xCAT/xNBA
2
0
Fork 0
mirror of https://github.com/xcat2/xNBA.git synced 2024-11-22 17:41:55 +00:00
Code Issues Projects Releases Wiki Activity

Documented the fact that the prefix can prot_call(main) without

Browse Source 
worrying about its stack being destroyed during the Etherboot run.
This commit is contained in:
Michael Brown 2006-05-25 22:04:17 +00:00
parent 0479e9f541
commit 29340d7728
1 changed files with 9 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
src/arch/i386/transitions/librm.S
View File

@ -328,6 +328,15 @@ rm_ds: .word 0
* function explicitly overwrites values in ix86. Interrupt status
* and GDT will also be preserved. Gate A20 will be enabled.
*
* Note that prot_call() does not rely on the real-mode stack
* remaining intact in order to return, since everything relevant is
* copied to the protected-mode stack for the duration of the call.
* In particular, this means that a real-mode prefix can make a call
* to main() which will return correctly even if the prefix's stack
* gets vapourised during the Etherboot run. (The prefix cannot rely
* on anything else on the stack being preserved, so should move any
* critical data to registers before calling main()).
*
* Parameters:
* function : virtual address of protected-mode function to call
*