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vm: explicitly initialise kmalloc in vm_bootstrap

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if kmalloc is called with count=N before vm_bootstrap is finished,
the request will be fulfilled using memblock_alloc.

if N is a power of 2, the returned pointer will be aligned to
an N-byte boundary.
This commit is contained in:
max 🍓
2023-02-06 20:46:38 +00:00
parent fe0b7e043f
commit 0516ef06a3
3 changed files with 36 additions and 6 deletions
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1
include/socks/vm.h
View File

@@ -234,6 +234,7 @@ extern void vm_cache_destroy(vm_cache_t *cache);
extern void *vm_cache_alloc(vm_cache_t *cache, vm_flags_t flags);
extern void vm_cache_free(vm_cache_t *cache, void *p);
extern void kmalloc_init(void);
extern void *kmalloc(size_t count, vm_flags_t flags);
extern void *kzalloc(size_t count, vm_flags_t flags);
extern void kfree(void *p);

1
vm/bootstrap.c
View File

@@ -22,6 +22,7 @@ kern_status_t vm_bootstrap(const vm_zone_descriptor_t *zones, size_t nr_zones)
vm_zone_init(&node_data->pg_zones[zones[i].zd_id], &zones[i]);
}
kmalloc_init();
return KERN_OK;
}

40
vm/kmalloc.c
View File

@@ -1,9 +1,14 @@
#include <socks/types.h>
#include <socks/memblock.h>
#include <socks/vm.h>
#include <socks/util.h>
#include <socks/libc/string.h>
#define SIZE_N_CACHE(s) \
{ .c_name = "size-" # s, .c_obj_size = s, .c_page_order = VM_PAGE_16K }
static int kmalloc_initialised = 0;
/* reserve space for the size-N caches: */
static vm_cache_t size_n_caches[] = {
SIZE_N_CACHE(16),
@@ -24,7 +29,16 @@ static vm_cache_t size_n_caches[] = {
SIZE_N_CACHE(3072),
SIZE_N_CACHE(4096),
};
static const size_t nr_size_n_caches = sizeof size_n_caches / sizeof size_n_caches[0];
static const unsigned int nr_size_n_caches = sizeof size_n_caches / sizeof size_n_caches[0];
void kmalloc_init(void)
{
for (unsigned int i = 0; i < nr_size_n_caches; i++) {
vm_cache_init(&size_n_caches[i]);
}
kmalloc_initialised = 1;
}
void *kmalloc(size_t count, vm_flags_t flags)
{
@@ -32,8 +46,20 @@ void *kmalloc(size_t count, vm_flags_t flags)
return NULL;
}
if (!kmalloc_initialised) {
/* if alloc size is a power of 2, align pointer to that same power of 2,
otherwise, align to 8-byte boundary. this emulates the behaviour of
the cache allocator. */
phys_addr_t align = 8;
if (power_of_2(count)) {
align = count;
}
return memblock_alloc(count, align);
}
vm_cache_t *best_fit = NULL;
for (size_t i = 0; i < nr_size_n_caches; i++) {
for (unsigned int i = 0; i < nr_size_n_caches; i++) {
if (size_n_caches[i].c_obj_size >= count) {
best_fit = &size_n_caches[i];
break;
@@ -44,10 +70,6 @@ void *kmalloc(size_t count, vm_flags_t flags)
return NULL;
}
if (!VM_CACHE_INITIALISED(best_fit)) {
vm_cache_init(best_fit);
}
return vm_cache_alloc(best_fit, flags);
}
@@ -63,6 +85,12 @@ void *kzalloc(size_t count, vm_flags_t flags)
void kfree(void *p)
{
if (!kmalloc_initialised) {
/* p was probably allocated using memblock. however, memblock requires that
we specify the amount of memory to free, which isn't possible here. */
return;
}
phys_addr_t phys = vm_virt_to_phys(p);
vm_page_t *pg = vm_page_get(phys);
if (!pg || !pg->p_slab) {