projects
/
bootcensus
/ blobdiff
commit
grep
author
committer
pickaxe
?
search:
re
summary
|
shortlog
|
log
|
commit
|
commitdiff
|
tree
raw
|
inline
| side by side
fixed int86 to return correctly from BIOS calls that internally change
[bootcensus]
/
src
/
boot
/
boot2.s
diff --git
a/src/boot/boot2.s
b/src/boot/boot2.s
index
f2aab01
..
7067a8f
100644
(file)
--- a/
src/boot/boot2.s
+++ b/
src/boot/boot2.s
@@
-763,6
+763,9
@@
rmidt: .short 0x3ff
saved_esp: .long 0
saved_ebp: .long 0
saved_esp: .long 0
saved_ebp: .long 0
+saved_eax: .long 0
+saved_es: .word 0
+saved_ds: .word 0
# drop back to unreal mode to call 16bit interrupt
.global int86
# drop back to unreal mode to call 16bit interrupt
.global int86
@@
-809,17
+812,18
@@
int86:
# ignore fs and gs for now, don't think I'm going to need them
mov saved_esp, %esp
# ignore fs and gs for now, don't think I'm going to need them
mov saved_esp, %esp
+ # move to the real-mode stack, accessible from ss=0
+ # just in case the BIOS call screws up our unreal mode
+ mov $0x7be0, %esp
+
# call 16bit interrupt
int_op: int $0
# call 16bit interrupt
int_op: int $0
- mov saved_ebp, %ebp
- mov 12(%ebp), %esp
- add $38, %esp
- push %ds
- push %es
- pushfw
- pushal
- mov saved_esp, %esp
+ # save all registers that we'll clobber before having the
+ # chance to populate the int86regs structure
+ mov %eax, saved_eax
+ mov %ds, saved_ds
+ mov %es, saved_es
# re-enable protection
mov %cr0, %eax
# re-enable protection
mov %cr0, %eax
@@
-836,6
+840,18
@@
int_op: int $0
mov %ax, %ss
nop
mov %ax, %ss
nop
+ mov saved_ebp, %ebp
+ mov 12(%ebp), %esp
+ add $38, %esp
+ mov saved_ds, %ax
+ pushw %ax
+ mov saved_es, %ax
+ pushw %ax
+ pushfw
+ mov saved_eax, %eax
+ pushal
+ mov saved_esp, %esp
+
# restore 32bit interrupt descriptor table
lidt (saved_idtr)
sti
# restore 32bit interrupt descriptor table
lidt (saved_idtr)
sti