Factorize region allocator between kernel and user processes (same code was there twice)

11 files changed, 103 insertions, 452 deletions

diff --git a/disasm.sh b/disasm.sh
new file mode 100755
index 0000000..eba8eb7
--- /dev/null
+++ b/disasm.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+gdb -batch -ex "file $1" -ex "disass /m $2"
diff --git a/src/common/include/region_alloc.h b/src/common/include/region_alloc.h
new file mode 100644
index 0000000..d314bd5
--- /dev/null
+++ b/src/common/include/region_alloc.h
@@ -0,0 +1,32 @@
+#pragma once
+
+// Virtual memory region allocator
+
+// This is entirely thread-safe
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+
+struct region_info;
+
+typedef bool (*map_page_fun_t)(void* addr);	// map a single page (used by region allocator)
+
+typedef struct region_info {
+	void* addr;
+	size_t size;
+	char* type;
+} region_info_t;
+
+// rsvd_end : when used for kernel memory region management, a reserved region
+// exists between begin (=K_HIGHHALF_ADDR) and the end of kernel static data
+// for user processes, use rsvd_end = begin (no reserved region)
+void region_allocator_init(void* begin, void* rsvd_end, void* end, map_page_fun_t map);
+
+void* region_alloc(size_t size, char* type);	// returns 0 on error
+region_info_t *find_region(void* addr);
+void region_free(void* addr);
+
+void dbg_print_region_info();
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/common/libkogata/Makefile b/src/common/libkogata/Makefile
index ea70be5..1c1113b 100644
--- a/src/common/libkogata/Makefile
+++ b/src/common/libkogata/Makefile
@@ -1,4 +1,4 @@
-OBJ = slab_alloc.o mutex.o
+OBJ = slab_alloc.o region_alloc.o mutex.o
 
 LIB = 
 
diff --git a/src/lib/libkogata/user_region.c b/src/common/libkogata/region_alloc.c
index 14c0898..8594643 100644
--- a/src/lib/libkogata/user_region.c
+++ b/src/common/libkogata/region_alloc.c
@@ -1,8 +1,15 @@
-#include <user_region.h>
+#include <region_alloc.h>
 #include <debug.h>
 #include <mutex.h>
 
-#include <syscall.h>
+// we cannot include sys...
+
+#define PAGE_SIZE		0x1000
+#define PAGE_MASK		0xFFFFF000
+#define PAGE_ALIGNED(x)     ((((size_t)(x)) & (~PAGE_MASK)) == 0)
+#define PAGE_ALIGN_DOWN(x)	(((size_t)(x)) & PAGE_MASK) 
+#define PAGE_ALIGN_UP(x)  	((((size_t)(x))&(~PAGE_MASK)) == 0 ? ((size_t)x) : (((size_t)x) & PAGE_MASK) + PAGE_SIZE)
+
 
 typedef union region_descriptor {
 	struct {
@@ -30,19 +37,21 @@ uint32_t n_unused_descriptors;
 static descriptor_t *first_free_region_by_addr, *first_free_region_by_size;
 static descriptor_t *first_used_region;
 
+static map_page_fun_t region_alloc_map_page_fun;
+
 STATIC_MUTEX(ra_mutex);	// region allocator mutex
 
 // ========================================================= //
 // HELPER FUNCTIONS FOR THE MANIPULATION OF THE REGION LISTS //
 // ========================================================= //
 
-static void add_unused_descriptor(descriptor_t *d) {
+void add_unused_descriptor(descriptor_t *d) {
 	n_unused_descriptors++;
 	d->unused_descriptor.next = first_unused_descriptor;
 	first_unused_descriptor = d;
 }
 
-static descriptor_t *get_unused_descriptor() {
+descriptor_t *get_unused_descriptor() {
 	descriptor_t *r = first_unused_descriptor;
 	if (r != 0) {
 		first_unused_descriptor = r->unused_descriptor.next;
@@ -51,7 +60,7 @@ static descriptor_t *get_unused_descriptor() {
 	return r;
 }
 
-static void remove_free_region(descriptor_t *d) {
+void remove_free_region(descriptor_t *d) {
 	if (first_free_region_by_size == d) {
 		first_free_region_by_size = d->free.next_by_size;
 	} else {
@@ -77,7 +86,7 @@ static void remove_free_region(descriptor_t *d) {
 	}
 }
 
-static void add_free_region(descriptor_t *d) {
+void add_free_region(descriptor_t *d) {
 	/*dbg_printf("Add free region 0x%p - 0x%p\n", d->free.addr, d->free.size + d->free.addr);*/
 	// Find position of region in address-ordered list
 	// Possibly concatenate free region
@@ -159,7 +168,7 @@ static void add_free_region(descriptor_t *d) {
 	}
 }
 
-static descriptor_t *find_used_region(void* addr) {
+descriptor_t *find_used_region(void* addr) {
 	for (descriptor_t *i = first_used_region; i != 0; i = i->used.next_by_addr) {
 		if (addr >= i->used.i.addr && addr < i->used.i.addr + i->used.i.size) return i;
 		if (i->used.i.addr > addr) break;
@@ -167,13 +176,13 @@ static descriptor_t *find_used_region(void* addr) {
 	return 0;
 }
 
-static void add_used_region(descriptor_t *d) {
+void add_used_region(descriptor_t *d) {
 	if (first_used_region == 0 || d->used.i.addr < first_used_region->used.i.addr) {
 		d->used.next_by_addr = first_used_region;
 		first_used_region = d;
 	} else {
 		descriptor_t *i = first_used_region;
-		ASSERT(i->used.i.addr < d->used.i.addr);	// first region by address is never free
+		ASSERT(i->used.i.addr < d->used.i.addr);
 
 		while (i != 0) {
 			ASSERT(i->used.i.addr < d->used.i.addr);
@@ -189,7 +198,7 @@ static void add_used_region(descriptor_t *d) {
 	}
 }
 
-static void remove_used_region(descriptor_t *d) {
+void remove_used_region(descriptor_t *d) {
 	if (first_used_region == d) {
 		first_used_region = d->used.next_by_addr;
 	} else {
@@ -207,24 +216,39 @@ static void remove_used_region(descriptor_t *d) {
 // THE ACTUAL CODE //
 // =============== //
 
-void region_allocator_init(void* begin, void* end) {
+void region_allocator_init(void* begin, void* rsvd_end, void* end, map_page_fun_t map_page_fun) {
 	n_unused_descriptors = 0;
 	first_unused_descriptor = 0;
 	for (int i = 0; i < N_BASE_DESCRIPTORS; i++) {
 		add_unused_descriptor(&base_descriptors[i]);
 	}
 
+	ASSERT(PAGE_ALIGNED(begin));
+	ASSERT(PAGE_ALIGNED(rsvd_end));
+	ASSERT(PAGE_ALIGNED(end));
+
 	descriptor_t *f0 = get_unused_descriptor();
-	f0->free.addr = (void*)PAGE_ALIGN_UP(begin);
-	f0->free.size = ((void*)PAGE_ALIGN_DOWN(end) - f0->free.addr);
+	f0->free.addr = rsvd_end;
+	f0->free.size = ((void*)end - rsvd_end);
 	f0->free.next_by_size = 0;
 	f0->free.first_bigger = 0;
 	first_free_region_by_size = first_free_region_by_addr = f0;
 
-	first_used_region = 0;
+	if (rsvd_end > begin) {
+		descriptor_t *u0 = get_unused_descriptor();
+		u0->used.i.addr = begin;
+		u0->used.i.size = rsvd_end - begin;
+		u0->used.i.type = "Reserved";
+		u0->used.next_by_addr = 0;
+		first_used_region = u0;
+	} else {
+		first_used_region = 0;
+	}
+
+	region_alloc_map_page_fun = map_page_fun;
 }
 
-static void region_free_inner(void* addr) {
+void region_free_inner(void* addr) {
 	descriptor_t *d = find_used_region(addr);
 	if (d == 0) return;
 
@@ -241,7 +265,7 @@ void region_free(void* addr) {
 	mutex_unlock(&ra_mutex);
 }
 
-static void* region_alloc_inner(size_t size, char* type, bool use_reserve) {
+void* region_alloc_inner(size_t size, char* type, bool use_reserve) {
 	size = PAGE_ALIGN_UP(size);
 
 	for (descriptor_t *i = first_free_region_by_size; i != 0; i = i->free.first_bigger) {
@@ -292,9 +316,10 @@ void* region_alloc(size_t size, char* type) {
 		void* descriptor_region = region_alloc_inner(PAGE_SIZE, "Region descriptors", true);
 		ASSERT(descriptor_region != 0);
 
-		bool map_ok = mmap(descriptor_region, PAGE_SIZE, MM_READ | MM_WRITE);
+		bool map_ok = region_alloc_map_page_fun(descriptor_region);
 		if (!map_ok) {
-			// this can happen if we weren't able to mmap the region (for whatever reason)
+			// this can happen if we weren't able to allocate a frame for
+			// a new pagetable
 			region_free_inner(descriptor_region);
 			goto try_anyway;
 		}
@@ -326,6 +351,7 @@ region_info_t *find_region(void* addr) {
 	return r;
 }
 
+
 // =========================== //
 // DEBUG LOG PRINTING FUNCTION //
 // =========================== //
@@ -333,19 +359,19 @@ region_info_t *find_region(void* addr) {
 void dbg_print_region_info() {
 	mutex_lock(&ra_mutex);
 
-	dbg_printf("/ Free process regions, by address:\n");
+	dbg_printf("/ Free kernel regions, by address:\n");
 	for (descriptor_t *d = first_free_region_by_addr; d != 0; d = d->free.next_by_addr) {
 		dbg_printf("| 0x%p - 0x%p\n", d->free.addr, d->free.addr + d->free.size);
 		ASSERT(d != d->free.next_by_addr);
 	}
-	dbg_printf("- Free process regions, by size:\n");
+	dbg_printf("- Free kernel regions, by size:\n");
 	for (descriptor_t *d = first_free_region_by_size; d != 0; d = d->free.next_by_size) {
 		dbg_printf("| 0x%p - 0x%p ", d->free.addr, d->free.addr + d->free.size);
 		dbg_printf("(0x%p, next in size: 0x%p)\n", d->free.size,
 			(d->free.first_bigger == 0 ? 0 : d->free.first_bigger->free.addr));
 		ASSERT(d != d->free.next_by_size);
 	}
-	dbg_printf("- Used process regions:\n");
+	dbg_printf("- Used kernel regions:\n");
 	for (descriptor_t *d = first_used_region; d != 0; d = d->used.next_by_addr) {
 		dbg_printf("| 0x%p - 0x%p  %s\n", d->used.i.addr, d->used.i.addr + d->used.i.size, d->used.i.type);
 		ASSERT(d != d->used.next_by_addr);
diff --git a/src/kernel/core/kmain.c b/src/kernel/core/kmain.c
index 3ee2238..2774e11 100644
--- a/src/kernel/core/kmain.c
+++ b/src/kernel/core/kmain.c
@@ -113,7 +113,8 @@ void kmain(multiboot_info_t *mbd, int32_t mb_magic) {
 	paging_setup(kernel_data_end);
 	dbg_printf("Paging seems to be working!\n");
 
-	region_allocator_init(kernel_data_end);
+	region_allocator_init((void*)K_HIGHHALF_ADDR, (void*)PAGE_ALIGN_UP(kernel_data_end),
+		(void*)LAST_KERNEL_ADDR, alloc_map_single_frame);
 	dbg_printf("Region allocator initialized.\n");
 	TEST_PLACEHOLDER_AFTER_REGION;
 
diff --git a/src/kernel/core/region.c b/src/kernel/core/region.c
index 6a4c7b4..2a55fb3 100644
--- a/src/kernel/core/region.c
+++ b/src/kernel/core/region.c
@@ -1,352 +1,23 @@
 #include <region.h>
-#include <dbglog.h>
 #include <frame.h>
-#include <mutex.h>
+#include <paging.h>
 
-typedef union region_descriptor {
-	struct {
-		union region_descriptor *next;
-	} unused_descriptor;
-	struct {
-		void* addr;
-		size_t size;
-		union region_descriptor *next_by_size, *first_bigger;
-		union region_descriptor *next_by_addr;
-	} free;
-	struct {
-		region_info_t i;
-		union region_descriptor *next_by_addr;
-	} used;
-} descriptor_t;
+bool alloc_map_single_frame(void* addr) {
+	int frame = frame_alloc(1);
+	if (frame == 0) return false;
 
-#define N_RESERVE_DESCRIPTORS 2		// always keep at least 2 unused descriptors
-
-#define N_BASE_DESCRIPTORS 12		// pre-allocate memory for 12 descriptors
-static descriptor_t base_descriptors[N_BASE_DESCRIPTORS];
-
-static descriptor_t *first_unused_descriptor; 
-uint32_t n_unused_descriptors;
-static descriptor_t *first_free_region_by_addr, *first_free_region_by_size;
-static descriptor_t *first_used_region;
-
-STATIC_MUTEX(ra_mutex);	// region allocator mutex
-
-// ========================================================= //
-// HELPER FUNCTIONS FOR THE MANIPULATION OF THE REGION LISTS //
-// ========================================================= //
-
-void add_unused_descriptor(descriptor_t *d) {
-	n_unused_descriptors++;
-	d->unused_descriptor.next = first_unused_descriptor;
-	first_unused_descriptor = d;
-}
-
-descriptor_t *get_unused_descriptor() {
-	descriptor_t *r = first_unused_descriptor;
-	if (r != 0) {
-		first_unused_descriptor = r->unused_descriptor.next;
-		n_unused_descriptors--;
+	if (!pd_map_page(addr, frame, true)) {
+		frame_free(frame, 1);
+		return false;
 	}
-	return r;
-}
 
-void remove_free_region(descriptor_t *d) {
-	if (first_free_region_by_size == d) {
-		first_free_region_by_size = d->free.next_by_size;
-	} else {
-		for (descriptor_t *i = first_free_region_by_size; i != 0; i = i->free.next_by_size) {
-			if (i->free.first_bigger == d) {
-				i->free.first_bigger = d->free.next_by_size;
-			}
-			if (i->free.next_by_size == d) {
-				i->free.next_by_size = d->free.next_by_size;
-				break;
-			}
-		}
-	}
-	if (first_free_region_by_addr == d) {
-		first_free_region_by_addr = d->free.next_by_addr;
-	} else {
-		for (descriptor_t *i = first_free_region_by_addr; i != 0; i = i->free.next_by_addr) {
-			if (i->free.next_by_addr == d) {
-				i->free.next_by_addr = d->free.next_by_addr;
-				break;
-			}
-		}
-	}
-}
-
-void add_free_region(descriptor_t *d) {
-	/*dbg_printf("Add free region 0x%p - 0x%p\n", d->free.addr, d->free.size + d->free.addr);*/
-	// Find position of region in address-ordered list
-	// Possibly concatenate free region
-	descriptor_t *i = first_free_region_by_addr;
-	if (i == 0) {
-		ASSERT(first_free_region_by_size == 0);
-		first_free_region_by_addr = first_free_region_by_size = d;
-		d->free.next_by_size = d->free.first_bigger = d->free.next_by_addr = 0;
-		return;
-	} else if (d->free.addr + d->free.size == i->free.addr) {
-		// concatenate d . i
-		remove_free_region(i);
-		d->free.size += i->free.size;
-		add_unused_descriptor(i);
-		add_free_region(d);
-		return;
-	} else if (i->free.addr > d->free.addr) {
-		// insert before i
-		d->free.next_by_addr = i;
-		first_free_region_by_addr = d;
-	} else {
-		while (i != 0) {
-			ASSERT(d->free.addr > i->free.addr);
-			if (i->free.addr + i->free.size == d->free.addr) {
-				// concatenate i . d
-				remove_free_region(i);
-				i->free.size += d->free.size;
-				add_unused_descriptor(d);
-				add_free_region(i);
-				return;
-			} else if (i->free.next_by_addr == 0 || i->free.next_by_addr->free.addr > d->free.addr) {
-				d->free.next_by_addr = i->free.next_by_addr;
-				i->free.next_by_addr = d;
-				break;
-			} else if (d->free.addr + d->free.size == i->free.next_by_addr->free.addr) {
-				// concatenate d . i->next_by_addr
-				descriptor_t *j = i->free.next_by_addr;
-				remove_free_region(j);
-				d->free.size += j->free.size;
-				add_unused_descriptor(j);
-				add_free_region(d);
-				return;
-			} else {
-				// continue
-				i = i->free.next_by_addr;
-			}
-		}
-	}
-	// Now add it in size-ordered list
-	i = first_free_region_by_size;
-	ASSERT(i != 0);
-	if (d->free.size <= i->free.size) {
-		d->free.next_by_size = i;
-		d->free.first_bigger = (i->free.size > d->free.size ? i : i->free.first_bigger);
-		first_free_region_by_size = d;
-	} else {
-		while (i != 0) {
-			ASSERT(d->free.size > i->free.size);
-			if (i->free.next_by_size == 0) {
-				d->free.next_by_size = 0;
-				d->free.first_bigger = 0;
-				i->free.next_by_size = d;
-				if (d->free.size > i->free.size) i->free.first_bigger = d;
-				break;
-			} else if (i->free.next_by_size->free.size >= d->free.size) {
-				d->free.next_by_size = i->free.next_by_size;
-				d->free.first_bigger =
-					(i->free.next_by_size->free.size > d->free.size
-						? i->free.next_by_size
-						: i->free.next_by_size->free.first_bigger);
-				i->free.next_by_size = d;
-				if (d->free.size > i->free.size) i->free.first_bigger = d;
-				break;
-			} else {
-				// continue
-				i = i->free.next_by_size;
-			}
-		}
-	}
-}
-
-descriptor_t *find_used_region(void* addr) {
-	for (descriptor_t *i = first_used_region; i != 0; i = i->used.next_by_addr) {
-		if (addr >= i->used.i.addr && addr < i->used.i.addr + i->used.i.size) return i;
-		if (i->used.i.addr > addr) break;
-	}
-	return 0;
-}
-
-void add_used_region(descriptor_t *d) {
-	descriptor_t *i = first_used_region;
-	ASSERT(i != 0);
-	ASSERT(i->used.i.addr < d->used.i.addr);	// first region by address is never free
-
-	while (i != 0) {
-		ASSERT(i != d);
-		ASSERT(i->used.i.addr != d->used.i.addr);
-		ASSERT(i->used.i.addr < d->used.i.addr);
-		if (i->used.next_by_addr == 0 || i->used.next_by_addr->used.i.addr > d->used.i.addr) {
-			d->used.next_by_addr = i->used.next_by_addr;
-			i->used.next_by_addr = d;
-			return;
-		} else {
-			i = i->used.next_by_addr;
-		}
-	}
-	ASSERT(false);
-}
-
-void remove_used_region(descriptor_t *d) {
-	if (first_used_region == d) {
-		first_used_region = d->used.next_by_addr;
-	} else {
-		for (descriptor_t *i = first_used_region; i != 0; i = i->used.next_by_addr) {
-			if (i->used.i.addr > d->used.i.addr) break;
-			if (i->used.next_by_addr == d) {
-				i->used.next_by_addr = d->used.next_by_addr;
-				break;
-			}
-		}
-	}
-}
-
-// =============== //
-// THE ACTUAL CODE //
-// =============== //
-
-void region_allocator_init(void* kernel_data_end) {
-	n_unused_descriptors = 0;
-	first_unused_descriptor = 0;
-	for (int i = 0; i < N_BASE_DESCRIPTORS; i++) {
-		add_unused_descriptor(&base_descriptors[i]);
-	}
-
-	descriptor_t *f0 = get_unused_descriptor();
-	f0->free.addr = (void*)PAGE_ALIGN_UP(kernel_data_end);
-	f0->free.size = ((void*)LAST_KERNEL_ADDR - f0->free.addr);
-	f0->free.next_by_size = 0;
-	f0->free.first_bigger = 0;
-	first_free_region_by_size = first_free_region_by_addr = f0;
-
-	descriptor_t *u0 = get_unused_descriptor();
-	u0->used.i.addr = (void*)K_HIGHHALF_ADDR;
-	u0->used.i.size = PAGE_ALIGN_UP(kernel_data_end) - K_HIGHHALF_ADDR;
-	u0->used.i.type = "Kernel code & data";
-	u0->used.next_by_addr = 0;
-	first_used_region = u0;
-}
-
-void region_free_inner(void* addr) {
-	descriptor_t *d = find_used_region(addr);
-	if (d == 0) return;
-
-	region_info_t i = d->used.i;
-
-	remove_used_region(d);
-	d->free.addr = i.addr;
-	d->free.size = i.size;
-	add_free_region(d);
-}
-void region_free(void* addr) {
-	mutex_lock(&ra_mutex);
-	region_free_inner(addr);
-	mutex_unlock(&ra_mutex);
-}
-
-void* region_alloc_inner(size_t size, char* type, bool use_reserve) {
-	size = PAGE_ALIGN_UP(size);
-
-	for (descriptor_t *i = first_free_region_by_size; i != 0; i = i->free.first_bigger) {
-		if (i->free.size >= size) {
-			// region i is the one we want to allocate in
-			descriptor_t *x = 0;
-			if (i->free.size > size) {
-				if (n_unused_descriptors <= N_RESERVE_DESCRIPTORS && !use_reserve) {
-					return 0;
-				}
-
-				// this assert basically means that the allocation function
-				// is called less than N_RESERVE_DESCRIPTORS times with
-				// the use_reserve flag before more descriptors
-				// are allocated.
-				x = get_unused_descriptor();
-				ASSERT(x != 0);
-
-				x->free.size = i->free.size - size;
-				if (size >= 0x4000) {
-					x->free.addr = i->free.addr + size;
-				} else {
-					x->free.addr = i->free.addr;
-					i->free.addr += x->free.size;
-				}
-			}
-			// do the allocation
-			remove_free_region(i);
-			if (x != 0) add_free_region(x);
-
-			void* addr = i->free.addr;
-			i->used.i.addr = addr;
-			i->used.i.size = size;
-			i->used.i.type = type;
-			add_used_region(i);
-
-			return addr;
-		}
-	}
-	return 0;	//No big enough block found
-}
-
-void* region_alloc(size_t size, char* type) {
-	void* result = 0;
-	mutex_lock(&ra_mutex);
-
-	if (n_unused_descriptors <= N_RESERVE_DESCRIPTORS) {
-		uint32_t frame = frame_alloc(1);
-		if (frame == 0) goto try_anyway;
-
-		void* descriptor_region = region_alloc_inner(PAGE_SIZE, "Region descriptors", true);
-		ASSERT(descriptor_region != 0);
-
-		bool map_ok = pd_map_page(descriptor_region, frame, 1);
-		if (!map_ok) {
-			// this can happen if we weren't able to allocate a frame for
-			// a new pagetable
-			frame_free(frame, 1);
-			region_free_inner(descriptor_region);
-			goto try_anyway;
-		}
-		
-		for (descriptor_t *d = (descriptor_t*)descriptor_region;
-				(void*)(d+1) <= (descriptor_region + PAGE_SIZE);
-				d++) {
-			add_unused_descriptor(d);
-		}
-	}
-	try_anyway:
-	// even if we don't have enough unused descriptors, we might find
-	// a free region that has exactly the right size and therefore
-	// does not require splitting, so we try the allocation in all cases
-	result = region_alloc_inner(size, type, false);
-
-	mutex_unlock(&ra_mutex);
-	return result;
-}
-
-region_info_t *find_region(void* addr) {
-	region_info_t *r = 0;
-	mutex_lock(&ra_mutex);
-
-	descriptor_t *d = find_used_region(addr);
-	if (d != 0) r = &d->used.i;
-
-	mutex_unlock(&ra_mutex);
-	return r;
+	return true;
 }
 
 // ========================================================= //
 // HELPER FUNCTIONS : SIMPLE PF HANDLERS ; FREEING FUNCTIONS //
 // ========================================================= //
 
-void pf_handler_unexpected(pagedir_t *pd, struct region_info *r, void* addr) {
-	dbg_printf("Unexpected page fault at 0x%p\n", addr);
-	PANIC("Unexpected page fault");
-}
-
-void pf_handler_stackoverflow(pagedir_t *pd, struct region_info *r, void* addr) {
-	dbg_printf("Kernel stack overflow at 0x%p\n", addr);
-	PANIC("Kernel stack overflow");
-}
-
 void region_free_unmap_free(void* ptr) {
 	region_info_t *i = find_region(ptr);
 	ASSERT(i != 0);
@@ -371,38 +42,4 @@ void region_free_unmap(void* ptr) {
 	region_free(ptr);
 }
 
-// =========================== //
-// DEBUG LOG PRINTING FUNCTION //
-// =========================== //
-
-void dbg_print_region_info() {
-	mutex_lock(&ra_mutex);
-
-	dbg_printf("/ Free kernel regions, by address:\n");
-	for (descriptor_t *d = first_free_region_by_addr; d != 0; d = d->free.next_by_addr) {
-		dbg_printf("| 0x%p - 0x%p\n", d->free.addr, d->free.addr + d->free.size);
-		ASSERT(d != d->free.next_by_addr);
-	}
-	dbg_printf("- Free kernel regions, by size:\n");
-	for (descriptor_t *d = first_free_region_by_size; d != 0; d = d->free.next_by_size) {
-		dbg_printf("| 0x%p - 0x%p ", d->free.addr, d->free.addr + d->free.size);
-		dbg_printf("(0x%p, next in size: 0x%p)\n", d->free.size,
-			(d->free.first_bigger == 0 ? 0 : d->free.first_bigger->free.addr));
-		ASSERT(d != d->free.next_by_size);
-	}
-	dbg_printf("- Used kernel regions:\n");
-	for (descriptor_t *d = first_used_region; d != 0; d = d->used.next_by_addr) {
-		dbg_printf("| 0x%p - 0x%p  %s\n", d->used.i.addr, d->used.i.addr + d->used.i.size, d->used.i.type);
-		ASSERT(d != d->used.next_by_addr);
-	}
-
-	int nfreerd = 0;
-	for (descriptor_t *i = first_unused_descriptor; i != 0; i = i->unused_descriptor.next)
-		nfreerd++;
-
-	dbg_printf("\\ Free region descriptors: %d (%d)\n", nfreerd, n_unused_descriptors);
-
-	mutex_unlock(&ra_mutex);
-}
-
 /* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/include/region.h b/src/kernel/include/region.h
index 2593dba..f4562ac 100644
--- a/src/kernel/include/region.h
+++ b/src/kernel/include/region.h
@@ -1,25 +1,7 @@
 #pragma once
 
-// Kernel virtual memory region allocator
+#include <region_alloc.h>
 
-// This is entirely thread-safe
-
-#include <sys.h>
-#include <paging.h>
-
-struct region_info;
-
-typedef struct region_info {
-	void* addr;
-	size_t size;
-	char* type;
-} region_info_t;
-
-void region_allocator_init(void* kernel_data_end);
-
-void* region_alloc(size_t size, char* type);	// returns 0 on error
-region_info_t *find_region(void* addr);
-void region_free(void* addr);
 
 // some functions for freeing regions and frames
 // region_free_unmap_free : deletes a region and frees all frames that were mapped in it
@@ -27,6 +9,6 @@ void region_free_unmap_free(void* addr);
 // region_free_unmap : deletes a region and unmaps all frames that were mapped in it, without freeing them
 void region_free_unmap(void* addr);
 
-void dbg_print_region_info();
+bool alloc_map_single_frame(void* addr);	// used by kernel region allocator
 
 /* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/lib/include/user_region.h b/src/lib/include/user_region.h
deleted file mode 100644
index 8a4c490..0000000
--- a/src/lib/include/user_region.h
+++ /dev/null
@@ -1,34 +0,0 @@
-#pragma once
-
-// User virtual memory region allocator
-
-// This is entirely thread-safe
-
-#include <stdint.h>
-#include <stddef.h>
-#include <stdbool.h>
-
-#include <syscall.h>
-
-#define PAGE_SIZE		0x1000
-#define PAGE_MASK		0xFFFFF000
-#define PAGE_ALIGN_DOWN(x)	(((size_t)x) & PAGE_MASK) 
-#define PAGE_ALIGN_UP(x)  	((((size_t)x)&(~PAGE_MASK)) == 0 ? ((size_t)x) : (((size_t)x) & PAGE_MASK) + PAGE_SIZE)
-
-struct region_info;
-
-typedef struct region_info {
-	void* addr;
-	size_t size;
-	char* type;
-} region_info_t;
-
-void region_allocator_init(void* begin, void* end);
-
-void* region_alloc(size_t size, char* type);	// returns 0 on error
-region_info_t *find_region(void* addr);
-void region_free(void* addr);
-
-void dbg_print_region_info();
-
-/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/lib/libkogata/Makefile b/src/lib/libkogata/Makefile
index 95de086..7a1a2ee 100644
--- a/src/lib/libkogata/Makefile
+++ b/src/lib/libkogata/Makefile
@@ -1,4 +1,4 @@
-OBJ = start.o malloc.o debug.o syscall.o user_region.o \
+OBJ = start.o malloc.o debug.o syscall.o \
 	mainloop.o gip.o draw.o keyboard.o \
 	stdio.o unistd.o
 
diff --git a/src/lib/libkogata/draw.c b/src/lib/libkogata/draw.c
index 0536c03..53070ad 100644
--- a/src/lib/libkogata/draw.c
+++ b/src/lib/libkogata/draw.c
@@ -5,7 +5,7 @@
 
 #include <proto/font_file.h>
 
-#include <user_region.h>
+#include <region_alloc.h>
 
 #include <draw.h>
 
diff --git a/src/lib/libkogata/malloc.c b/src/lib/libkogata/malloc.c
index 56a5397..2a3345f 100644
--- a/src/lib/libkogata/malloc.c
+++ b/src/lib/libkogata/malloc.c
@@ -2,7 +2,7 @@
 #include <slab_alloc.h>
 
 #include <syscall.h>
-#include <user_region.h>
+#include <region_alloc.h>
 
 static void* heap_alloc_pages(size_t s) {
 	void* addr = region_alloc(s, "Heap");
@@ -37,8 +37,12 @@ static slab_type_t slab_sizes[] = {
 	{ 0, 0, 0 }
 };
 
+bool mmap_single_page(void* addr) {
+	return mmap(addr, PAGE_SIZE, MM_READ | MM_WRITE);
+}
+
 void malloc_setup() {
-	region_allocator_init((void*)0x40000000, (void*)0xB0000000);
+	region_allocator_init((void*)0x40000000, (void*)0x40000000, (void*)0xB0000000, mmap_single_page);
 
 	mem_allocator = create_slab_allocator(slab_sizes, heap_alloc_pages, heap_free_pages);