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#include <lib.h>
#include <comus/memory.h>
#include "virtalloc.h"
static struct virt_addr_node *get_node_idx(struct virt_ctx *ctx, int idx)
{
if (idx < BOOTSTRAP_VIRT_ALLOC_NODES) {
return &ctx->bootstrap_nodes[idx];
} else {
return &ctx->alloc_nodes[idx - BOOTSTRAP_VIRT_ALLOC_NODES];
}
}
static void update_node_ptrs(struct virt_addr_node *old,
struct virt_addr_node *new, int old_len,
int new_len)
{
if (old == NULL)
return;
int idx = 0;
for (int i = 0; i < old_len; i++) {
struct virt_addr_node *o = &old[i];
if (o && !o->is_used)
continue;
struct virt_addr_node *n = &new[idx++];
*n = *o;
if (n->prev != NULL)
n->prev->next = n;
if (n->next != NULL)
n->next->prev = n;
}
for (int i = idx; i < new_len; i++) {
struct virt_addr_node *n = &new[idx++];
n->is_used = false;
}
}
static struct virt_addr_node *get_node(struct virt_ctx *ctx)
{
size_t count = BOOTSTRAP_VIRT_ALLOC_NODES + ctx->alloc_node_count;
if (!ctx->is_allocating && ctx->used_node_count + 16 >= count) {
ctx->is_allocating = true;
int new_alloc = ctx->alloc_node_count * 2;
if (new_alloc < 8)
new_alloc = 8;
struct virt_addr_node *new_nodes;
new_nodes = kalloc(sizeof(struct virt_addr_node) * new_alloc);
if (new_nodes == NULL)
panic("virt addr alloc nodes is null");
update_node_ptrs(ctx->alloc_nodes, new_nodes, ctx->alloc_node_count,
new_alloc);
kfree(ctx->alloc_nodes);
ctx->alloc_nodes = new_nodes;
ctx->alloc_node_count = new_alloc;
ctx->is_allocating = false;
count = BOOTSTRAP_VIRT_ALLOC_NODES + ctx->alloc_node_count;
}
size_t idx = ctx->free_node_start;
for (; idx < count; idx++) {
struct virt_addr_node *node = get_node_idx(ctx, idx);
if (!node->is_used) {
ctx->used_node_count++;
return node;
}
}
panic("could not get virtaddr node");
}
static void free_node(struct virt_ctx *ctx, struct virt_addr_node *node)
{
node->is_used = false;
ctx->used_node_count--;
}
void virtaddr_init(struct virt_ctx *ctx)
{
struct virt_addr_node init = {
.start = 0x40005000, // map after paging pt
.end = 0x1000000000000, // 48bit memory address max
.next = NULL,
.prev = NULL,
.is_alloc = false,
.is_used = true,
};
memset(ctx, 0, sizeof(struct virt_ctx));
ctx->bootstrap_nodes[0] = init;
ctx->alloc_nodes = NULL;
ctx->start_node = &ctx->bootstrap_nodes[0];
ctx->free_node_start = 0;
ctx->alloc_node_count = 0;
ctx->used_node_count = 0;
ctx->is_allocating = false;
}
static void merge_back(struct virt_ctx *ctx, struct virt_addr_node *node)
{
while (node->prev) {
if (node->is_alloc != node->prev->is_alloc)
break;
struct virt_addr_node *temp = node->prev;
node->start = temp->start;
node->prev = temp->prev;
if (temp->prev)
temp->prev->next = node;
free_node(ctx, temp);
}
if (node->prev == NULL) {
ctx->start_node = node;
}
}
static void merge_forward(struct virt_ctx *ctx, struct virt_addr_node *node)
{
while (node->next) {
if (node->is_alloc != node->next->is_alloc)
break;
struct virt_addr_node *temp = node->next;
node->end = temp->end;
node->next = temp->next;
if (temp->next)
temp->next->prev = node;
free_node(ctx, temp);
}
}
void *virtaddr_alloc(struct virt_ctx *ctx, int n_pages)
{
if (n_pages < 1)
return NULL;
long n_length = n_pages * PAGE_SIZE;
struct virt_addr_node *node = ctx->start_node;
for (; node != NULL; node = node->next) {
long length = node->end - node->start;
if (node->is_alloc)
continue;
if (length >= n_length) {
struct virt_addr_node *new = get_node(ctx);
if (node->prev != NULL) {
node->prev->next = new;
} else {
ctx->start_node = new;
}
new->next = node;
new->prev = node->prev;
node->prev = new;
new->start = node->start;
new->end = new->start + n_length;
node->start = new->end;
new->is_alloc = true;
new->is_used = true;
new->next = node;
void *mem = (void *)new->start;
merge_back(ctx, new);
merge_forward(ctx, new);
return mem;
}
}
return NULL;
}
long virtaddr_free(struct virt_ctx *ctx, void *virtaddr)
{
if (virtaddr == NULL)
return -1;
uintptr_t virt = (uintptr_t)virtaddr;
if (virt % PAGE_SIZE)
return -1; // not page aligned, we did not give this out!!!
struct virt_addr_node *node = ctx->start_node;
for (; node != NULL; node = node->next) {
if (node->start == virt) {
int length = node->end - node->start;
int pages = length / PAGE_SIZE;
merge_back(ctx, node);
merge_forward(ctx, node);
return pages;
}
}
return -1;
}
void virtaddr_cleanup(struct virt_ctx *ctx)
{
kfree(ctx->alloc_nodes);
}
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