kernel: x86-64 idt

kernel-src/arch/x86-64/idt.c

@@ -0,0 +1,41 @@
+#include <arch/idt.h>
+#include <stdint.h>
+#include <stddef.h>
+
+typedef struct {
+	uint16_t size;
+	uint64_t offset;
+} __attribute__((packed)) idtr_t;
+
+typedef struct {
+	uint16_t offset;
+	uint16_t segment;
+	uint8_t ist;
+	uint8_t flags;
+	uint16_t offset2;
+	uint32_t offset3;
+} __attribute__((packed)) idtentry_t;
+
+static idtentry_t idt[256];
+
+static idtr_t idtr = {
+	.size = sizeof(idt) - 1,
+	.offset = (uint64_t)idt
+};
+
+extern const uint64_t isr_table[256];
+
+void arch_idt_setup() {
+	for (int i = 0; i < 256; ++i) {
+		idt[i].offset = isr_table[i] & 0xffff;
+		idt[i].segment = 0x8;
+		idt[i].ist = 0;
+		idt[i].flags = 0x8e;
+		idt[i].offset2 = (isr_table[i] >> 16) & 0xffff;
+		idt[i].offset3 = (isr_table[i] >> 32) & 0xffffffff;
+	}
+}
+
+void arch_idt_reload() {
+	asm volatile("lidt (%%rax)" : : "a"(&idtr));
+}

kernel-src/arch/x86-64/isr.asm

@@ -0,0 +1,89 @@
+section .text
+%assign i 0
+%rep 256
+isr_%+ i:
+	; push an error code if the cpu did not
+	%if (i == 8 || i == 10 || i == 11 || i == 12 || i == 13 || i == 14) == 0
+		push qword 0
+	%endif
+
+	; check if swapgs is needed
+
+	cmp qword [rsp+16], 0x18
+	jne .notneeded1
+	swapgs
+	.notneeded1:
+
+	; push context
+	push rsi
+	push rdi
+	push r15
+	push r14
+	push r13
+	push r12
+	push r11
+	push r10
+	push r9
+	push r8
+	push rdx
+	push rcx
+	push rbx
+	push rax
+	mov rax, ds
+	push rax
+	mov rax, es
+	push rax
+	mov rax, fs
+	push rax
+	mov rax, gs
+	push rax	
+	mov rdi,cr2
+	push rdi
+
+	; save ctx pointer and interrupt vector number
+	mov rdi, i
+	mov rsi, rsp
+
+	cld
+	extern interrupt_isr
+	call interrupt_isr
+
+	; pop context
+	add rsp, 24 ; cr2 gs and fs are not popped.
+	pop rax
+	mov es,rax
+	pop rax
+	mov ds,rax
+	pop rax
+	pop rbx
+	pop rcx
+	pop rdx
+	pop r8
+	pop r9
+	pop r10
+	pop r11
+	pop r12
+	pop r13
+	pop r14
+	pop r15
+	pop rdi
+	pop rsi
+	pop rbp
+	add rsp,8 ; remove error code
+
+	; check if swapgs is needed
+	cmp qword [rsp+8], 0x18
+	jne .notneeded2
+	swapgs
+	.notneeded2:
+	iret
+%assign i i+1
+%endrep
+
+section .rodata
+global isr_table
+isr_table:
+	%assign i 0
+	%rep 256
+	dq isr_%+ i
+	%endrep

kernel-src/arch/x86-64/main.c

@@ -2,6 +2,7 @@
 #include <logging.h>
 #include <arch/cpu.h>
 #include <arch/gdt.h>
+#include <arch/idt.h>
 
 static cpu_t bsp_cpu;
 
@@ -9,5 +10,7 @@ void kernel_entry() {
 	cpu_set(&bsp_cpu);
 	logging_sethook(arch_e9_putc);
 	arch_gdt_reload();
+	arch_idt_setup();
+	arch_idt_reload();
 	__assert(!"kernel entry end");
 }