Add more explanation on resident components

hardware_init_review.tex

@@ -793,7 +793,7 @@
         study on the 4.11 version of \textit{coreboot} \cite{coreboot_4_11},
         which is the last version that supported the ASUS KGPE-D16 mainboard. \\
 
-        For the firmware tasks to be done efficiently, \textit{coreboot} is
+        For the initialization tasks to be done efficiently, \textit{coreboot} is
         organized in different stages (fig. \ref{fig:coreboot_stages})
         \cite{coreboot_docs}.
 
@@ -1045,7 +1045,10 @@
             to the appropriate CPUs. Additionally, the firmware configures the
             HyperTransport (HT) technology, a high-speed communication protocol
             that facilitates data exchange between the processor and the
-            northbridge, ensuring smooth data flow between these components. \\
+            northbridge, ensuring smooth data flow between these components.
+            During this stage, microcode patches may be loaded into CPU and
+            remain resident, settings related to memory controllers and CPU
+            too. \\
 
             The \textit{romstage} begins with a call to the
             \path{_start} function, defined in
@@ -1153,8 +1156,13 @@
             x86), coreboot tables, and updates to the device tree (specific to
             ARM). Additionally, the ramstage locks down the hardware and
             firmware by applying write protection to boot media, locking
-            security-related registers, and locking SMM (specific to x86)
+            security-related registers, and locking SMM (specific to x86),
-            \cite{coreboot_docs}.
+            which is a resident component in a protected area.
+            \cite{coreboot_docs}. CBMEM data structures (like coreboot tables,
+            memory map, etc.) are populated during this stage and left resident
+            for the OS or payload to access, same for SMBIOS tables, ACPI tables
+            and eventually option ROMS. \\
+
             Effective resource allocation is essential for system stability,
             particularly in complex configurations involving multiple CPUs
             and peripherals. This stage manages initial resource allocation,
@@ -1179,7 +1187,9 @@
                 At its core,
                 ACPI is implemented through a series of data structures and
                 executable code known as ACPI tables, which are provided by the
-                system firmware and interpreted by the OS. These tables describe
+                system firmware and interpreted by the OS at runtime. It means
+                that these are components from the firmware that remain resident
+                while the OS runs. These tables describe
                 various aspects of the system, including hardware resources,
                 device power states, and thermal zones. The ACPI Specification
                 outlines these structures and provides the necessary
@@ -1229,7 +1239,8 @@
                 applications. Introduced by Intel, SMM operates in an
                 environment separate from the main operating system, offering a
                 controlled space for executing sensitive operations
-                \cite{uefi_smm_security}. \\
+                \cite{uefi_smm_security}. This is another firmware component
+                that remains resident while the OS runs. \\
 
                 SMM is triggered by a System Management Interrupt (SMI), which
                 is a non-maskable interrupt that causes the CPU to save its
@@ -1319,6 +1330,8 @@
             BIOS routines used in legacy BIOS systems. With GOP drivers,
             the system can initialize the GPU and display a graphical interface
             even before the operating system loads \cite{osdev_gop}.
+            These are other examples of resident firmware components while the
+            OS is running. \\
             Hardware manufacturers can distribute proprietary UEFI drivers as
             part of firmware updates, making it straightforward for end-users
             to install and use them. This is especially useful for specialized
@@ -1326,7 +1339,7 @@
             free software community. It also gives hardware vendors more control
             over how their devices are initialized and used, which can be
             an advantage for vendors but is a freedom and user control
-            limitation. \\
+            limitation.
 
             Payloads are then definitely important parts of the firmware.