vmm: display segment map info

10 files changed, 85 insertions, 36 deletions

diff --git a/linker.ld b/linker.ld
index 5ff3b62..e9f1d73 100644
--- a/linker.ld
+++ b/linker.ld
@@ -20,32 +20,40 @@ SECTIONS
     . = VADDR_BASE + 1M;
 
     .text ALIGN(4K) : AT(ADDR(.text) - VADDR_BASE) {
+        begin_text = .;
         *(.text*)
+        end_text = .;
     }
  
     /* Read-only data. */
     .rodata ALIGN(4K) : AT(ADDR(.rodata) - VADDR_BASE) {
+        begin_rodata = .;
         *(.rodata*)
+        end_rodata = .;
     }
  
     /* Read-write data (initialized) */
     .data ALIGN(4K) : AT(ADDR(.data) - VADDR_BASE) {
-        begin_ctors = .;
-        KEEP(*(.init_array));   /* global constructors */
-        end_ctors = .;
-
         begin_constinit = .;
         *(.constinit)
         end_constinit = .;
 
+        begin_ctors = .;
+        KEEP(*(.init_array));   /* global constructors */
+        end_ctors = .;
+
+        begin_data = .;
         *(.data)
+        end_data = .;
     }
  
     /* Read-write data (uninitialized) and stack */
     .bss ALIGN(4K) : AT(ADDR(.bss) - VADDR_BASE) {
+        begin_bss = .;
         *(.pages)
         *(.bss)
         *(.stack)
+        end_bss = .;
     }
     _kernel_end = .;
 }
diff --git a/src/boot.S b/src/boot.S
index 635b38f..e5686c8 100644
--- a/src/boot.S
+++ b/src/boot.S
@@ -55,12 +55,9 @@ _start:
     # Physical address of boot_page_table1.
     movl $(boot_page_table1 - 0xC0000000), %edi
     # First address to map is address 0.
-	# TODO: Start at the first kernel page instead. Alternatively map the first
-	#       1 MiB as it can be generally useful, and there's no need to
-	#       specially map the VGA buffer.
-	movl $0, %esi
-	# Map 1023 pages. The 1024th will be the VGA text buffer.
-	movl $1023, %ecx
+    movl $0, %esi
+    # Map 1023 pages. The 1024th will be the VGA text buffer.
+    movl $1023, %ecx
 
 1:
 	# Only map the kernel.
diff --git a/src/gdt.cc b/src/gdt.cc
index 0712187..7b5e3df 100644
--- a/src/gdt.cc
+++ b/src/gdt.cc
@@ -13,7 +13,7 @@ constexpr uint32_t null_sz = 0;
 constexpr uint32_t kseg_start = 0;
 constexpr uint32_t kseg_sz = 0xffffffff;
 
-static GDT::SegmentDescriptor segments[256]{
+__attribute__((section(".constinit"))) static GDT::SegmentDescriptor segments[256]{
     [GDT::null0] = seg::make<null_sz>(0, {}),
     [GDT::kcode] = seg::make<kseg_sz>(kseg_start, {.r_w = true, .exe = true, .segment = true, .present = true}),
     [GDT::kdata] = seg::make<kseg_sz>(kseg_start, {.r_w = true, .segment = true, .present = true}),
diff --git a/src/idt.cc b/src/idt.cc
index edf7b37..19865f6 100644
--- a/src/idt.cc
+++ b/src/idt.cc
@@ -39,14 +39,6 @@ bool IDT::uninstall(uint8_t irq, InterruptHandler* h) {
 #define ICW4_BUF_MASTER 0x0C /* Buffered mode/master */
 #define ICW4_SFNM 0x10       /* Special fully nested (not) */
 
-extern "C" uint32_t handle_exception(cpu_state_t* r) {
-  printk("exception ", uhex{r->irq}, " error ", uhex{r->error}, '\n');
-  asm volatile("cli");
-  while (true) asm volatile("hlt");
-  __builtin_unreachable();
-
-  return reinterpret_cast<uint32_t>(r);
-};
 
 extern "C" uint32_t handle_interrupt(cpu_state_t* r) {
   if (r->irq < irq_base) return reinterpret_cast<uint32_t>(r);
diff --git a/src/idt/exception.cc b/src/idt/exception.cc
new file mode 100644
index 0000000..efffd95
--- /dev/null
+++ b/src/idt/exception.cc
@@ -0,0 +1,8 @@
+#include <stdlib.h>
+#include "cpu/registers.h"
+
+extern "C" void handle_exception(const cpu_state_t* r) {
+  printk("exception ", uhex{r->irq}, " error ", uhex{r->error}, "eip: ", uhex{r->eip}, '\n');
+
+  abort();
+};
diff --git a/src/idt/stubs.S b/src/idt/stubs.S
index d4fb56f..568b0dc 100644
--- a/src/idt/stubs.S
+++ b/src/idt/stubs.S
@@ -73,7 +73,7 @@ exception_common:
 
     push %esp
     call handle_exception
-    mov %eax, %esp
+    add $4, %esp
 
     popa
     /* remove error code and irq from stack */
diff --git a/src/kernel.cc b/src/kernel.cc
index 33282db..98c3a1a 100644
--- a/src/kernel.cc
+++ b/src/kernel.cc
@@ -13,23 +13,14 @@
 #include "cga.h"
 #include "gdt.h"
 #include "idt.h"
+#include "keyboard.h"
 #include "scheduler.h"
 #include "serial.h"
-
-#include "keyboard.h"
+#include "vmm.h"
 
 #include "hardware.h"
 
-typedef void (*constructor)();
-
 extern "C" {
-
-constructor begin_ctors;
-constructor end_ctors;
-void kernel_constructors() {
-  for (constructor* i = &begin_ctors; i != &end_ctors; ++i) (*i)();
-}
-
 void dump_multiboot(uint32_t mb_magic, uint32_t mb_addr);
 void dump_gdt();
 
@@ -45,12 +36,13 @@ void kernel_main([[maybe_unused]] uint32_t mb_magic, [[maybe_unused]] uint32_t m
 
   printk("Hello, kernel World!\n");
 
-  dump_multiboot(mb_magic, mb_addr + 0xc0000000);
+  dump_address();
+  // dump_multiboot(mb_magic, mb_addr + 0xc0000000);
   // dump_gdt();
 
   GDT gdt;
   IDT idt{gdt.descriptor(GDT::kcode)};
-  Scheduler s{gdt.descriptor(GDT::kcode)};
+  // Scheduler s{gdt.descriptor(GDT::kcode)};
   Keyboard kb;
 
   idt.enable();
diff --git a/src/makefile b/src/makefile
index ceaf5ef..47e8762 100644
--- a/src/makefile
+++ b/src/makefile
@@ -2,13 +2,13 @@ AS_OBJ += src/boot.o \
 	  src/idt/stubs.o
 
 CXX_OBJ += src/kernel.o \
-	   src/kernel/dump_gdt.o \
-	   src/kernel/dump_multiboot.o \
+	   src/kernel/dump_gdt.o src/kernel/dump_multiboot.o \
 	   src/memory.o \
 	   src/gdt.o \
 	   src/gdt/segmentdescriptor.o \
 	   src/idt.o \
-	   src/idt/interruptgate.o src/idt/interrupthandler.o \
+	   src/idt/exception.o src/idt/interruptgate.o src/idt/interrupthandler.o \
+	   src/vmm.o \
 	   src/scheduler.o
 
 src/cpu/irq.h: $(OBJ_DIR)/src/idt/stubs.o
diff --git a/src/vmm.cc b/src/vmm.cc
new file mode 100644
index 0000000..346e6ab
--- /dev/null
+++ b/src/vmm.cc
@@ -0,0 +1,49 @@
+#include <stdlib.h>
+
+typedef void (*constructor)();
+
+extern "C" {
+/* .text */
+uint32_t begin_text;
+uint32_t end_text;
+
+/* .rodata */
+uint32_t begin_rodata;
+uint32_t end_rodata;
+
+/* .data */
+uint32_t begin_constinit;
+uint32_t end_constinit;
+constructor begin_ctors;
+constructor end_ctors;
+uint32_t begin_data;
+uint32_t end_data;
+
+/* .bss */
+uint32_t begin_bss;
+uint32_t end_bss;
+
+void kernel_constructors() {
+  for (constructor* i = &begin_ctors; i != &end_ctors; ++i) (*i)();
+}
+
+void dump_address() {
+  printk("text      begin: ", uhex{reinterpret_cast<uint32_t>(&begin_text)},
+         " end: ", uhex{reinterpret_cast<uint32_t>(&end_text)}, '\n');
+
+  printk("rodata    begin: ", uhex{reinterpret_cast<uint32_t>(&begin_rodata)},
+         " end: ", uhex{reinterpret_cast<uint32_t>(&end_rodata)}, '\n');
+
+  printk("constinit begin: ", uhex{reinterpret_cast<uint32_t>(&begin_constinit)},
+         " end: ", uhex{reinterpret_cast<uint32_t>(&end_constinit)}, '\n');
+
+  printk("ctors     begin: ", uhex{reinterpret_cast<uint32_t>(&begin_ctors)},
+         " end: ", uhex{reinterpret_cast<uint32_t>(&end_ctors)}, '\n');
+
+  printk("data      begin: ", uhex{reinterpret_cast<uint32_t>(&begin_data)},
+         " end: ", uhex{reinterpret_cast<uint32_t>(&end_data)}, '\n');
+
+  printk("bss       begin: ", uhex{reinterpret_cast<uint32_t>(&begin_bss)},
+         " end: ", uhex{reinterpret_cast<uint32_t>(&end_bss)}, '\n');
+}
+}  // extern "C"
diff --git a/src/vmm.h b/src/vmm.h
new file mode 100644
index 0000000..45aa1e8
--- /dev/null
+++ b/src/vmm.h
@@ -0,0 +1,3 @@
+#pragma once
+
+extern "C" void dump_address();