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[docs] Update docs: kernel mem, process init

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Updated documentation: Added documentation on the kernel address space
layout, process initialization, and rebuilt the syscall docs.
This commit is contained in:
Justin C. Miller
2024-08-10 23:11:14 -07:00
parent d3f5db2479
commit ff64d1989f
7 changed files with 265 additions and 13 deletions
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.. jsix syscall interface.
.. Automatically updated from the definition files using cog!
.. [[[cog code generation
.. from os.path import join
.. from memory import Layout, unit
..
.. layout = Layout(join(definitions_path, "memory_layout.yaml"))
.. l = max([len(r.name) for r in layout.regions])
.. ]]]
.. [[[end]]] (checksum: d41d8cd98f00b204e9800998ecf8427e)
Kernel memory
=============
While jsix probably should eventually use KASLR to randomize its memory layout,
currently the layout is mostly fixed. (Kernel code locations are not consistent
but aren't explicitly randomized.)
.. [[[cog code generation
.. line_size = 128 * 1024**3 # Each line represents up to 32 GiB
.. max_lines = 32
.. totals = sum([r.size for r in layout.regions])
.. remain = unit((128 * 1024**4) - totals)
..
.. def split(val):
.. return f"0x {val >> 48:04x} {(val >> 32) & 0xffff:04x} {(val >> 16) & 0xffff:04x} {val & 0xffff:04x}"
..
.. cog.outl()
.. cog.outl(f"+-+-----------------------------+----------+---------------------------------------+")
.. cog.outl(f"| | Address | Size | Use |")
.. cog.outl(f"+=+=============================+==========+=======================================+")
..
.. for region in layout.regions:
.. cog.outl(f"| | ``{split(region.start)}`` | {unit(region.size):>8} | {region.desc:37} |")
.. lines = min(max_lines, region.size // line_size)
.. for i in range(1, lines):
.. cog.outl(f"+-+ | | |")
.. cog.outl(f"| | | | |")
.. cog.outl(f"+-+-----------------------------+----------+---------------------------------------+")
..
.. cog.outl(f"| | ... | | |")
.. cog.outl(f"+-+-----------------------------+----------+---------------------------------------+")
.. cog.outl(f"| | ``0x ffff 0000 0000 0000`` | | Kernel code / headers |")
.. cog.outl(f"+-+-----------------------------+----------+---------------------------------------+")
.. cog.outl("")
.. cog.outl("")
.. cog.outl(f"Un-reserved virtual memory address space in the higher half: {remain}")
.. cog.outl("")
..
.. ]]]
+-+-----------------------------+----------+---------------------------------------+
| | Address | Size | Use |
+=+=============================+==========+=======================================+
| | ``0x ffff c000 0000 0000`` | 64 TiB | Linearly-mapped physical memory |
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+-+-----------------------------+----------+---------------------------------------+
| | ``0x ffff bf00 0000 0000`` | 1 TiB | Used/free page tracking bitmap |
+-+ | | |
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+-+-----------------------------+----------+---------------------------------------+
| | ``0x ffff be00 0000 0000`` | 1 TiB | Per-page state tracking structures |
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+-+-----------------------------+----------+---------------------------------------+
| | ``0x ffff bdf8 0000 0000`` | 32 GiB | Kernel heap accounting structures |
+-+-----------------------------+----------+---------------------------------------+
| | ``0x ffff bdf0 0000 0000`` | 32 GiB | Kernel heap |
+-+-----------------------------+----------+---------------------------------------+
| | ``0x ffff bde8 0000 0000`` | 32 GiB | Capabilities accounting structures |
+-+-----------------------------+----------+---------------------------------------+
| | ``0x ffff bde0 0000 0000`` | 32 GiB | Capabilities |
+-+-----------------------------+----------+---------------------------------------+
| | ``0x ffff bdd0 0000 0000`` | 64 GiB | Kernel thread stacks |
+-+-----------------------------+----------+---------------------------------------+
| | ``0x ffff bdc0 0000 0000`` | 64 GiB | Kernel buffers |
+-+-----------------------------+----------+---------------------------------------+
| | ``0x ffff bdbf 8000 0000`` | 2 GiB | Kernel logs circular buffer |
+-+-----------------------------+----------+---------------------------------------+
| | ... | | |
+-+-----------------------------+----------+---------------------------------------+
| | ``0x ffff 0000 0000 0000`` | | Kernel code / headers |
+-+-----------------------------+----------+---------------------------------------+
Un-reserved virtual memory address space in the higher half: 61 TiB
.. [[[end]]] (checksum: 8c336cc8151beba1a79c8d3b653f1109)
* :ref:`genindex`
* :ref:`search`