diff options
Diffstat (limited to 'sys/vm/vm_physseg.c')
| -rw-r--r-- | sys/vm/vm_physseg.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/sys/vm/vm_physseg.c b/sys/vm/vm_physseg.c new file mode 100644 index 0000000..3b546e7 --- /dev/null +++ b/sys/vm/vm_physseg.c @@ -0,0 +1,180 @@ +/* + * Copyright (c) 2023 Ian Marco Moffett and the VegaOS team. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of VegaOS nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +/* $Id$ */ + +#include <sys/limine.h> +#include <sys/cdefs.h> +#include <sys/syslog.h> +#include <vm/vm_physseg.h> +#include <vm/vm.h> +#include <bitmap.h> +#include <string.h> + +__MODULE_NAME("vm_physseg"); + +__KERNEL_META("$Vega$: vm_physseg.c, Ian Marco Moffett, " + "The Vega physical memory manager"); + +#define VM_PHYSSEG_DEBUG + +#if defined(VM_PHYSSEG_DEBUG) +#define DPRINTF(...) KDEBUG(__VA_ARGS__) +#else +#define DPRINTF(...) __nothing +#endif /* defined(VM_PHYSSEG_DEBUG) */ + +static struct limine_memmap_request mmap_req = { + .id = LIMINE_MEMMAP_REQUEST, + .revision = 0 +}; + +static struct limine_memmap_response *resp = NULL; + +__used static const char *segment_name[] = { + [LIMINE_MEMMAP_USABLE] = "usable", + [LIMINE_MEMMAP_RESERVED] = "reserved", + [LIMINE_MEMMAP_ACPI_RECLAIMABLE] = "ACPI reclaimable", + [LIMINE_MEMMAP_ACPI_NVS] = "ACPI NVS", + [LIMINE_MEMMAP_BAD_MEMORY] = "bad", + [LIMINE_MEMMAP_BOOTLOADER_RECLAIMABLE] = "bootloader reclaimable", + [LIMINE_MEMMAP_KERNEL_AND_MODULES] = "kernel and modules", + [LIMINE_MEMMAP_FRAMEBUFFER] = "framebuffer" +}; + +static const int MAX_SEGMENTS = __ARRAY_COUNT(segment_name); + + +static bitmap_t bitmap = NULL; +static size_t bitmap_size = 0; +static size_t bitmap_free_start; /* Beginning bit of free region */ + +static void +vm_physseg_bitmap_alloc(void) +{ + struct limine_memmap_entry *entry; + + for (size_t i = 0; i < resp->entry_count; ++i) { + entry = resp->entries[i]; + + /* Drop any entries with an invalid type */ + if (entry->type >= MAX_SEGMENTS) { + continue; + } + + if (entry->type != LIMINE_MEMMAP_USABLE) { + /* This memory is not usable */ + continue; + } + + if (entry->length >= bitmap_size) { + bitmap = PHYS_TO_VIRT(entry->base); + memset(bitmap, 0xFF, bitmap_size); + entry->length -= bitmap_size; + entry->base += bitmap_size; + return; + } + } +} + +static void +vm_physseg_bitmap_populate(void) +{ + struct limine_memmap_entry *entry; + size_t start, end; + + for (size_t i = 0; i < resp->entry_count; ++i) { + entry = resp->entries[i]; + + /* Drop any entries with an invalid type */ + if (entry->type >= MAX_SEGMENTS) { + continue; + } + + /* Dump the memory map if we are debugging */ + start = entry->base; + end = entry->base + entry->length; + DPRINTF("0x%x - 0x%x, size: 0x%x, type: %s\n", + start, end, entry->length, + segment_name[entry->type]); + + /* Don't set non-usable entries as free */ + if (entry->type != LIMINE_MEMMAP_USABLE) { + continue; + } + + /* Populate */ + if (bitmap_free_start == 0) { + bitmap_free_start = entry->base/0x1000; + } + for (size_t j = 0; j < entry->length; j += 0x1000) { + bitmap_unset_bit(bitmap, (entry->base + j) / 0x1000); + } + } +} + +static void +vm_physseg_bitmap_init(void) +{ + uintptr_t highest_addr; + size_t highest_page_idx; + struct limine_memmap_entry *entry; + + highest_addr = 0; + highest_page_idx = 0; + + /* Find the highest entry */ + for (size_t i = 0; i < resp->entry_count; ++i) { + entry = resp->entries[i]; + + if (entry->type != LIMINE_MEMMAP_USABLE) { + /* Memeory not usable */ + continue; + } + + highest_addr = __MAX(highest_addr, entry->base + entry->length); + } + + highest_page_idx = highest_addr / 0x1000; + bitmap_size = __ALIGN_UP(highest_page_idx / 8, 0x1000); + + DPRINTF("Bitmap size: %d bytes\n", bitmap_size); + DPRINTF("Allocating and populating bitmap now...\n"); + + vm_physseg_bitmap_alloc(); + vm_physseg_bitmap_populate(); +} + +void +vm_physseg_init(void) +{ + resp = mmap_req.response; + + vm_physseg_bitmap_init(); +} |