Files
LithosAnanke/kernel/include/starkernel/plic.h
T
Claude 16b9747d33 chore(license): the source headers name the Starship License 1.0 (SL-1.0), as LICENSE does [skip ci]
347 headers said "Licensed under the StarForth License, Version 1.0" -- a
shortening (Captain Bob, 2026-11-08: "License file SL I think I shortened
accidently"); LICENSE is, and has been since the first commit, the
Starship License 1.0 (SL-1.0, SPDX LicenseRef-Starship-1.0). 349 files,
566 occurrences, now "Starship License, Version 1.0 (SL-1.0)".

Left as they are, pending a ruling: docs/patent/ (the patent figures),
docs/formal/ (the citable volumes) and the generated reports under
docs/working/experiments/ (32 files). Comments and license text only:
the amd64 kernel builds, every changed script parses.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GE3SDvQn5EoxdGufk84zz2
2026-11-08 17:54:24 +00:00

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/*
StarForth — Steady-State Virtual Machine Runtime
Copyright (c) 2023–2025 Robert A. James. All rights reserved.
Licensed under the Starship License, Version 1.0 (SL-1.0).
*/
/**
* plic.h - Platform-Level Interrupt Controller interface (riscv64 only)
*
* Item 4.3.5a (FABRIC-0.md §27.5): Phase 0 (0.2/0.3) only ever enabled the
* S-mode *timer* interrupt (sie.STIE). External interrupts (sie.SEIE) were
* never touched, and the PLIC -- the only external-interrupt path on
* RISC-V, there is no legacy PIC or I/O APIC equivalent -- had no driver
* at all before this item. Pure substrate: this item wires the mechanism
* (claim/dispatch/complete) with no permanent source enabled by default;
* a real consumer (4.3.5b, virtio-keyboard) enables its own source later.
*
* @c plic_init() takes the boot DTB as of FABRIC-3.md §V.3 item 3's fix,
* 2026-09-05: the base address was previously a QEMU-virt-specific
* hardcoded constant, unconditionally wrong on the Milk-V Mars's real
* JH7110 PLIC. See @c plic.c's file header for the discovery mechanism.
*/
#ifndef STARKERNEL_PLIC_H
#define STARKERNEL_PLIC_H
#include <stdint.h>
/**
* Map the PLIC and set the S-mode hart-0 context's priority threshold to 0
* (maximally permissive -- safe because nothing is enabled at any source
* by default; enabling a source is what actually lets it reach claim()).
* Also sets sie.SEIE. Does not touch sstatus.SIE -- arch_enable_interrupts()
* still owns that, same as the timer.
*
* @param dtb Candidate devicetree blob (@c BootInfo->dtb); NULL-safe. When
* a real @c "sifive,plic-1.0.0" node is found, the PLIC base
* address is read from its @c reg property; otherwise falls
* back to the QEMU-virt-machine constant, unchanged from this
* function's previous unconditional behaviour.
* @return 0 on success.
*/
int plic_init(const void *dtb);
/** Set a source's interrupt priority (1-7; 0 means "never interrupt"). */
void plic_set_priority(uint32_t irq, uint32_t priority);
/** Enable a source for the S-mode hart-0 context. */
void plic_enable(uint32_t irq);
/** Disable a source for the S-mode hart-0 context. */
void plic_disable(uint32_t irq);
/**
* Claim the highest-priority pending interrupt for the S-mode hart-0
* context. Returns the source ID, or 0 if none is pending.
*/
uint32_t plic_claim(void);
/** Signal completion of the source previously returned by plic_claim(). */
void plic_complete(uint32_t irq);
#endif /* STARKERNEL_PLIC_H */