fef
5c0fa715a4
Now that memory allocation finally kind of works, we can finally start focusing on the core system architecture. This commit also fixes some bugs in get_page() and friends, as well as performance improvements because the page map is addressed as unsigned longs rather than individual bytes.
134 lines
3.7 KiB
C
134 lines
3.7 KiB
C
/* See the end of this file for copyright and license terms. */
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#pragma once
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/**
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* @file include/gay/mm.h
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* @brief Header for dynamic memory management
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*
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* To avoid possible confusion, physical memory addresses always use type
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* `uintptr_t` and virtual ones are `void *`. This should give at least some
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* type of compiler warning if they are accidentally mixed up.
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*/
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#include <arch/page.h>
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#include <gay/types.h>
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/**
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* @brief Memory allocation flags passed to `kmalloc()`.
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*/
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enum mm_flags {
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/** @brief Kernel memory */
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MM_KERNEL = (1 << 0),
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/*
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* This will be extended once we have a base system and everything
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* in place. I've only defined this because i know we'll need it
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* later anyway and it would take more effort to change all occurrences
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* of kmalloc() to use flags rather than do it properly right now.
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*/
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};
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/**
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* @brief Allocate memory.
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*
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* Memory must be released with `kfree()` after use.
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*
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* @param size Memory size in bytes
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* @param flags Allocation flags
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* @returns The allocated memory area, or `NULL` if OOM
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*/
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__attribute__(( malloc ))
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void *kmalloc(size_t size, enum mm_flags flags);
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/**
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* @brief Release memory.
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*
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* @param ptr The pointer returned by `kmalloc()`.
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*/
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void kfree(void *ptr);
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enum mm_page_flags {
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MM_PAGE_PRESENT = (1 << 0),
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MM_PAGE_RW = (1 << 1),
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MM_PAGE_USER = (1 << 2),
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MM_PAGE_ACCESSED = (1 << 3),
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MM_PAGE_DIRTY = (1 << 4),
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MM_PAGE_GLOBAL = (1 << 5),
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MM_PAGE_NOCACHE = (1 << 6),
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};
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/**
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* @brief Get a free memory page.
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*
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* This is only called internally by `kmalloc()`, don't use.
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* Must be deallocated with `put_page()` after use.
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*
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* @returns A pointer to the beginning of the (physical) page address, or `NULL` if OOM
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*/
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uintptr_t get_page(void);
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/**
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* @brief Release a memory page.
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*
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* This is only called internally by `kmalloc()`, don't use.
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*
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* @param phys The pointer returned by `get_page()`
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*/
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void put_page(uintptr_t phys);
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/**
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* @brief Map a page in physical memory to a virtual address.
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* Remember that if `vm` is the memory map currently in use, you will most
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* likely need to call `vm_update()` when you've finished mapping everything
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* to flush the TLB.
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*
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* @param phys Physical address of the page
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* @param virt Virtual address to map the page to
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* @param flags Flags to apply to the page
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* @returns 0 on success, or `-ENOMEM` if OOM (for allocating new page tables)
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*/
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int map_page(uintptr_t phys, void *virt, enum mm_page_flags flags);
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/**
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* @brief Remove a page mapping.
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*
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* @param virt Virtual address the page is mapped to, must be page aligned
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* @returns The physical page address that was being mapped
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*/
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uintptr_t unmap_page(void *virt);
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/** @brief Flush the TLB. */
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void vm_flush(void);
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/**
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* @brief Called internally by `kmalloc_init()` to set up the page frame
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* allocator and other low level paging related stuff.
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*/
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int mem_init(uintptr_t start, uintptr_t end);
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/**
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* @brief Initialize the memory allocator.
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*
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* This can only be called once, from the early `_boot()` routine.
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*
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* @param start Physical start address of the page area
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* @param end Physical end address of the page area
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* @returns 0 on success, or -1 if the pointers were garbage
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*/
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int kmalloc_init(uintptr_t start, uintptr_t end);
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/*
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* This file is part of GayBSD.
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* Copyright (c) 2021 fef <owo@fef.moe>.
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*
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* GayBSD is nonviolent software: you may only use, redistribute, and/or
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* modify it under the terms of the Cooperative Nonviolent Public License
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* (CNPL) as found in the LICENSE file in the source code root directory
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* or at <https://git.pixie.town/thufie/npl-builder>; either version 7
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* of the license, or (at your option) any later version.
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*
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* GayBSD comes with ABSOLUTELY NO WARRANTY, to the extent
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* permitted by applicable law. See the CNPL for details.
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*/
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