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#include "drive.h"
#include "elf.h"
#include "util.h"
#include "idt.h"
#include "log.h"
#include "panic.h"
#include "task.h"
#include "paging.h"
enum {
IDT_PRESENT = 0x80,
IDT_INT = 0x0e,
IDT_TRAP = 0x0f
};
struct idt_entry {
uint16_t addr_low;
uint16_t cs;
uint8_t zero;
uint8_t flags;
uint16_t addr_high;
} __attribute__ ((packed));
struct idt_entry idt[256];
struct {
uint16_t limit;
uint32_t start;
} __attribute__ ((packed)) idtr = {
.limit = 256 * sizeof(struct idt_entry) - 1,
.start = (uint32_t)idt
};
//file handles as (drive_number << 8) + file_id_t
static uint32_t sc_open_file(uint32_t drive_number, char *path) {
return (drive_number << 8) + drives[drive_number].get_file(drives + drive_number, path);
}
static void sc_close_file(uint32_t handle) {
drives[handle >> 8].free_file(drives + (handle >> 8), handle & 0xff);
}
static uint32_t sc_file_get_size(uint32_t handle) {
return drives[handle >> 8].get_file_length(drives + (handle >> 8), handle & 0xff);
}
static uint32_t sc_file_read(uint32_t handle, uint32_t file_offset, uint32_t count, void *buffer) {
uint32_t len = sc_file_get_size(handle);
if (file_offset + count > len)
count = len - file_offset;
fmcpy(buffer, drives + (handle >> 8), handle & 0xff, file_offset, count);
return count;
}
static bool sc_start_task(uint32_t drive_number, char *path) {
switch_to_kernel_cr3();
bool result = try_elf_run(drives + drive_number, path);
switch_to_task_cr3();
return result;
}
static void sc_log_string(char *sz) {
logsz(sz);
}
static char sc_get_key() {
panic("TODO: get key system call");
}
static void *sc_allocate_ram(uint32_t pages) {
return pd_user_allocate_anywhere_writable(active_task->page_directory, pages);
}
void const *syscall_table[] = {
&sc_open_file,
&sc_close_file,
&sc_file_read,
&sc_file_get_size,
&sc_start_task,
&sc_log_string,
&sc_get_key,
&sc_allocate_ram
};
extern void syscall_isr;
extern void quit_isr;
extern void yield_isr;
static void register_int(uint8_t n, void *isr, uint8_t dpl) {
idt[n].addr_low = (uint32_t)isr & 0xffff;
idt[n].addr_high = (uint32_t)isr >> 16;
idt[n].cs = 0x10;
idt[n].flags = IDT_PRESENT | (dpl << 5) | IDT_INT;
}
void init_idt() {
for (uint16_t i = 0; i < 256; ++i) {
idt[i].flags = 0;
idt[i].zero = 0;
}
register_int(0x30, &syscall_isr, 3);
register_int(0x38, &quit_isr, 3);
register_int(0x39, &yield_isr, 3);
outb(0x0021, 0xff);
outb(0x00a1, 0xff);
asm volatile (
"lidt %0"
: : "m" (idtr) : "al");
}
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