The generic RecursiveWalker computed the coverage region for each
page-table entry as:
VirtMemoryRegion::new(entry_va, table_coverage).intersection(region)
For the last entry at the PML4 level (PML4[511]) in the kernel
high-half, entry_va + table_coverage wraps past usize::MAX, causing an
arithmetic overflow panic inside end_address().
Fix this in walk.rs by computing the intersection bounds with
saturating_add/min/max directly.
Add regression tests for all levels, ensuring last-element walking is
correct.
- 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.
Bit 7 on various descriptors in x86_64 can take on varying values
depending upon the descriptor type. Refelect that in the implementation
and fix a bug whereby the PAT bit would have been set when creating a
PTE.
The test harness code is useful across architectures. Therefore, move it
out of the arm64 directory so it can be used by other architectures
implementing paging unit-tests.
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.
