rulimine/stage23/mm/pmm.c
2021-02-25 01:24:54 +01:00

341 lines
9.5 KiB
C

#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#include <mm/pmm.h>
#include <sys/e820.h>
#include <lib/blib.h>
#include <lib/libc.h>
#include <lib/print.h>
#define PAGE_SIZE 4096
#define MEMMAP_BASE ((size_t)0x100000)
#define MEMMAP_MAX_ENTRIES 256
struct e820_entry_t memmap[MEMMAP_MAX_ENTRIES];
size_t memmap_entries = 0;
static const char *memmap_type(uint32_t type) {
switch (type) {
case MEMMAP_USABLE:
return "Usable RAM";
case MEMMAP_RESERVED:
return "Reserved";
case MEMMAP_ACPI_RECLAIMABLE:
return "ACPI reclaimable";
case MEMMAP_ACPI_NVS:
return "ACPI NVS";
case MEMMAP_BAD_MEMORY:
return "Bad memory";
case MEMMAP_BOOTLOADER_RECLAIMABLE:
return "Bootloader reclaimable";
case MEMMAP_KERNEL_AND_MODULES:
return "Kernel/Modules";
default:
return "???";
}
}
void print_memmap(struct e820_entry_t *mm, size_t size) {
for (size_t i = 0; i < size; i++) {
print("[%X -> %X] : %X <%s>\n",
mm[i].base,
mm[i].base + mm[i].length,
mm[i].length,
memmap_type(mm[i].type));
}
}
static bool align_entry(uint64_t *base, uint64_t *length) {
if (*length < PAGE_SIZE)
return false;
uint64_t orig_base = *base;
*base = ALIGN_UP(*base, PAGE_SIZE);
*length -= (*base - orig_base);
*length = ALIGN_DOWN(*length, PAGE_SIZE);
if (!length)
return false;
uint64_t top = *base + *length;
if (*base < MEMMAP_BASE) {
if (top > MEMMAP_BASE) {
*length -= MEMMAP_BASE - *base;
*base = MEMMAP_BASE;
} else {
return false;
}
}
return true;
}
static void sanitise_entries(bool align_entries) {
for (size_t i = 0; i < memmap_entries; i++) {
if (memmap[i].type != MEMMAP_USABLE)
continue;
// Check if the entry overlaps other entries
for (size_t j = 0; j < memmap_entries; j++) {
if (j == i)
continue;
uint64_t base = memmap[i].base;
uint64_t length = memmap[i].length;
uint64_t top = base + length;
uint64_t res_base = memmap[j].base;
uint64_t res_length = memmap[j].length;
uint64_t res_top = res_base + res_length;
// TODO actually handle splitting off usable chunks
if ( (res_base >= base && res_base < top)
&& (res_top >= base && res_top < top) ) {
panic("A non-usable e820 entry is inside a usable section.");
}
if (res_base >= base && res_base < top) {
top = res_base;
}
if (res_top >= base && res_top < top) {
base = res_top;
}
memmap[i].base = base;
memmap[i].length = top - base;
}
if (!memmap[i].length
|| (align_entries && !align_entry(&memmap[i].base, &memmap[i].length))) {
// Eradicate from memmap
for (size_t j = i; j < memmap_entries - 1; j++) {
memmap[j] = memmap[j+1];
}
memmap_entries--;
i--;
}
}
// Sort the entries
for (size_t p = 0; p < memmap_entries - 1; p++) {
uint64_t min = memmap[p].base;
size_t min_index = p;
for (size_t i = p; i < memmap_entries; i++) {
if (memmap[i].base < min) {
min = memmap[i].base;
min_index = i;
}
}
struct e820_entry_t min_e = memmap[min_index];
memmap[min_index] = memmap[p];
memmap[p] = min_e;
}
// Merge contiguous bootloader-reclaimable entries
for (size_t i = 0; i < memmap_entries - 1; i++) {
if (memmap[i].type != MEMMAP_BOOTLOADER_RECLAIMABLE)
continue;
if (memmap[i+1].type == MEMMAP_BOOTLOADER_RECLAIMABLE
&& memmap[i+1].base == memmap[i].base + memmap[i].length) {
memmap[i].length += memmap[i+1].length;
// Eradicate from memmap
for (size_t j = i+1; j < memmap_entries - 1; j++) {
memmap[j] = memmap[j+1];
}
memmap_entries--;
i--;
}
}
// Align bootloader-reclaimable entries
if (align_entries) {
for (size_t i = 0; i < memmap_entries; i++) {
if (memmap[i].type != MEMMAP_BOOTLOADER_RECLAIMABLE)
continue;
if (!align_entry(&memmap[i].base, &memmap[i].length)) {
// Eradicate from memmap
for (size_t j = i; j < memmap_entries - 1; j++) {
memmap[j] = memmap[j+1];
}
memmap_entries--;
i--;
}
}
}
}
static bool allocations_disallowed = true;
struct e820_entry_t *get_memmap(size_t *entries) {
sanitise_entries(true);
*entries = memmap_entries;
allocations_disallowed = true;
return memmap;
}
void init_memmap(void) {
for (size_t i = 0; i < e820_entries; i++) {
if (memmap_entries == MEMMAP_MAX_ENTRIES) {
panic("Memory map exhausted.");
}
memmap[memmap_entries++] = e820_map[i];
}
sanitise_entries(false);
allocations_disallowed = false;
}
void *ext_mem_alloc(size_t count) {
return ext_mem_alloc_type(count, MEMMAP_BOOTLOADER_RECLAIMABLE);
}
void *ext_mem_alloc_aligned(size_t count, size_t alignment) {
return ext_mem_alloc_aligned_type(count, alignment, MEMMAP_BOOTLOADER_RECLAIMABLE);
}
void *ext_mem_alloc_type(size_t count, uint32_t type) {
return ext_mem_alloc_aligned_type(count, 4, type);
}
// Allocate memory top down, hopefully without bumping into kernel or modules
void *ext_mem_alloc_aligned_type(size_t count, size_t alignment, uint32_t type) {
if (allocations_disallowed)
panic("Extended memory allocations disallowed");
for (int i = memmap_entries - 1; i >= 0; i--) {
if (memmap[i].type != 1)
continue;
int64_t entry_base = (int64_t)(memmap[i].base);
int64_t entry_top = (int64_t)(memmap[i].base + memmap[i].length);
// Let's make sure the entry is not > 4GiB
if (entry_base >= 0x100000000 || entry_top >= 0x100000000) {
// Theoretically there could be an entry which crosses the 4GiB
// boundary, but realistically this does not happen as far as I
// have seen. Let's just discard the entry.
continue;
}
int64_t alloc_base = ALIGN_DOWN(entry_top - (int64_t)count, alignment);
// This entry is too small for us.
if (alloc_base < entry_base)
continue;
// We now reserve the range we need.
int64_t aligned_length = entry_top - alloc_base;
memmap_alloc_range((uint64_t)alloc_base, (uint64_t)aligned_length, type, true, true);
void *ret = (void *)(size_t)alloc_base;
// Zero out allocated space
memset(ret, 0, count);
sanitise_entries(false);
return ret;
}
panic("High memory allocator: Out of memory");
}
bool memmap_alloc_range(uint64_t base, uint64_t length, uint32_t type, bool free_only, bool do_panic) {
uint64_t top = base + length;
if (base < 0x100000) {
if (do_panic) {
// We don't do allocations below 1 MiB
panic("Attempt to allocate memory below 1 MiB (%X-%X)",
base, base + length);
} else {
return false;
}
}
for (size_t i = 0; i < memmap_entries; i++) {
if (free_only && memmap[i].type != 1)
continue;
uint64_t entry_base = memmap[i].base;
uint64_t entry_top = memmap[i].base + memmap[i].length;
if (base >= entry_base && base < entry_top &&
top >= entry_base && top <= entry_top) {
memmap[i].length = base - entry_base;
if (memmap[i].length == 0) {
// Eradicate from memmap
for (size_t j = i; j < memmap_entries - 1; j++) {
memmap[j] = memmap[j+1];
}
memmap_entries--;
}
if (memmap_entries >= MEMMAP_MAX_ENTRIES) {
panic("Memory map exhausted.");
}
struct e820_entry_t *target = &memmap[memmap_entries];
target->length = entry_top - top;
if (target->length != 0) {
target->base = top;
target->type = 1;
memmap_entries++;
}
if (memmap_entries >= MEMMAP_MAX_ENTRIES) {
panic("Memory map exhausted.");
}
target = &memmap[memmap_entries++];
target->type = type;
target->base = base;
target->length = length;
return true;
}
}
if (do_panic)
panic("Out of memory");
return false;
}
extern symbol bss_end;
static size_t bump_allocator_base = (size_t)bss_end;
static size_t bump_allocator_limit = 0x70000;
void *conv_mem_alloc(size_t count) {
return conv_mem_alloc_aligned(count, 4);
}
void *conv_mem_alloc_aligned(size_t count, size_t alignment) {
size_t new_base = ALIGN_UP(bump_allocator_base, alignment);
void *ret = (void *)new_base;
new_base += count;
if (new_base >= bump_allocator_limit)
panic("Memory allocation failed");
bump_allocator_base = new_base;
// Zero out allocated space
memset(ret, 0, count);
return ret;
}