arno/linux-insides
1
0
Fork 0
mirror of https://github.com/0xAX/linux-insides.git synced 2024-12-22 06:38:07 +00:00
Code Issues Releases Wiki Activity

Booting/linux-bootstrap-4.md: fix typo

Browse Source
This commit is contained in:
Arnaud BOIVIN 2020-04-05 23:32:10 +02:00
parent 9e1318f3ec
commit aa2ccb403f
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Booting/linux-bootstrap-4.md
View File

@ -210,7 +210,7 @@ startup_32 (0x0) +-----------------------+
+-----------------------+ +-----------------------+
``` ```
The `startup_32` function is linked to run at the address `0x0` and this means that `1f` has the address `0x0 + offset to 1f`, which is approximately `0x21` bytes. The `ebp` register contains the real physical address of the `1f` label. So, if we subtract `1f` from the `ebp` register, we will get the real physical address of the `startup_32` function. The Linux kernel [boot protocol](https://www.kernel.org/doc/Documentation/x86/boot.txt) saysthe base of the protected mode kernel is `0x100000`. We can verify this with [gdb](https://en.wikipedia.org/wiki/GNU_Debugger). Let's start the debugger and add a breakpoint at the address of `1f`, which is `0x100021`. If this is correct we will see the value `0x100021` in the `ebp` register: The `startup_32` function is linked to run at the address `0x0` and this means that `1f` has the address `0x0 + offset to 1f`, which is approximately `0x21` bytes. The `ebp` register contains the real physical address of the `1f` label. So, if we subtract `1f` from the `ebp` register, we will get the real physical address of the `startup_32` function. The Linux kernel [boot protocol](https://www.kernel.org/doc/Documentation/x86/boot.txt) says the base of the protected mode kernel is `0x100000`. We can verify this with [gdb](https://en.wikipedia.org/wiki/GNU_Debugger). Let's start the debugger and add a breakpoint at the address of `1f`, which is `0x100021`. If this is correct we will see the value `0x100021` in the `ebp` register:
``` ```
$ gdb $ gdb