source: soft/giet_vm/giet_kernel/kernel_init.c @ 301

///////////////////////////////////////////////////////////////////////////////////
// File     : kernel_init.c
// Date     : 26/05/2012
// Authors  : alain greiner & mohamed karaoui
// Copyright (c) UPMC-LIP6
////////////////////////////////////////////////////////////////////////////////////
// The kernel_init.c file is part of the GIET-VM nano-kernel.
//
// This nano-kernel has been written for the MIPS32 processor.
// The virtual adresses are on 32 bits and use the (unsigned int) type, but the 
// physicals addresses can have up to 40 bits, and use the  (unsigned long long) type.
// It natively supports clusterised shared mmemory multi-processors architectures, 
// where each processor is identified by a composite index (cluster_xy, local_id),
// and where there is one physical memory bank per cluster.
//
// This file contains the _kernel_init() function, that performs the second 
// phase of system initialisation.  The three significant actions are:
// 1) processor 0 makes peripherals and system FAT initialisation.
// 2) processor 0 awake all other processors by an IPI.
// 3) all processors running in parallel perform register initialisation,
//    from their private scheduler, and jump to user code.
////////////////////////////////////////////////////////////////////////////////////

#include <giet_config.h>

// kernel libraries
#include <utils.h>
#include <fat32.h>

//for peripheral initialisation
#include <dma_driver.h>
#include <fbf_driver.h>
#include <tty_driver.h>
#include <icu_driver.h>
#include <xcu_driver.h>
#include <ioc_driver.h>
#include <mmc_driver.h>
#include <mwr_driver.h>
#include <nic_driver.h>
#include <tim_driver.h>

#include <ctx_handler.h>
#include <irq_handler.h>

#include <mapping_info.h>
#include <mips32_registers.h>

///////////////////////////////////////////////////////////////////////////////////
// array of pointers on the page tables (virtual addresses)
///////////////////////////////////////////////////////////////////////////////////

__attribute__((section (".kdata"))) 
unsigned int _ptabs_vaddr[GIET_NB_VSPACE_MAX];    // virtual addresses

__attribute__((section (".kdata")))        
unsigned int _ptabs_ptprs[GIET_NB_VSPACE_MAX];    // physical addresses >> 13

///////////////////////////////////////////////////////////////////////////////////
// array of pointers on the schedulers (physical addresses)
///////////////////////////////////////////////////////////////////////////////////

__attribute__((section (".kdata"))) 
static_scheduler_t* _schedulers[NB_PROCS_MAX<<(X_WIDTH+Y_WIDTH)]; // virtual addresses

////////////////////////////////////////////////////////////////////////////////////
// staks for the "idle" tasks (512 bytes for each processor)
////////////////////////////////////////////////////////////////////////////////////

__attribute__((section (".kdata"))) 
unsigned int _idle_stack[X_SIZE * Y_SIZE * NB_PROCS_MAX * 128 ]; 

////////////////////////////////////////////////////////////////////////////////////
// Synchonisation Barrier before jumping to user code
////////////////////////////////////////////////////////////////////////////////////

__attribute__((section (".kdata"))) 
unsigned int _init_barrier = 0;

////////////////////////////////////////////////////////////////////////////////////
// This function is the entry point in kernel for all processors.
// It is executed in parallel by all procesors, and completes the system 
// initialisation that has been started by processor 0 in the boot_init() function.
//
// This kernel code makes the following assuptions, regarding the work bone 
// by the boot code:
//
// 1) The page tables associated to the various vspaces have been build
//    in physical memory, and can be used by the kernel code.
//
// 2) All schedulers (this include all task contexts) have been initialised, 
//    Both the virtual and the physical base addresses of the page tables
//    are available in the CTX_PTAB and CTX_PTPR slots.
//
// 3) The CP0_SCHED register of each processor contains a pointer on its 
//    private scheduler (virtual address).
//
// 4) The CP2_PTPR register of each processor contains a pointer on 
//    the vspace_0 page table (physical address>>13). 
//
// 5) For all processors, the MMU is activated (CP2_MODE contains 0xF).
// 
// This code must be loaded in .kinit section, in order to control seg_kinit_base,
// as this address is used by the boot code to jump into kernel code.
////////////////////////////////////////////////////////////////////////////////////
// Each processor performs the following actions:
// 1/ contribute to _schedulers_paddr[] array initialisation.
// 2/ contribute to _ptabs_paddr[] and _ptabs_vaddr arrays initialisation 
// 3/ completes task context initialisation for ech allocated task
// 4/ compute and set the ICU mask for its private ICU channel
// 5/ initialise its private TICK timer (if tasks > 0)
// 6/ initialise the "idle" task context in its private scheduler
// 7/ initialise SP, SR, PTPR, EPC registers and jump to user code with an eret. 
////////////////////////////////////////////////////////////////////////////////////
__attribute__((section (".kinit"))) void kernel_parallel_init() 
{
    unsigned int global_pid = _get_procid();
    unsigned int cluster_xy = global_pid / NB_PROCS_MAX;
    unsigned int x          = cluster_xy >> Y_WIDTH;
    unsigned int y          = cluster_xy & ((1<<Y_WIDTH)-1);
    unsigned int lpid       = global_pid % NB_PROCS_MAX;

    // Step 1 : each processor get its scheduler virtual address
    //          and contribute to initialise the _schedulers[] array

    static_scheduler_t* psched     = (static_scheduler_t*)_get_sched();
    unsigned int        tasks      = psched->tasks;

    _schedulers[global_pid] = psched;

#if GIET_DEBUG_INIT
_printf("\n[GIET DEBUG INIT] Processor[%d,%d,%d]\n"
        " - scheduler vbase = %x\n"
        " - tasks           = %d\n",
        x, y, lpid, (unsigned int)psched, tasks );
#endif

    // step 2 : each processor that is allocated at least one task loops 
    //          on all allocated tasks: 
    //          - contributes to _ptabs_vaddr[] & _ptabs_ptprs[] initialisation.
    //          - set CTX_RA slot  with the kernel _ctx_eret() virtual address.
    //          - set CTX_EPC slot that must contain the task entry point, 
    //            and contain only at this point the virtual address of the memory 
    //            location containing this entry point. We must switch the PTPR
    //            to use the page table corresponding to the task.

    unsigned int ltid;

    for (ltid = 0; ltid < tasks; ltid++) 
    {
        unsigned int vsid = _get_task_slot( global_pid, ltid , CTX_VSID_ID ); 
        unsigned int ptab = _get_task_slot( global_pid, ltid , CTX_PTAB_ID ); 
        unsigned int ptpr = _get_task_slot( global_pid, ltid , CTX_PTPR_ID ); 

        // initialize PTABS arrays
        _ptabs_vaddr[vsid] = ptab;
        _ptabs_ptprs[vsid] = ptpr;

#if GIET_DEBUG_INIT
_printf("\n[GIET DEBUG INIT] Processor[%d,%d,%d] contributes to PTABS arrays\n"
        " - ptabs_vaddr[%d] = %x / ptpr_paddr[%d] = %l\n",
        x, y, lpid,  
        vsid, ptab, vsid, ((unsigned long long)ptpr)<<13 );
#endif

        // set the ptpr to use the task page table
        asm volatile( "mtc2    %0,   $0   \n"
                      : : "r" (ptpr) );

        // compute ctx_ra
        unsigned int ctx_ra = (unsigned int)(&_ctx_eret);
        _set_task_slot( global_pid, ltid, CTX_RA_ID, ctx_ra );

        // compute ctx_epc
        unsigned int* ptr = (unsigned int*)_get_task_slot( global_pid, ltid, CTX_EPC_ID );
        _set_task_slot( global_pid, ltid, CTX_EPC_ID, *ptr );

#if GIET_DEBUG_INIT
_printf("\n[GIET DEBUG INIT] Processor[%d,%d,%d] update context for task %d\n"
        " - ctx_epc   = %x\n"
        " - ctx_ra    = %x\n",
        x, y, lpid, ltid,
        _get_task_slot( global_pid, ltid, CTX_EPC_ID ),
        _get_task_slot( global_pid, ltid, CTX_RA_ID ) );
#endif

    }  // end for tasks

    // step 4 : compute and set ICU or XCU masks

    unsigned int isr_switch_index = 0xFFFFFFFF;
    unsigned int hwi_mask = 0;
    unsigned int pti_mask = 0;
    unsigned int wti_mask = 0;
    unsigned int irq_id;            // IN_IRQ index
    unsigned int entry;             // interrupt vector entry

    for (irq_id = 0; irq_id < 32; irq_id++) 
    {
        entry = psched->hwi_vector[irq_id];
        if ( entry & 0x80000000 ) hwi_mask = hwi_mask | (1<<irq_id);
        if ( (entry & 0x0000FFFF) == ISR_TICK ) isr_switch_index = irq_id;

        entry = psched->pti_vector[irq_id];
        if ( entry & 0x80000000 ) pti_mask = pti_mask | (1<<irq_id);
        if ( (entry & 0x0000FFFF) == ISR_TICK ) isr_switch_index = irq_id;

        entry = psched->wti_vector[irq_id];
        if ( entry & 0x80000000 ) wti_mask = wti_mask | (1<<irq_id);
        if ( (entry & 0x0000FFFF) == ISR_TICK ) isr_switch_index = irq_id;
    }

#if GIET_DEBUG_INIT
_printf("\n[GIET DEBUG INIT] Processor[%d,%d,%d] set XCU masks\n"
        " - ICU HWI_MASK = %x\n"
        " - ICU WTI_MASK = %x\n"
        " - ICU PTI_MASK = %x\n",
        x, y, lpid, hwi_mask, wti_mask, pti_mask );
#endif

    unsigned int channel = lpid * IRQ_PER_PROCESSOR; 

#if USE_XICU
    _xcu_set_mask( cluster_xy, channel, hwi_mask, IRQ_TYPE_HWI ); 
    _xcu_set_mask( cluster_xy, channel, wti_mask, IRQ_TYPE_WTI );
    _xcu_set_mask( cluster_xy, channel, pti_mask, IRQ_TYPE_PTI );
#else
    _icu_set_mask( cluster_xy, channel, hwi_mask );   
#endif

    // step 5 : start TICK timer if at least one task
    if (tasks > 0) 
    {
        // one ISR_TICK must be defined for each proc
        if (isr_switch_index == 0xFFFFFFFF) 
        {
            _printf("\n[GIET ERROR] ISR_TICK not found for processor[%d,%d,%d]\n",
                    x, y, lpid );
            _exit();
        }

        // start system timer

#if USE_XICU
        _xcu_timer_start( cluster_xy, isr_switch_index, GIET_TICK_VALUE ); 
#else
        _timer_start( cluster_xy, isr_switch_index, GIET_TICK_VALUE ); 
#endif

    }

#if GIET_DEBUG_INIT
_printf("\n[GIET DEBUG INIT] Processor[%d,%d,%d] start TICK timer\n",
        x, y, lpid );
#endif

    // step 6 : each processor updates the idle_task context:
    //          (only CTX_SP, CTX_RA, CTX_EPC).
    //          The stack size is 512 bytes, reserved in seg_kdata.
    //          The PTPR register, the CTX_PTPR and CTX_PTAB slots 
    //          have been initialised in boot code.

    unsigned int p = ((x * Y_SIZE) + y) * NB_PROCS_MAX + lpid; 

    unsigned int stack = (unsigned int)_idle_stack + ((p + 1)<<9);

    _set_task_slot( global_pid, IDLE_TASK_INDEX, CTX_SP_ID,  stack);
    _set_task_slot( global_pid, IDLE_TASK_INDEX, CTX_RA_ID,  (unsigned int) &_ctx_eret);
    _set_task_slot( global_pid, IDLE_TASK_INDEX, CTX_EPC_ID, (unsigned int) &_idle_task);

#if GIET_DEBUG_INIT
_printf("\n[GIET DEBUG INIT] Processor[%d,%d,%d] initialize IDLE task\n",
        x, y, lpid );
#endif

    // step 7 : when all processors reach the synchronisation barrier, 
    //          each processor set registers SP, SR, PTPR, EPC,
    //          with the values corresponding to the first allocated task,
    //          or to the idle_task if there is no task allocated,
    //          and jump to user code 

    if (tasks == 0) 
    {
        ltid = IDLE_TASK_INDEX;

        _printf("\n[GIET WARNING] No task allocated to processor[%d,%d,%d]\n",
                x, y, lpid );
    }
    else
    {
        ltid = 0;
    }

    unsigned int sp_value   = _get_task_slot(global_pid, ltid, CTX_SP_ID);
    unsigned int sr_value   = _get_task_slot(global_pid, ltid, CTX_SR_ID);
    unsigned int ptpr_value = _get_task_slot(global_pid, ltid, CTX_PTPR_ID);
    unsigned int epc_value  = _get_task_slot(global_pid, ltid, CTX_EPC_ID);

#if GIET_DEBUG_INIT
_printf("\n[GIET DEBUG INIT] Processor[%d,%d,%d] reach barrier at cycle %d\n"
        " - sp   = %x\n"
        " - sr   = %x\n"
        " - ptpr = %x\n"
        " - epc  = %x\n",
        x, y, lpid, _get_proctime(),
        sp_value, sr_value, ptpr_value, epc_value );
#endif

    unsigned int*  pcount = &_init_barrier;
    unsigned int   nprocs = TOTAL_PROCS;
    unsigned int   count;

    // increment barrier counter with atomic LL/SC
    asm volatile ( "_init_barrier_loop:             \n"
                   "ll    %0,   0(%1)               \n"   /* count <= *pcount  */
                   "addi  $3,   %0,   1             \n"   /* $3 <= count + 1  */
                   "sc    $3,   0(%1)               \n"   /* *pcount <= $3  */
                   "beqz  $3,   _init_barrier_loop  \n"   /* retry if failure */
                   "nop                             \n" 
                   : "=&r"(count)
                   : "r"(pcount) 
                   : "$3" );
   
    // busy waiting until all processors synchronized
    while ( *pcount != nprocs ) asm volatile ("nop");

    _printf("\n[GIET] Processor[%d,%d,%d] jumps to user code at cycle %d\n",
            x, y, lpid, _get_proctime() );
        
    // set registers and jump to user code
    asm volatile ( "move  $29,  %0                  \n"   /* SP <= ctx[CTX_SP_ID] */
                   "mtc0  %1,   $12                 \n"   /* SR <= ctx[CTX_SR_ID] */
                   "mtc2  %2,   $0                  \n"   /* PTPR <= ctx[CTX_PTPR] */
                   "mtc0  %3,   $14                 \n"   /* EPC <= ctx[CTX_EPC]  */
                   "eret                            \n"   /* jump to user code  */
                   "nop                             \n"
                   : 
                   : "r"(sp_value), "r"(sr_value), "r"(ptpr_value), "r"(epc_value)
                   : "$29" );

} // end kernel_parallel_init()


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