Daniel Samson
8754d4e46a
The source layout now mirrors the runtime filesystem hierarchy
(docs/danos-file-system-hierarchy-FSH.md): what lives under system/ in the
source is what a running danos represents under /system. Each service and
driver is a sub-project directory that is its own Zig module — cross-project
references go by module name, never by a path into another project's files.
Moves (all git mv, history preserved):
- src/ -> system/ (danos internals; the self-representation)
root.zig -> danos.zig (the kernel<->user contract module)
kernel/arch/ -> kernel/architecture/ (arch -> architecture)
device/ -> devices/ (what /system/devices reflects)
boot/ -> /boot (the loaders, top level)
- sbin/ -> split by role:
init, vfs -> system/services/<name>/<name>.zig
hpetd, busd -> system/drivers/<name>/<name>.zig
vfs-test -> system/services/vfs/vfs-test.zig (inside the vfs project)
- lib/ -> library/runtime/ (room for other libraries beside runtime)
The VFS wire protocol becomes its own module, system/services/vfs/protocol.zig
("vfs-protocol"): the vfs sub-project exposes its interface, and the runtime's
file layer imports it by name. First instance of the "protocol module" pattern
(docs/driver-model.md); usb/block will expose theirs the same way.
Also: fix a naming-standard violation in the protocol — Op -> Operation (and
req -> request, _pad -> _padding). Docs updated: /system/services added to the
FHS doc, a repository-layout section added to the docs index, and stale source
paths swept across comments and docs.
Runtime boot paths are unchanged (the bootloader still loads /sbin/init);
aligning the runtime filesystem to the FHS is a separate follow-up. Suite 35/35
plus host tests green.
53 lines
1.7 KiB
Plaintext
53 lines
1.7 KiB
Plaintext
/* Kernel link layout — higher half.
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*
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* The kernel is linked to *run* in the higher half (virtual base
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* 0xFFFF_FFFF_8000_0000, matching danos.kernel_virt_base and build.zig's
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* image_base) but is *loaded* low. Each section's load address (LMA) is its
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* virtual address minus KERNEL_VIRT_BASE via AT(), so the ELF's p_paddr lands
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* at a low physical address (.text at 1 MiB) that the loader can allocate and
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* copy into. The loader maps p_vaddr (high) -> p_paddr (low) in its bootstrap
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* tables and jumps to the high entry; the kernel then builds its own tables
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* with the physmap and abandons the identity map. Requires LLD (build.zig pins
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* it) — the self-hosted linker ignores PHDRS/AT()/section order.
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*/
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KERNEL_VIRT_BASE = 0xFFFFFFFF80000000;
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ENTRY(_start)
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/* One loadable segment per permission set, so the loader can map .text as R+X,
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* .rodata as R, and .data/.bss as R+W. FLAGS bits: 1=X, 2=W, 4=R. */
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PHDRS {
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text PT_LOAD FLAGS(5); /* R + X */
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rodata PT_LOAD FLAGS(4); /* R */
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data PT_LOAD FLAGS(6); /* R + W */
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}
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SECTIONS {
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.text ALIGN(4K) : AT(ADDR(.text) - KERNEL_VIRT_BASE) {
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*(.text .text.*)
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} :text
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.rodata ALIGN(4K) : AT(ADDR(.rodata) - KERNEL_VIRT_BASE) {
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*(.rodata .rodata.*)
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} :rodata
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.data ALIGN(4K) : AT(ADDR(.data) - KERNEL_VIRT_BASE) {
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*(.data .data.*)
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} :data
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/* .bss occupies memory but not file space. The loader zeroes it via the
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* gap between each PT_LOAD segment's file size and memory size, so no
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* boundary symbols are needed here. */
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.bss ALIGN(4K) : AT(ADDR(.bss) - KERNEL_VIRT_BASE) {
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*(.bss .bss.*)
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*(COMMON)
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} :data
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/DISCARD/ : {
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*(.comment)
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*(.note .note.*)
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*(.eh_frame .eh_frame_hdr)
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}
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}
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