aboutsummaryrefslogtreecommitdiff
path: root/kernel/l0/idt.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/l0/idt.c')
-rw-r--r--kernel/l0/idt.c153
1 files changed, 99 insertions, 54 deletions
diff --git a/kernel/l0/idt.c b/kernel/l0/idt.c
index 2d7b3bc..76aa225 100644
--- a/kernel/l0/idt.c
+++ b/kernel/l0/idt.c
@@ -1,8 +1,31 @@
#include <idt.h>
+#include <gdt.h>
#include <sys.h>
#include <string.h>
#include <dbglog.h>
+struct idt_entry {
+ uint16_t base_lo; //Low part of address to jump to
+ uint16_t sel; //Kernel segment selector
+ uint8_t always0;
+ uint8_t type_attr; //Type
+ uint16_t base_hi; //High part of address to jump to
+} __attribute__((packed));
+typedef struct idt_entry idt_entry_t;
+
+struct idt_ptr {
+ uint16_t limit;
+ uint32_t base;
+} __attribute__((packed));
+typedef struct idt_ptr idt_ptr_t;
+
+#define GATE_TYPE_INTERRUPT 14 // IF is cleared on interrupt
+#define GATE_TYPE_TRAP 15 // IF stays as is
+
+#define GATE_PRESENT (1<<7)
+#define GATE_DPL_SHIFT 5
+
+
void isr0();
void isr1();
void isr2();
@@ -91,15 +114,84 @@ void idt_syscallHandler(registers_t *regs) {
}
/* For internal use only. Sets up an entry of the IDT with given parameters. */
-static void idt_setGate(uint8_t num, uint32_t base, uint16_t sel, uint8_t flags) {
+static void idt_set_gate(uint8_t num, void (*fun)(), uint8_t type) {
+ uint32_t base = (uint32_t)fun;
+
idt_entries[num].base_lo = base & 0xFFFF;
idt_entries[num].base_hi = (base >> 16) & 0xFFFF;
- idt_entries[num].sel = sel;
+ idt_entries[num].sel = K_CODE_SEGMENT;
idt_entries[num].always0 = 0;
- idt_entries[num].flags = flags | 0x60;
+ idt_entries[num].type_attr = GATE_PRESENT
+ | (3 << GATE_DPL_SHIFT) // accessible from user mode
+ | type;
}
+static const struct {
+ uint8_t num;
+ void (*fun)();
+ uint8_t type;
+} gates[] = {
+ // Processor exceptions are traps : handling them should be preemptible
+ { 0, isr0, GATE_TYPE_TRAP },
+ { 1, isr1, GATE_TYPE_TRAP },
+ { 2, isr2, GATE_TYPE_TRAP },
+ { 3, isr3, GATE_TYPE_TRAP },
+ { 4, isr4, GATE_TYPE_TRAP },
+ { 5, isr5, GATE_TYPE_TRAP },
+ { 6, isr6, GATE_TYPE_TRAP },
+ { 7, isr7, GATE_TYPE_TRAP },
+ { 8, isr8, GATE_TYPE_TRAP },
+ { 9, isr9, GATE_TYPE_TRAP },
+ { 10, isr10, GATE_TYPE_TRAP },
+ { 11, isr11, GATE_TYPE_TRAP },
+ { 12, isr12, GATE_TYPE_TRAP },
+ { 13, isr13, GATE_TYPE_TRAP },
+ { 14, isr14, GATE_TYPE_TRAP },
+ { 15, isr15, GATE_TYPE_TRAP },
+ { 16, isr16, GATE_TYPE_TRAP },
+ { 17, isr17, GATE_TYPE_TRAP },
+ { 18, isr18, GATE_TYPE_TRAP },
+ { 19, isr19, GATE_TYPE_TRAP },
+ { 20, isr20, GATE_TYPE_TRAP },
+ { 21, isr21, GATE_TYPE_TRAP },
+ { 22, isr22, GATE_TYPE_TRAP },
+ { 23, isr23, GATE_TYPE_TRAP },
+ { 24, isr24, GATE_TYPE_TRAP },
+ { 25, isr25, GATE_TYPE_TRAP },
+ { 26, isr26, GATE_TYPE_TRAP },
+ { 27, isr27, GATE_TYPE_TRAP },
+ { 28, isr28, GATE_TYPE_TRAP },
+ { 29, isr29, GATE_TYPE_TRAP },
+ { 30, isr30, GATE_TYPE_TRAP },
+ { 31, isr31, GATE_TYPE_TRAP },
+
+ // IRQs are not preemptible ; an IRQ handler should do the bare minimum
+ // (communication with the hardware), and then pass a message to a worker
+ // process in order to do further processing
+ { 32, irq0, GATE_TYPE_INTERRUPT },
+ { 33, irq1, GATE_TYPE_INTERRUPT },
+ { 34, irq2, GATE_TYPE_INTERRUPT },
+ { 35, irq3, GATE_TYPE_INTERRUPT },
+ { 36, irq4, GATE_TYPE_INTERRUPT },
+ { 37, irq5, GATE_TYPE_INTERRUPT },
+ { 38, irq6, GATE_TYPE_INTERRUPT },
+ { 39, irq7, GATE_TYPE_INTERRUPT },
+ { 40, irq8, GATE_TYPE_INTERRUPT },
+ { 41, irq9, GATE_TYPE_INTERRUPT },
+ { 42, irq10, GATE_TYPE_INTERRUPT },
+ { 43, irq11, GATE_TYPE_INTERRUPT },
+ { 44, irq12, GATE_TYPE_INTERRUPT },
+ { 45, irq13, GATE_TYPE_INTERRUPT },
+ { 46, irq14, GATE_TYPE_INTERRUPT },
+ { 47, irq15, GATE_TYPE_INTERRUPT },
+
+ // Of course, syscalls are preemptible
+ { 64, syscall64, GATE_TYPE_TRAP },
+
+ { 0, 0, 0 }
+};
+
/* Remaps the IRQs. Sets up the IDT. */
void idt_init() {
memset((uint8_t*)&idt_entries, 0, sizeof(idt_entry_t) * 256);
@@ -116,62 +208,15 @@ void idt_init() {
outb(0x21, 0x0);
outb(0xA1, 0x0);
- idt_setGate(0, (int32_t)isr0, 0x08, 0x8E);
- idt_setGate(1, (int32_t)isr1, 0x08, 0x8E);
- idt_setGate(2, (int32_t)isr2, 0x08, 0x8E);
- idt_setGate(3, (int32_t)isr3, 0x08, 0x8E);
- idt_setGate(4, (int32_t)isr4, 0x08, 0x8E);
- idt_setGate(5, (int32_t)isr5, 0x08, 0x8E);
- idt_setGate(6, (int32_t)isr6, 0x08, 0x8E);
- idt_setGate(7, (int32_t)isr7, 0x08, 0x8E);
- idt_setGate(8, (int32_t)isr8, 0x08, 0x8E);
- idt_setGate(9, (int32_t)isr9, 0x08, 0x8E);
- idt_setGate(10, (int32_t)isr10, 0x08, 0x8E);
- idt_setGate(11, (int32_t)isr11, 0x08, 0x8E);
- idt_setGate(12, (int32_t)isr12, 0x08, 0x8E);
- idt_setGate(13, (int32_t)isr13, 0x08, 0x8E);
- idt_setGate(14, (int32_t)isr14, 0x08, 0x8E);
- idt_setGate(15, (int32_t)isr15, 0x08, 0x8E);
- idt_setGate(16, (int32_t)isr16, 0x08, 0x8E);
- idt_setGate(17, (int32_t)isr17, 0x08, 0x8E);
- idt_setGate(18, (int32_t)isr18, 0x08, 0x8E);
- idt_setGate(19, (int32_t)isr19, 0x08, 0x8E);
- idt_setGate(20, (int32_t)isr20, 0x08, 0x8E);
- idt_setGate(21, (int32_t)isr21, 0x08, 0x8E);
- idt_setGate(22, (int32_t)isr22, 0x08, 0x8E);
- idt_setGate(23, (int32_t)isr23, 0x08, 0x8E);
- idt_setGate(24, (int32_t)isr24, 0x08, 0x8E);
- idt_setGate(25, (int32_t)isr25, 0x08, 0x8E);
- idt_setGate(26, (int32_t)isr26, 0x08, 0x8E);
- idt_setGate(27, (int32_t)isr27, 0x08, 0x8E);
- idt_setGate(28, (int32_t)isr28, 0x08, 0x8E);
- idt_setGate(29, (int32_t)isr29, 0x08, 0x8E);
- idt_setGate(30, (int32_t)isr30, 0x08, 0x8E);
- idt_setGate(31, (int32_t)isr31, 0x08, 0x8E);
-
- idt_setGate(32, (int32_t)irq0, 0x08, 0x8E);
- idt_setGate(33, (int32_t)irq1, 0x08, 0x8E);
- idt_setGate(34, (int32_t)irq2, 0x08, 0x8E);
- idt_setGate(35, (int32_t)irq3, 0x08, 0x8E);
- idt_setGate(36, (int32_t)irq4, 0x08, 0x8E);
- idt_setGate(37, (int32_t)irq5, 0x08, 0x8E);
- idt_setGate(38, (int32_t)irq6, 0x08, 0x8E);
- idt_setGate(39, (int32_t)irq7, 0x08, 0x8E);
- idt_setGate(40, (int32_t)irq8, 0x08, 0x8E);
- idt_setGate(41, (int32_t)irq9, 0x08, 0x8E);
- idt_setGate(42, (int32_t)irq10, 0x08, 0x8E);
- idt_setGate(43, (int32_t)irq11, 0x08, 0x8E);
- idt_setGate(44, (int32_t)irq12, 0x08, 0x8E);
- idt_setGate(45, (int32_t)irq13, 0x08, 0x8E);
- idt_setGate(46, (int32_t)irq14, 0x08, 0x8E);
- idt_setGate(47, (int32_t)irq15, 0x08, 0x8E);
-
- idt_setGate(64, (int32_t)syscall64, 0x08, 0x8E);
+ for (int i = 0; gates[i].type != 0; i++) {
+ idt_set_gate(gates[i].num, gates[i].fun, gates[i].type);
+ }
idt_ptr.limit = (sizeof(idt_entry_t) * 256) - 1;
idt_ptr.base = (uint32_t)&idt_entries;
asm volatile ("lidt %0"::"m"(idt_ptr):"memory");
+ asm volatile ("sti"); // from now on we accept interruptions... although we don't do much with them
}
/* Sets up an IRQ handler for given IRQ. */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-25 14:51:18 +0000