Refactor PF handlers and region freeing functions.

4 files changed, 87 insertions, 48 deletions

diff --git a/kernel/include/region.h b/kernel/include/region.h
index bc26bfe..4bc8917 100644
--- a/kernel/include/region.h
+++ b/kernel/include/region.h
@@ -8,9 +8,10 @@
 // Region types
 #define REGION_T_KERNEL_BASE	0x00000001		// base kernel code & data
 #define REGION_T_DESCRIPTORS	0x00000002		// contains more region descriptors
-#define REGION_T_PAGETABLE		0x00000010		// used to map a page table/page directory
 #define REGION_T_CORE_HEAP		0x00000100		// used for the core kernel heap
-#define REGION_T_PROC_HEAP		0x00000200		// used for a kernel process' heap
+#define REGION_T_KPROC_HEAP		0x00000200		// used for a kernel process' heap
+#define REGION_T_KPROC_STACK	0x00000400		// used for a kernel process' heap
+#define REGION_T_PROC_KSTACK	0x00000800		// used for a process' kernel heap
 #define REGION_T_CACHE			0x00001000		// used for cache
 #define REGION_T_HW				0x00002000		// used for hardware access
 
@@ -30,4 +31,16 @@ void* region_alloc(size_t size, uint32_t type, page_fault_handler_t pf);	// retu
 region_info_t *find_region(void* addr);
 void region_free(void* addr);
 
+// some usefull PF handlers
+// stack_pf_handler : allocates new frames and panics on access to first page of region (stack overflow)
+void stack_pf_handler(pagedir_t *pd, struct region_info *r, void* addr);
+// default_allocator_pf_handler : just allocates new frames on page faults
+void default_allocator_pf_handler(pagedir_t *pd, struct region_info *r, 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
+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_stats();
diff --git a/kernel/l0/kmain.c b/kernel/l0/kmain.c
index 53afb6b..63ed6ac 100644
--- a/kernel/l0/kmain.c
+++ b/kernel/l0/kmain.c
@@ -18,39 +18,12 @@ void breakpoint_handler(registers_t *regs) {
 	BOCHS_BREAKPOINT;
 }
 
-void test_pf_handler(pagedir_t *pd, region_info_t *i, void* addr) {
-	dbg_printf(" {0x%p", addr);
-
-	uint32_t f = frame_alloc(1);
-	if (f == 0) PANIC("Out Of Memory");
-	dbg_printf(" -> %i} ", f);
-
-	int error = pd_map_page(addr, f, 1);
-	if (error) PANIC("Could not map frame (OOM)");
-}
-
 void* page_alloc_fun_for_kmalloc(size_t bytes) {
-	void* addr = region_alloc(bytes, REGION_T_CORE_HEAP, test_pf_handler);
+	void* addr = region_alloc(bytes, REGION_T_CORE_HEAP, default_allocator_pf_handler);
 	dbg_printf("[alloc 0x%p for kmalloc : %p]\n", bytes, addr);
 	return addr;
 }
-void page_free_fun_for_kmalloc(void* ptr) {
-	dbg_printf("[Free 0x%p", ptr);
-
-	region_info_t *i = find_region(ptr);
-	ASSERT(i != 0 && i->type == REGION_T_CORE_HEAP);
-	for (void* x = i->addr; x < i->addr + i->size; x += PAGE_SIZE) {
-		uint32_t f = pd_get_frame(x);
-		dbg_printf(" %i", f);
-		if (f != 0) {
-			pd_unmap_page(x);
-			frame_free(f, 1);
-		}
-	}
-	dbg_printf(" : ");
-	region_free(ptr);
-	dbg_printf("ok]\n");
-}
+
 slab_type_t slab_sizes[] = {
 	{ "8B obj", 8, 2 },
 	{ "16B obj", 16, 2 },
@@ -128,7 +101,7 @@ void kmain(struct multiboot_info_t *mbd, int32_t mb_magic) {
 
 	// allocate a big region and try to write into it
 	const size_t n = 200;
-	void* p0 = region_alloc(n * PAGE_SIZE, REGION_T_HW, test_pf_handler);
+	void* p0 = region_alloc(n * PAGE_SIZE, REGION_T_HW, default_allocator_pf_handler);
 	for (size_t i = 0; i < n; i++) {
 		uint32_t *x = (uint32_t*)(p0 + i * PAGE_SIZE);
 		dbg_printf("[%i : ", i);
@@ -157,7 +130,7 @@ void kmain(struct multiboot_info_t *mbd, int32_t mb_magic) {
 	// Test slab allocator !
 	mem_allocator_t *a =
 		create_slab_allocator(slab_sizes, page_alloc_fun_for_kmalloc,
-										  page_free_fun_for_kmalloc);
+										  region_free_unmap_free);
 	dbg_printf("Created slab allocator at 0x%p\n", a);
 	dbg_print_region_stats();
 	const int m = 200;
diff --git a/kernel/l0/paging.c b/kernel/l0/paging.c
index d289712..811b677 100644
--- a/kernel/l0/paging.c
+++ b/kernel/l0/paging.c
@@ -80,6 +80,7 @@ void page_fault_handler(registers_t *regs) {
 		if (i->pf == 0) {
 			dbg_printf("Kernel pagefault in region with no handler at 0x%p\n", vaddr);
 			dbg_dump_registers(regs);
+			dbg_print_region_stats();
 			PANIC("Unhandled kernel space page fault");
 		}
 		i->pf(current_pd_d, i, vaddr);
diff --git a/kernel/l0/region.c b/kernel/l0/region.c
index 7b1d138..513af45 100644
--- a/kernel/l0/region.c
+++ b/kernel/l0/region.c
@@ -196,26 +196,26 @@ static void remove_used_region(descriptor_t *d) {
 // =============== //
 
 void region_allocator_init(void* kernel_data_end) {
-	descriptor_t *u0 = &base_descriptors[0];
-	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 = REGION_T_KERNEL_BASE;
-	u0->used.i.pf = 0;
-	u0->used.next_by_addr = 0;
-	first_used_region = u0;
+	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 = &base_descriptors[1];
+	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;
 
-	n_unused_descriptors = 0;
-	first_unused_descriptor = 0;
-	for (int i = 2; i < N_BASE_DESCRIPTORS; i++) {
-		add_unused_descriptor(&base_descriptors[i]);
-	}
+	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 = REGION_T_KERNEL_BASE;
+	u0->used.i.pf = 0;
+	u0->used.next_by_addr = 0;
+	first_used_region = u0;
 }
 
 static void* region_alloc_inner(size_t size, uint32_t type, page_fault_handler_t pf, bool use_reserve) {
@@ -305,6 +305,57 @@ void region_free(void* addr) {
 	add_free_region(d);
 }
 
+// ========================================================= //
+// HELPER FUNCTIONS : SIMPLE PF HANDLERS ; FREEING FUNCTIONS //
+// ========================================================= //
+
+void stack_pf_handler(pagedir_t *pd, struct region_info *r, void* addr) {
+	if (addr < r->addr + PAGE_SIZE) {
+		dbg_printf("Stack overflow at 0x%p.", addr);
+		dbg_print_region_stats();
+		PANIC("Stack overflow.");
+	}
+	default_allocator_pf_handler(pd, r, addr);
+}
+
+void default_allocator_pf_handler(pagedir_t *pd, struct region_info *r, void* addr) {
+	ASSERT(pd_get_frame(addr) == 0);	// if error is of another type (RO, protected), we don't do anyting
+
+	uint32_t f = frame_alloc(1);
+	if (f == 0) PANIC("Out Of Memory");
+
+	int error = pd_map_page(addr, f, 1);
+	if (error) PANIC("Could not map frame (OOM)");
+}
+
+void region_free_unmap_free(void* ptr) {
+	region_info_t *i = find_region(ptr);
+	ASSERT(i != 0);
+
+	for (void* x = i->addr; x < i->addr + i->size; x += PAGE_SIZE) {
+		uint32_t f = pd_get_frame(x);
+		if (f != 0) {
+			pd_unmap_page(x);
+			frame_free(f, 1);
+		}
+	}
+	region_free(ptr);
+}
+
+void region_free_unmap(void* ptr) {
+	region_info_t *i = find_region(ptr);
+	ASSERT(i != 0);
+
+	for (void* x = i->addr; x < i->addr + i->size; x += PAGE_SIZE) {
+		pd_unmap_page(x);
+	}
+	region_free(ptr);
+}
+
+// =========================== //
+// DEBUG LOG PRINTING FUNCTION //
+// =========================== //
+
 void dbg_print_region_stats() {
 	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) {
@@ -321,9 +372,10 @@ void dbg_print_region_stats() {
 		dbg_printf("| 0x%p - 0x%p", d->used.i.addr, d->used.i.addr + d->used.i.size);
 		if (d->used.i.type & REGION_T_KERNEL_BASE)	dbg_printf("  Kernel code & base data");
 		if (d->used.i.type & REGION_T_DESCRIPTORS)	dbg_printf("  Region descriptors");
-		if (d->used.i.type & REGION_T_PAGETABLE)	dbg_printf("  Mapped PD/PT");
 		if (d->used.i.type & REGION_T_CORE_HEAP) 	dbg_printf("  Core heap");
-		if (d->used.i.type & REGION_T_PROC_HEAP)	dbg_printf("  Kernel process heap");
+		if (d->used.i.type & REGION_T_KPROC_HEAP)	dbg_printf("  Kernel process heap");
+		if (d->used.i.type & REGION_T_KPROC_STACK)	dbg_printf("  Kernel process stack");
+		if (d->used.i.type & REGION_T_PROC_KSTACK)	dbg_printf("  Process kernel stack");
 		if (d->used.i.type & REGION_T_CACHE)		dbg_printf("  Cache");
 		if (d->used.i.type & REGION_T_HW)			dbg_printf("  Hardware");
 		dbg_printf("\n");