reactos/subsystems/win32/csrss/video.c

/*
 * PROJECT:         ReactOS Client/Server Runtime subsystem
 * LICENSE:         GPL v2 or later - See COPYING in the top level directory
 * FILE:            subsystems/win32/csrss/video.c
 * PURPOSE:         Video memory initialization.
 * PROGRAMMERS:     ReactOS Development Team
 */

/* INCLUDES ******************************************************************/

#include <csrss.h>

#define NDEBUG
#include <debug.h>

/* FUNCTIONS *****************************************************************/

ULONG
InitializeVideoAddressSpace(VOID)
{
    OBJECT_ATTRIBUTES ObjectAttributes;
    UNICODE_STRING PhysMemName = RTL_CONSTANT_STRING(L"\\Device\\PhysicalMemory");
    NTSTATUS Status;
    HANDLE PhysMemHandle;
    PVOID BaseAddress;
    LARGE_INTEGER Offset;
    SIZE_T ViewSize;
    CHAR IVTAndBda[1024+256];

    /* Open the physical memory section */
    InitializeObjectAttributes(&ObjectAttributes,
                               &PhysMemName,
                               0,
                               NULL,
                               NULL);
    Status = ZwOpenSection(&PhysMemHandle,
                           SECTION_ALL_ACCESS,
                           &ObjectAttributes);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("Couldn't open \\Device\\PhysicalMemory\n");
        return 0;
    }

    /* Map the BIOS and device registers into the address space */
    Offset.QuadPart = 0xa0000;
    ViewSize = 0x100000 - 0xa0000;
    BaseAddress = (PVOID)0xa0000;
    Status = ZwMapViewOfSection(PhysMemHandle,
                                NtCurrentProcess(),
                                &BaseAddress,
                                0,
                                ViewSize,
                                &Offset,
                                &ViewSize,
                                ViewUnmap,
                                0,
                                PAGE_EXECUTE_READWRITE);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("Couldn't map physical memory (%x)\n", Status);
        ZwClose(PhysMemHandle);
        return 0;
    }

    /* Close physical memory section handle */
    ZwClose(PhysMemHandle);

    if (BaseAddress != (PVOID)0xa0000)
    {
        DPRINT1("Couldn't map physical memory at the right address (was %x)\n",
                BaseAddress);
        return 0;
    }

    /* Allocate some low memory to use for the non-BIOS
     * parts of the v86 mode address space
     */
    BaseAddress = (PVOID)0x1;
    ViewSize = 0xa0000 - 0x1000;
    Status = ZwAllocateVirtualMemory(NtCurrentProcess(),
                                     &BaseAddress,
                                     0,
                                     &ViewSize,
                                     MEM_COMMIT,
                                     PAGE_EXECUTE_READWRITE);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("Failed to allocate virtual memory (Status %x)\n", Status);
        return 0;
    }
    if (BaseAddress != (PVOID)0x0)
    {
        DPRINT1("Failed to allocate virtual memory at right address (was %x)\n",
                BaseAddress);
        return 0;
    }

    /* Get the real mode IVT and BDA from the kernel */
    Status = NtVdmControl(VdmInitialize, IVTAndBda);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("NtVdmControl failed (status %x)\n", Status);
        return 0;
    }

    /* Return success */
    return 1;
}

/* EOF */