Struct Boundary

pub struct Boundary;

Defines the usermode-kernelmode ABI for x86 platforms.

Implementations

impl Boundary

pub fn new() -> Self

Constructs a new instance of SysCall.

Trait Implementations

impl Default for Boundary

fn default() -> Self

Returns the “default value” for a type.

impl UserspaceKernelBoundary for Boundary

type StoredState = UserContext

Some architecture-specific struct containing per-process state that must be kept while the process is not running. For example, for keeping CPU registers that aren’t stored on the stack.

fn initial_process_app_brk_size(&self) -> usize

Called by the kernel during process creation to inform the kernel of the minimum amount of process-accessible RAM needed by a new process. This allows for architecture-specific process layout decisions, such as stack pointer initialization.

unsafe fn initialize_process( &self, accessible_memory_start: *const u8, app_brk: *const u8, state: &mut Self::StoredState, ) -> Result<(), ()>

Called by the kernel after it has memory allocated to it but before it is allowed to begin executing. Allows for architecture-specific process setup, e.g. allocating a syscall stack frame.

unsafe fn set_syscall_return_value( &self, accessible_memory_start: *const u8, app_brk: *const u8, state: &mut Self::StoredState, return_value: SyscallReturn, ) -> Result<(), ()>

Set the return value the process should see when it begins executing again after the syscall. This will only be called after a process has called a syscall.

unsafe fn set_process_function( &self, accessible_memory_start: *const u8, app_brk: *const u8, state: &mut Self::StoredState, upcall: FunctionCall, ) -> Result<(), ()>

Set the function that the process should execute when it is resumed. This has two major uses: 1) sets up the initial function call to _start when the process is started for the very first time; 2) tells the process to execute a upcall function after calling yield().

unsafe fn switch_to_process( &self, accessible_memory_start: *const u8, app_brk: *const u8, state: &mut Self::StoredState, ) -> (ContextSwitchReason, Option<*const u8>)

Context switch to a specific process.

unsafe fn print_context( &self, _accessible_memory_start: *const u8, _app_brk: *const u8, state: &Self::StoredState, writer: &mut dyn Write, )

Display architecture specific (e.g. CPU registers or status flags) data for a process identified by the stored state for that process.

fn store_context( &self, _state: &Self::StoredState, _out: &mut [u8], ) -> Result<usize, ErrorCode>

Store architecture specific (e.g. CPU registers or status flags) data for a process. On success returns the number of elements written to out.