///////////////////////////////////////////////////////////////////////////////////
// File     : vm_handler.c
// Date     : 01/07/2012
// Author   : alain greiner
// Copyright (c) UPMC-LIP6
///////////////////////////////////////////////////////////////////////////////////
// The vm_handler.c and vm_handler.h files are part ot the GIET nano kernel.
// They contains the kernel data structures and functions used to dynamically
// handle the iommu page table.
///////////////////////////////////////////////////////////////////////////////////

#include <vm_handler.h>
#include <sys_handler.h>
#include <common.h>
#include <giet_config.h>
#include <drivers.h>

/////////////////////////////////////////////////////////////////////////////
//     Global variable : IOMMU page table
/////////////////////////////////////////////////////////////////////////////

__attribute__((section (".iommu"))) page_table_t _iommu_ptab;

//////////////////////////////////////////////////////////////////////////////
// _iommu_add_pte2()
//////////////////////////////////////////////////////////////////////////////
void _iommu_add_pte2(
        unsigned int ix1,
        unsigned int ix2,
        unsigned int ppn,
        unsigned int flags) 
{
    unsigned int ptba;
    unsigned int * pt_ppn;
    unsigned int * pt_flags;

    // get pointer on iommu page table
    page_table_t * pt = &_iommu_ptab;

    // get ptba and update PT2
    if ((pt->pt1[ix1] & PTE_V) == 0) 
    {
        _get_lock(&_tty_put_lock);
        _puts("\n[GIET ERROR] in iommu_add_pte2 function\n");
        _puts("the IOMMU PT1 entry is not mapped / ix1 = ");
        _putx( ix1 );
        _puts("\n");
        _release_lock(&_tty_put_lock);
        _exit();
    }
    else 
    {
        ptba = pt->pt1[ix1] << 12;
        pt_flags = (unsigned int *) (ptba + 8 * ix2);
        pt_ppn = (unsigned int *) (ptba + 8 * ix2 + 4);
        *pt_flags = flags;
        *pt_ppn = ppn;
    }
} // end _iommu_add_pte2()


//////////////////////////////////////////////////////////////////////////////
// _iommu_inval_pte2()
//////////////////////////////////////////////////////////////////////////////
void _iommu_inval_pte2(unsigned int ix1, unsigned int ix2) {
    unsigned int ptba;
    unsigned int * pt_flags;

    // get pointer on iommu page table
    page_table_t * pt = &_iommu_ptab;

    // get ptba and inval PTE2
    if ((pt->pt1[ix1] & PTE_V) == 0)
    {
        _puts("\n[GIET ERROR] in iommu_inval_pte2 function\n");
        _puts("the IOMMU PT1 entry is not mapped / ix1 = ");
        _putx( ix1 );
        _puts("\n");
        _exit();
    }
    else {
        ptba = pt->pt1[ix1] << 12;
        pt_flags = (unsigned int *) (ptba + 8 * ix2);
        *pt_flags = 0;
    }   
} // end _iommu_inval_pte2()


//////////////////////////////////////////////////////////////////////////////
// _v2p_translate()
// Returns 0 if success, 1 if PTE1 or PTE2 unmapped
//////////////////////////////////////////////////////////////////////////////
unsigned int _v2p_translate(page_table_t * pt,
                            unsigned int   vpn,
                            unsigned int * ppn,
                            unsigned int * flags) 
{
    paddr_t ptba;
    paddr_t pte2;

    register unsigned int pte2_msb;
    register unsigned int pte2_lsb;
    register unsigned int flags_value;
    register unsigned int ppn_value;

    unsigned int ix1 = vpn >> 9;
    unsigned int ix2 = vpn & 0x1FF;

    // check PTE1 mapping
    if ((pt->pt1[ix1] & PTE_V) == 0)
    {
        return 1;
    }
    else 
    {
        // get physical addresses of pte2 
        ptba     = (paddr_t) (pt->pt1[ix1] & 0x0FFFFFFF) << 12;
        pte2     = ptba + 8 * ix2;
        pte2_lsb = (unsigned int) pte2;
        pte2_msb = (unsigned int) (pte2 >> 32);

        // gets ppn_value and flags_value, after temporary DTLB desactivation
        asm volatile (
                "li      $2,     0xFFFFFFFE  \n"     /* Mask for IE bits     */
                "mfc0    $4,     $12         \n"     /* $4 <= SR             */ 
                "and     $2,     $2,    $4   \n"
                "mtc0    $2,     $12         \n"     /* disable Interrupts   */

                "li      $3,     0xB         \n"     
                "mtc2    $3,     $1          \n"     /* DTLB unactivated     */ 

                "mtc2    %2,     $24         \n"     /* PADDR_EXT <= msb     */
                "lw      %0,     0(%3)       \n"     /* read flags           */ 
                "lw      %1,     4(%3)       \n"     /* read ppn             */
                "mtc2    $0,     $24         \n"     /* PADDR_EXT <= 0       */

                "li      $3,     0xF         \n" 
                "mtc2    $3,     $1          \n"     /* DTLB activated       */

                "mtc0    $4,     $12         \n"     /* restore SR           */
                : "=r" (flags_value), "=r" (ppn_value)
                : "r" (pte2_msb), "r" (pte2_lsb)
                : "$2","$3","$4");

        // check PTE2 mapping
        if ((flags_value & PTE_V) == 0) {
            return 1;
        }

        // set return values 
        *ppn = ppn_value;
        *flags = flags_value;
    }
    return 0;
} // end _v2p_translate()

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