[Solved] Fixing the IDT caused a breakpoint exception.

Question about which tools to use, bugs, the best way to implement a function, etc should go here. Don't forget to see if your question is answered in the wiki first! When in doubt post here.
Post Reply
psimonson1988
Member
Member
Posts: 40
Joined: Tue Jul 16, 2019 8:40 pm

[Solved] Fixing the IDT caused a breakpoint exception.

Post by psimonson1988 »

Hey all, now I have another problem. After fixing the IDT it was lgdt instead of lidt (what it should've been). But, now that that is fixed it's causing the Breakpoint exception to occur. Not sure why or how to debug it, especially since I don't even call that interrupt in any part of my code (interrupt 3). So I guess what I'm asking is. Why is it causing the breakpoint exception and how do I go about fixing that issue. I would really love to finally be able to type in my OS. Thanks in advanced, I'm pretty new at 32 bit protected mode so. Any and all comment/suggestions are welcome. Please help, thank you all again for all the help so far its much appreciated.

EDIT: Oops forgot to post a link to the code. Code: boot32-barebones
Last edited by psimonson1988 on Mon Jul 06, 2020 10:41 am, edited 1 time in total.
Top
Octocontrabass
Member
Member
Posts: 5885
Joined: Mon Mar 25, 2013 7:01 pm

Re: Fixing the IDT caused a breakpoint exception.

Post by Octocontrabass »

psimonson1988 wrote:Not sure why or how to debug it, especially since I don't even call that interrupt in any part of my code (interrupt 3).
QEMU can log when and where the interrupt occurs if you add "-d int" to your command line. The log includes every interrupt, not just exceptions, and for each interrupt it dumps a large portion of the CPU state, so it can be quite large - but it's sometimes enough information to see exactly why the interrupt happened. (I suggest posting the entries from while your kernel is running.)

If nothing else, you'll be able to get the address of the instruction where the interrupt happens so you can try to work from there.
Top
psimonson1988
Member
Member
Posts: 40
Joined: Tue Jul 16, 2019 8:40 pm

Re: Fixing the IDT caused a breakpoint exception.

Post by psimonson1988 »

Here is the log your requested I ran the command.

Code: Select all

qemu-system-i386 -fda floppy.img -boot a -d int
Below is what that command gave me. Although I'm not sure what I'm looking for in it.

qemu-int.log:

Code: Select all

WARNING: Image format was not specified for 'floppy.img' and probing guessed raw.
         Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted.
         Specify the 'raw' format explicitly to remove the restrictions.
SMM: enter
EAX=00000001 EBX=00000000 ECX=02000000 EDX=02000628
ESI=0000000b EDI=02000000 EBP=000f2c72 ESP=00006d98
EIP=000ebaef EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00cf9b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f6280 00000037
IDT=     000f62be 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000080 CCD=00000001 CCO=LOGICB  
EFER=0000000000000000
SMM: after RSM
EAX=00000001 EBX=00000000 ECX=02000000 EDX=02000628
ESI=0000000b EDI=02000000 EBP=000f2c72 ESP=00006d98
EIP=000ebaef EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f6280 00000037
IDT=     000f62be 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=00000000 CCO=EFLAGS  
EFER=0000000000000000
SMM: enter
EAX=000000b5 EBX=000f7bfc ECX=00001234 EDX=00006dff
ESI=00006d3c EDI=07fbedc5 EBP=00006cfc ESP=00006cfc
EIP=00007bfb EFL=00000006 [-----P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =db80 000db800 ffffffff 008f9300
CS =f000 000f0000 ffffffff 008f9b00
SS =0000 00000000 ffffffff 008f9300
DS =0000 00000000 ffffffff 008f9300
FS =0000 00000000 ffffffff 008f9300
GS =0000 00000000 ffffffff 008f9300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     00000000 00000000
IDT=     00000000 000003ff
CR0=00000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000004 CCD=00006cfc CCO=EFLAGS  
EFER=0000000000000000
SMM: after RSM
EAX=000000b5 EBX=000f7bfc ECX=00001234 EDX=00006dff
ESI=00006d3c EDI=07fbedc5 EBP=00006cfc ESP=00006cfc
EIP=000f7bfc EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f6280 00000037
IDT=     000f62be 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=00000000 CCO=EFLAGS  
EFER=0000000000000000
SMM: enter
EAX=000000b5 EBX=00007c16 ECX=00005678 EDX=07fabb00
ESI=000ea600 EDI=07fbedc5 EBP=00006cfc ESP=00006cfc
EIP=000f7c15 EFL=00000016 [----AP-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f6280 00000037
IDT=     000f62be 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000014 CCD=00006ce8 CCO=EFLAGS  
EFER=0000000000000000
SMM: after RSM
EAX=000000b5 EBX=00007c16 ECX=00005678 EDX=07fabb00
ESI=000ea600 EDI=07fbedc5 EBP=00006cfc ESP=00006cfc
EIP=00007c16 EFL=00000006 [-----P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =db80 000db800 ffffffff 00809300
CS =f000 000f0000 ffffffff 00809b00
SS =0000 00000000 ffffffff 00809300
DS =0000 00000000 ffffffff 00809300
FS =0000 00000000 ffffffff 00809300
GS =0000 00000000 ffffffff 00809300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     00000000 00000000
IDT=     00000000 000003ff
CR0=00000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000004 CCD=00000001 CCO=EFLAGS  
EFER=0000000000000000
SMM: enter
EAX=000000b5 EBX=000f7bfc ECX=00001234 EDX=00006aff
ESI=00006a22 EDI=07fbedc5 EBP=000069e2 ESP=000069e2
EIP=00007bfb EFL=00000006 [-----P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =db80 000db800 ffffffff 008f9300
CS =f000 000f0000 ffffffff 008f9b00
SS =0000 00000000 ffffffff 008f9300
DS =0000 00000000 ffffffff 008f9300
FS =0000 00000000 ffffffff 008f9300
GS =ca00 000ca000 ffffffff 008f9300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     00000000 00000000
IDT=     00000000 000003ff
CR0=00000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000004 CCD=000069e2 CCO=EFLAGS  
EFER=0000000000000000
SMM: after RSM
EAX=000000b5 EBX=000f7bfc ECX=00001234 EDX=00006aff
ESI=00006a22 EDI=07fbedc5 EBP=000069e2 ESP=000069e2
EIP=000f7bfc EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f6280 00000037
IDT=     000f62be 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=00000000 CCO=EFLAGS  
EFER=0000000000000000
SMM: enter
EAX=000000b5 EBX=00007c16 ECX=00005678 EDX=00000005
ESI=00000000 EDI=07fbedc5 EBP=000069e2 ESP=000069e2
EIP=000f7c15 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f6280 00000037
IDT=     000f62be 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=000069ce CCO=EFLAGS  
EFER=0000000000000000
SMM: after RSM
EAX=000000b5 EBX=00007c16 ECX=00005678 EDX=00000005
ESI=00000000 EDI=07fbedc5 EBP=000069e2 ESP=000069e2
EIP=00007c16 EFL=00000006 [-----P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =db80 000db800 ffffffff 00809300
CS =f000 000f0000 ffffffff 00809b00
SS =0000 00000000 ffffffff 00809300
DS =0000 00000000 ffffffff 00809300
FS =0000 00000000 ffffffff 00809300
GS =ca00 000ca000 ffffffff 00809300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     00000000 00000000
IDT=     00000000 000003ff
CR0=00000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000004 CCD=00000001 CCO=EFLAGS  
EFER=0000000000000000
SMM: enter
EAX=000000b5 EBX=000f7bfc ECX=00001234 EDX=00006aff
ESI=00006a1c EDI=07fbedc5 EBP=000069dc ESP=000069dc
EIP=00007bfb EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =db80 000db800 ffffffff 00809300
CS =f000 000f0000 ffffffff 00809b00
SS =0000 00000000 ffffffff 00809300
DS =0000 00000000 ffffffff 00809300
FS =0000 00000000 ffffffff 00809300
GS =ca00 000ca000 ffffffff 00809300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     00000000 00000000
IDT=     00000000 000003ff
CR0=00000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=000069dc CCO=EFLAGS  
EFER=0000000000000000
SMM: after RSM
EAX=000000b5 EBX=000f7bfc ECX=00001234 EDX=00006aff
ESI=00006a1c EDI=07fbedc5 EBP=000069dc ESP=000069dc
EIP=000f7bfc EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f6280 00000037
IDT=     000f62be 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=00000000 CCO=EFLAGS  
EFER=0000000000000000
SMM: enter
EAX=000000b5 EBX=00007c16 ECX=00005678 EDX=00000003
ESI=07f8cb00 EDI=07fbedc5 EBP=000069dc ESP=000069dc
EIP=000f7c15 EFL=00000012 [----A--] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f6280 00000037
IDT=     000f62be 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000010 CCD=000069c8 CCO=EFLAGS  
EFER=0000000000000000
SMM: after RSM
EAX=000000b5 EBX=00007c16 ECX=00005678 EDX=00000003
ESI=07f8cb00 EDI=07fbedc5 EBP=000069dc ESP=000069dc
EIP=00007c16 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =db80 000db800 ffffffff 00809300
CS =f000 000f0000 ffffffff 00809b00
SS =0000 00000000 ffffffff 00809300
DS =0000 00000000 ffffffff 00809300
FS =0000 00000000 ffffffff 00809300
GS =ca00 000ca000 ffffffff 00809300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     00000000 00000000
IDT=     00000000 000003ff
CR0=00000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=00000001 CCO=EFLAGS  
EFER=0000000000000000
SMM: enter
EAX=000000b5 EBX=000f7bfc ECX=00001234 EDX=00006aff
ESI=00006a22 EDI=07fbedc5 EBP=000069e2 ESP=000069e2
EIP=00007bfb EFL=00000006 [-----P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =db80 000db800 ffffffff 00809300
CS =f000 000f0000 ffffffff 00809b00
SS =0000 00000000 ffffffff 00809300
DS =0000 00000000 ffffffff 00809300
FS =0000 00000000 ffffffff 00809300
GS =ca00 000ca000 ffffffff 00809300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     00000000 00000000
IDT=     00000000 000003ff
CR0=00000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000004 CCD=000069e2 CCO=EFLAGS  
EFER=0000000000000000
SMM: after RSM
EAX=000000b5 EBX=000f7bfc ECX=00001234 EDX=00006aff
ESI=00006a22 EDI=07fbedc5 EBP=000069e2 ESP=000069e2
EIP=000f7bfc EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f6280 00000037
IDT=     000f62be 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=00000000 CCO=EFLAGS  
EFER=0000000000000000
SMM: enter
EAX=000000b5 EBX=00007c16 ECX=00005678 EDX=00000005
ESI=00000000 EDI=07fbedc5 EBP=000069e2 ESP=000069e2
EIP=000f7c15 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f6280 00000037
IDT=     000f62be 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=000069ce CCO=EFLAGS  
EFER=0000000000000000
SMM: after RSM
EAX=000000b5 EBX=00007c16 ECX=00005678 EDX=00000005
ESI=00000000 EDI=07fbedc5 EBP=000069e2 ESP=000069e2
EIP=00007c16 EFL=00000006 [-----P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =db80 000db800 ffffffff 00809300
CS =f000 000f0000 ffffffff 00809b00
SS =0000 00000000 ffffffff 00809300
DS =0000 00000000 ffffffff 00809300
FS =0000 00000000 ffffffff 00809300
GS =ca00 000ca000 ffffffff 00809300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     00000000 00000000
IDT=     00000000 000003ff
CR0=00000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000004 CCD=00000001 CCO=EFLAGS  
EFER=0000000000000000
SMM: enter
EAX=000000b5 EBX=000f7bfc ECX=00001234 EDX=00006aff
ESI=00006a1c EDI=07fbedc5 EBP=000069dc ESP=000069dc
EIP=00007bfb EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =db80 000db800 ffffffff 00809300
CS =f000 000f0000 ffffffff 00809b00
SS =0000 00000000 ffffffff 00809300
DS =0000 00000000 ffffffff 00809300
FS =0000 00000000 ffffffff 00809300
GS =ca00 000ca000 ffffffff 00809300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     00000000 00000000
IDT=     00000000 000003ff
CR0=00000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=000069dc CCO=EFLAGS  
EFER=0000000000000000
SMM: after RSM
EAX=000000b5 EBX=000f7bfc ECX=00001234 EDX=00006aff
ESI=00006a1c EDI=07fbedc5 EBP=000069dc ESP=000069dc
EIP=000f7bfc EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f6280 00000037
IDT=     000f62be 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=00000000 CCO=EFLAGS  
EFER=0000000000000000
SMM: enter
EAX=000000b5 EBX=00007c16 ECX=00005678 EDX=00000003
ESI=07eccb00 EDI=07fbedc5 EBP=000069dc ESP=000069dc
EIP=000f7c15 EFL=00000012 [----A--] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
SS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f6280 00000037
IDT=     000f62be 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000010 CCD=000069c8 CCO=EFLAGS  
EFER=0000000000000000
SMM: after RSM
EAX=000000b5 EBX=00007c16 ECX=00005678 EDX=00000003
ESI=07eccb00 EDI=07fbedc5 EBP=000069dc ESP=000069dc
EIP=00007c16 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =db80 000db800 ffffffff 00809300
CS =f000 000f0000 ffffffff 00809b00
SS =0000 00000000 ffffffff 00809300
DS =0000 00000000 ffffffff 00809300
FS =0000 00000000 ffffffff 00809300
GS =ca00 000ca000 ffffffff 00809300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     00000000 00000000
IDT=     00000000 000003ff
CR0=00000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=00000001 CCO=EFLAGS  
EFER=0000000000000000
     0: v=20 e=0000 i=0 cpl=0 IP=0008:00010e64 pc=00010e64 SP=0010:0008ff9c env->regs[R_EAX]=0000005d
EAX=0000005d EBX=0000005d ECX=000000a0 EDX=00000040
ESI=00007fc1 EDI=00000005 EBP=00090000 ESP=0008ff9c
EIP=00010e64 EFL=00000212 [----A--] CPL=0 II=0 A20=0 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00cf9a00 DPL=0 CS32 [-R-]
SS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     00007f53 00000017
IDT=     00011680 000007ff
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000008 CCD=0008ffa4 CCO=ADDL    
EFER=0000000000000000
     1: v=20 e=0000 i=0 cpl=0 IP=0008:00010006 pc=00010006 SP=0010:0008fffc env->regs[R_EAX]=00000002
EAX=00000002 EBX=00001600 ECX=00000aa4 EDX=00000000
ESI=00007fc1 EDI=00000005 EBP=00090000 ESP=0008fffc
EIP=00010006 EFL=00000212 [----A--] CPL=0 II=0 A20=0 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00cf9a00 DPL=0 CS32 [-R-]
SS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     00007f53 00000017
IDT=     00011680 000007ff
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000010 CCD=0008fff8 CCO=EFLAGS  
EFER=0000000000000000
     2: v=20 e=0000 i=0 cpl=0 IP=0008:00010e64 pc=00010e64 SP=0010:0008ffa0 env->regs[R_EAX]=0000005d
EAX=0000005d EBX=0000005d ECX=00000aa4 EDX=00000040
ESI=00007fc1 EDI=00000005 EBP=00090000 ESP=0008ffa0
EIP=00010e64 EFL=00000202 [-------] CPL=0 II=0 A20=0 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00cf9a00 DPL=0 CS32 [-R-]
SS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     00007f53 00000017
IDT=     00011680 000007ff
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000008 CCD=0008ffa8 CCO=ADDL    
EFER=0000000000000000
     3: v=20 e=0000 i=0 cpl=0 IP=0008:00007f8c pc=00007f8c SP=0010:00090000 env->regs[R_EAX]=00000002
EAX=00000002 EBX=00001600 ECX=00000644 EDX=00000000
ESI=00007fc1 EDI=00000005 EBP=00090000 ESP=00090000
EIP=00007f8c EFL=00000206 [-----P-] CPL=0 II=0 A20=0 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00cf9a00 DPL=0 CS32 [-R-]
SS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     00007f53 00000017
IDT=     00011680 000007ff
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000004 CCD=0008fffc CCO=EFLAGS  
EFER=0000000000000000
     4: v=20 e=0000 i=0 cpl=0 IP=0008:00002d70 pc=00002d70 SP=0010:00090000 env->regs[R_EAX]=00000002
EAX=00000002 EBX=00001600 ECX=00000644 EDX=00000000
ESI=00007fc1 EDI=00000005 EBP=00090000 ESP=00090000
EIP=00002d70 EFL=00000202 [-------] CPL=0 II=0 A20=0 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00cf9a00 DPL=0 CS32 [-R-]
SS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     00007f53 00000017
IDT=     00011680 000007ff
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000000 CCD=00000073 CCO=EFLAGS  
EFER=0000000000000000
     5: v=20 e=0000 i=0 cpl=0 IP=0008:00005c50 pc=00005c50 SP=0010:00090000 env->regs[R_EAX]=00000002
EAX=00000002 EBX=00001600 ECX=00000644 EDX=00000000
ESI=00007fc1 EDI=00000005 EBP=00090000 ESP=00090000
EIP=00005c50 EFL=00000206 [-----P-] CPL=0 II=0 A20=0 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00cf9a00 DPL=0 CS32 [-R-]
SS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     00007f53 00000017
IDT=     00011680 000007ff
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000004 CCD=00000053 CCO=EFLAGS  
EFER=0000000000000000
     6: v=03 e=0000 i=1 cpl=0 IP=0008:0000691d pc=0000691d SP=0010:00090004 env->regs[R_EAX]=00000002
EAX=00000002 EBX=00001600 ECX=00000644 EDX=00001600
ESI=00007fc1 EDI=00000005 EBP=00090000 ESP=00090004
EIP=0000691d EFL=00000202 [-------] CPL=0 II=0 A20=0 SMM=0 HLT=0
ES =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
CS =0008 00000000 ffffffff 00cf9a00 DPL=0 CS32 [-R-]
SS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
DS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
FS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
GS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     00007f53 00000017
IDT=     00011680 000007ff
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
CCS=00000002 CCD=0000001f CCO=ADDB    
EFER=0000000000000000
Top
MichaelPetch
Member
Member
Posts: 832
Joined: Fri Aug 26, 2016 1:41 pm
Libera.chat IRC: mpetch

Re: Fixing the IDT caused a breakpoint exception.

Post by MichaelPetch »

In entry.asm you do this:

Code: Select all

_start:
        call kernel_main
        hlt
The problem is that you have enabled interrupts with STI in your kernel after setting up your interrupts. The kernel_main returns to execute the HLT instruction. HLT will wait until the next interrupt occurs, execute the interrupt handler for it and then continue after the HLT instruction. At that point you just execute whatever semi random data and instructions that are in memory after the HLT. What you want to do is put an infinite loop around the HLT so that after each interrupt is serviced it goes back and does another HLT waiting for the next interrupt. Something like

Code: Select all

_start:
        call kernel_main
.hltloop:
        hlt
        jmp .hltloop
Top
psimonson1988
Member
Member
Posts: 40
Joined: Tue Jul 16, 2019 8:40 pm

Re: [Solved] Fixing the IDT caused a breakpoint exception.

Post by psimonson1988 »

Thank you so much, that worked like a charm.
Top
Post Reply

Return to “OS Development”