arno/linux-insides
1
0
Fork 0
mirror of https://github.com/0xAX/linux-insides.git synced 2024-12-22 14:48:08 +00:00
Code Issues Releases Wiki Activity

fix logic error about KEEP_SEGMENTS flags

Browse Source
This commit is contained in:
zhaoxiaoqiang 2015-11-25 18:34:32 +08:00
parent f245f5b9fa
commit bd7d8e6af0
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

@ -153,7 +153,7 @@ and if `KEEP_SEGMENTS` is not set, we need to set `ds`, `ss` and `es` registers
movl %eax, %ss
```
remember that `__BOOT_DS` is `0x18` (index of data segment in the Global Descriptor Table). If `KEEP_SEGMENTS` is not set, we jump to the label `1f` or update segment registers with `__BOOT_DS` if this flag is set.
remember that `__BOOT_DS` is `0x18` (index of data segment in the Global Descriptor Table). If `KEEP_SEGMENTS` is set, we jump to the label `1f` or update segment registers with `__BOOT_DS` if this flag is not set.
If you read the previous [part](https://github.com/0xAX/linux-insides/blob/master/Booting/linux-bootstrap-3.md), you can remember that we already updated segment registers in the [arch/x86/boot/pmjump.S](https://github.com/torvalds/linux/blob/master/arch/x86/boot/pmjump.S), so why do we need to set up it again? Actually linux kernel also has the 32-bit boot protocol, so `startup_32` can be the first function which will be executed right after a bootloader transfers control to the kernel.