From 1bf5e324005ce7122a195af106cec656960648dc Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sat, 10 Jul 2021 17:41:32 +0200
Subject: a sensible source structure
The idea is that src/kernel/ is only allowed to interface with the
hardware using whatever's defined in src/arch/generic.h. I'll probably
write a small script for checking this later on.
This is a giant commit so I've probably fucked something up. It boots
fine on Bochs and QEMU, so at least there's that.
---
src/arch/generic.h | 14 +++++
src/arch/i386/boot.c | 16 ++++++
src/arch/i386/boot.s | 25 +++++++++
src/arch/i386/gdt.h | 16 ++++++
src/arch/i386/gdt/farjump.s | 9 +++
src/arch/i386/gdt/gdt.c | 119 ++++++++++++++++++++++++++++++++++++++++
src/arch/i386/interrupts/idt.c | 75 +++++++++++++++++++++++++
src/arch/i386/interrupts/idt.h | 3 +
src/arch/i386/interrupts/isr.c | 24 ++++++++
src/arch/i386/interrupts/isr.h | 15 +++++
src/arch/i386/multiboot.s | 11 ++++
src/arch/i386/sysenter.h | 2 +
src/arch/i386/sysenter.s | 31 +++++++++++
src/arch/i386/tty.c | 36 ++++++++++++
src/arch/i386/tty.h | 8 +++
src/kernel/gdt.c | 121 -----------------------------------------
src/kernel/gdt.h | 15 -----
src/kernel/idt.c | 75 -------------------------
src/kernel/idt.h | 3 -
src/kernel/isr.c | 24 --------
src/kernel/isr.h | 15 -----
src/kernel/main.c | 15 +----
src/kernel/main.h | 3 +
src/kernel/mem.c | 1 +
src/kernel/mem.h | 2 -
src/kernel/panic.h | 4 +-
src/kernel/proc.c | 2 +-
src/kernel/tty.c | 38 -------------
src/kernel/tty.h | 8 ---
src/platform/asm.h | 9 ---
src/platform/boot.s | 47 ----------------
src/platform/sysenter.s | 31 -----------
32 files changed, 413 insertions(+), 404 deletions(-)
create mode 100644 src/arch/generic.h
create mode 100644 src/arch/i386/boot.c
create mode 100644 src/arch/i386/boot.s
create mode 100644 src/arch/i386/gdt.h
create mode 100644 src/arch/i386/gdt/farjump.s
create mode 100644 src/arch/i386/gdt/gdt.c
create mode 100644 src/arch/i386/interrupts/idt.c
create mode 100644 src/arch/i386/interrupts/idt.h
create mode 100644 src/arch/i386/interrupts/isr.c
create mode 100644 src/arch/i386/interrupts/isr.h
create mode 100644 src/arch/i386/multiboot.s
create mode 100644 src/arch/i386/sysenter.h
create mode 100644 src/arch/i386/sysenter.s
create mode 100644 src/arch/i386/tty.c
create mode 100644 src/arch/i386/tty.h
delete mode 100644 src/kernel/gdt.c
delete mode 100644 src/kernel/gdt.h
delete mode 100644 src/kernel/idt.c
delete mode 100644 src/kernel/idt.h
delete mode 100644 src/kernel/isr.c
delete mode 100644 src/kernel/isr.h
create mode 100644 src/kernel/main.h
delete mode 100644 src/kernel/tty.c
delete mode 100644 src/kernel/tty.h
delete mode 100644 src/platform/asm.h
delete mode 100644 src/platform/boot.s
delete mode 100644 src/platform/sysenter.s
diff --git a/src/arch/generic.h b/src/arch/generic.h
new file mode 100644
index 0000000..7807316
--- /dev/null
+++ b/src/arch/generic.h
@@ -0,0 +1,14 @@
+#pragma once
+
+// i have no idea where else to put it
+#define PAGE_SIZE 4096
+
+// src/arch/i386/boot.s
+extern void stack_top;
+
+__attribute__((noreturn))
+void halt_cpu();
+
+// src/arch/i386/sysenter.s
+void sysexit(void (*fun)(), void *stack_top);
+void sysenter_setup();
diff --git a/src/arch/i386/boot.c b/src/arch/i386/boot.c
new file mode 100644
index 0000000..b2b84f0
--- /dev/null
+++ b/src/arch/i386/boot.c
@@ -0,0 +1,16 @@
+#include <arch/i386/gdt.h>
+#include <arch/i386/interrupts/idt.h>
+#include <arch/i386/sysenter.h>
+#include <arch/i386/tty.h>
+#include <kernel/main.h>
+
+void kmain_early() {
+ tty_clear();
+ tty_const("gdt...");
+ gdt_init();
+ tty_const("idt...");
+ idt_init();
+ tty_const("sysenter...");
+ sysenter_setup();
+ kmain();
+}
diff --git a/src/arch/i386/boot.s b/src/arch/i386/boot.s
new file mode 100644
index 0000000..74ec312
--- /dev/null
+++ b/src/arch/i386/boot.s
@@ -0,0 +1,25 @@
+/* a lil stack TODO move to linker.ld */
+.section .bss
+.global stack_top
+.type stack_top, @object
+.align 16
+stack_bottom:
+.skip 16384
+stack_top:
+
+
+.section .text
+.global _start
+.type _start, @function
+_start:
+ mov $stack_top, %esp
+ call kmain_early
+
+.global halt_cpu
+.type halt_cpu, @function
+halt_cpu:
+ cli
+1: hlt
+ jmp 1b
+
+.size _start, . - _start
diff --git a/src/arch/i386/gdt.h b/src/arch/i386/gdt.h
new file mode 100644
index 0000000..bcb9870
--- /dev/null
+++ b/src/arch/i386/gdt.h
@@ -0,0 +1,16 @@
+#pragma once
+
+enum {
+ SEG_null,
+ // order dictated by SYSENTER
+ SEG_r0code,
+ SEG_r0data,
+ SEG_r3code,
+ SEG_r3data,
+ SEG_TSS,
+
+ SEG_end
+};
+
+void gdt_init();
+void gdt_farjump(int segment);
diff --git a/src/arch/i386/gdt/farjump.s b/src/arch/i386/gdt/farjump.s
new file mode 100644
index 0000000..85d8ba5
--- /dev/null
+++ b/src/arch/i386/gdt/farjump.s
@@ -0,0 +1,9 @@
+.section .text
+.global gdt_farjump
+.type gdt_farjump, @function
+gdt_farjump:
+ /* retf pops off the return address and code segment off the stack.
+ * it turns out that in the i386 cdecl calling convention they're in
+ * the correct place already.
+ */
+ retf
diff --git a/src/arch/i386/gdt/gdt.c b/src/arch/i386/gdt/gdt.c
new file mode 100644
index 0000000..3e0647b
--- /dev/null
+++ b/src/arch/i386/gdt/gdt.c
@@ -0,0 +1,119 @@
+#include <arch/generic.h>
+#include <arch/i386/gdt.h>
+#include <kernel/util.h>
+#include <stdint.h>
+
+
+struct gdt_entry {
+ uint64_t limit_low : 16;
+ uint64_t base_low : 24;
+ uint64_t accessed : 1; // set by the processor
+ // CODE | DATA
+ uint64_t rw : 1; // readable? | writeable?
+ uint64_t conforming : 1; // conforming? | expands down?
+ uint64_t code : 1; // 1 | 0
+
+ uint64_t codeordata : 1; // 1 for everything other than TSS and LDT
+ uint64_t ring : 2;
+ uint64_t present : 1; // always 1
+ uint64_t limit_high : 4;
+ uint64_t available : 1; // ???
+ uint64_t long_mode : 1;
+ uint64_t x32 : 1;
+ uint64_t gran : 1; // 1 - 4kb, 0 - 1b
+ uint64_t base_high : 8;
+} __attribute__((packed));
+
+struct tss_entry {
+ uint32_t prev_tss; // unused
+ uint32_t esp0; // kernel mode stack pointer
+ uint32_t ss0; // kernel mode stack segment
+ // total size = 0x68 (?) - 3 * sizeof(uint32_t) = 5c
+ uint8_t _unused[0x5c];
+} __attribute__((packed));
+
+struct lgdt_arg {
+ uint16_t limit;
+ uint32_t base;
+} __attribute__((packed));
+
+static struct gdt_entry GDT[SEG_end];
+static struct tss_entry TSS;
+static struct lgdt_arg lgdt_arg; // probably doesn't need to be global
+
+static void gdt_prepare();
+static void gdt_load();
+
+
+static void gdt_prepare() {
+ GDT[SEG_null].present = 0;
+
+ GDT[SEG_r0data].limit_low = 0xFFFF;
+ GDT[SEG_r0data].limit_high = 0xF;
+ GDT[SEG_r0data].gran = 1; // 4KB * 0xFFFFF = (almost) 4GB
+ GDT[SEG_r0data].base_low = 0;
+ GDT[SEG_r0data].base_high = 0;
+ GDT[SEG_r0data].accessed = 0;
+ GDT[SEG_r0data].rw = 1;
+ GDT[SEG_r0data].conforming = 0;
+ GDT[SEG_r0data].code = 0;
+ GDT[SEG_r0data].codeordata = 1;
+ GDT[SEG_r0data].ring = 0;
+ GDT[SEG_r0data].present = 1;
+ GDT[SEG_r0data].long_mode = 0; // ???
+ GDT[SEG_r0data].available = 1; // ???
+ GDT[SEG_r0data].x32 = 1;
+
+ // copy to r0 code
+ GDT[SEG_r0code] = GDT[SEG_r0data];
+ GDT[SEG_r0code].code = 1;
+
+ GDT[SEG_r3data] = GDT[SEG_r0data];
+ GDT[SEG_r3data].ring = 3;
+ GDT[SEG_r3code] = GDT[SEG_r0code];
+ GDT[SEG_r3code].ring = 3;
+
+ // tss
+ memset(&TSS, 0, sizeof(TSS));
+ TSS.ss0 = SEG_r0data << 3; // kernel data segment
+ TSS.esp0 = (uint32_t) &stack_top;
+
+ GDT[SEG_TSS].limit_low = sizeof(TSS);
+ GDT[SEG_TSS].base_low = (uint32_t) &TSS;
+ GDT[SEG_TSS].accessed = 1; // 1 for TSS
+ GDT[SEG_TSS].rw = 0; // 1 busy / 0 not busy
+ GDT[SEG_TSS].conforming = 0; // 0 for TSS
+ GDT[SEG_TSS].code = 1; // 32bit
+ GDT[SEG_TSS].codeordata = 0; // is a system entry
+ GDT[SEG_TSS].ring = 3;
+ GDT[SEG_TSS].present = 1;
+ GDT[SEG_TSS].limit_high = (sizeof(TSS) >> 16) & 0xf;
+ GDT[SEG_TSS].available = 0; // 0 for TSS
+ GDT[SEG_TSS].long_mode = 0;
+ GDT[SEG_TSS].x32 = 0; // idk
+ GDT[SEG_TSS].gran = 0;
+ GDT[SEG_TSS].base_high = (((uint32_t) &TSS) >> 24) & 0xff;
+}
+
+static void gdt_load() {
+ lgdt_arg.limit = sizeof(GDT) - 1;
+ lgdt_arg.base = (uint32_t) &GDT;
+ asm("lgdt (%0)"
+ : : "r" (&lgdt_arg) : "memory");
+ asm("ltr %%ax"
+ : : "a" (SEG_TSS << 3 | 3) : "memory");
+
+ // update all segment registers
+ gdt_farjump(SEG_r0code << 3);
+ asm("mov %0, %%ds;"
+ "mov %0, %%ss;"
+ "mov %0, %%es;"
+ "mov %0, %%fs;"
+ "mov %0, %%gs;"
+ : : "r" (SEG_r0data << 3) : "memory");
+}
+
+void gdt_init() {
+ gdt_prepare();
+ gdt_load();
+}
diff --git a/src/arch/i386/interrupts/idt.c b/src/arch/i386/interrupts/idt.c
new file mode 100644
index 0000000..4e23118
--- /dev/null
+++ b/src/arch/i386/interrupts/idt.c
@@ -0,0 +1,75 @@
+#include <arch/i386/gdt.h>
+#include <arch/i386/interrupts/idt.h>
+#include <arch/i386/interrupts/isr.h>
+#include <kernel/panic.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+struct idt_entry {
+ uint16_t offset_low ;
+ uint16_t code_seg ;
+ uint8_t zero ; // unused, has to be 0
+ uint8_t type : 4; // 16/32 bit, task/interrupt/task gate
+ uint8_t storage : 1; // 0 for interrupt/trap gates
+ uint8_t ring : 2;
+ uint8_t present : 1;
+ uint16_t offset_high ;
+} __attribute__((packed));
+
+// is exactly the same as lgdt_arg, i should combine them into a single struct
+// later
+struct lidt_arg {
+ uint16_t limit;
+ uint32_t base;
+} __attribute__((packed));
+
+
+static struct idt_entry IDT[256];
+static struct lidt_arg lidt_arg;
+
+static inline void idt_add(uint8_t num, bool user, void (*isr));
+static void idt_prepare();
+static void idt_load();
+static void idt_test();
+
+
+static inline void idt_add(uint8_t num, bool user, void (*isr)) {
+ uintptr_t offset = (uintptr_t) isr;
+
+ IDT[num] = (struct idt_entry) {
+ .offset_low = offset,
+ .offset_high = offset >> 16,
+ .code_seg = SEG_r0code << 3,
+ .zero = 0,
+ .present = 1,
+ .ring = user ? 3 : 0,
+ .storage = 0,
+ .type = 0xE, // 32-bit interrupt gate
+ };
+}
+
+static void idt_prepare() {
+ for (int i = 0; i < 256; i++)
+ IDT[i].present = 0;
+
+ idt_add(0x08, false, isr_double_fault);
+ idt_add(0x0d, false, isr_general_protection_fault);
+ idt_add(0x34, false, isr_test_interrupt);
+}
+
+static void idt_load() {
+ lidt_arg.limit = sizeof(IDT) - 1;
+ lidt_arg.base = (uintptr_t) &IDT;
+ asm("lidt (%0)" : : "r" (&lidt_arg) : "memory");
+}
+
+static void idt_test() {
+ asm("int $0x34" : : : "memory");
+ if (!isr_test_interrupt_called) panic();
+}
+
+void idt_init() {
+ idt_prepare();
+ idt_load();
+ idt_test();
+}
diff --git a/src/arch/i386/interrupts/idt.h b/src/arch/i386/interrupts/idt.h
new file mode 100644
index 0000000..5627657
--- /dev/null
+++ b/src/arch/i386/interrupts/idt.h
@@ -0,0 +1,3 @@
+#pragma once
+
+void idt_init();
diff --git a/src/arch/i386/interrupts/isr.c b/src/arch/i386/interrupts/isr.c
new file mode 100644
index 0000000..03399ea
--- /dev/null
+++ b/src/arch/i386/interrupts/isr.c
@@ -0,0 +1,24 @@
+#include <arch/i386/interrupts/isr.h>
+#include <arch/i386/tty.h>
+#include <kernel/panic.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+bool isr_test_interrupt_called = false;
+
+__attribute__((interrupt))
+void isr_double_fault(struct interrupt_frame *frame) {
+ tty_const("#DF");
+ panic();
+}
+
+__attribute__((interrupt))
+void isr_general_protection_fault(struct interrupt_frame *frame) {
+ tty_const("#GP");
+ panic();
+}
+
+__attribute__((interrupt))
+void isr_test_interrupt(struct interrupt_frame *frame) {
+ isr_test_interrupt_called = true;
+}
diff --git a/src/arch/i386/interrupts/isr.h b/src/arch/i386/interrupts/isr.h
new file mode 100644
index 0000000..150fc46
--- /dev/null
+++ b/src/arch/i386/interrupts/isr.h
@@ -0,0 +1,15 @@
+#pragma once
+#include <stdbool.h>
+
+struct interrupt_frame;
+
+extern bool isr_test_interrupt_called; // used in the self-test in idt.c
+
+__attribute__((interrupt))
+void isr_double_fault(struct interrupt_frame *frame);
+
+__attribute__((interrupt))
+void isr_general_protection_fault(struct interrupt_frame *frame);
+
+__attribute__((interrupt))
+void isr_test_interrupt(struct interrupt_frame *frame);
diff --git a/src/arch/i386/multiboot.s b/src/arch/i386/multiboot.s
new file mode 100644
index 0000000..2194982
--- /dev/null
+++ b/src/arch/i386/multiboot.s
@@ -0,0 +1,11 @@
+.set MAGIC, 0x1BADB002
+.set FLAG_ALIGN, 1<<0 /* align modules on page boundaries */
+.set FLAG_MEMINFO, 1<<1 /* memory map */
+.set FLAGS, FLAG_ALIGN | FLAG_MEMINFO
+.set CHECKSUM, -(MAGIC + FLAGS)
+
+.section .multiboot
+.align 4
+.long MAGIC
+.long FLAGS
+.long CHECKSUM
diff --git a/src/arch/i386/sysenter.h b/src/arch/i386/sysenter.h
new file mode 100644
index 0000000..b531fe8
--- /dev/null
+++ b/src/arch/i386/sysenter.h
@@ -0,0 +1,2 @@
+#pragma once
+void sysenter_setup();
diff --git a/src/arch/i386/sysenter.s b/src/arch/i386/sysenter.s
new file mode 100644
index 0000000..666c0f0
--- /dev/null
+++ b/src/arch/i386/sysenter.s
@@ -0,0 +1,31 @@
+/* arch/i386/gdt.c */
+.set SEG_r0code, 1
+.set SEG_r3code, 3
+.set SEG_r3data, 4
+
+.set IA32_SYSENTER_CS, 0x174
+
+.section .text
+.global sysexit
+.type sysexit, @function
+sysexit:
+ pop %ecx
+ pop %edx
+
+ mov $(SEG_r3data << 3 | 3), %ax
+ mov %ax, %ds
+ mov %ax, %es
+ mov %ax, %fs
+ mov %ax, %gs
+
+ sysexit
+
+
+.global sysenter_setup
+.type sysenter_setup, @function
+sysenter_setup:
+ xor %edx, %edx
+ mov $(SEG_r0code << 3), %eax
+ mov $IA32_SYSENTER_CS, %ecx
+ wrmsr
+ ret
diff --git a/src/arch/i386/tty.c b/src/arch/i386/tty.c
new file mode 100644
index 0000000..a7c74f5
--- /dev/null
+++ b/src/arch/i386/tty.c
@@ -0,0 +1,36 @@
+#include <arch/i386/tty.h>
+
+struct vga_cell {
+ unsigned char c;
+ unsigned char style;
+} __attribute__((__packed__));
+
+static const size_t vga_len = 80 * 25;
+static struct vga_cell *vga = (void*) 0xB8000;
+static size_t vga_pos = 0;
+
+static void tty_scroll() {
+ for (int i = 0; i < vga_len - 80; i++) {
+ vga[i] = vga[i + 80];
+ }
+ vga_pos -= 80;
+}
+
+void tty_putchar(char c)
+{
+ if (vga_pos >= vga_len - 80) tty_scroll();
+ vga[vga_pos++].c = c;
+}
+
+void tty_write(const char *buf, size_t len)
+{
+ for (size_t i = 0; i < len; i++) {
+ tty_putchar(buf[i]);
+ }
+}
+
+void tty_clear() {
+ for (size_t i = 0; i < vga_len; i++)
+ vga[i].c = ' ';
+ vga_pos = 0;
+}
diff --git a/src/arch/i386/tty.h b/src/arch/i386/tty.h
new file mode 100644
index 0000000..3dc1525
--- /dev/null
+++ b/src/arch/i386/tty.h
@@ -0,0 +1,8 @@
+#pragma once
+#include <stddef.h>
+
+void tty_putchar(char c);
+void tty_write(const char *buf, size_t len);
+void tty_clear();
+
+#define tty_const(str) tty_write(str, sizeof(str) - 1)
diff --git a/src/kernel/gdt.c b/src/kernel/gdt.c
deleted file mode 100644
index b0d6320..0000000
--- a/src/kernel/gdt.c
+++ /dev/null
@@ -1,121 +0,0 @@
-#include <kernel/gdt.h>
-#include <kernel/util.h>
-#include <stdint.h>
-
-extern void stack_top; // platform/boot.s
-
-struct gdt_entry {
- uint64_t limit_low : 16;
- uint64_t base_low : 24;
- uint64_t accessed : 1; // set by the processor
- // CODE | DATA
- uint64_t rw : 1; // readable? | writeable?
- uint64_t conforming : 1; // conforming? | expands down?
- uint64_t code : 1; // 1 | 0
-
- uint64_t codeordata : 1; // 1 for everything other than TSS and LDT
- uint64_t ring : 2;
- uint64_t present : 1; // always 1
- uint64_t limit_high : 4;
- uint64_t available : 1; // ???
- uint64_t long_mode : 1;
- uint64_t x32 : 1;
- uint64_t gran : 1; // 1 - 4kb, 0 - 1b
- uint64_t base_high : 8;
-} __attribute__((packed));
-
-struct tss_entry {
- uint32_t prev_tss; // unused
- uint32_t esp0; // kernel mode stack pointer
- uint32_t ss0; // kernel mode stack segment
- // total size = 0x68 (?) - 3 * sizeof(uint32_t) = 5c
- uint8_t _unused[0x5c];
-} __attribute__((packed));
-
-struct lgdt_arg {
- uint16_t limit;
- uint32_t base;
-} __attribute__((packed));
-
-static struct gdt_entry GDT[SEG_end];
-static struct tss_entry TSS;
-static struct lgdt_arg lgdt_arg; // probably doesn't need to be global
-
-static void gdt_prepare();
-static void gdt_load();
-
-
-static void gdt_prepare() {
- GDT[SEG_null].present = 0;
-
- GDT[SEG_r0data].limit_low = 0xFFFF;
- GDT[SEG_r0data].limit_high = 0xF;
- GDT[SEG_r0data].gran = 1; // 4KB * 0xFFFFF = (almost) 4GB
- GDT[SEG_r0data].base_low = 0;
- GDT[SEG_r0data].base_high = 0;
- GDT[SEG_r0data].accessed = 0;
- GDT[SEG_r0data].rw = 1;
- GDT[SEG_r0data].conforming = 0;
- GDT[SEG_r0data].code = 0;
- GDT[SEG_r0data].codeordata = 1;
- GDT[SEG_r0data].ring = 0;
- GDT[SEG_r0data].present = 1;
- GDT[SEG_r0data].long_mode = 0; // ???
- GDT[SEG_r0data].available = 1; // ???
- GDT[SEG_r0data].x32 = 1;
-
- // copy to r0 code
- GDT[SEG_r0code] = GDT[SEG_r0data];
- GDT[SEG_r0code].code = 1;
-
- GDT[SEG_r3data] = GDT[SEG_r0data];
- GDT[SEG_r3data].ring = 3;
- GDT[SEG_r3code] = GDT[SEG_r0code];
- GDT[SEG_r3code].ring = 3;
-
- // tss
- memset(&TSS, 0, sizeof(TSS));
- TSS.ss0 = SEG_r0data << 3; // kernel data segment
- TSS.esp0 = (uint32_t) &stack_top;
-
- GDT[SEG_TSS].limit_low = sizeof(TSS);
- GDT[SEG_TSS].base_low = (uint32_t) &TSS;
- GDT[SEG_TSS].accessed = 1; // 1 for TSS
- GDT[SEG_TSS].rw = 0; // 1 busy / 0 not busy
- GDT[SEG_TSS].conforming = 0; // 0 for TSS
- GDT[SEG_TSS].code = 1; // 32bit
- GDT[SEG_TSS].codeordata = 0; // is a system entry
- GDT[SEG_TSS].ring = 3;
- GDT[SEG_TSS].present = 1;
- GDT[SEG_TSS].limit_high = (sizeof(TSS) >> 16) & 0xf;
- GDT[SEG_TSS].available = 0; // 0 for TSS
- GDT[SEG_TSS].long_mode = 0;
- GDT[SEG_TSS].x32 = 0; // idk
- GDT[SEG_TSS].gran = 0;
- GDT[SEG_TSS].base_high = (((uint32_t) &TSS) >> 24) & 0xff;
-}
-
-void change_cs(int seg); // temporary
-
-static void gdt_load() {
- lgdt_arg.limit = sizeof(GDT) - 1;
- lgdt_arg.base = (uint32_t) &GDT;
- asm("lgdt (%0)"
- : : "r" (&lgdt_arg) : "memory");
- asm("ltr %%ax"
- : : "a" (SEG_TSS << 3 | 3) : "memory");
-
- // update all segment registers
- change_cs(SEG_r0code << 3);
- asm("mov %0, %%ds;"
- "mov %0, %%ss;"
- "mov %0, %%es;"
- "mov %0, %%fs;"
- "mov %0, %%gs;"
- : : "r" (SEG_r0data << 3) : "memory");
-}
-
-void gdt_init() {
- gdt_prepare();
- gdt_load();
-}
diff --git a/src/kernel/gdt.h b/src/kernel/gdt.h
deleted file mode 100644
index 9e5a6a5..0000000
--- a/src/kernel/gdt.h
+++ /dev/null
@@ -1,15 +0,0 @@
-#pragma once
-
-enum {
- SEG_null,
- // order dictated by SYSENTER
- SEG_r0code,
- SEG_r0data,
- SEG_r3code,
- SEG_r3data,
- SEG_TSS,
-
- SEG_end
-};
-
-void gdt_init();
diff --git a/src/kernel/idt.c b/src/kernel/idt.c
deleted file mode 100644
index 65f511f..0000000
--- a/src/kernel/idt.c
+++ /dev/null
@@ -1,75 +0,0 @@
-#include <kernel/gdt.h>
-#include <kernel/idt.h>
-#include <kernel/isr.h>
-#include <kernel/panic.h>
-#include <stdbool.h>
-#include <stdint.h>
-
-struct idt_entry {
- uint16_t offset_low ;
- uint16_t code_seg ;
- uint8_t zero ; // unused, has to be 0
- uint8_t type : 4; // 16/32 bit, task/interrupt/task gate
- uint8_t storage : 1; // 0 for interrupt/trap gates
- uint8_t ring : 2;
- uint8_t present : 1;
- uint16_t offset_high ;
-} __attribute__((packed));
-
-// is exactly the same as lgdt_arg, i should combine them into a single struct
-// later
-struct lidt_arg {
- uint16_t limit;
- uint32_t base;
-} __attribute__((packed));
-
-
-static struct idt_entry IDT[256];
-static struct lidt_arg lidt_arg;
-
-static inline void idt_add(uint8_t num, bool user, void (*isr));
-static void idt_prepare();
-static void idt_load();
-static void idt_test();
-
-
-static inline void idt_add(uint8_t num, bool user, void (*isr)) {
- uintptr_t offset = (uintptr_t) isr;
-
- IDT[num] = (struct idt_entry) {
- .offset_low = offset,
- .offset_high = offset >> 16,
- .code_seg = SEG_r0code << 3,
- .zero = 0,
- .present = 1,
- .ring = user ? 3 : 0,
- .storage = 0,
- .type = 0xE, // 32-bit interrupt gate
- };
-}
-
-static void idt_prepare() {
- for (int i = 0; i < 256; i++)
- IDT[i].present = 0;
-
- idt_add(0x08, false, isr_double_fault);
- idt_add(0x0d, false, isr_general_protection_fault);
- idt_add(0x34, false, isr_test_interrupt);
-}
-
-static void idt_load() {
- lidt_arg.limit = sizeof(IDT) - 1;
- lidt_arg.base = (uintptr_t) &IDT;
- asm("lidt (%0)" : : "r" (&lidt_arg) : "memory");
-}
-
-static void idt_test() {
- asm("int $0x34" : : : "memory");
- if (!isr_test_interrupt_called) panic();
-}
-
-void idt_init() {
- idt_prepare();
- idt_load();
- idt_test();
-}
diff --git a/src/kernel/idt.h b/src/kernel/idt.h
deleted file mode 100644
index 5627657..0000000
--- a/src/kernel/idt.h
+++ /dev/null
@@ -1,3 +0,0 @@
-#pragma once
-
-void idt_init();
diff --git a/src/kernel/isr.c b/src/kernel/isr.c
deleted file mode 100644
index b715de0..0000000
--- a/src/kernel/isr.c
+++ /dev/null
@@ -1,24 +0,0 @@
-#include <kernel/isr.h>
-#include <kernel/panic.h>
-#include <kernel/tty.h>
-#include <stdbool.h>
-#include <stdint.h>
-
-bool isr_test_interrupt_called = false;
-
-__attribute__((interrupt))
-void isr_double_fault(struct interrupt_frame *frame) {
- tty_const("#DF");
- panic();
-}
-
-__attribute__((interrupt))
-void isr_general_protection_fault(struct interrupt_frame *frame) {
- tty_const("#GP");
- panic();
-}
-
-__attribute__((interrupt))
-void isr_test_interrupt(struct interrupt_frame *frame) {
- isr_test_interrupt_called = true;
-}
diff --git a/src/kernel/isr.h b/src/kernel/isr.h
deleted file mode 100644
index 150fc46..0000000
--- a/src/kernel/isr.h
+++ /dev/null
@@ -1,15 +0,0 @@
-#pragma once
-#include <stdbool.h>
-
-struct interrupt_frame;
-
-extern bool isr_test_interrupt_called; // used in the self-test in idt.c
-
-__attribute__((interrupt))
-void isr_double_fault(struct interrupt_frame *frame);
-
-__attribute__((interrupt))
-void isr_general_protection_fault(struct interrupt_frame *frame);
-
-__attribute__((interrupt))
-void isr_test_interrupt(struct interrupt_frame *frame);
diff --git a/src/kernel/main.c b/src/kernel/main.c
index 0193514..aa67d7c 100644
--- a/src/kernel/main.c
+++ b/src/kernel/main.c
@@ -1,22 +1,11 @@
-#include <kernel/gdt.h>
-#include <kernel/idt.h>
+#include <arch/generic.h>
#include <kernel/mem.h>
#include <kernel/panic.h>
#include <kernel/proc.h>
-#include <kernel/tty.h>
-#include <platform/asm.h>
void r3_test();
-void kmain()
-{
- tty_clear();
- tty_const("gdt...");
- gdt_init();
- tty_const("idt...");
- idt_init();
- tty_const("sysenter...");
- sysenter_setup();
+void kmain() {
tty_const("mem...");
mem_init();
diff --git a/src/kernel/main.h b/src/kernel/main.h
new file mode 100644
index 0000000..6f27386
--- /dev/null
+++ b/src/kernel/main.h
@@ -0,0 +1,3 @@
+#pragma once
+
+void kmain();
diff --git a/src/kernel/mem.c b/src/kernel/mem.c
index 08eb285..f383e8b 100644
--- a/src/kernel/mem.c
+++ b/src/kernel/mem.c
@@ -1,3 +1,4 @@
+#include <arch/generic.h>
#include <kernel/mem.h>
extern void *_kernel_end;
diff --git a/src/kernel/mem.h b/src/kernel/mem.h
index e8e6a4f..efa65d6 100644
--- a/src/kernel/mem.h
+++ b/src/kernel/mem.h
@@ -1,8 +1,6 @@
#pragma once
#include <stddef.h>
-#define PAGE_SIZE 4096
-
void mem_init();
// allocates `pages` consecutive pages
diff --git a/src/kernel/panic.h b/src/kernel/panic.h
index 7d2ea5f..54a0b8b 100644
--- a/src/kernel/panic.h
+++ b/src/kernel/panic.h
@@ -1,6 +1,6 @@
#pragma once
-#include <kernel/tty.h>
-#include <platform/asm.h>
+#include <arch/generic.h>
+#include <arch/i386/tty.h> // TODO abstract away
// dumb c shit
#define panic_tostr2(x) #x
diff --git a/src/kernel/proc.c b/src/kernel/proc.c
index 776238c..7d42bce 100644
--- a/src/kernel/proc.c
+++ b/src/kernel/proc.c
@@ -1,6 +1,6 @@
+#include <arch/generic.h>
#include <kernel/mem.h>
#include <kernel/proc.h>
-#include <platform/asm.h>
struct process *process_current;
diff --git a/src/kernel/tty.c b/src/kernel/tty.c
deleted file mode 100644
index 5c4c47d..0000000
--- a/src/kernel/tty.c
+++ /dev/null
@@ -1,38 +0,0 @@
-/* will be moved to userspace later on */
-
-#include <kernel/tty.h>
-
-struct vga_cell {
- unsigned char c;
- unsigned char style;
-} __attribute__((__packed__));
-
-static const size_t vga_len = 80 * 25;
-static struct vga_cell *vga = (void*) 0xB8000;
-static size_t vga_pos = 0;
-
-static void tty_scroll() {
- for (int i = 0; i < vga_len - 80; i++) {
- vga[i] = vga[i + 80];
- }
- vga_pos -= 80;
-}
-
-void tty_putchar(char c)
-{
- if (vga_pos >= vga_len - 80) tty_scroll();
- vga[vga_pos++].c = c;
-}
-
-void tty_write(const char *buf, size_t len)
-{
- for (size_t i = 0; i < len; i++) {
- tty_putchar(buf[i]);
- }
-}
-
-void tty_clear() {
- for (size_t i = 0; i < vga_len; i++)
- vga[i].c = ' ';
- vga_pos = 0;
-}
diff --git a/src/kernel/tty.h b/src/kernel/tty.h
deleted file mode 100644
index 3dc1525..0000000
--- a/src/kernel/tty.h
+++ /dev/null
@@ -1,8 +0,0 @@
-#pragma once
-#include <stddef.h>
-
-void tty_putchar(char c);
-void tty_write(const char *buf, size_t len);
-void tty_clear();
-
-#define tty_const(str) tty_write(str, sizeof(str) - 1)
diff --git a/src/platform/asm.h b/src/platform/asm.h
deleted file mode 100644
index 6f72617..0000000
--- a/src/platform/asm.h
+++ /dev/null
@@ -1,9 +0,0 @@
-#pragma once
-
-// boot.s
-__attribute__((noreturn))
-void halt_cpu();
-
-// sysenter.c
-void sysexit(void (*fun)(), void *stack_top);
-void sysenter_setup();
diff --git a/src/platform/boot.s b/src/platform/boot.s
deleted file mode 100644
index d5bfda5..0000000
--- a/src/platform/boot.s
+++ /dev/null
@@ -1,47 +0,0 @@
-.set MAGIC, 0x1BADB002
-.set FLAG_ALIGN, 1<<0 /* align modules on page boundaries */
-.set FLAG_MEMINFO, 1<<1 /* memory map */
-.set FLAGS, FLAG_ALIGN | FLAG_MEMINFO
-.set CHECKSUM, -(MAGIC + FLAGS)
-
-.section .multiboot
-.align 4
-.long MAGIC
-.long FLAGS
-.long CHECKSUM
-
-/* a lil stack */
-.section .bss
-.global stack_top
-.type stack_top, @object
-.align 16
-stack_bottom:
-.skip 16384
-stack_top:
-
-
-.section .text
-.global _start
-.type _start, @function
-_start:
- mov $stack_top, %esp
- call kmain
-
-.global halt_cpu
-.type halt_cpu, @function
-halt_cpu:
- cli
-1: hlt
- jmp 1b
-
-// temporary, will be moved to another file soon
-.global change_cs
-.type change_cs, @function
-change_cs:
- /* retf pops off the return address and code segment off the stack.
- * it turns out that in the i386 cdecl calling convention they're in
- * the correct place already.
- */
- retf
-
-.size _start, . - _start
diff --git a/src/platform/sysenter.s b/src/platform/sysenter.s
deleted file mode 100644
index 270dc08..0000000
--- a/src/platform/sysenter.s
+++ /dev/null
@@ -1,31 +0,0 @@
-/* kernel/gdt.c */
-.set SEG_r0code, 1
-.set SEG_r3code, 3
-.set SEG_r3data, 4
-
-.set IA32_SYSENTER_CS, 0x174
-
-.section .text
-.global sysexit
-.type sysexit, @function
-sysexit:
- pop %ecx
- pop %edx
-
- mov $(SEG_r3data << 3 | 3), %ax
- mov %ax, %ds
- mov %ax, %es
- mov %ax, %fs
- mov %ax, %gs
-
- sysexit
-
-
-.global sysenter_setup
-.type sysenter_setup, @function
-sysenter_setup:
- xor %edx, %edx
- mov $(SEG_r0code << 3), %eax
- mov $IA32_SYSENTER_CS, %ecx
- wrmsr
- ret
--
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