In prep for the coming change to keep log entries as a true ring buffer,
move the log buffer from bss into its own memory section.
Related changes in this commit:
- New vm_area_ring, which maps a set of pages twice to allow easy linear
reading of data from a ring buffer when it wraps around the end.
- logger_init() went away, and the logger ctor is called from
mem::initialize()
- Instead of an event object, the logger just has a bare wait_queue
- util::counted::from template type changed slightly to allow easy
conversion from an intptr_t as well as a pointer
- Previously added debugcon_logger code removed - this will be added in
a separate file in a followup commit
I often want to use util::counted as a bool, like with a regular
pointer. There was some basic support for that, but it didn't cover
every case - now it should.
Restructuring paging into an object that carries its page cache with it
and makes for simpler code. Program loading is also changed to not copy
the pages loaded from the file into new pages - we can impose a new
constraint that anything loaded by boot have a simple, page-aligned
layout so that we can just map the existing pages into the right
addresses. Also included are some linker script changes to help
accommodate this.
The symbol table needs to be passed to the panic handler very early in
the kernel, loading it in init is far less useful. Return it to the boot
directory and remove it from the initrd.
I added util::format as a replacement for other printf implementations
last year, but it sat there only being used by the kernel all this time.
Now I've templated it so that it can be used by the bootloader, and
removed printf from panic.serial as well.
Using `-fvisibility=hidden` when building the kernel, and then
`--discard-all` when stripping it, we shave almost 100KiB off of the
resulting ELF file.
Also dropped some unused symbols from the linker script, and rearranged
the sections so that the file is able to be mapped directly into memory
instead of having each section copied.
It felt clunky to have zstd.module in src/libraries/zstd by itself, and
doesn't make much sense in src/libraries as it's an external library
anyway.
Now the ./configure script will pick up .module files in the top-level
external directory as well.
I've been using `const util::buffer` a lot of places where that's not
really what I mean, because I was avoiding having a separate type for
buffers with const pointers. But really this needed to happen.
The initrd image is now created by the build system, loaded by the
bootloader, and passed to srv.init, which loads it (but doesn't do
anything with it yet, so this is actually a functional regression).
This simplifies a lot of the modules code between boot and init as well:
Gone are the many subclasses of module and all the data being inline
with the module structs, except for any loaded files. Now the only
modules loaded and passed will be the initrd, and any devices only the
bootloader has knowledge of, like the UEFI framebuffer.
A new compressed initrd format for srv.init to load drivers, services,
and data from, instead of every file getting loaded by the bootloader.
This will allow for less memory allocated by the bootloader and passed
to init if not every driver or data file is loaded.
Loading, passing, and using the new initrd will be done in a coming
commit.
The clang __builtin_* functions cannot be relied upon, as they may just
emit a call to the stdlib version. So this commit adds an implementation
for ceil and frexpr, as well as their float versions.
This new class makes it easier for user programs to spawn threads. This
change also includes support for .hh files in modules, to differentiate
headers that are C++-only in system libraries.
A number of simplifications of mailboxes now that the interface is much
simpler, and synchronous.
* call and respond can now only transfer one handle at a time
* mailbox objects got rid of the message queue, and just have
wait_queues of blocked threads, and a reply_to map.
* threads now have a message_data struct on them for use by mailboxes
Instead of handles / capabilities having numeric ids that are only valid
for the owning process, they are now global in a system capabilities
table. This will allow for specifying capabilities in IPC that doesn't
need to be kernel-controlled.
Processes will still need to be granted access to given capabilities,
but that can become a simpler system call than the current method of
sending them through mailbox messages (and worse, having to translate
every one into a new capability like was the case before). In order to
track which handles a process has access to, a new node_set based on
node_map allows for an efficient storage and lookup of handles.
When node_map grew, it was not properly applying the fixup routine to
non-moved elements. This fixes the grow algorithm to:
1. Realloc the array and set all new slots to empty/invalid
2. Check each old slot and remove/reinsert the item if it exists and its
optimal slot is later in the array than its current slot
3. Reverse-iterate the original slots and call fixup() on empty slots to
keep items from being located after a more-optimal empty slot
Also fixed the fixup() function to not need to be called in a loop
anymore, as it's only used the one way - on a given empty slot, looping
until it hits an empty slot or optimally-placed item.
The allocator is a interface for types that expose allocator functions
for use in container templates like node_map (usage coming soon).
Also added an implementation for the kernel heap allocator.
Created a new util/node_map.h that implements a map that grows in-place.
Now this is used for tracking blocks' size orders, instead of a header
at the start of the memory block. This allows the whole buddy block to
be allocated, allowing for page-aligned (or greater) blocks to be
requested from the heap.
The kernel log levels are now numerically reversed so that more-verbose
levels can be added to the end. Replaced 'debug' with 'verbose', and
added new 'spam' level.
In order to more easily express constants as bitsets, add more constexpr
to util::bitset. This allows expressing uint64_t constants as bitsets in
the code instead, without changing the generated assembly, to make code
more readable.
The printf library I have been using, while useful, has way more than I
need in it, and had comparably huge stack space requirements. This
change adds a new util::format() which is a replacement for snprintf,
but with only the features used by kernel logging.
The logger has been changed to use it, as well as the few instances of
snprintf in the interrupt handling code before calling kassert.
Also part of this change: the logger's (now vestigial) immediate output
handling code is removed, as well as the "sequence" field on log
message headers.
The cpu::cpu_id class no longer looks up all known features in the
constructor, but instead provides access to the map of supported
features as a bitset from the verify() method. It also exposes the
brand_name() method instead of loading the brand name string in the
constructor and storing it as part of the object.
Add a new bitset class which allows for arbitrarily-large bit sets, with
specializations for 32 and 64 bit sets.
Eventually the enum_bitfields code should probably be reconsidered and
moved to bitsets, since it doesn't work everywhere.
The init process now serves as a service locator for its children,
passing all children a mailbox handle on which it is serving the service
locator protocol.
This commit adds a new flag, j6_channel_block, and a new flags param to
the channel_receive syscall. When the block flag is specified, the
caller will block waiting for data on the channel if the channel is
empty.
Influenced by other libc implementations, I had tried to make memcpy
smarter for differently-sized ranges, but my benchmarks showed no real
change. So change memcpy back to the simple rep movsb implementation.
There was a specialization of util::hash() for uint64_t (which just
returns the integer value), but other integer sizes did not previously
have similar specializations.
Also, two minor semi-related changes to util::map - skip copying empty
nodes when growing the map, and assert that the hash is non-zero when
inserting a new node.
The constexpr_hash.h header has fallen out of use. As constexpr hashing
will be used for IDs with the service locator protocol, update these
hashes to be 32 and 64 bit FNV-1a, and replace the _h user-defined
literal with _id (a 64-bit hash), and _id8 (a 32-bit hash folded down to
8 bits). These are now in the util/hash.h header along with the runtime
hash functions.
Three issues that caused build breaks when regenerating the build
directory after the previous commits:
- system.def was including endpoint.def
- syscalls/vm_area.cpp was including j6/signals.h
- util/util.h was missing an include of stddef.h
The new mailbox kernel object API offers asynchronous message-based IPC
for sending data and handles between threads, as opposed to endpoint's
synchronous model.
In preparation for the new mailbox IPC model, blocking threads needed an
overhaul. The `wait_on_*` and `wake_on_*` methods are gone, and the
`block()` and `wake()` calls on threads now pass a value between the
waker and the blocked thread.
As part of this change, the concept of signals on the base kobject class
was removed, along with the queue of blocked threads waiting on any
given object. Signals are now exclusively the domain of the event object
type, and the new wait_queue utility class helps manage waiting threads
when an object does actually need this functionality. In some cases (eg,
logger) an event object is used instead of the lower-level wait_queue.
Since this change has a lot of ramifications, this large commit includes
the following additional changes:
- The j6_object_wait, j6_object_wait_many, and j6_thread_pause syscalls
have been removed.
- The j6_event_clear syscall has been removed - events are "cleared" by
reading them now. A new j6_event_wait syscall has been added to read
events.
- The generic close() method on kobject has been removed.
- The on_no_handles() method on kobject now deletes the object by
default, and needs to be overridden by classes that should not be.
- The j6_system_bind_irq syscall now takes an event handle, as well as a
signal that the IRQ should set on the event. IRQs will cause a waiting
thread to be woken with the appropriate bit set.
- Threads waking due to timeout is simplified to just having a
wake_timeout() accessor that returns a timestamp.
- The new wait_queue uses util::deque, which caused the disovery of two
bugs in the deque implementation: empty deques could still have a
single array allocated and thus return true for empty(), and new
arrays getting allocated were not being zeroed first.
- Exposed a new erase() method on util::map that takes a node pointer
instead of a key, skipping lookup.
The __init_libc function was already running the .init_array functions,
but was never running the .preinit_array functions. Now it runs them
both, in the correct order.
This commit joins the implementation of exit, _Exit, and abort into a
single translation unit, and also adds atexit, at_quick_exit, and
quick_exit. While this does go against the ideal of all libc functions
being in their own translation unit, their implementations are very
related, and so I think this makes sense.
The ctype functions are now both macros and functions (as allowed by the
spec). They're now implemented in the ctype_b style of glibc, as
libunwind wants __ctype_b_loc to work.
The new "noreturn" option tag on syscall methods causes those methods to
be generated with [[noreturn]] / _Noreturn to avoid clang complaining
that other functions marked noreturn, like exit(), because it can't tell
that the syscall never returns.
This new libc is mostly from scratch, with *printf() functions provided
by Marco Paland and Eyal Rozenberg's tiny printf library, and malloc and
friends provided by dlmalloc.
