/*
 * kcm.c -  Kernel Cache Manager implementation.
 *
 * Author  Alain Greiner    (2016,2017,2018,2019)
 *
 * Copyright (c) UPMC Sorbonne Universites
 *
 * This file is part of ALMOS-MKH.
 *
 * ALMOS-MKH 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; version 2.0 of the License.
 *
 * ALMOS-MKH 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 ALMOS-MKH; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <kernel_config.h>
#include <hal_kernel_types.h>
#include <hal_special.h>
#include <busylock.h>
#include <list.h>
#include <printk.h>
#include <bits.h>
#include <ppm.h>
#include <thread.h>
#include <page.h>
#include <cluster.h>
#include <kmem.h>
#include <kcm.h>


/////////////////////////////////////////////////////////////////////////////////////
//        Local access functions
/////////////////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////////////////
// This static function must be called by a local thread.
// It returns a pointer on a block allocated from a non-full kcm_page.
// It makes a panic if no block is available in selected page.
// It changes the page status as required.
//////////////////////////////////////////////////////////////////////////////////////
// @ kcm      : pointer on KCM allocator.
// @ kcm_page : pointer on a non-full kcm_page.
// @ return pointer on allocated block.
/////////////////////////////////////////////////////////////////////////////////////
static void * __attribute__((noinline)) kcm_get_block( kcm_t      * kcm,
                                                       kcm_page_t * kcm_page )
{
    // initialise variables
    uint32_t size   = 1 << kcm->order;
    uint32_t max    = kcm->max_blocks;
    uint32_t count  = kcm_page->count;
    uint64_t status = kcm_page->status;

assert( (count < max) , "kcm_page should not be full" );

    uint32_t index  = 1;
    uint64_t mask   = (uint64_t)0x2;
    uint32_t found  = 0;

	// allocate first free block in kcm_page, update status,
    // and count , compute index of allocated block in kcm_page 
    while( index <= max )
    {
        if( (status & mask) == 0 )   // block non allocated
        {
            kcm_page->status = status | mask;
            kcm_page->count  = count + 1;
            found  = 1;

            break;      
        }
        
        index++;
        mask <<= 1;
    }

    // change the page list if almost full
    if( count == max-1 )
    {
		list_unlink( &kcm_page->list);
		kcm->active_pages_nr--;

        list_add_first( &kcm->full_root , &kcm_page->list );
		kcm->full_pages_nr ++;
    }

	// compute return pointer
	void * ptr = (void *)((intptr_t)kcm_page + (index * size) );

#if (DEBUG_KCM & 1)
thread_t * this  = CURRENT_THREAD;
uint32_t   cycle = (uint32_t)hal_get_cycles();
if( DEBUG_KCM < cycle )
printk("\n[%s] thread[%x,%x] allocated block %x in page %x / size %d / count %d / cycle %d\n",
__FUNCTION__, this->process->pid, this->trdid, ptr, kcm_page, size, count + 1, cycle );
#endif

	return ptr;

}  // end kcm_get_block()

/////////////////////////////////////////////////////////////////////////////////////
// This private static function must be called by a local thread.
// It releases a previously allocated block to the relevant kcm_page.
// It makes a panic if the released block is not allocated in this page.
// It changes the kcm_page status as required.
/////////////////////////////////////////////////////////////////////////////////////
// @ kcm        : pointer on kcm allocator.
// @ kcm_page   : pointer on kcm_page.
// @ block_ptr  : pointer on block to be released.
/////////////////////////////////////////////////////////////////////////////////////
static void __attribute__((noinline)) kcm_put_block ( kcm_t      * kcm,
                                                      kcm_page_t * kcm_page,
                                                      void       * block_ptr )
{
    // initialise variables
    uint32_t max    = kcm->max_blocks;
    uint32_t size   = 1 << kcm->order;
    uint32_t count  = kcm_page->count;
    uint64_t status = kcm_page->status;
    
	// compute block index from block pointer
	uint32_t index = ((intptr_t)block_ptr - (intptr_t)kcm_page) / size;

    // compute mask in bit vector
    uint64_t mask = ((uint64_t)0x1) << index;

assert( (status & mask) , "released block not allocated : status (%x,%x) / mask(%x,%x)",
GET_CXY(status), GET_PTR(status), GET_CXY(mask  ), GET_PTR(mask  ) );

    // update status & count in kcm_page 
	kcm_page->status = status & ~mask;
	kcm_page->count  = count - 1;

	// change the page mode if page was full
	if( count == max )
	{
		list_unlink( &kcm_page->list );
		kcm->full_pages_nr --;

		list_add_last( &kcm->active_root, &kcm_page->list );
		kcm->active_pages_nr ++;
	}

#if (DEBUG_KCM & 1)
thread_t * this  = CURRENT_THREAD;
uint32_t   cycle = (uint32_t)hal_get_cycles();
if( DEBUG_KCM < cycle )
printk("\n[%s] thread[%x,%x] released block %x in page %x / size %d / count %d / cycle %d\n",
__FUNCTION__, this->process->pid, this->trdid, block_ptr, kcm_page, size, count - 1, cycle );
#endif

}  // kcm_put_block()

/////////////////////////////////////////////////////////////////////////////////////
// This private static function must be called by a local thread.
// It returns one non-full kcm_page with te following policy :
// - if the "active_list" is non empty, it returns the first "active" page,
//   without modifying the KCM state.
// - if the "active_list" is empty, it allocates a new page fromm PPM, inserts
//   this page in the active_list, and returns it. 
/////////////////////////////////////////////////////////////////////////////////////
// @ kcm      : local pointer on local KCM allocator.
// @ return pointer on a non-full kcm page if success / returns NULL if no memory.
/////////////////////////////////////////////////////////////////////////////////////
static kcm_page_t * __attribute__((noinline)) kcm_get_page( kcm_t * kcm )
{
    kcm_page_t * kcm_page;

    uint32_t active_pages_nr = kcm->active_pages_nr;

    if( active_pages_nr > 0 )       // return first active page
    {
        kcm_page = LIST_FIRST( &kcm->active_root , kcm_page_t , list );
    }
    else                            // allocate a new page from PPM
	{
        // get one 4 Kbytes page from local PPM
        page_t * page = ppm_alloc_pages( 0 );

	    if( page == NULL )
	    {
		    printk("\n[ERROR] in %s : failed to allocate page in cluster %x\n",
	        __FUNCTION__ , local_cxy );

		    return NULL;
        }

	    // get page base address
	    xptr_t base_xp = ppm_page2base( XPTR( local_cxy , page ) );

        // get local pointer on kcm_page
	    kcm_page = GET_PTR( base_xp );

	    // initialize kcm_page descriptor
	    kcm_page->status = 0;
	    kcm_page->count  = 0;
	    kcm_page->kcm    = kcm;
	    kcm_page->page   = page;

	    // introduce new page in KCM active_list
	    list_add_first( &kcm->active_root , &kcm_page->list );
	    kcm->active_pages_nr ++;
	}

	return kcm_page;

}  // end kcm_get_page()

//////////////////////////////
void kcm_init( kcm_t    * kcm,
	           uint32_t   order)
{

assert( ((order > 5) && (order < 12)) , "order must be in [6,11]" );

	// initialize lock
	remote_busylock_init( XPTR( local_cxy , &kcm->lock ) , LOCK_KCM_STATE );

	// initialize KCM page lists
	kcm->full_pages_nr   = 0;
	kcm->active_pages_nr = 0;
	list_root_init( &kcm->full_root );
	list_root_init( &kcm->active_root );

	// initialize order and max_blocks
	kcm->order      = order;
    kcm->max_blocks = ( CONFIG_PPM_PAGE_SIZE >> order ) - 1;
 
#if DEBUG_KCM
thread_t * this  = CURRENT_THREAD;
uint32_t   cycle = (uint32_t)hal_get_cycles();
if( DEBUG_KCM < cycle )
printk("\n[%s] thread[%x,%x] initialised KCM / order %d / max_blocks %d\n",
__FUNCTION__, this->process->pid, this->trdid, order, kcm->max_blocks );
#endif

}  // end kcm_init()

///////////////////////////////
void kcm_destroy( kcm_t * kcm )
{
	kcm_page_t   * kcm_page;

    // build extended pointer on  KCM lock
    xptr_t lock_xp = XPTR( local_cxy , &kcm->lock );

	// get KCM lock
	remote_busylock_acquire( lock_xp );

	// release all full pages
	while( list_is_empty( &kcm->full_root ) == false )
	{
		kcm_page = LIST_FIRST( &kcm->full_root , kcm_page_t , list );
		list_unlink( &kcm_page->list );
		ppm_free_pages( kcm_page->page );
	}

    // release all empty pages
    while( list_is_empty( &kcm->active_root ) == false )
	{
		kcm_page = LIST_FIRST( &kcm->active_root , kcm_page_t , list );
		list_unlink( &kcm_page->list );
		ppm_free_pages( kcm_page->page );
	}

	// release KCM lock
	remote_busylock_release( lock_xp );
}

//////////////////////////////////
void * kcm_alloc( uint32_t order )
{
    kcm_t      * kcm_ptr;
	kcm_page_t * kcm_page;
	void       * block_ptr;

    // min block size is 64 bytes
    if( order < 6 ) order = 6;

assert( (order < 12) , "order = %d / must be less than 12" , order );

    // get local pointer on relevant KCM allocator
    kcm_ptr = &LOCAL_CLUSTER->kcm[order - 6];

    // build extended pointer on local KCM lock
    xptr_t lock_xp = XPTR( local_cxy , &kcm_ptr->lock );

	// get KCM lock
	remote_busylock_acquire( lock_xp );

    // get a non-full kcm_page
    kcm_page = kcm_get_page( kcm_ptr );

    if( kcm_page == NULL )
	{
		remote_busylock_release( lock_xp );
		return NULL;
	}

	// get a block from selected active page
	block_ptr = kcm_get_block( kcm_ptr , kcm_page );

	// release lock
	remote_busylock_release( lock_xp );

#if DEBUG_KCM
thread_t * this  = CURRENT_THREAD;
uint32_t   cycle = (uint32_t)hal_get_cycles();
if( DEBUG_KCM < cycle )
printk("\n[%s] thread[%x,%x] allocated block %x / order %d / kcm %x / status[%x,%x] / count %d\n",
__FUNCTION__, this->process->pid, this->trdid, block_ptr, order, kcm_ptr,
GET_CXY(kcm_page->status), GET_PTR(kcm_page->status), kcm_page->count );
#endif

	return block_ptr;

}  // end kcm_alloc()

/////////////////////////////////
void kcm_free( void * block_ptr )
{
    kcm_t      * kcm_ptr;
	kcm_page_t * kcm_page;

// check argument
assert( (block_ptr != NULL) , "block pointer cannot be NULL" );

    // get local pointer on KCM page
	kcm_page = (kcm_page_t *)((intptr_t)block_ptr & ~CONFIG_PPM_PAGE_MASK);

    // get local pointer on KCM descriptor
	kcm_ptr = kcm_page->kcm;

#if DEBUG_KCM
thread_t * this  = CURRENT_THREAD;
uint32_t   cycle = (uint32_t)hal_get_cycles();
if( DEBUG_KCM < cycle )
printk("\n[%s] thread[%x,%x] release block %x / order %d / kcm %x / status [%x,%x] / count %d\n",
__FUNCTION__, this->process->pid, this->trdid, block_ptr, kcm_ptr->order, kcm_ptr,
GET_CXY(kcm_page->status), GET_PTR(kcm_page->status), kcm_page->count );
#endif

    // build extended pointer on local KCM lock
    xptr_t lock_xp = XPTR( local_cxy , &kcm_ptr->lock );

	// get lock
	remote_busylock_acquire( lock_xp );

	// release block
	kcm_put_block( kcm_ptr , kcm_page , block_ptr );

	// release lock
	remote_busylock_release( lock_xp );
}

/////////////////////////////////////////////////////////////////////////////////////
//        Remote access functions
/////////////////////////////////////////////////////////////////////////////////////

/////////////////////////////////////////////////////////////////////////////////////
// This static function can be called by any thread running in any cluster.
// It returns a local pointer on a block allocated from an non-full kcm_page.
// It makes a panic if no block available in selected page.
// It changes the page status as required.
/////////////////////////////////////////////////////////////////////////////////////
// @ kcm_cxy  : remote KCM cluster identidfier.
// @ kcm_ptr  : local pointer on remote KCM allocator.
// @ kcm_page : pointer on active kcm page to use.
// @ return a local pointer on the allocated block. 
/////////////////////////////////////////////////////////////////////////////////////
static void * __attribute__((noinline)) kcm_remote_get_block( cxy_t        kcm_cxy,
                                                              kcm_t      * kcm_ptr,
                                                              kcm_page_t * kcm_page )
{
    uint32_t order  = hal_remote_l32( XPTR( kcm_cxy , &kcm_ptr->order ) );
    uint32_t max    = hal_remote_l32( XPTR( kcm_cxy , &kcm_ptr->max_blocks ) );
    uint32_t count  = hal_remote_l32( XPTR( kcm_cxy , &kcm_page->count ) );
    uint64_t status = hal_remote_l64( XPTR( kcm_cxy , &kcm_page->status ) );
    uint32_t size   = 1 << order;

assert( (count < max) , "kcm_page should not be full" );

    uint32_t index  = 1;
    uint64_t mask   = (uint64_t)0x2;
    uint32_t found  = 0;
    
	// allocate first free block in kcm_page, update status,
    // and count , compute index of allocated block in kcm_page 
    while( index <= max )
    {
        if( (status & mask) == 0 )   // block non allocated
        {
            hal_remote_s64( XPTR( kcm_cxy , &kcm_page->status ) , status | mask );
            hal_remote_s64( XPTR( kcm_cxy , &kcm_page->count  ) , count + 1 );
            found  = 1; 
            break;      
        }
        
        index++;
        mask <<= 1;
    }

	// change the page list if almost full
	if( count == max-1 )
	{
		list_remote_unlink( kcm_cxy , &kcm_page->list );
		hal_remote_atomic_add( XPTR( kcm_cxy , &kcm_ptr->active_pages_nr ) , -1 );

		list_remote_add_first( kcm_cxy , &kcm_ptr->full_root , &kcm_page->list );
		hal_remote_atomic_add( XPTR( kcm_cxy , &kcm_ptr->full_pages_nr ) , 1 );
	}

	// compute return pointer
	void * ptr = (void *)((intptr_t)kcm_page + (index * size) );

#if DEBUG_KCM_REMOTE
thread_t * this  = CURRENT_THREAD;
uint32_t   cycle = (uint32_t)hal_get_cycles();
if( DEBUG_KCM_REMOTE < cycle )
printk("\n[%s] thread[%x,%x] get block %x in page %x / cluster %x / size %x / count %d\n",
__FUNCTION__, this->process->pid, this->trdid, 
ptr, kcm_page, kcm_cxy, size, count + 1 );
#endif

	return ptr;

}  // end kcm_remote_get_block()

/////////////////////////////////////////////////////////////////////////////////////
// This private static function can be called by any thread running in any cluster.
// It releases a previously allocated block to the relevant kcm_page.
// It changes the kcm_page status as required.
/////////////////////////////////////////////////////////////////////////////////////
// @ kcm_cxy   : remote KCM cluster identifier
// @ kcm_ptr   : local pointer on remote KCM.
// @ kcm_page  : local pointer on kcm_page.
// @ block_ptr : pointer on block to be released.
/////////////////////////////////////////////////////////////////////////////////////
static void __attribute__((noinline)) kcm_remote_put_block ( cxy_t        kcm_cxy,
                                                             kcm_t      * kcm_ptr,
                                                             kcm_page_t * kcm_page,
                                                             void       * block_ptr )
{
    uint32_t max    = hal_remote_l32( XPTR( kcm_cxy , &kcm_ptr->max_blocks ) );
    uint32_t order  = hal_remote_l32( XPTR( kcm_cxy , &kcm_ptr->order ) );
    uint32_t count  = hal_remote_l32( XPTR( kcm_cxy , &kcm_page->count ) );
    uint64_t status = hal_remote_l64( XPTR( kcm_cxy , &kcm_page->status ) );
    uint32_t size   = 1 << order;
    
	// compute block index from block pointer
	uint32_t index = ((intptr_t)block_ptr - (intptr_t)kcm_page) / size;

    // compute mask in bit vector
    uint64_t mask = 1 << index;

assert( (status & mask) , "released page not allocated" );

    // update status & count in kcm_page 
	hal_remote_s64( XPTR( kcm_cxy , &kcm_page->status ) , status & ~mask );
	hal_remote_s32( XPTR( kcm_cxy , &kcm_page->count  ) , count - 1 );

	// change the page list if page was full
	if( count == max )
	{
		list_remote_unlink( kcm_cxy , &kcm_page->list );
		hal_remote_atomic_add( XPTR( kcm_cxy , &kcm_ptr->full_pages_nr ) , -1 );

		list_remote_add_last( kcm_cxy , &kcm_ptr->active_root, &kcm_page->list );
		hal_remote_atomic_add( XPTR( kcm_cxy , &kcm_ptr->active_pages_nr ) , 1 );
	}

#if (DEBUG_KCM_REMOTE & 1)
thread_t * this  = CURRENT_THREAD;
uint32_t   cycle = (uint32_t)hal_get_cycles();
if( DEBUG_KCM_REMOTE < cycle )
printk("\n[%s] thread[%x,%x] released block %x in page %x / cluster %x / size %x / count %d\n",
__FUNCTION__, this->process->pid, this->trdid, block_ptr, kcm_page, size, count - 1 )
#endif

}  // end kcm_remote_put_block()

/////////////////////////////////////////////////////////////////////////////////////
// This private static function can be called by any thread running in any cluster.
// It gets one non-full KCM page from the remote KCM.
// It allocates a page from remote PPM to populate the freelist, and initialises
// the kcm_page descriptor when required.
/////////////////////////////////////////////////////////////////////////////////////
static kcm_page_t * __attribute__((noinline)) kcm_remote_get_page( cxy_t    kcm_cxy,
                                                                   kcm_t  * kcm_ptr )
{
    kcm_page_t * kcm_page;    // local pointer on remote KCM page 

    uint32_t active_pages_nr = hal_remote_l32( XPTR( kcm_cxy , &kcm_ptr->active_pages_nr ) );

    if( active_pages_nr > 0 )       // return first active page
    {
        kcm_page = LIST_REMOTE_FIRST( kcm_cxy , &kcm_ptr->active_root , kcm_page_t , list );
    }
    else                            // allocate a new page from PPM
	{
        // get one 4 Kbytes page from remote PPM
        page_t * page = ppm_remote_alloc_pages( kcm_cxy , 0 );

	    if( page == NULL )
	    {
		    printk("\n[ERROR] in %s : failed to allocate page in cluster %x\n",
	        __FUNCTION__ , kcm_cxy );

		    return NULL;
        }

	    // get remote page base address
	    xptr_t base_xp = ppm_page2base( XPTR( kcm_cxy , page ) );

        // get local pointer on kcm_page
	    kcm_page = GET_PTR( base_xp );

	    // initialize kcm_page descriptor
	    hal_remote_s32( XPTR( kcm_cxy , &kcm_page->count )  , 0 );
	    hal_remote_s64( XPTR( kcm_cxy , &kcm_page->status ) , 0 );
	    hal_remote_spt( XPTR( kcm_cxy , &kcm_page->kcm )    , kcm_ptr );
	    hal_remote_spt( XPTR( kcm_cxy , &kcm_page->page )   , page );

	    // introduce new page in remote KCM active_list
	    list_remote_add_first( kcm_cxy , &kcm_ptr->active_root , &kcm_page->list );
	    hal_remote_atomic_add( XPTR( kcm_cxy , &kcm_ptr->active_pages_nr ) , 1 );
	}

	return kcm_page;

}  // end kcm_remote_get_page()

/////////////////////////////////////////
void * kcm_remote_alloc( cxy_t    kcm_cxy,
                         uint32_t order )
{
    kcm_t      * kcm_ptr;
    kcm_page_t * kcm_page;
    void       * block_ptr;

    if( order < 6 ) order = 6;

assert( (order < 12) , "order = %d / must be less than 12" , order );

    // get local pointer on relevant KCM allocator
    kcm_ptr = &LOCAL_CLUSTER->kcm[order - 6];

    // build extended pointer on remote KCM lock
    xptr_t lock_xp = XPTR( kcm_cxy , &kcm_ptr->lock );

	// get lock
	remote_busylock_acquire( lock_xp );

    // get a non-full kcm_page
    kcm_page = kcm_remote_get_page( kcm_cxy , kcm_ptr );

    if( kcm_page == NULL )
	{
		remote_busylock_release( lock_xp );
		return NULL;
	}

	// get a block from selected active page
	block_ptr = kcm_remote_get_block( kcm_cxy , kcm_ptr , kcm_page );

	// release lock
	remote_busylock_release( lock_xp );

#if DEBUG_KCM_REMOTE
thread_t * this  = CURRENT_THREAD;
uint32_t   cycle = (uint32_t)hal_get_cycles();
if( DEBUG_KCM_REMOTE < cycle )
printk("\n[%s] thread[%x,%x] allocated block %x / order %d / kcm[%x,%x]\n",
__FUNCTION__, this->process->pid, this->trdid, block_ptr, order, kcm_cxy, kcm_ptr );
#endif

	return block_ptr;

}  // end kcm_remote_alloc()

/////////////////////////////////////
void kcm_remote_free( cxy_t  kcm_cxy,
                      void * block_ptr )
{
	kcm_t      * kcm_ptr;
	kcm_page_t * kcm_page;

// check argument
assert( (block_ptr != NULL) , "block pointer cannot be NULL" );

    // get local pointer on remote KCM page
	kcm_page = (kcm_page_t *)((intptr_t)block_ptr & ~CONFIG_PPM_PAGE_MASK);

    // get local pointer on remote KCM
	kcm_ptr = hal_remote_lpt( XPTR( kcm_cxy , &kcm_page->kcm ) );

    // build extended pointer on remote KCM lock
    xptr_t lock_xp = XPTR( kcm_cxy , &kcm_ptr->lock );

	// get lock
	remote_busylock_acquire( lock_xp );

	// release block
	kcm_remote_put_block( kcm_cxy , kcm_ptr , kcm_page , block_ptr );

	// release lock
	remote_busylock_release( lock_xp );

#if DEBUG_KCM_REMOTE
thread_t * this  = CURRENT_THREAD;
uint32_t   cycle = (uint32_t)hal_get_cycles();
uint32_t   order = hal_remote_l32( XPTR( kcm_cxy , &kcm_ptr->order ) );
if( DEBUG_KCM_REMOTE < cycle )
printk("\n[%s] thread[%x,%x] released block %x / order %d / kcm[%x,%x]\n",
__FUNCTION__, this->process->pid, this->trdid, block_ptr, order, kcm_cxy, kcm_ptr );
#endif

}  // end kcm_remote_free

/////////////////////////////////////////
void kcm_remote_display( cxy_t   kcm_cxy,
                         kcm_t * kcm_ptr )
{
    uint32_t order           = hal_remote_l32( XPTR( kcm_cxy , &kcm_ptr->order) );
    uint32_t full_pages_nr   = hal_remote_l32( XPTR( kcm_cxy , &kcm_ptr->full_pages_nr ) );
    uint32_t active_pages_nr = hal_remote_l32( XPTR( kcm_cxy , &kcm_ptr->active_pages_nr ) );

	printk("*** KCM / cxy %x / order %d / full_pages %d / empty_pages %d / active_pages %d\n",
	kcm_cxy, order, full_pages_nr, active_pages_nr );
}