hook the vectors the b9/b11 jumps to on interrupt

kernel/hw/3ds11/config.py

@@ -7,5 +7,6 @@ if config["ENABLE_I2C"]:
     add_driver(False, "mcu")
 add_driver(True, "framebuffer")
 add_driver(False, "picafb")
+add_driver(False, "vectorinit")
 print("Enable complete Unicode font: NO (because of the size)")
 config["ENABLE_FRAMEBUFFER_UNICODE"] = False

kernel/hw/3ds11/vectorinit/vectorinit.cpp

@@ -0,0 +1,26 @@
+#include "vectorinit.hpp"
+extern "C" {
+extern uintptr_t branch_macro;
+void data_abort();
+void fast_irq();
+void normal_irq();
+void prefetch_abort();
+void svc_call();
+void undefined_op();
+}
+void initVectors() {
+    uintptr_t *vectors = (uintptr_t *)0x1FFFFFA0;
+    // branch_macro is a ldr pc, [pc,#-4], meaning it reads the following word as PC
+    vectors[0] = branch_macro;
+    vectors[1] = (uintptr_t)&normal_irq;
+    vectors[2] = branch_macro;
+    vectors[3] = (uintptr_t)&fast_irq;
+    vectors[4] = branch_macro;
+    vectors[5] = (uintptr_t)&svc_call;
+    vectors[6] = branch_macro;
+    vectors[7] = (uintptr_t)&undefined_op;
+    vectors[8] = branch_macro;
+    vectors[9] = (uintptr_t)&prefetch_abort;
+    vectors[10] = branch_macro;
+    vectors[11] = (uintptr_t)&data_abort;
+}

kernel/hw/3ds11/vectorinit/vectorinit.hpp

@@ -0,0 +1,2 @@
+#include <stdint.h>
+void initVectors();

kernel/hw/3ds9/config.py

@@ -1,5 +1,6 @@
 config["ENABLE_EXTRA_MEMORY"] = get_yes_no("Enable 512KB of memory on n3DS", True)
 add_driver(True, "framebuffer")
 add_driver(False, "picafb")
+add_driver(False, "vectorinit")
 print("Enable complete Unicode font: NO (because of the size)")
 config["ENABLE_FRAMEBUFFER_UNICODE"] = False

kernel/hw/3ds9/vectorinit/vectorinit.cpp

@@ -0,0 +1,26 @@
+#include "vectorinit.hpp"
+extern "C" {
+extern uintptr_t branch_macro;
+void data_abort();
+void fast_irq();
+void normal_irq();
+void prefetch_abort();
+void svc_call();
+void undefined_op();
+}
+void initVectors() {
+    uintptr_t *vectors = (uintptr_t *)0x08000000;
+    // branch_macro is a ldr pc, [pc,#-4], meaning it reads the following word as PC
+    vectors[0] = branch_macro;
+    vectors[1] = (uintptr_t)&normal_irq;
+    vectors[2] = branch_macro;
+    vectors[3] = (uintptr_t)&fast_irq;
+    vectors[4] = branch_macro;
+    vectors[5] = (uintptr_t)&svc_call;
+    vectors[6] = branch_macro;
+    vectors[7] = (uintptr_t)&undefined_op;
+    vectors[8] = branch_macro;
+    vectors[9] = (uintptr_t)&prefetch_abort;
+    vectors[10] = branch_macro;
+    vectors[11] = (uintptr_t)&data_abort;
+}

kernel/hw/3ds9/vectorinit/vectorinit.hpp

@@ -0,0 +1,2 @@
+#include <stdint.h>
+void initVectors();

kernel/hw/pc/idt/idt.cpp

@@ -0,0 +1,35 @@
+#include "idt.hpp"
+extern "C" void intr_stub_0();
+IDT_entry entries[256];
+void setIDTEntry(int i, void *entry) {
+    uintptr_t p = (uintptr_t)entry;
+    entries[i].offset0 = (uint16_t)p;
+    p >>= 16;
+#ifndef __x86_64__
+    entries[i].selector = 0x8;
+#else
+    entries[i].selector = 0x28;
+#endif
+    entries[i].zero = 0;
+    entries[i].type = 0b1110;
+    entries[i].storageSeg = false;
+    entries[i].dpl = 3;
+    entries[i].used = true;
+    entries[i].offset1 = (uint16_t)p;
+    p >>= 16;
+#ifdef __x86_64__
+    entries[i].offset2 = (uint32_t)p;
+    entries[i].zero2 = 0;
+#endif
+}
+void initIDT() {
+    void *start_vectors = (void *)&intr_stub_0;
+    for (int i = 0; i < 256; i++) setIDTEntry(i, start_vectors + 16 * i);
+    struct {
+        uint16_t size;
+        uint32_t off;
+    } __attribute__((packed)) idtr;
+    idtr.size = sizeof(entries);
+    idtr.off = (uint32_t)((uintptr_t)entries);
+    asm volatile("lidt %0" : : "m"(idtr));
+}

kernel/hw/pc/idt/idt.hpp

@@ -0,0 +1,20 @@
+#pragma once
+#include <stdint.h>
+/**
+ * Element of the interrupt descriptor table.
+ */
+struct IDT_entry {
+    uint16_t offset0;    ///< bits 0…15 of interrupt entry address
+    uint16_t selector;   ///< segment of the interrupt handler
+    uint8_t zero;        ///< has to be zero
+    uint8_t type : 4;    ///< Type of the interrupt
+    bool storageSeg : 1; ///< 0 for interrupt gates (???)
+    uint8_t dpl : 2;     ///< Priviledge level required for calling this interrupt
+    bool used : 1;       ///< true if the entry is usable
+    uint16_t offset1;    ///< Bits 16…31 of the entrypoint
+#ifdef __x86_64__
+    uint32_t offset2; ///< Bits 32…63 of the entrypoint. Only present on AMD64
+    uint32_t zero2;   ///< Must be zero. Only present on AMD64
+#endif
+} __attribute__((packed));
+void initIDT();