8.3 Obtaining Services Tables
DXE drivers may consume the UEFI Boot Services, UEFI Runtime Services, and DXE Services. In addition, a DXE driver can also refer to UEFI System Table.
UEFI Boot Services, UEFI Runtime Services, and UEFI System Table are defined in the UEFI Specification. DXE Services are defined in the PI Specification.
DXE driver can retrieve these tables via global variables provided by the following library classes:

Table 11 Reference to Services Tables for DXE Drivers

Global variable
Library Class
UEFI System Table
gST
UefiBootServicesTableLib
UEFI Boot Services Table
gBS
UefiBootServicesTableLib
UEFI Runtime Services Table
gRT
UefiRuntimeServicesTableLib
DXE Services Table
gDS
DxeServicesTableLib
Last modified 1yr ago