First attempt at a UART driver. I'm not sure it's the most stable. Now
that userspace is handling displaying logs, also removed serial and log
output support from the kernel.
This is a rather large commit that is widely focused on cleaning things
out of the 'junk drawer' that is src/include. Most notably, several
things that were put in there because they needed somewhere where both
the kernel, boot, and init could read them have been moved to a new lib,
'bootproto'.
- Moved kernel_args.h and init_args.h to bootproto as kernel.h and
init.h, respectively.
- Moved counted.h and pointer_manipulation.h into util, renaming the
latter to util/pointers.h.
- Created a new src/include/arch for very arch-dependent definitions,
and moved some kernel_memory.h constants like frame size, page table
entry count, etc to arch/amd64/memory.h. Also created arch/memory.h
which detects platform and includes the former.
- Got rid of kernel_memory.h entirely in favor of a new, cog-based
approach. The new definitions/memory_layout.csv lists memory regions
in descending order from the top of memory, their sizes, and whether
they are shared outside the kernel (ie, boot needs to know them). The
new header bootproto/memory.h exposes the addresses of the shared
regions, while the kernel's memory.h gains the start and size of all
the regions. Also renamed the badly-named page-offset area the linear
area.
- The python build scripts got a few new features: the ability to parse
the csv mentioned above in a new memory.py module; the ability to add
dependencies to existing source files (The list of files that I had to
pull out of the main list just to add them with the dependency on
memory.h was getting too large. So I put them back into the sources
list, and added the dependency post-hoc.); and the ability to
reference 'source_root', 'build_root', and 'module_root' variables in
.module files.
- Some utility functions that were in the kernel's memory.h got moved to
util/pointers.h and util/misc.h, and misc.h's byteswap was renamed
byteswap32 to be more specific.
Now that kutil has no kernel-specific code in it anymore, it can
actually be linked to by anything, so I'm renaming it 'util'.
Also, I've tried to unify the way that the system libraries from
src/libraries are #included using <> instead of "".
Other small change: util::bip_buffer got a spinlock to guard against
state corruption.
Continuing moving things out of kutil. The assert as implemented could
only ever work in the kernel, so remaining kutil uses of kassert have
been moved to including standard C assert instead.
Along the way, kassert was broken out into panic::panic and kassert,
and the panic.serial namespace was renamed panicking.
The moving of kernel-only code out of kutil continues. (See 042f061)
This commit moves the following:
- The heap allocator code
- memory.cpp/h which means:
- letting string.h be the right header for memset and memcpy, still
including an implementation of it for the kernel though, since
we're not linking libc to the kernel
- Changing calls to kalloc/kfree to new/delete in kutil containers
that aren't going to be merged into the kernel
- Fixing a problem with stdalign.h from libc, which was causing issues
for type_traits.
Fixing two page allocation issues I came across while debugging:
- Added a spinlock to the page_table static page cache, to avoid
multiple CPUs grabbing the same page. This cache should probably
just be made into per-CPU caches.
- Fixed a bitwise math issue ("1" instead of "1ull" when working with
64-bit numbers) that made it so that pages were never marked as
allocated when allocating 32 or more.
I'm a tabs guy. I like tabs, it's an elegant way to represent
indentation instead of brute-forcing it. But I have to admit that the
world seems to be going towards spaces, and tooling tends not to play
nice with tabs. So here we go, changing the whole repo to spaces since
I'm getting tired of all the inconsistent formatting.
The kernel::args namespace is really the protocol for initializing the
kernel from the bootloader. Also, the header struct in that namespace
isn't actually a header, but a collection of parameters. This change
renames the namespace to kernel::init and the struct to args.
The frame allocator was causing page faults when exhausting the first
(well, last, because it starts from the end) block of free pages. Turns
out it was just incrementing instead of decrementing and thus running
off the end.
The previous frame allocator involved a lot of splitting and merging
linked lists and lost all information about frames while they were
allocated. The new allocator is based on an array of descriptor
structures and a bitmap. Each memory map region of allocatable memory
becomes one or more descriptors, each mapping up to 1GiB of physical
memory. The descriptors implement two levels of a bitmap tree, and have
a pointer into the large contiguous bitmap to track individual pages.
Finished the VMA kobject and added the related syscalls. Processes can
now allocate memory! Other changes in this commit:
- stop using g_frame_allocator and add frame_allocator::get()
- make sure to release all handles in the process dtor
- fix kutil::map::iterator never comparing to end()
Add an iterator type to kutil::map, and allow for each loops. Also
unify the compare() signature expected by sorting containers, and fixes
to adding and sorting in kutil::vector.
Defer from calling process::thread_exited() in scheduler::prune() if the
thread in question is the currently-executing thread, so that we don't
blow away the stack we're executing on. The next call to prune will pick
up the exited thread.
Removing the `allocator.h` file defining the `kutil::allocator`
interface, now that explicit allocators are not being passed around.
Also removed the unused `frame_allocator::raw_allocator` class and
`kutil::invalid_allocator` object.
Tags: memory
Look up the global constructor list that the linker outputs, and run
them all. Required creation of the `kutil::no_construct` template for
objects that are constructed before the global constructors are run.
Also split the `memory_initialize` function into two - one for just
those objects that need to happen before the global ctors, and one
after.
Tags: memory c++
This commit makes several fundamental changes to memory handling:
- the frame allocator is now only an allocator for free frames, and does
not track used frames.
- the frame allocator now stores its free list inside the free frames
themselves, as a hybrid stack/span model.
- This has the implication that all frames must currently fit within
the offset area.
- kutil has a new allocator interface, which is the only allowed way for
any code outside of src/kernel to allocate. Code under src/kernel
_may_ use new/delete, but should prefer the allocator interface.
- the heap manager has become heap_allocator, which is merely an
implementation of kutil::allocator which doles out sections of a given
address range.
- the heap manager now only writes block headers when necessary,
avoiding page faults until they're actually needed
- page_manager now has a page fault handler, which checks with the
address_manager to see if the address is known, and provides a frame
mapping if it is, allowing heap manager to work with its entire
address size from the start. (Currently 32GiB.)
