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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Copyright (C) 2026 Richard Qin */
#ifndef _ASM_RISCV_PGTABLE_H
#define _ASM_RISCV_PGTABLE_H
/*
* Early page-table construction API used by arch/riscv/mm/init.cc::setup_vm.
*
* Mirrors the create_pgd_mapping interface from Linux's
* arch/riscv/mm/init.c — same name, same semantics:
*
* create_pgd_mapping(pgdir, va, pa, sz, prot)
*
* pgdir : root of the page table to populate
* va : virtual address to map
* pa : physical address to map to
* sz : mapping size — must be a supported leaf size (PAGE_SIZE,
* 2 MiB megapage, or 1 GiB gigapage)
* prot : PTE flag bits (PAGE_KERNEL_EXEC etc., from <asm/page.h>)
*
* The boot-time variant in this file only supports gigapage (1 GiB)
* mappings — that is all setup_vm needs for the early_pg_dir / trampoline_pg_dir
* built before the slab allocator exists. Finer-grained mappings come
* later via vmm_init().
*/
#include <lume/types.h>
#include <asm/page.h>
#ifdef __cplusplus
extern "C" {
#endif
typedef struct { unsigned long pgd; } pgd_t;
/* Linker-provided early page-table storage (defined in lumeos.lds.S
* ARCH_BSS_EXTRA, lives in .bss so it's zero-initialized). Allocating
* them in the linker script — not in C — mirrors Linux and keeps the
* symbols visible from head.S without a forward C decl mismatch. */
extern pgd_t early_pg_dir[PTRS_PER_PGD];
extern pgd_t trampoline_pg_dir[PTRS_PER_PGD];
extern pgd_t fixmap_pg_dir[PTRS_PER_PGD];
/* Install a single PGD entry mapping `va` → `pa` with size `sz` and PTE
* flags `prot`. Only sz == PGDIR_SIZE (1 GiB) is supported in this early
* variant — vmm_init() takes over with create_pgd_mapping_pmd later. */
void create_pgd_mapping(pgd_t *pgdir, unsigned long va, unsigned long pa,
unsigned long sz, unsigned long prot);
#ifdef __cplusplus
}
#endif
#endif /* _ASM_RISCV_PGTABLE_H */
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