Additionally, there were several bug fixes needed to allow this:
- frame_allocator was allocating its frame_blocks from the heap, causing
a circular dependency. Now it gives itself a page on its own when
needed.
- frame_allocator::free was putting any trailing pages in a block back
into the list after the current block, so they would be the next block
iterated to.
- frame_allocator::free was updating the address it was looking for
after freeing some pages, but not the count it was looking for, so it
would eventually free all pages after the initial address.
There are a lot of under the hood changes here:
- Move syscalls to be a dispatch table, defined by syscalls.inc
- Don't need a full process state (push_all) in syscalls now
- In push_all, define REGS instead of using offsets
- Save TWO stack pointers as well as current saved stack pointer in TCB:
- rsp0 is the base of the kernel stack for interrupts
- rsp3 is the saved user stack from cpu_data
- Update syscall numbers in nulldrv
- Some asm-debugging enhancements to the gdb script
- fork() still not working
- More sensible stack tracer, in C++ (no symbols yet)
- Was forgetting to add null frame to new kernel stacks
- __kernel_assert was using an old vector
- A GP fault will only print its associated table entry
Instead of building nested page tables for the offset region, just
offset map the entire thing into kernel memory with one PDP mapping
1GiB large pages. This is more efficient and avoids the "need a
page table to map in a page table" dependency loop.
2MiB large pages were being used for any large page mapping, but the
page manager doesn't correctly handle them everywhere yet. Now only
allow them for offset pointers (eg MMIO space) that will never be
unmapped.
* Non-blocksize-aligned regions could fail to be found. Have the
bootloader load them aligned.
* Consolidating used frame blocks in the bootstrap means these would
have been impossible to free as address space
* mark_permanent wasn't actually removing blocks from the free list
Removed the frame allocation logic from page_manager and replaced it
with using an instance of frame_allocator instead. This had several
major ripple effects:
- memory_initalize() had to change to support this new world
- Where to map used blocks is now passed as a flag, since blocks don't
track their virtual address anymore
- Instead of the complicated "find N contiguous pages that can be
mapped in with one page table", we now just have the bootloader give
us some (currently 64) pages to use both for tables and scratch
space.
- frame_allocator initialization was split into two steps to allow
mapping used blocks before std::move()ing them over
