot_puts("\n[BOOT] MMU activation completed at cycle ");
    boot_putw( boot_proctime() );
    boot_puts("\n");

    // vobjs initialisation
    boot_vobjs_init();

    boot_puts("\n[BOOT] Vobjs initialisation completed at cycle : ");
    boot_putw( boot_proctime() );
    boot_puts("\n");

    // schedulers initialisation
    boot_schedulers_init();

    boot_puts("\n[BOOT] Schedulers initialisation completed at cycle ");
    boot_putw( boot_proctime() );
    boot_puts("\n");

    // start all processors
    boot_start_all_procs();

} // end boot_init()

// Local Variables:
// tab-width: 4
// c-basic-offset: 4
// c-file-offsets:((innamespace . 0)(inline-open . 0))
// indent-tabs-mode: nil
// End:
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=4:softtabstop=4