Benji Dial
e8c6577617
big kernel additions: paging, elf loading, separate kernel and user page allocation it now properly loads and runs sd0:bin/init.elf still need to determine which disk was booted from, and start the init on that disk
116 lines
No EOL
2.5 KiB
C
116 lines
No EOL
2.5 KiB
C
#include "drive.h"
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#include "elf.h"
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#include "util.h"
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#include "idt.h"
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#include "log.h"
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#include "panic.h"
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#include "task.h"
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#include "paging.h"
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enum {
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IDT_PRESENT = 0x80,
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IDT_INT = 0x0e,
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IDT_TRAP = 0x0f
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};
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struct idt_entry {
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uint16_t addr_low;
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uint16_t cs;
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uint8_t zero;
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uint8_t flags;
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uint16_t addr_high;
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} __attribute__ ((packed));
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struct idt_entry idt[256];
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struct {
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uint16_t limit;
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uint32_t start;
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} __attribute__ ((packed)) idtr = {
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.limit = 256 * sizeof(struct idt_entry) - 1,
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.start = (uint32_t)idt
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};
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//file handles as (drive_number << 8) + file_id_t
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static uint32_t sc_open_file(uint32_t drive_number, char *path) {
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return (drive_number << 8) + drives[drive_number].get_file(drives + drive_number, path);
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}
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static void sc_close_file(uint32_t handle) {
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drives[handle >> 8].free_file(drives + (handle >> 8), handle & 0xff);
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}
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static uint32_t sc_file_get_size(uint32_t handle) {
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return drives[handle >> 8].get_file_length(drives + (handle >> 8), handle & 0xff);
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}
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static uint32_t sc_file_read(uint32_t handle, uint32_t file_offset, uint32_t count, void *buffer) {
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uint32_t len = sc_file_get_size(handle);
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if (file_offset + count > len)
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count = len - file_offset;
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fmcpy(buffer, drives + (handle >> 8), handle & 0xff, file_offset, count);
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return count;
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}
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static bool sc_start_task(uint32_t drive_number, char *path) {
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switch_to_kernel_cr3();
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bool result = try_elf_run(drives + drive_number, path);
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switch_to_task_cr3();
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return result;
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}
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static void sc_log_string(char *sz) {
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logsz(sz);
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}
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static char sc_get_key() {
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panic("TODO: get key system call");
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}
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static void *sc_allocate_ram(uint32_t pages) {
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//switch_to_kernel_cr3();
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void *result = pd_user_allocate_anywhere_writable(active_task->page_directory, pages);
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//switch_to_task_cr3();
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}
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void const *syscall_table[] = {
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&sc_open_file,
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&sc_close_file,
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&sc_file_read,
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&sc_file_get_size,
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&sc_start_task,
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&sc_log_string,
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&sc_get_key,
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&sc_allocate_ram
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};
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extern void syscall_isr;
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extern void quit_isr;
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extern void yield_isr;
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void register_int(uint8_t n, void *isr, uint8_t dpl) {
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idt[n].addr_low = (uint32_t)isr & 0xffff;
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idt[n].addr_high = (uint32_t)isr >> 16;
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idt[n].cs = 0x10;
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idt[n].flags = IDT_PRESENT | (dpl << 5) | IDT_INT;
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}
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void init_idt() {
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for (uint16_t i = 0; i < 256; ++i) {
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idt[i].flags = 0;
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idt[i].zero = 0;
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}
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register_int(0x30, &syscall_isr, 3);
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register_int(0x38, &quit_isr, 3);
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register_int(0x39, &yield_isr, 3);
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outb(0x0021, 0xff);
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outb(0x00a1, 0xff);
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asm volatile (
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"lidt %0"
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: : "m" (idtr) : "al");
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} |