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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"
#include "pmap.h"
#include "kbd.h"
enum {
IDT_PRESENT = 0x80,
IDT_INT = 0x0e,
};
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, const char *pass) {
switch_to_kernel_cr3();
bool result = try_elf_run(drives + drive_number, vma_to_pma(active_task->page_directory, path), pass);
switch_to_task_cr3();
return result;
}
static void *sc_allocate_ram(uint32_t pages) {
return pd_user_allocate_anywhere_writable(active_task->page_directory, pages);
}
enum mi_arg {
MI_KERNEL_MAX,
MI_KERNEL_LEFT,
MI_USER_MAX,
MI_USER_LEFT,
MI_TASK_LEFT
};
__attribute__ ((pure))
static uint32_t sc_memory_info(enum mi_arg arg) {
switch (arg) {
case MI_KERNEL_MAX:
return max_kernel_pages;
case MI_KERNEL_LEFT:
return kernel_pages_left;
case MI_USER_MAX:
return max_user_pages;
case MI_USER_LEFT:
return user_pages_left;
case MI_TASK_LEFT:
PANIC("TODO: memory info task left");
default:
return -1;
}
}
void const *syscall_table[] = {
&sc_open_file,
&sc_close_file,
&sc_file_read,
&sc_file_get_size,
&sc_start_task,
&logsz,
&get_key_code,
&sc_allocate_ram,
&sc_memory_info
};
//these aren't really void ()'s, but gcc complains if we take an address of a void, so we give it a type
typedef void isr_t();
extern isr_t syscall_isr;
extern isr_t quit_isr;
extern isr_t yield_isr;
extern isr_t kbd_isr;
extern isr_t udf_isr;
extern isr_t dfa_isr;
extern isr_t tsf_isr;
extern isr_t npf_isr;
extern isr_t ssf_isr;
extern isr_t gpf_isr;
extern isr_t pff_isr;
__attribute__ ((noreturn))
void exception_halt(const char *id, uint32_t code, uint32_t eip, uint32_t cs) {
char nbuf[11];
set_log_mode(LOG_PANIC);
logsz("Exception #");
logsz(id);
logsz(" at 0x");
u8_hex(cs, nbuf);
logsz(nbuf);
logsz(":0x");
u32_hex(eip, nbuf);
logsz(nbuf);
logsz("\nerror code = 0x");
u32_hex(code, nbuf);
logsz(nbuf);
logsz("\ntask name = ");
logsz(active_task->name);
logsz("\ncr3 = 0x");
uint32_t cr3;
asm (
"mov %%cr3, %0"
: "=r" (cr3));
u32_hex(cr3, nbuf);
logsz(nbuf);
logsz("\nHalting.");
while (1)
asm ("hlt");
}
static void register_int(uint8_t n, isr_t *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;
}
enum {
PIC_MCMD = 0x0020,
PIC_MDATA = 0x0021,
PIC_SCMD = 0x00a0,
PIC_SDATA = 0x00a1
};
enum {
PIC_RESET = 0x11
};
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);
register_int(0x21, &kbd_isr, 0);
register_int(0x08, &udf_isr, 0);
register_int(0x08, &dfa_isr, 0);
register_int(0x0a, &tsf_isr, 0);
register_int(0x0b, &npf_isr, 0);
register_int(0x0c, &ssf_isr, 0);
register_int(0x0d, &gpf_isr, 0);
register_int(0x0e, &pff_isr, 0);
outb(PIC_MCMD, PIC_RESET);
outb(PIC_SCMD, PIC_RESET);
outb(PIC_MDATA, 0x20);
outb(PIC_SDATA, 0x28);
outb(PIC_MDATA, 0x04);
outb(PIC_SDATA, 0x02);
outb(PIC_MDATA, 0x01);
outb(PIC_SDATA, 0x01);
outb(PIC_MDATA, 0xfd);
outb(PIC_SDATA, 0xff);
asm volatile (
"lidt %0"
: : "m" (idtr) : "al");
}
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