The current tear down implementation assumes that all data mappings &
intermediate tables need to be free'd. That might not provide enough
flexibility for all tear-down scenarios.
Provide a more flexible API, passing current walk state into a control
function which makes a descision regarding tear-down and recursion.
The `SmallocPageAlloc` type is generic and architecture-independent, so
it belongs in libkernel rather than the kernel's arm64-specific code. It
is placed in memory::paging::smalloc_page_allocator and gated by the
existing paging feature.
The kernel's copy is replaced with a thin re-export so all call sites
are unaffected.
Since the only requirement for a `PageOffsetTranslator` is a constant
offset, pass that in as a generic parameter, allowing it to be decoupled
from the `VirtualMemory` trait.
- add per-task signal waiter notifier
- wake waiters when task/group signals are queued
- replace signalfd polling sleep with waker-based waiting
- route SIGCHLD and other signal enqueue sites through shared helpers
Move the NextLevel AT into the TableMapper (descriptor-level) trait.
This allows us to provide a blanket implementation of TableMapperTable
for all tables where, Table::Descriptor : TableMapper.
Since the architectural details of descriptor implementation is hidden
behind traits, the code for walking page tables is arch-agnostic.
Therefore, promote it to shared code for use by other architectures.
We currently define the MAP_SHIFT for a page-table level in two places,
`TableMapper` and `PgTable`. Store only one shift trait constant value
in the `PageTableEntry` trait.
Any traits which are architecture agnostic should be available to be
implemented by other architectures. Move them out from the arm64 module
into a non-architecure specific location.
Move PtePermissions to paging module which is feature-gated behind
`paging`.
Also move all AddressSpace related functionality behind the `proc_vm`
feature gate.
ptrace 'child' events are treated differently during a wait than
'normal' child events. Speciecially, a process that is being traced
receives events for all threads (all `Tid`s) from a process, rather than
the `Tgid`.
This fixes running strace on multi-threaded programs.
Make the `Tid` globally unique, rather than `Tgid` creating a new number
space. This allows ptrace to differentiate between threads when using
`-f` on a program which spawns threads.
