Struct slos_hal::null_system::NullSystem

pub struct NullSystem {
    pub has_requested_return: bool,
    pub is_virtualized: bool,
}

A SystemHardware implementation where (almost) everything has no-op implementations

Behaviour

The following general rules apply:

Methods on HAL traits that return &'static mut T references to other HAL trait objects return references to valid things, but those things are also all no-op implementations (for example, NullConsole).

All methods that do not return a value are implemented as empty functions.

All methods that return a value will return either (a) a “sensible” value, in the case where the value is critical to the kernel, (b) the same value that Default::default would return, where Default is implemented for the type, or (c) a manually-constructed default value for the type that will make any operations on that type into no-ops.

Exceptions to the rules

• SystemHardware::system_name returns “slos-hal-nullsystem”.

• SystemHardware::has_requested_return will return the value of the has_requested_return field of the struct - this field is set to false in the constructor, and set to true on every call to the SystemKmainHooks::hook_kmain_loop_head method. This is done so that kmain will iterate exactly once before returning.

• If the is_virtualized field of this struct is set to true, the SystemHardware::virtualization method will return a value indicating that the system is virtualized (the “virtualization type” field of the value is set to SystemHardware::system_name). If the field is set to false, None is returned.

Default values

This struct implements the Default trait, these are the values that are set in that constructor:

NullSystem {
    has_requested_return: false,
    is_virtualized: true,
}

Safety

This implementation will never panic directly.

Fields

has_requested_return: bool

Whether to request a kmain return

is_virtualized: bool

Whether to indicate the system is virtualized

Trait Implementations

impl Debug for NullSystem

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for NullSystem

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq<NullSystem> for NullSystem

fn eq(&self, other: &NullSystem) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &NullSystem) -> bool

This method tests for !=.

impl SystemCpu for NullSystem

fn interrupts_disable(&mut self)

Disable interrupts on the current CPU

fn interrupts_enable(&mut self)

Enable interrupts on the current CPU

fn halt(&mut self)

Halt the current CPU

fn interrupts_are_enabled(&self) -> bool

Return whether interrupts are enabled on the current CPU

impl SystemHardware for NullSystem

fn system_name(&self) -> &'static str

Name of the crate implementing this system

fn console(&mut self) -> &'static mut dyn SystemConsole

Get a reference to the default SystemConsole instance

fn has_requested_return(&self) -> bool

Has the HAL has requested an immediate kmain return?

fn current_cpu(&mut self) -> &'static mut dyn SystemCpu

Current CPU

fn virtualization(&self) -> Option<(&'static str, ())>

Virtualization

impl SystemKmainHooks for NullSystem

fn hook_kmain_loop_head(&mut self)

kmain loop head hook

fn hook_kmain_loop_inner_part(&mut self)

kmain inner partial loop hook

impl StructuralPartialEq for NullSystem