### Install Minimal OS with debootstrap

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/virt/uml/user_mode_linux_howto_v2.rst

Installs a minimal Debian system (Buster in this example) into the mounted filesystem image using `debootstrap`. This command fetches necessary packages from a specified repository and sets up a basic root filesystem.

```shell
# debootstrap buster /mnt http://deb.debian.org/debian
```

--------------------------------

### Starting a UML Instance

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/virt/uml/user_mode_linux_howto_v2.rst

Provides an example command to launch a User-Mode Linux instance with specified memory, root filesystem image, network interface, and console configurations. It details how to set RAM, use a disk image, configure tap networking, and direct console output.

```shell
# linux mem=2048M umid=TEST \
    ubd0=Filesystem.img \
    vec0:transport=tap,ifname=tap0,depth=128,gro=1 \
    root=/dev/ubda con=null con0=null,fd:2 con1=fd:0,fd:1
```

--------------------------------

### DM Setup Create Example

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/admin-guide/device-mapper/cache-policies.rst

An example of creating a mapped device with a cache target using dmsetup, specifying all necessary parameters including policy tunables.

```shell
dmsetup create blah --table "0 268435456 cache /dev/sdb /dev/sdc \
	/dev/sdd 512 0 mq 4 sequential_threshold 1024 random_threshold 8"
```

--------------------------------

### Clock Management Example

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/driver-api/driver-model/platform.rst

Example of how to get a clock associated with a platform device. Embedded systems often use clocks for power saving, and they are linked to devices via setup code.

```C
clk_get(&pdev->dev, clock_name)
```

--------------------------------

### Boot Setup Commands and Parameters

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/scsi/sym53c8xx_2.rst

Explains how to pass setup commands and parameters to the driver at boot time, either via the bootloader prompt (e.g., LILO) or as arguments to the 'modprobe' command.

```APIDOC
Boot Setup Command Syntax:
  - Commands can be passed at boot time or via modprobe.

Example (LILO prompt):
  lilo: linux root=/dev/sda2 sym53c8xx.cmd_per_lun=4 sym53c8xx.sync=10 sym53c8xx.debug=0x200
  - Enables tagged commands (4 per LUN).
  - Sets synchronous negotiation speed to 10 Mega-transfers/sec.
  - Sets the DEBUG_NEGO flag.

Example (modprobe):
  modprobe sym53c8xx cmd_per_lun=4 sync=10 debug=0x200

Available Arguments:

cmd_per_lun:
  - Description: Controls the default number of tagged commands per logical unit.
  - Values:
    - cmd_per_lun=0 or cmd_per_lun=1: Tagged command queuing disabled.
    - cmd_per_lun=#tags (#tags > 1): Tagged command queuing enabled.
  - Note: #tags will be truncated to the 'Maximum number of queued commands' configuration parameter.

burst:
  - Description: Controls burst transfer settings.
  - Values:
    - burst=0: Burst transfer disabled.
    - burst=255: Get burst length from initial IO register settings.
```

--------------------------------

### Unbindable Mount Example - Setup

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/filesystems/sharedsubtree.rst

Demonstrates the initial setup for using unbindable mounts to replicate a directory tree efficiently, starting with a simple root structure.

```bash
# Initial tree structure:
#     root
#    /    \
#   tmp    usr
```

--------------------------------

### BPF Filesystem Setup Example

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/tools/bpf/bpftool/Documentation/bpftool-cgroup.rst

Demonstrates the steps to mount the BPF filesystem and prepare it for BPF program operations.

```shell
# mount -t bpf none /sys/fs/bpf/
```

--------------------------------

### Example Git Log Command

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/process/submitting-patches.rst

An example of how to use the Git log command with a custom pretty format to display commit information, including the 'Fixes:' tag. This is useful for reviewing commit history.

```bash
$ git log -1 --pretty=fixes 54a4f0239f2e
Fixes: 54a4f0239f2e ("KVM: MMU: make kvm_mmu_zap_page() return the number of pages it actually freed")
```

--------------------------------

### Create and Test a Simple Initramfs with Hello World

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/filesystems/ramfs-rootfs-initramfs.rst

This snippet demonstrates how to create a basic C program, compile it statically, package it into a cpio.gz archive, and test it using QEMU. This serves as a fundamental example for understanding initramfs creation and execution.

```c
#include <stdio.h>
#include <unistd.h>

int main(int argc, char *argv[])
{
  printf("Hello world!\n");
  sleep(999999999);
}
```

```bash
gcc -static hello.c -o init
echo init | cpio -o -H newc | gzip > test.cpio.gz
qemu -kernel /boot/vmlinuz -initrd test.cpio.gz /dev/zero
```

--------------------------------

### Example: Starting ADSL Connection

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/networking/device_drivers/atm/cxacru.rst

Example of how to start the ADSL connection for the cxacru device by writing 'start' to the 'adsl_state' sysfs attribute.

```shell
echo "start" > /sys/class/atm/cxacru0/adsl_state
```

--------------------------------

### Co-developed-by and Signed-off-by Example

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/process/submitting-patches.rst

Illustrates the correct structure for commit messages involving co-authorship, demonstrating the required sequence of Co-developed-by: and Signed-off-by: tags for multiple contributors.

```APIDOC
Example 1: Patch submitted by the From: author

<changelog>

Co-developed-by: First Co-Author <first@coauthor.example.org>
Signed-off-by: First Co-Author <first@coauthor.example.org>
Co-developed-by: Second Co-Author <second@coauthor.example.org>
Signed-off-by: Second Co-Author <second@coauthor.example.org>
Signed-off-by: From Author <from@author.example.org>

Example 2: Patch submitted by a Co-developed-by: author

From: From Author <from@author.example.org>

<changelog>

Co-developed-by: Random Co-Author <random@coauthor.example.org>
Signed-off-by: Random Co-Author <random@coauthor.example.org>
Signed-off-by: From Author <from@author.example.org>
Co-developed-by: Submitting Co-Author <sub@coauthor.example.org>
Signed-off-by: Submitting Co-Author <sub@coauthor.example.org>
```

--------------------------------

### Build OrangeFS from Source

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/filesystems/orangefs.rst

Provides instructions for building OrangeFS from source code, including configuration with specific backends, compilation, installation, and generating configuration files. It also covers starting the server and client, and mounting the filesystem.

```shell
./configure --prefix=/opt/ofs --with-db-backend=lmdb --disable-usrint

make
make install

# Create an orangefs config file
/opt/ofs/bin/pvfs2-genconfig /etc/pvfs2.conf

# Create an /etc/pvfs2tab file
echo tcp://localhost:3334/orangefs /pvfsmnt pvfs2 defaults,noauto 0 0 > \
	/etc/pvfs2tab

# Create the mount point
mkdir /pvfsmnt

# Bootstrap the server
/opt/ofs/sbin/pvfs2-server -f /etc/pvfs2.conf

# Start the server
/opt/ofs/sbin/pvfs2-server /etc/pvfs2.conf

# Test the server
/opt/ofs/bin/pvfs2-ls /pvfsmnt

# Load kernel module and turn on client core
/opt/ofs/sbin/pvfs2-client -p /opt/ofs/sbin/pvfs2-client-core

# Mount your filesystem
mount -t pvfs2 tcp://`hostname`:3334/orangefs /pvfsmnt
```

--------------------------------

### dmsetup Create Cache Device Examples

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/admin-guide/device-mapper/cache.rst

Examples demonstrating how to create a cache device using the `dmsetup create` command with various configurations for block size, cache type, and policy arguments.

```shell
dmsetup create my_cache --table '0 41943040 cache /dev/mapper/metadata \
	  /dev/mapper/ssd /dev/mapper/origin 512 1 writeback default 0'
```

```shell
dmsetup create my_cache --table '0 41943040 cache /dev/mapper/metadata \
	  /dev/mapper/ssd /dev/mapper/origin 1024 1 writeback \
	  mq 4 sequential_threshold 1024 random_threshold 8'
```

--------------------------------

### Setup Static CPUHP State Example

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/core-api/cpu_hotplug.rst

Demonstrates how to set up a statically allocated CPUHP state for notifications on CPU online and offline operations. It includes registering callback functions for subsystem starting and dying events.

```c
int ret;

ret = cpuhp_setup_state(CPUHP_SUBSYS_STARTING, "subsys:starting",
                        subsys_cpu_starting, subsys_cpu_dying);
if (ret < 0)
     return ret;

/* ... operations ... */

cpuhp_remove_state(CPUHP_SUBSYS_STARTING);

```

--------------------------------

### Load hvcs Kernel Module with Parameter

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/powerpc/hvcs.rst

Example of loading the hvcs kernel module with a parameter to override the default number of tty devices, requesting 4 devices in this case.

```shell
insmod hvcs.ko hvcs_parm_num_devs=4
```

--------------------------------

### Manually Creating hvcs Device Nodes

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/powerpc/hvcs.rst

Provides examples of using the 'mknod' command to manually create persistent device nodes for the hvcs driver. This is necessary if udev does not create them automatically.

```bash
mknod /dev/hvcs0 c 254 0
mknod /dev/hvcs1 c 254 1
mknod /dev/hvcs2 c 254 2
mknod /dev/hvcs3 c 254 3
```

--------------------------------

### F2FS Basic Usage

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/filesystems/f2fs.rst

Outlines the fundamental steps for using the F2FS filesystem, including loading the kernel module, creating a mount point, formatting a block device, and mounting the filesystem.

```shell
# Load the f2fs.ko module if not compiled statically
insmod f2fs.ko

# Create a directory for mounting
mkdir /mnt/f2fs

# Format a block device and mount it as f2fs
mkfs.f2fs -l label /dev/block_device
mount -t f2fs /dev/block_device /mnt/f2fs
```

--------------------------------

### Build hvcs Driver as Kernel Module

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/powerpc/hvcs.rst

Example of selecting the IBM Hypervisor Virtual Console Server Support option as a module (<M>) in the kernel's menuconfig, enabling dynamic loading and unloading.

```shell
Device Drivers  --->
	Character devices  --->
		<M> IBM Hypervisor Virtual Console Server Support
```

--------------------------------

### bpftool Map Examples: Show, Update, Lookup, Dump, Getnext

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/tools/bpf/bpftool/Documentation/bpftool-map.rst

Illustrates common map operations with concrete examples, including showing map details, updating entries, looking up keys, dumping contents, and retrieving the next key.

```shell
# bpftool map show

::

  10: hash  name some_map  flags 0x0
        key 4B  value 8B  max_entries 2048  memlock 167936B
        pids systemd(1)

```

```shell
# bpftool map update id 10 key hex   20   c4   b7   00 value hex   0f   ff   ff   ab   01   02   03   4c
# bpftool map update id 10 key     0x20 0xc4 0xb7 0x00 value     0x0f 0xff 0xff 0xab 0x01 0x02 0x03 0x4c
# bpftool map update id 10 key       32  196  183    0 value       15  255  255  171    1    2    3   76

```

```shell
# bpftool map lookup id 10 key 0 1 2 3

::

  key: 00 01 02 03 value: 00 01 02 03 04 05 06 07

```

```shell
# bpftool map dump id 10

::

  key: 00 01 02 03  value: 00 01 02 03 04 05 06 07
  key: 0d 00 07 00  value: 02 00 00 00 01 02 03 04
  Found 2 elements

```

```shell
# bpftool map getnext id 10 key 0 1 2 3

::

  key:
  00 01 02 03
  next key:
  0d 00 07 00

```

--------------------------------

### Sample Network Interface Configuration Script

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/networking/device_drivers/ethernet/dlink/dl2k.rst

Example of a basic network configuration script (ifcfg-ethx) for a Linux system. It defines the device name, IP address, netmask, broadcast address, and boot protocol.

```shell
DEVICE=eth0
USERCTL=no
ONBOOT=yes
POOTPROTO=none
BROADCAST=207.200.5.255
NETWORK=207.200.5.0
NETMASK=255.255.255.0
IPADDR=207.200.5.2
```

--------------------------------

### SYM-2 Driver Boot Setup Commands

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/scsi/sym53c8xx_2.rst

This section details the syntax and available arguments for boot setup commands used to configure the SYM-2 driver at system startup, including options for default commands, burst limits, LED support, and SCSI bus checking.

```APIDOC
Boot Setup Commands:

Syntax:
  The boot setup commands follow a specific syntax, typically involving kernel command-line parameters.

Available arguments:
  - Default number of tagged commands: Sets the default number of tagged commands.
  - Burst max: Configures the maximum burst size.
  - LED support: Controls LED functionality.
  - Differential mode: Sets the SCSI differential mode.
  - IRQ mode: Configures the interrupt request mode.
  - Check SCSI BUS: Enables or disables SCSI bus checking.
  - Suggest a default SCSI id for hosts: Assigns a default SCSI ID.
  - Verbosity level: Sets the initial verbosity level.
  - Debug mode: Enables or disables initial debug mode.
  - Settle delay: Configures the signal settle delay.
  - Serial NVRAM: Enables or disables serial NVRAM support.
  - Exclude a host from being attached: Prevents a host from being attached.

Converting from old options:
  Information on how to convert older configuration options to the new format.

SCSI BUS checking boot option:
  Specific boot option for enabling SCSI BUS checking.
```

--------------------------------

### Run Installed Selftests

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/dev-tools/kselftest.rst

Executes the installed kernel selftests. After installation, navigate to the installation directory and run the provided script. Some tests may require root privileges.

```shell
cd kselftest_install
./run_kselftest.sh
```

--------------------------------

### ksmbd Setup and Build Instructions

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/filesystems/smb/ksmbd.rst

Steps to download, compile, and install ksmbd-tools, a utility suite for managing the ksmbd kernel module. This includes autogen, configure, and make commands.

```shell
# Download ksmbd-tools (e.g., from https://github.com/cifsd-team/ksmbd-tools/releases)
# Refer to README for usage details.

$ ./autogen.sh
$ ./configure --with-rundir=/run
$ make && sudo make install
```

--------------------------------

### Load hvcs Kernel Modules with modprobe

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/powerpc/hvcs.rst

Recommended method to load hvcs and hvcserver modules using modprobe, which respects module dependencies defined in modules.dep. This example also sets the number of devices to 4.

```shell
modprobe hvcs hvcs_parm_num_devs=4
```

--------------------------------

### F2FS Filesystem Management Examples

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/filesystems/f2fs.rst

Demonstrates common filesystem operations using shell commands, including creating F2FS filesystems with device aliasing, mounting, checking disk usage, and manipulating file flags using the f2fs_io utility.

```shell
# List devices
ls /dev/vd*

# Create ext4 filesystem on vdc
mkfs.ext4 /dev/vdc

# Create F2FS filesystem on vdb, aliasing vdc.file
mkfs.f2fs -c /dev/vdc@vdc.file /dev/vdb

# Mount F2FS filesystem
mount /dev/vdb /mnt/f2fs
ls -l /mnt/f2fs

# Check disk usage
df -h

# Mount vdc as ext4 via loop device
mount -o loop /dev/vdc /mnt/ext4
df -h

# Unmount ext4
umount /mnt/ext4

# Get flags for the aliased file
f2fs_io getflags /mnt/f2fs/vdc.file

# Set flags (e.g., remove immutable)
f2fs_io setflags noimmutable /mnt/f2fs/vdc.file

# Remove the aliased file to release space
rm /mnt/f2fs/vdc.file
```

--------------------------------

### Linux Boot Process with initrd

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/admin-guide/initrd.rst

Describes the typical steps involved when a system boots using an initrd, from loading the minimal kernel to installing the boot loader.

```APIDOC
Linux Boot Process with initrd:
  1. System boots from minimal kernel (e.g., with RAM disk, initrd support).
  2. Loads initrd.
  3. `/sbin/init` in initrd determines requirements for mounting the real root FS and distribution media.
  4. `/sbin/init` loads necessary kernel modules.
  5. `/sbin/init` creates and populates the root file system.
  6. `/sbin/init` invokes `pivot_root` to change the root file system and executes the real `/sbin/init` via chroot.
  7. Boot loader is installed.
  8. Boot loader is configured to load an initrd with appropriate modules.
```

--------------------------------

### Commit Message Tags and Linking Conventions

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/process/submitting-patches.rst

Examples of standard tags used in Linux kernel commit messages for referencing external discussions, bug reports, and specific fixes. These tags aid in tracking the context and resolution of changes.

```text
Link: https://lore.kernel.org/r/30th.anniversary.repost@klaava.Helsinki.FI/

Closes: https://example.com/issues/1234

Fixes: 54a4f0239f2e ("KVM: MMU: make kvm_mmu_zap_page() return the number of pages it actually freed")
```

--------------------------------

### Base Devicetree Example (foo.dts)

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/devicetree/overlay-notes.rst

Illustrates a base Devicetree source file for a 'foo' board, defining compatible devices and resources.

```Devicetree
/* FOO platform */
	/dts-v1/;
	/ {
		compatible = "corp,foo";

		/* shared resources */
		res: res {
		};

		/* On chip peripherals */
		ocp: ocp {
			/* peripherals that are always instantiated */
			peripheral1 {
			};
		};
	};

```

--------------------------------

### Build hvcs Driver Built-in to Kernel

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/powerpc/hvcs.rst

Example of selecting the IBM Hypervisor Virtual Console Server Support option within the Linux kernel's menuconfig utility to build the driver directly into the kernel image.

```shell
Device Drivers  --->
	Character devices  --->
		<*> IBM Hypervisor Virtual Console Server Support
```

--------------------------------

### seq_file Iterator start() Function Example

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/filesystems/seq_file.rst

Provides an example implementation of the `start()` function for a seq_file iterator. This function initializes the session and returns an iterator object, taking a position argument and allocating memory for it.

```c
static void *ct_seq_start(struct seq_file *s, loff_t *pos)
{
        loff_t *spos = kmalloc(sizeof(loff_t), GFP_KERNEL);
        if (! spos)

```

--------------------------------

### Cpuset Setup and Configuration Example

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/admin-guide/cgroup-v1/cpusets.rst

Demonstrates the sequence of shell commands to mount the cpuset filesystem, create a new cpuset named 'Charlie', configure its CPU and memory nodes, attach the current shell as a task, and verify the setup.

```bash
mount -t cgroup -ocpuset cpuset /sys/fs/cgroup/cpuset
cd /sys/fs/cgroup/cpuset
mkdir Charlie
cd Charlie
/bin/echo 2-3 > cpuset.cpus
/bin/echo 1 > cpuset.mems
/bin/echo $$ > tasks
sh
cat /proc/self/cpuset
```

--------------------------------

### ALSA Get Callback Example

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/sound/kernel-api/writing-an-alsa-driver.rst

Provides an example of a 'get' callback function used to read the current value of an ALSA control from user-space. It illustrates accessing chip-specific data and filling the value field.

```c
static int snd_myctl_get(struct snd_kcontrol *kcontrol,
                               struct snd_ctl_elem_value *ucontrol)
{
        struct mychip *chip = snd_kcontrol_chip(kcontrol);
        ucontrol->value.integer.value[0] = get_some_value(chip);
        return 0;
}
```

--------------------------------

### HugeTLB Cgroup Setup and Task Management

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/admin-guide/cgroup-v1/hugetlb.rst

Demonstrates mounting the HugeTLB cgroup controller and creating a new cgroup to move processes into. This involves basic shell commands for system administration.

```shell
mount -t cgroup -o hugetlb none /sys/fs/cgroup
```

```shell
cd /sys/fs/cgroup
```

```shell
mkdir g1
```

```shell
echo $$ > g1/tasks
```

--------------------------------

### setup_data Structure and Usage

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/arch/x86/boot.rst

Defines the `setup_data` structure and its usage for an extensible boot parameters passing mechanism. It details the structure's fields, linked list management, and the introduction of `setup_indirect` for larger data objects.

```APIDOC
Field name: setup_data
Type: write (special)
Offset/size: 0x250/8
Protocol: 2.09+
Description: A 64-bit physical pointer to a NULL-terminated single linked list of `struct setup_data`. This mechanism allows for extensible boot parameter passing.

struct setup_data:
  - next: 64-bit physical pointer to the next node in the linked list. The last node's next field is 0.
  - type: Identifies the contents of the data field.
  - len: The length of the data field.
  - data: Holds the real payload.

Notes:
  - The list may be modified during bootup; consider existing entries when modifying.
  - Awkward for extremely large data objects due to header adjacency and 32-bit length field.

struct setup_indirect (introduced in protocol 2.15):
  - Used for pointing to larger data objects.
  - type: SETUP_INDIRECT | SETUP_* type. Cannot be SETUP_INDIRECT itself.
  - reserved: Must be set to zero.
  - len: Length of the data object (64-bit).
  - addr: Physical address of the data object.

Example of pointing to SETUP_E820_EXT data using setup_indirect:
struct setup_data {
  __u64 next = 0 or <addr_of_next_setup_data_struct>;
  __u32 type = SETUP_INDIRECT;
  __u32 len = sizeof(setup_indirect);
  __u8 data[sizeof(setup_indirect)] = struct setup_indirect {
    __u32 type = SETUP_INDIRECT | SETUP_E820_EXT;
    __u32 reserved = 0;
    __u64 len = <len_of_SETUP_E820_EXT_data>;
    __u64 addr = <addr_of_SETUP_E820_EXT_data>;
  }
}

Limitation:
  - SETUP_INDIRECT | SETUP_NONE objects cannot be properly distinguished from SETUP_INDIRECT itself.
```

--------------------------------

### Install Selftests

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/dev-tools/kselftest.rst

Installs kernel selftests to a user-specified directory. This command requires navigating to the tools/testing/selftests directory and specifying the target installation path.

```shell
make -C tools/testing/selftests install INSTALL_PATH=/some/other/path
```

--------------------------------

### Procfs Mounting and Remounting Examples

Source: https://github.com/nothingoss/android_kernel_msm-6.6_nothing_sm8735/blob/sm8735/v/mr/Documentation/filesystems/proc.rst

Demonstrates how to mount and remount the procfs filesystem with different options, showing the effects on /proc/mounts and using strace for command tracing.

```shell
# Example of initial procfs mount
grep ^proc /proc/mounts
proc /proc proc rw,relatime,hidepid=2 0 0

# Example of mounting with strace output
strace -e mount mount -o hidepid=1 -t proc proc /tmp/proc
mount("proc", "/tmp/proc", "proc", 0, "hidepid=1") = 0
+++ exited with 0 +++

# Verifying mounts after strace example
grep ^proc /proc/mounts
proc /proc proc rw,relatime,hidepid=2 0 0
proc /tmp/proc proc rw,relatime,hidepid=2 0 0

# Example of remounting to change options globally
mount -o remount,hidepid=1 -t proc proc /tmp/proc

# Verifying mounts after remount
grep ^proc /proc/mounts
proc /proc proc rw,relatime,hidepid=1 0 0
proc /tmp/proc proc rw,relatime,hidepid=1 0 0

# Example of mounting multiple procfs instances with different options
mount -o hidepid=invisible -t proc proc /proc
mount -o hidepid=noaccess -t proc proc /tmp/proc

# Verifying multiple instances
grep ^proc /proc/mounts
proc /proc proc rw,relatime,hidepid=invisible 0 0
proc /tmp/proc proc rw,relatime,hidepid=noaccess 0 0
```