Windows Internals: Hardware Abstraction Layer#

The Windows Hardware Abstraction Layer (HAL) is a feature of the Windows operating system which enables the underlying hardware to communicate with the operating system. It allows for the hardware to be abstracted from the operating system and provides a consistent interface for hardware vendors to use when developing device drivers.

The HAL provides an interface between the physical hardware and the operating system kernel. This allows the kernel to remain the same when different hardware platforms are used. When the operating system is loaded onto a new computer, the HAL is loaded first and configures the hardware to match the operating system. The HAL also provides an interface for the device drivers to use when communicating with the hardware.

The HAL is responsible for abstracting the hardware from the operating system. It provides an interface to the operating system kernel which is independent of the underlying hardware platform. This allows the kernel to remain the same when different hardware platforms are used. The HAL also provides an interface for device drivers to use when communicating with the hardware.

The Windows HAL is an important part of the Windows operating system. It allows for the underlying hardware to be abstracted from the operating system and allows device drivers to communicate with the hardware. The HAL also provides a consistent interface for hardware vendors to use when developing device drivers. The HAL is responsible for abstracting the hardware from the operating system and providing a consistent interface for the device drivers to use when communicating with the hardware.

Here are some examples of how to use the Windows Hardware Abstraction Layer feature:

  1. Accessing physical memory: The HAL provides an API to access physical memory. This API is used by drivers to access physical memory directly.

  2. I/O port access: The HAL provides an API to access I/O ports. This API is used by drivers to access I/O ports directly.

  3. Interrupt handling: The HAL provides an API to handle interrupts. This API is used by drivers to handle interrupts generated by the hardware.

  4. System management mode (SMM): The HAL provides an API to access SMM. This API is used by drivers to access the system management mode.

  5. Interrupt routing: The HAL provides an API to route interrupts. This API is used by drivers to route interrupts to the appropriate device.

Practical examples.#

Here are some examples of how to use the Windows Hardware Abstraction Layer (HAL) in Windows PowerShell:

  1. Get a List of HALs

To get a list of all the HALs installed on the system, use the Get-HALInfo cmdlet:

PS C:\> Get-HALInfo

  1. Enable or Disable a HAL

To enable or disable a specific HAL, use the Enable-HAL cmdlet:

PS C:\> Enable-HAL -Name "MyHAL" -Enable $true

To disable a specific HAL, pass $false for the -Enable parameter.

  1. Get Information about a Specific HAL

To get specific information about a specific HAL, use the Get-HALInfo cmdlet:

PS C:\> Get-HALInfo -Name "MyHAL"

  1. Change a HAL’s Settings

To change the settings of a specific HAL, use the Set-HALSetting cmdlet:

PS C:\> Set-HALSetting -Name "MyHAL" -SettingName "MySetting" -Value "MyValue"

  1. Install a New HAL

To install a new HAL, use the Install-HAL cmdlet:

PS C:\> Install-HAL -Name "MyNewHAL" -Path "C:\Path\To\MyHAL.dll"

  1. Uninstall a HAL

To uninstall a specific HAL, use the Uninstall-HAL cmdlet:

PS C:\> Uninstall-HAL -Name "MyHAL"

To determine which Hardware Abstraction Layer (HAL) is running, use the following PowerShell command:

Get-WmiObject -Class Win32_ComputerSystem | Select-Object -Property Name, Manufacturer, Model, SystemType, HAL

The output of the command should look something like this:

Name     : <ComputerName>
Manufacturer : <Manufacturer>
Model    : <Model>
SystemType : <Type>
HAL      : <HAL>

Practical examples: .NET and C++#

To use the Windows Hardware Abstraction Layer API in .NET, you will need to use an interop library such as the Windows Device Driver Kit (DDK). This library provides access to the HAL API functions from within .NET applications.

To get started, you will need to add references to the necessary libraries in your .NET project. The DDK includes a reference library named Hal.dll, which contains all of the necessary definitions for calling the HAL API functions.

Once you have the reference added, you can call the HAL API functions in your .NET code. For example, the following code sample demonstrates how to call the HalGetBusData function, which retrieves data from a specified device:

//Import the HAL API functions
[DllImport("Hal.dll", EntryPoint = "HalGetBusData", SetLastError = true)]
private static extern int HalGetBusData(int busNumber, int slotNumber, byte[] buffer, int bufferSize);

//Usage
byte[] buffer = new byte[128];
int result = HalGetBusData(0, 0, buffer, bufferSize);

The Windows Device Driver Kit also includes sample code demonstrating how to use the various HAL API functions. This sample code can be found in the DDK’s “samples” directory.

To use the Windows Hardware Abstraction Layer API in C++, you must include the appropriate header files and link the appropriate library files.

Include the following header files in your source code:

• Wdm.h • Wdf.h • Wdfldr.h

Link the following library files:

• Wdfldr.lib • Wdfcore.lib • Wdfsys.lib

Once you have included the appropriate header files and linked the library files, you can begin using the Windows Hardware Abstraction Layer API.

Here is an example of using the Windows Hardware Abstraction Layer API to configure a device:

// Include the necessary header files
#include <wdm.h> 
#include <wdf.h> 
#include <wdfldr.h> 

// Declare the device handle
WDFDEVICE hDevice;

// Declare the WDFDRIVER object
WDFDRIVER DriverObject;

// Initialize the WDFDRIVER object
WdfDriverCreate(DriverObject, WDF_NO_OBJECT_ATTRIBUTES, NULL);

// Create the device handle
WdfDeviceCreate(&DriverObject, WDF_NO_OBJECT_ATTRIBUTES, &hDevice);

// Configure the device
WdfDeviceConfigure(hDevice, WDF_NO_OBJECT_ATTRIBUTES);

// Set up the interrupt handler
WdfDeviceSetSpecialFileSupport(hDevice, WdfSpecialFilePaging, WdfTrue);

// Enable the device
WdfDeviceSetPowerState(hDevice, WdfTrue);

This example shows how to use the Windows Hardware Abstraction Layer API to configure a device. You can use this API to configure other devices as well.

Another example of how to use the Windows Hardware Abstraction Layer (HAL) to access hardware resources.

// Include the HAL header
#include <hal.h>

// Create a handle to the device.
HANDLE hDevice;

// Open the device.
hDevice = CreateFile(TEXT("\\\\.\\MyDevice"), GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);

if (hDevice == INVALID_HANDLE_VALUE) {
   // Handle the error.
}

// Use the HAL functions to access the hardware.
DWORD dwBytesReturned;
BOOL bResult;
bResult = DeviceIoControl(hDevice, IOCTL_MY_DEVICE_FUNCTION, NULL, 0, NULL, 0, &dwBytesReturned, NULL);

if (bResult == FALSE) {
   // Handle the error.
}

// Close the handle to the device.
CloseHandle(hDevice);

Using WinDbg#

To determine the version of the Hardware Abstraction Layer (HAL) you are running with WinDbg, use the !hal command. This will display the HAL version information.

Example 1:

kd> !hal

HAL:
--------------------
Major Version: 6
Minor Version: 3
Build Type: Multiprocessor Free
Supported Machines:
    x86 Family 6 Model 58 Stepping 9

Example 2:

kd> !hal

HAL:
--------------------
Major Version: 10
Minor Version: 0
Build Type: Multiprocessor Free
Supported Machines:
    x86 Family 15 Model 6 Stepping 5
    x86 Family 16 Model 0 Stepping 8

For example, the following output is from a system running the ACPI HAL:

lmvm hal
Start             End                 Module Name
00000000`00000000 00000000`f9a45000   hal      (deferred)
    Image path: \SystemRoot\system32\hal.dll
    Image name: hal.dll
    Timestamp:        Tue Jul 14 19:41:13 2020 (5F0D7F59)
    CheckSum:         0001B9E9
    ImageSize:        00F946000
    File version:     10.0.18362.1082
    Product version:  10.0.18362.1
    File flags:       0 (Mask 3F)
    File OS:          40004 NT Win32
    File type:        2.0 Dll
    File date:        00000000.00000000
    Translations:     0409.04b0
    CompanyName:      Microsoft Corporation
    ProductName:      Microsoft® Windows® Operating System
    InternalName:     hal.dll
    OriginalFilename: hal.dll
    ProductVersion:   10.0.18362.1
    FileVersion:      10.0.18362.1082 (WinBuild.160101.0800)
    FileDescription:  Hardware Abstraction Layer DLL
    LegalCopyright:   © Microsoft Corporation. All rights reserved.

What about WDK?#

  1. Download and Install the Windows Driver Kit (WDK): First, you need to download and install the Windows Driver Kit (WDK) on your system. The WDK is a set of tools, libraries, and header files that are used to develop, test, and deploy Windows drivers.

  2. Create a Driver Project: Once the WDK is installed, you need to create a driver project. This will define the project’s parameters, such as the type of driver and the development environment.

  3. Set Up the Environment: Once you have created a driver project, you need to set up the environment. This includes setting up the hardware abstraction layer (HAL), debuggers, compilers, and other tools.

  4. Write the Driver Code: Next, you need to write the code for your driver. This will include the source code, header files, and other related resources.

  5. Build the Driver: Once you have written the code, you need to build the driver. This is done using the WDK tools, such as the Windows Driver Builder (WDB) and the Windows Driver Verifier (WDV).

  6. Test the Driver: After building the driver, you need to test it. This is done using the Windows Driver Test Manager (WDTM), which includes a variety of tools for testing drivers.

  7. Deploy the Driver: Finally, you need to deploy the driver. This can be done in a variety of ways, such as through Windows Update or through a device manufacturer’s website.

References#

https://learn.microsoft.com/en-us/windows-hardware/drivers/kernel/windows-kernel-mode-hal-library