path: root/kernel/l0/kmain.c

#include <multiboot.h>
#include <config.h>
#include <dbglog.h>
#include <sys.h>

#include <gdt.h>
#include <idt.h>
#include <frame.h>
#include <paging.h>
#include <region.h>

void breakpoint_handler(registers_t *regs) {
	dbg_printf("Breakpoint! (int3)\n");
	BOCHS_BREAKPOINT;
}

void test_pf_handler(pagedir_t *pd, region_info_t *i, size_t 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)");
}

extern char k_end_addr;	// defined in linker script : 0xC0000000
 
void kmain(struct multiboot_info_t *mbd, int32_t mb_magic) {
	dbglog_setup();

	dbg_printf("Hello, kernel World!\n");
	dbg_printf("This is %s, version %s.\n", OS_NAME, OS_VERSION);

	ASSERT(mb_magic == MULTIBOOT_BOOTLOADER_MAGIC);

	gdt_init(); dbg_printf("GDT set up.\n");

	idt_init(); dbg_printf("IDT set up.\n");
	idt_set_ex_handler(EX_BREAKPOINT, breakpoint_handler);
	// asm volatile("int $0x3");	// test breakpoint

	size_t total_ram = ((mbd->mem_upper + mbd->mem_lower) * 1024);
	dbg_printf("Total ram: %d Kb\n", total_ram / 1024);
	// paging_init(totalRam);

	// used for allocation of data structures before malloc is set up
	// a pointer to this pointer is passed to the functions that might have
	// to allocate memory ; they just increment it of the allocated quantity
	void* kernel_data_end = (void*)&k_end_addr;

	frame_init_allocator(total_ram, &kernel_data_end);
	dbg_printf("kernel_data_end: 0x%p\n", kernel_data_end);
	dbg_print_frame_stats();

	paging_setup(kernel_data_end);
	dbg_printf("Paging seems to be working!\n");

	region_allocator_init(kernel_data_end);
	dbg_print_region_stats();

	size_t p = region_alloc(0x1000, REGION_T_HW, 0);
	dbg_printf("Allocated one-page region: 0x%p\n", p);
	dbg_print_region_stats();
	size_t q = region_alloc(0x1000, REGION_T_HW, 0);
	dbg_printf("Allocated one-page region: 0x%p\n", q);
	dbg_print_region_stats();
	size_t r = region_alloc(0x2000, REGION_T_HW, 0);
	dbg_printf("Allocated two-page region: 0x%p\n", r);
	dbg_print_region_stats();
	size_t s = region_alloc(0x10000, REGION_T_CORE_HEAP, 0);
	dbg_printf("Allocated 16-page region: 0x%p\n", s);
	dbg_print_region_stats();
	region_free(p);
	dbg_printf("Freed region 0x%p\n", p);
	dbg_print_region_stats();
	region_free(q);
	dbg_printf("Freed region 0x%p\n", q);
	dbg_print_region_stats();
	region_free(r);
	dbg_printf("Freed region 0x%p\n", r);
	dbg_print_region_stats();
	region_free(s);
	dbg_printf("Freed region 0x%p\n", s);
	dbg_print_region_stats();

	// allocate a big region and try to write into it
	const size_t n = 1000;
	size_t p0 = region_alloc(n * PAGE_SIZE, REGION_T_HW, test_pf_handler);
	for (size_t i = 0; i < n; i++) {
		uint32_t *x = (uint32_t*)(p0 + i * PAGE_SIZE);
		dbg_printf("[%i : ", i);
		x[0] = 12;
		dbg_printf(" : .");
		x[1] = (i * 20422) % 122;
		dbg_printf("]\n", i);
	}
	// unmap memory
	for (size_t i = 0; i < n; i++) {
		uint32_t *x = (uint32_t*)(p0 + i * PAGE_SIZE);
		ASSERT(x[1] == (i * 20422) % 122);

		size_t f = pd_get_frame((size_t)x);
		ASSERT(f != 0);
		pd_unmap_page((size_t)x);

		frame_free(f, 1);
	}
	region_free(s);


	// TODO:
	// - setup allocator for physical pages (eg: buddy allocator, see OSDev wiki)
	// - setup allocator for virtual memory space
	// - setup paging

	PANIC("Reached kmain end! Falling off the edge.");
}

/* vim: set ts=4 sw=4 tw=0 noet :*/