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Move links down to avoid splitting list items

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Philipp Oppermann
2017-06-25 21:00:08 +02:00
parent d5fe84e1c6
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blog/content/posts/07-remap-the-kernel/index.md
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@@ -818,21 +818,18 @@ These lines are the important ones. We can read many useful information from the
- `v=0e`: An exception with number `0xe` occurred, which is a page fault according to the [OSDev Wiki][osdev exception overview].
[osdev exception overview]: http://wiki.osdev.org/Exceptions
[page fault]: http://wiki.osdev.org/Exceptions#Page_Fault
- `e=0002`: The CPU set an [error code][page fault error code], which tells us why the exception occurred. The `0x2` bit tells us that it was caused by a write operation. And since the `0x1` bit is not set, the target page was not present.
[page fault error code]: http://wiki.osdev.org/Exceptions#Error_code
- `IP=0008:000000000010ab97` or `pc=000000000010ab97`: The program counter register tells us that the exception occurred when the CPU tried to execute the instruction at `0x10ab97`. We can disassemble this address to see the corresponding function. The `0008:` prefix in `IP` indicates the code [GDT segment].
[GDT segment]: ./posts/02-entering-longmode/index.md#loading-the-gdt
- `SP=0010:00000000001182d0`: The stack pointer was `0x1182d0` (the `0010:` prefix indicates the data [GDT segment]). This tells us if it the stack overflowed.
- `CR2=00000000000b8f00`: Finally the most useful register. It tells us which virtual address caused the page fault. In our case it's `0xb8f00`, which is part of the [VGA text buffer].
[osdev exception overview]: http://wiki.osdev.org/Exceptions
[page fault]: http://wiki.osdev.org/Exceptions#Page_Fault
[page fault error code]: http://wiki.osdev.org/Exceptions#Error_code
[GDT segment]: ./posts/02-entering-longmode/index.md#loading-the-gdt
[VGA text buffer]: ./posts/04-printing-to-screen/index.md#the-vga-text-buffer
So let's find out which function caused the exception: