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-rw-r--r--sys/include/vm/physmem.h39
-rw-r--r--sys/include/vm/vm.h4
-rw-r--r--sys/vm/vm_init.c7
-rw-r--r--sys/vm/vm_physmem.c184
4 files changed, 234 insertions, 0 deletions
diff --git a/sys/include/vm/physmem.h b/sys/include/vm/physmem.h
new file mode 100644
index 0000000..196a9a8
--- /dev/null
+++ b/sys/include/vm/physmem.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora 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 Hyra 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.
+ */
+
+#ifndef _VM_PHYSMEM_H_
+#define _VM_PHYSMEM_H_
+
+#include <sys/types.h>
+
+void vm_physmem_init(void);
+uintptr_t vm_alloc_frame(size_t count);
+void vm_free_frame(uintptr_t base, size_t count);
+
+#endif /* !_VM_PHYSMEM_H_ */
diff --git a/sys/include/vm/vm.h b/sys/include/vm/vm.h
index a4a073f..a2caa8c 100644
--- a/sys/include/vm/vm.h
+++ b/sys/include/vm/vm.h
@@ -39,4 +39,8 @@ extern volatile struct limine_hhdm_request g_hhdm_request;
#define PHYS_TO_VIRT(phys) (void *)((uintptr_t)phys + VM_HIGHER_HALF)
#define VIRT_TO_PHYS(virt) ((uintptr_t)virt - VM_HIGHER_HALF)
+#define DEFAULT_PAGESIZE 4096
+
+void vm_init(void);
+
#endif
diff --git a/sys/vm/vm_init.c b/sys/vm/vm_init.c
index 255821a..3e9718d 100644
--- a/sys/vm/vm_init.c
+++ b/sys/vm/vm_init.c
@@ -29,8 +29,15 @@
#include <sys/limine.h>
#include <vm/vm.h>
+#include <vm/physmem.h>
volatile struct limine_hhdm_request g_hhdm_request = {
.id = LIMINE_HHDM_REQUEST,
.revision = 0
};
+
+void
+vm_init(void)
+{
+ vm_physmem_init();
+}
diff --git a/sys/vm/vm_physmem.c b/sys/vm/vm_physmem.c
new file mode 100644
index 0000000..19e3927
--- /dev/null
+++ b/sys/vm/vm_physmem.c
@@ -0,0 +1,184 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora 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 Hyra 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.
+ */
+
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/limine.h>
+#include <sys/syslog.h>
+#include <sys/spinlock.h>
+#include <vm/physmem.h>
+#include <vm/vm.h>
+#include <string.h>
+
+size_t highest_frame_idx = 0;
+size_t bitmap_size = 0;
+size_t bitmap_free_start = 0;
+
+uint8_t *bitmap;
+static struct limine_memmap_response *resp = NULL;
+static struct spinlock lock = {0};
+
+static struct limine_memmap_request mmap_req = {
+ .id = LIMINE_MEMMAP_REQUEST,
+ .revision = 0
+};
+
+/*
+ * Populate physical memory bitmap.
+ */
+static void
+physmem_populate_bitmap(void)
+{
+ struct limine_memmap_entry *ent;
+
+ for (size_t i = 0; i < resp->entry_count; ++i) {
+ ent = resp->entries[i];
+
+ if (ent->type != LIMINE_MEMMAP_USABLE) {
+ /* This memory is not usable */
+ continue;
+ }
+
+ if (bitmap_free_start == 0) {
+ bitmap_free_start = ent->base / DEFAULT_PAGESIZE;
+ }
+
+ for (size_t j = 0; j < ent->length; j += DEFAULT_PAGESIZE) {
+ clrbit(bitmap, (ent->base + j) / DEFAULT_PAGESIZE);
+ }
+ }
+}
+
+/*
+ * Allocate physical memory for the bitmap
+ * we'll use to keep track of free memory.
+ */
+static void
+physmem_alloc_bitmap(void)
+{
+ struct limine_memmap_entry *ent;
+ uintptr_t highest_addr = 0;
+
+ for (size_t i = 0; i < resp->entry_count; ++i) {
+ ent = resp->entries[i];
+
+ if (ent->type != LIMINE_MEMMAP_USABLE) {
+ /* This memory is not usable */
+ continue;
+ }
+
+ if (ent->length >= bitmap_size) {
+ bitmap = PHYS_TO_VIRT(ent->base);
+ memset(bitmap, 0xFF, bitmap_size);
+ ent->length -= bitmap_size;
+ ent->base += bitmap_size;
+ return;
+ }
+
+ highest_addr = MAX(highest_addr, ent->base + ent->length);
+ }
+}
+
+
+/*
+ * Init the physical memory bitmap.
+ */
+static void
+physmem_init_bitmap(void)
+{
+ uintptr_t highest_addr = 0;
+ struct limine_memmap_entry *ent;
+
+ for (size_t i = 0; i < resp->entry_count; ++i) {
+ ent = resp->entries[i];
+
+ if (ent->type != LIMINE_MEMMAP_USABLE) {
+ continue;
+ }
+
+ highest_addr = MAX(highest_addr, ent->base + ent->length);
+ }
+
+ highest_frame_idx = highest_addr / DEFAULT_PAGESIZE;
+ bitmap_size = ALIGN_UP(highest_frame_idx / 8, DEFAULT_PAGESIZE);
+
+ physmem_alloc_bitmap();
+ physmem_populate_bitmap();
+}
+
+/*
+ * Allocate page frames.
+ *
+ * @count: Number of frames to allocate.
+ */
+uintptr_t
+vm_alloc_frame(size_t count)
+{
+ size_t frames = 0;
+ uintptr_t ret = 0;
+
+ spinlock_acquire(&lock);
+ for (size_t i = 0; i < highest_frame_idx; ++i) {
+ if (!testbit(bitmap, i)) {
+ /* We have a free page */
+ if (++frames != count) {
+ continue;
+ }
+
+ for (size_t j = i; j < i + count; ++j) {
+ setbit(bitmap, j);
+ }
+
+ ret = i * DEFAULT_PAGESIZE;
+ break;
+ }
+ }
+
+ spinlock_release(&lock);
+ return ret;
+}
+
+void
+vm_free_frame(uintptr_t base, size_t count)
+{
+ size_t stop_at = base + (count * DEFAULT_PAGESIZE);
+
+ spinlock_acquire(&lock);
+ for (uintptr_t p = base; p < stop_at; p += DEFAULT_PAGESIZE) {
+ clrbit(bitmap, p / DEFAULT_PAGESIZE);
+ }
+ spinlock_release(&lock);
+}
+
+void
+vm_physmem_init(void)
+{
+ resp = mmap_req.response;
+ physmem_init_bitmap();
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-23 14:09:15 +0000