/* See the end of this file for copyright and license terms. */

#include <gay/kprintf.h>
#include <gay/mm.h>
#include <gay/types.h>
#include <gay/util.h>

extern void _image_start_phys;
extern void _image_end_phys;

/* these are initialized by pages_init() */
void *kheap_start;
void *kheap_end;

int kmalloc_init(uintptr_t _phys_start, uintptr_t _phys_end)
{
	phys_start = _phys_start;
	phys_end = _phys_end;

	/*
	 * The kernel image is very likely gonna be within the physical memory
	 * range, so we're gonna need to do some cropping in order to not hand
	 * out pages that actually contain kernel code.
	 * Furthermore, somebody should probably clean up this mess somehow.
	 */
	uintptr_t image_start_phys = (uintptr_t)&_image_start_phys;
	uintptr_t image_end_phys = (uintptr_t)&_image_end_phys;
	if (phys_start < image_start_phys && phys_end > image_start_phys) {
		if (image_start_phys - phys_start > phys_end - image_start_phys)
			phys_end = image_start_phys;
		else
			phys_start = image_end_phys;
	}
	if (phys_start < image_end_phys && _phys_end > image_end_phys) {
		if (image_end_phys - phys_start > phys_end - image_end_phys)
			phys_end = image_start_phys;
		else
			phys_start = image_end_phys;
	}

	phys_start = align_ceil(phys_start, HUGEPAGE_SIZE);
	/*
	 * This is intentionally not aligned to hugepages, because __early_get_page()
	 * shrinks it in single PAGE_SIZE steps whenever it is called anyway.
	 * I know, this is a terrible hack, but it will be aligned to a hugepage
	 * from within pages_init(), right after the entire physical memory has
	 * been mapped to the direct area (which is the only reason we need to
	 * be able to allocate pages before the page frame allocator is set up
	 * in the first place).
	 */
	phys_end = align_floor(phys_end, PAGE_SIZE);

	int err = pages_init();
	if (err)
		return err;

	slab_init();
	return 0;
}

/*
 * This file is part of GayBSD.
 * Copyright (c) 2021 fef <owo@fef.moe>.
 *
 * GayBSD is nonviolent software: you may only use, redistribute, and/or
 * modify it under the terms of the Cooperative Nonviolent Public License
 * (CNPL) as found in the LICENSE file in the source code root directory
 * or at <https://git.pixie.town/thufie/npl-builder>; either version 7
 * of the license, or (at your option) any later version.
 *
 * GayBSD comes with ABSOLUTELY NO WARRANTY, to the extent
 * permitted by applicable law.  See the CNPL for details.
 */