Meta: Move kernel and userland to their own folders.

This is to allow both the kernel and the userland to share certain
header files and to make the folder structure a bit more clear.

1 files changed, 70 insertions, 0 deletions

diff --git a/kernel/cpu/idt.h b/kernel/cpu/idt.h
new file mode 100644
index 0000000..025ba75
--- /dev/null
+++ b/kernel/cpu/idt.h
@@ -0,0 +1,70 @@
+typedef struct kernel_registers kernel_registers_t;
+typedef struct registers registers_t;
+#ifndef IDT_H
+#define IDT_H
+#include <cpu/gdt.h>
+#include <cpu/io.h>
+#include <log.h>
+#include <stdint.h>
+#include <stdio.h>
+
+/*
+ * the type_attribute in the IDT_Entry struct
+ * is divded like this
+ *   7                           0
+ * +---+---+---+---+---+---+---+---+
+ * | P |  DPL  | S |    GateType   |
+ * +---+---+---+---+---+---+---+---+
+ * It is 8 bits(1 byte) long
+ *
+ * P
+ *	Present bit. Should be zero for unused
+ *	interrupts.
+ *
+ * DPL
+ *	Specifices the maximum ring(0 to 3) the
+ *	interrupt can be called from.
+ *
+ * S
+ *	Storage segment. This should be set to
+ *	zero for all interrupt and trap gates.
+ *
+ * GateType
+ *	Possible IDT gate types:
+ *	0b0101	0x5	5	80386 32 bit task gate
+ *	0b0110	0x6	6	80286 16-bit interrupt gate
+ *	0b0111	0x7	7	80286 16-bit trap gate
+ *	0b1110	0xE	14	80386 32-bit interrupt gate
+ *	0b1111	0xF	15	80386 32-bit trap gate
+ */
+
+// This enables the present bit.
+#define INT_PRESENT 0x80 /* 0b10000000 */
+
+#define INT_32_TASK_GATE(min_privlege)                                         \
+  (INT_PRESENT | 0x05 | (min_privlege << 5))
+#define INT_16_INTERRUPT_GATE(min_privlege)                                    \
+  (INT_PRESENT | 0x06 | (min_privlege << 5))
+#define INT_16_TRAP_GATE(min_privlege)                                         \
+  (INT_PRESENT | 0x07 | (min_privlege << 5))
+#define INT_32_INTERRUPT_GATE(min_privlege)                                    \
+  (INT_PRESENT | 0x0E | (min_privlege << 5))
+#define INT_32_TRAP_GATE(min_privlege)                                         \
+  (INT_PRESENT | 0x0F | (min_privlege << 5))
+
+struct interrupt_frame;
+
+struct registers {
+  uint32_t error_code;
+  uint32_t eip;
+  uint32_t cs;
+  uint32_t eflags;
+  uint32_t esp;
+  uint32_t ss;
+};
+
+void idt_init(void);
+__attribute__((no_caller_saved_registers)) void EOI(unsigned char irq);
+void install_handler(void (*handler_function)(), uint16_t type_attribute,
+                     uint8_t entry);
+#endif