source: trunk/hal/tsar_mips32/hal_ppm.c @ 50

/*
 * hal_gpt.C - Generic Physcal Page Table API implementation for the TSAR archtecture.
 *
 * Authors  Alain Greiner (2016,2017)
 * 
 *
 * 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
 */


//////////////////////////////////////////////////////////////////////////////////////////
// For The TSAR architecture, the kernel pointers are identity mapping: 
// - the 32 bits PTR value is identical to the 32 bits LPA value, 
// - the 64 bits XPTR value is identical to the 64 bits PADDR value.
// The pages_tbl[] is mapped in first free page after kernel code.
// There is no other reserved zones than the zone occupied by the kernel code.
//////////////////////////////////////////////////////////////////////////////////////////


//////////////////////////////////////////////////
struct page_s * hal_ppm_init( boot_info_t * info )
{
    // get relevant info from boot_info structure
        uint32_t   pages_nr         = info->pages_nr;
    uint32_t   pages_tbl_offset = info->pages_offset;
    uint32_t   rsvd_nr          = info->rsvd_nr;

    // check no reserved zones other than kernel code for TSAR
    assert( (rsvd_nr == 0 ) , __FUNCTION__ , "NO reserved zones for TSAR\n" ); 

    // get pointer on local Physical Page Manager
    ppm_t * ppm = &LOCAL_CLUSTER->ppm;
    
    // initialize lock protecting the free_pages[] lists 
        spinlock_init( &ppm->free_lock );

    // initialize lock protecting the dirty_pages list 
        spinlock_init( &ppm->dirty_lock );

    // initialize all free_pages[] lists as empty
        ppm->total_free_pages = 0;
        for( i = 0 ; i < CONFIG_PPM_MAX_ORDER ; i++ )
        {
                list_root_init( &ppm->free_pages_root[i] );
                ppm->free_pages_nr[i] = 0;
        }

    // initialize dirty_list as empty
    list_root_init( &ppm->dirty_root );

    // initialize pages_nr, pages_tbl, and vaddr_base pointers
    // (TSAR uses identity mapping for kernel pointers)
    // I86 architectures should use vaddr_base = 0xFFFF8000000000 + (cxy << 36)

        ppm->pages_nr      = pages_nr;
    ppm->vaddr_base = NULL;
        ppm->pages_tbl  = (page_t*)( vaddr_base + (pages_offset << CONFIG_PPM_PAGE_SHIFT) );

    // compute size of pages_tbl[] array rounded to an integer number of pages
    uint32_t bytes = ARROUND_UP( pages_nr * sizeof(page_t), CONFIG_PPM_PAGE_SIZE );

    // compute number of pages required to store page descriptor array
        uint32_t pages_tbl_nr = bytes >> CONFIG_PPM_PAGE_SHIFT;

    // compute total number of reserved pages (kernel code & pages_tbl[])
        uint32_t reserved_pages = pages_offset + tbl_nb_pages;

    // initialises all page descriptors in pages_tbl[]
        for( i = 0 ; i < pages_nr ; i++ )
    {
        page_init( &ppm->pages_tbl[i] );

        // TODO optimisation for this enormous loop on small pages:
        // make only a partial init with a memset, and complete the 
        // initialisation when page is allocated [AG]
    }

    // - set PG_RESERVED flag for reserved pages (kernel code & pages_tbl[])
    // - release all other pages to populate the free lists
        for( i = 0 ; i < reserved_pages ; i++)
    {
        page_set_flag( &ppm->pages_tbl[i] , PG_RESERVED );
    }
        for( i = reserved_pages ; i < pages_nr ; i++ )
        {
            ppm_free_pages_nolock( &ppm->pages_tbl[i] );

        // TODO optimisation : decompose this enormous set of small pages
        // to several sets of big pages with various order values
        }

    // check consistency
    ppm_assert_order( ppm );

    // success
    return ppm->pages_tbl;

}