add serial logging for exceptions, fix virtualbox issue

kernel/include/hilbert/kernel/serial.hpp

@@ -0,0 +1,27 @@
+#pragma once
+
+#include <stdint.h>
+
+namespace hilbert::kernel {
+
+  extern "C" void serial_init();
+
+  extern "C" void serial_putchar(char ch);
+
+  static inline void serial_putstr(const char *str) {
+    while (*str) {
+      serial_putchar(*str);
+      ++str;
+    }
+  }
+
+  template <int digits, int dot_every = 4>
+  static inline void serial_puthex(uint64_t n) {
+    for (int d = digits - 1; d >= 0; --d) {
+      serial_putchar("0123456789abcdef"[(n >> (d * 4)) & 0xf]);
+      if (d % dot_every == 0 && d != 0)
+        serial_putchar('.');
+    }
+  }
+
+}

kernel/makefile

@@ -2,7 +2,7 @@ SOURCES = \
   storage/bd/memory.cpp storage/fs/tarfs.cpp application.asm application.cpp \
   framebuffer.cpp interrupts.asm interrupts.cpp allocator.cpp storage.cpp \
   syscall.cpp utility.cpp paging.asm paging.cpp entry.cpp input.cpp panic.cpp \
-  vfile.cpp
+  vfile.cpp serial.asm
 
 build/%.asm.o: source/%.asm
 	@mkdir -p $(@D)

kernel/source/entry.cpp

@@ -3,6 +3,7 @@
 #include <hilbert/kernel/application.hpp>
 #include <hilbert/kernel/framebuffer.hpp>
 #include <hilbert/kernel/paging.hpp>
+#include <hilbert/kernel/serial.hpp>
 #include <hilbert/kernel/input.hpp>
 #include <hilbert/kernel/panic.hpp>
 #include <hilbert/kernel/vfile.hpp>
@@ -97,6 +98,8 @@ static bool have_initfs;
 
 extern "C" [[noreturn]] void entry() {
 
+  serial_init();
+
   //TODO?: maybe we should check if the limine requests were
   //       fulfilled and display some error message if not
 

kernel/source/interrupts.asm

@@ -227,19 +227,51 @@ section .bss
 
 section .text
 
+isr_start:
+
+  push rcx
+  mov rcx, qword [rsp + 8]
+  mov qword [rsp + 8], rax
+  push rdx
+  push rdi
+  push rsi
+  push r8
+  push r9
+  push r10
+  push r11
+  push rcx
+
+  ;this is a complete hack but it works
+  mov rdi, qword [rsp + 10 * 8 + 4 * 8]
+  cmp rdi, 0x38
+  je .fix_ss
+  ret
+
+.fix_ss:
+  mov qword [rsp + 10 * 8 + 4 * 8], 0x3b
+  ret
+
+isr_end:
+
+  pop rcx
+  pop r11
+  pop r10
+  pop r9
+  pop r8
+  pop rsi
+  pop rdi
+  pop rdx
+  mov rax, qword [rsp + 8]
+  mov qword [rsp + 8], rcx
+  pop rcx
+
+  ret
+
 extern on_keyboard_interrupt
 
 keyboard_isr:
 
-  push r11
-  push r10
-  push r9
-  push r8
-  push rsi
-  push rdi
-  push rdx
-  push rcx
-  push rax
+  call isr_start
 
   call wait_read_ps2
   in al, 0x60
@@ -250,15 +282,7 @@ keyboard_isr:
   mov al, 0x20
   out 0x20, al
 
-  pop rax
-  pop rcx
-  pop rdx
-  pop rdi
-  pop rsi
-  pop r8
-  pop r9
-  pop r10
-  pop r11
+  call isr_end
 
   iretq
 
@@ -266,15 +290,7 @@ extern on_mouse_interrupt
 
 mouse_isr:
 
-  push r11
-  push r10
-  push r9
-  push r8
-  push rsi
-  push rdi
-  push rdx
-  push rcx
-  push rax
+  call isr_start
 
   call wait_read_ps2
   in al, 0x60
@@ -286,15 +302,7 @@ mouse_isr:
   out 0x20, al
   out 0xa0, al
 
-  pop rax
-  pop rcx
-  pop rdx
-  pop rdi
-  pop rsi
-  pop r8
-  pop r9
-  pop r10
-  pop r11
+  call isr_end
 
   iretq
 

kernel/source/interrupts.cpp

@@ -1,4 +1,5 @@
 #include <hilbert/kernel/framebuffer.hpp>
+#include <hilbert/kernel/serial.hpp>
 #include <hilbert/kernel/input.hpp>
 #include <hilbert/kernel/panic.hpp>
 
@@ -36,13 +37,47 @@ struct [[gnu::packed]] exception_info_t {
 
 extern exception_info_t exception_info;
 
+static inline void print_reg(const char *regname, uint64_t value) {
+  serial_putstr("  ");
+  serial_putstr(regname);
+  serial_putstr(" = 0x");
+  serial_puthex<16>(value);
+  serial_putchar('\n');
+}
+
 extern "C" [[noreturn]] void print_exception() {
 
   //so exception_info's type is known by gdb
   exception_info_t the_exception_info = exception_info;
   (void)the_exception_info;
 
-  //TODO: log exception, and recover if possible.
+  serial_putstr("exception 0x");
+  serial_puthex<2>(exception_info.exception_number);
+  serial_putchar('\n');
+
+  if (exception_info.has_error)
+    print_reg("error code", exception_info.error);
+
+  print_reg("rflags", exception_info.rflags);
+  print_reg("rip", exception_info.rip);
+  print_reg("cr2", exception_info.cr2);
+  print_reg("cr3", exception_info.cr3);
+  print_reg("rax", exception_info.rax);
+  print_reg("rbx", exception_info.rbx);
+  print_reg("rcx", exception_info.rcx);
+  print_reg("rdx", exception_info.rdx);
+  print_reg("rdi", exception_info.rdi);
+  print_reg("rsi", exception_info.rsi);
+  print_reg("rbp", exception_info.rbp);
+  print_reg("rsp", exception_info.rsp);
+  print_reg("r8 ", exception_info.r8 );
+  print_reg("r9 ", exception_info.r9 );
+  print_reg("r10", exception_info.r10);
+  print_reg("r11", exception_info.r11);
+  print_reg("r12", exception_info.r12);
+  print_reg("r13", exception_info.r13);
+  print_reg("r14", exception_info.r14);
+  print_reg("r15", exception_info.r15);
 
   panic(0xba40bb);
 

kernel/source/serial.asm

@@ -0,0 +1,58 @@
+bits 64
+
+global serial_init
+global serial_putchar
+
+section .text
+
+serial_init:
+
+  xor al, al
+  mov dx, 0x03f9
+  out dx, al
+
+  mov al, 0x80
+  mov dx, 0x03fb
+  out dx, al
+
+  mov al, 0x03
+  mov dx, 0x03f8
+  out dx, al
+
+  xor al, al
+  mov dx, 0x03f9
+  out dx, al
+
+  mov al, 0x03
+  mov dx, 0x03fb
+  out dx, al
+
+  mov al, 0xc7
+  mov dx, 0x03fa
+  out dx, al
+
+  ret
+
+serial_putchar:
+
+  cmp dil, 0x0a
+  je .do_cr
+.cr_ret:
+
+  mov dx, 0x03fd
+
+.loop:
+  in al, dx
+  test al, 0x20
+  jz .loop
+
+  mov al, dil
+  mov dx, 0x03f8
+  out dx, al
+  ret
+
+.do_cr:
+  mov dil, 0x0d
+  call serial_putchar
+  mov dil, 0x0a
+  jmp .cr_ret