Debugging - Revision history

PatrickGeorgi: Add Windows Debugger Instructions

2013-01-24T22:04:36Z

Add Windows Debugger Instructions

GNUtoo at 12:15, 23 June 2012

2012-06-23T12:15:49Z

GNUtoo at 12:14, 23 June 2012

2012-06-23T12:14:23Z

GNUtoo: update location of coreboot_ram.debug that changed over time

2012-06-23T12:12:12Z

update location of coreboot_ram.debug that changed over time

GNUtoo at 12:10, 23 June 2012

2012-06-23T12:10:44Z

Stepan at 19:56, 29 March 2012

2012-03-29T19:56:03Z

Stepan: d'uh... Mentioned the wrong file name

2009-05-29T18:34:45Z

d'uh... Mentioned the wrong file name

Stepan: /* GDB Interface */

2009-05-29T17:33:14Z

‎GDB Interface

Stepan: /* GDB Interface */

2009-04-27T10:40:07Z

‎GDB Interface

Stepan: New page: = GDB Interface = coreboot has an easy to use interface to the GNU debugger gdb. To enable it, add the following two lines to your mainboard's config.-lb: uses CONFIG_GDB_STUB default ...

2009-03-01T10:52:23Z

New page: = GDB Interface = coreboot has an easy to use interface to the GNU debugger gdb. To enable it, add the following two lines to your mainboard's config.-lb: uses CONFIG_GDB_STUB default ...

New page

= GDB Interface =

coreboot has an easy to use interface to the GNU debugger gdb. To enable it, add the following two lines to your mainboard's config.-lb:

uses CONFIG_GDB_STUB
default CONFIG_GDB_STUB=1

Then you will not get exceptions like this:

Unexpected Exception: 0 @ 10:0012724b - Halting
Code: 0 eflags: 00010046
eax: 00000001 ebx: 00000061 ecx: 00000004 edx: 00000000
edi: 00000000 esi: 00000061 ebp: 00163abc esp: 00163a98

But instead you will be able to connect to the machine using gdb over a serial line in case of an exception:

(gdb) file coreboot-v2/coreboot-builds/kontron_986lcd-m/fallback/coreboot_ram
Reading symbols from coreboot-v2/coreboot-builds/kontron_986lcd-m/fallback/coreboot_ram...done.
(gdb) set remotebaud 115200
(gdb) target remote /dev/ttyUSB0
Remote debugging using /dev/ttyUSB0
0x0012824b in __udivdi3 (n=17082841390, d=0) at ...
...
(gdb) bt
#0 0x0012824b in __udivdi3 (n=17082841390, d=0)
at /usr/lib/gcc/gcc- 4.3.2/libgcc/../gcc/libgcc2.c:899
#1 0x0011efa2 in handle_port_61h ()
#2 0x0011fbc3 in my_inb ()
#3 0x001189f5 in x86emuOp_in_byte_AL_IMM ()
#4 0x001092f1 in X86EMU_exec ()
#5 0x0010a06f in biosemu ()
#6 0x0011fcfb in run_bios ()
#7 0x0010cbcb in pci_dev_init ()
#8 0x00103d9b in dev_initialize ()
#9 0x0010f8b5 in hardwaremain ()
#10 0x00100099 in _text ()

← Older revision		Revision as of 22:04, 24 January 2013
Line 59:		Line 59:
	#9 0x0010f8b5 in hardwaremain ()		#9 0x0010f8b5 in hardwaremain ()
	#10 0x00100099 in _text ()		#10 0x00100099 in _text ()
		+
		+	= Windows 7 USB =
		+	This is documentation on how to setup Windows 7 on USB, so it can be used with a USB debug device and WinDbg to track down Windows errors that are otherwise hard to debug (eg. black screen, Stop codes, ACPI issues).
		+
		+	== Prepare Windows Media ==
		+	=== Step 1: Get media ===
		+	I used Windows 7 Ultimate 64bit English, ISO image has SHA1: 36AE90DEFBAD9D9539E649B193AE573B77A71C83
		+
		+	I also tried Windows 8 Consumer Preview 64bit English, ISO image has SHA1: 1288519C5035BCAC83CBFA23A33038CCF5522749
		+
		+
		+	=== Step 2: Prepare disk ===
		+	Use some sufficiently large USB media (4GB+), and format it as NTFS.
		+
		+	Windows 7 might work on FAT, but Windows 8 definitely won’t, as the main file archive is >4GB, which even FAT32 doesn't like.
		+
		+	For reference, I called the volume “WININST”, but I doubt that matters.
		+
		+	=== Step 3: Copy the entire disk content to disk ===
		+	I started out from an ISO image (as obtained from digitalriver), and extracted it using 7-zip to the media.
		+	After that I had a directory that looks like this:
		+
		+	E:\>dir
		+	Datenträger in Laufwerk E: ist WININST
		+	Volumeseriennummer: 86DF-6846
		+
		+	Verzeichnis von E:\
		+
		+	12.04.2011 11:38 122 autorun.inf
		+	03.05.2012 18:54 <DIR> boot
		+	12.04.2011 11:38 383.786 bootmgr
		+	12.04.2011 11:38 669.568 bootmgr.efi
		+	03.05.2012 18:54 <DIR> efi
		+	12.04.2011 11:38 106.768 setup.exe
		+	03.05.2012 18:56 <DIR> sources
		+	03.05.2012 18:56 <DIR> support
		+	03.05.2012 18:56 <DIR> upgrade
		+	4 Datei(en), 1.160.244 Bytes
		+	5 Verzeichnis(se), 4.976.803.840 Bytes frei
		+
		+	=== Step 4: Install boot sector ===
		+	For this, you need to run a Windows Console prompt as Administrator. It’s not enough to run as the admin user, but you need to go through the “run as administrator” + UAC motions.
		+
		+	On Windows 7, the fastest way is to open the start menu, type “cmd” in the search field, wait for cmd to appear (with that black window + C:\ icon), right click it, and select “run as administrator”. On Windows 8, there's an Admin Command Line in the Win+X menu.
		+
		+	Move to the drive with the install data (E:\ in my case), enter boot\, and run bootsect like this:
		+
		+	C:\Windows\System32>e:
		+
		+	E:\>cd boot
		+
		+	E:\boot>bootsect /nt60 e: /force /mbr
		+	Target volumes will be updated with BOOTMGR compatible bootcode.
		+
		+	E: (\\?\Volume{39f55ea8-3ea1-11e1-afe7-005056c00008})
		+
		+	Forced dismount complete, open handles to this volume are now invalid.
		+
		+	Successfully updated NTFS filesystem bootcode.
		+
		+	\??\PhysicalDrive2
		+
		+	Successfully updated disk bootcode.
		+
		+	Bootcode was successfully updated on all targeted volumes.
		+
		+	=== Step 5: Prepare installer for USB debug device ===
		+	In the same Console prompt (and same directory), run:
		+
		+	bcdedit /store bcd /dbgsettings usb targetname:TargetSystem
		+	bcdedit /store bcd /set {default} debug yes
		+
		+	If you have access to the legacy serial port, you can use that to run a kernel debugger session without usb debug device (and its setup, which can be complicated in the presence of Rate Matching Hubs).
		+
		+	In such a setup, instead of the first command use
		+	bcdedit /store bcd /dbgsettings serial debugport:1 baudrate:115200
		+
		+	=== Step 6: Install ===
		+	Start your coreboot + seabios system, and make it boot from your USB device.
		+	If everything is well, dance and jump with joy! If not, you have a chance to improve coreboot!
		+
		+	=== Step 7: Boot Windows ===
		+	Once installation is done, boot the new system. That’s another source of trouble, since this is a slightly different Windows than the one driving the installer.
		+	And there was no chance to setup debug mode for it yet! (TBD)
		+
		+	== Setup Debugging Environment ==
		+	=== Configuring WinDbg ===
		+	First, install WinDbg. You can find in the Debugging Utilities for Windows. Set up the symbol file path, so it can resolve the addresses it gets from the target:
		+
		+	* Create a directory somewhere (C:\Symbols is the default).
		+	* Create an empty "index2.txt" in there.
		+	* Start Windbg
		+	* File, Symbol File Path
		+	* Enter <code>"SRVC:\Symbolshttp://msdl.microsoft.com/download/symbols"</code> (fill in your path instead of <code>C:\Symbols</code>)
		+
		+	With this configuration, WinDbg will fetch symbol files from the Microsoft server.
		+
		+	=== Start debug operation ===
		+	Select the communication channel in File, Kernel Debug (USB 2.0 or serial).
		+
		+	For USB, fill in the name (TargetSystem in the example above), for serial, configure the port. Press OK.
		+
		+	WinDbg will wait for the target to break into the kernel debugger now. It might take a while on the first runs as it has to download the symbol files. Eventually it will print the error and location.

@@ Line 23: / Line 23: @@
   Remote debugging using /dev/ttyUSB0
   _text () at src/arch/x86/lib/c_start.S:85
 		call	hardwaremain
   (gdb)

@@ Line 5: / Line 5: @@
   [*]   Wait for a GDB connection
 Then Coreboot will stop and wait for a GDB connection.
 == Exceptions with GDB ==

@@ Line 19: / Line 19: @@
 But instead you will be able to connect to the machine using gdb over a serial line in case of an exception:
-  (gdb) file coreboot/build/coreboot_ram.debug
+  (gdb) file coreboot/build/cbfs/fallback/coreboot_ram.debug
-  Reading symbols from coreboot/build/coreboot_ram.debug...done.
+  Reading symbols from coreboot/build/cbfs/fallback/coreboot_ram.debug...done.
   (gdb) set remotebaud 115200
   (gdb) target remote /dev/ttyUSB0

@@ Line 1: / Line 1: @@
 = GDB Interface =
-coreboot has an easy to use interface to the GNU debugger gdb. To enable it, select the CONFIG_GDB_STUB option in the Debugging menu of coreboot's configuration:
+== Exceptions with GDB ==
   [*] GDB debugging support
-Then you will not get exceptions like this:
+For instance you will not get exceptions like this:
   Unexpected Exception: 0 @ 10:0012724b - Halting

@@ Line 1: / Line 1: @@
 = GDB Interface =
-coreboot has an easy to use interface to the GNU debugger gdb. To enable it, add the following two lines to your mainboard's Options.lb:
+coreboot has an easy to use interface to the GNU debugger gdb. To enable it, select the CONFIG_GDB_STUB option in the Debugging menu of coreboot's configuration:
+  [*] GDB debugging support
- uses CONFIG_GDB_STUB
- ...
- default CONFIG_GDB_STUB=1
-−
-'''NOTE:''' You need to put the '''uses''' line into the uses-section of the Options.lb, and the '''default''' line into the configuration section, or the coreboot config tool will print an error.
-−
-Compiling coreboot with debugging symbols might help:
-  Index: src/config/Config.lb
- ===================================================================
- --- src/config/Config.lb	(revision 1578)
- +++ src/config/Config.lb	(working copy)
- @@ -10,7 +10,7 @@
-  makedefine GCC_INC_DIR := $(shell LC_ALL=C $(GCC) -print-search-dirs | sed -ne "s/install: \(.*\)/\1include/gp")
-−
-  makedefine CPPFLAGS := -I$(TOP)/src/include -I$(TOP)/src/arch/$(ARCH)/include -I$(GCC_INC_DIR) $(CPUFLAGS)
- -makedefine CFLAGS := $(CPU_OPT) $(DISTRO_CFLAGS) $(CPPFLAGS) -Os -nostdinc -nostdlib -Wall -Wundef ...
- +makedefine CFLAGS := $(CPU_OPT) $(DISTRO_CFLAGS) $(CPPFLAGS) -O2 -g -nostdinc -nostdlib -Wall -Wundef ...
-−
-  if ASSEMBLER_DEBUG
-  makedefine DEBUG_CFLAGS := -g -dA -fverbose-asm
 Then you will not get exceptions like this:
@@ Line 33: / Line 13: @@
 But instead you will be able to connect to the machine using gdb over a serial line in case of an exception:
-  (gdb) file coreboot-v2/coreboot-builds/kontron_986lcd-m/fallback/coreboot_ram
+  (gdb) file coreboot/build/coreboot_ram.debug
-  Reading symbols from coreboot-v2/coreboot-builds/kontron_986lcd-m/fallback/coreboot_ram...done.
+  Reading symbols from coreboot/build/coreboot_ram.debug...done.
   (gdb) set remotebaud 115200
   (gdb) target remote /dev/ttyUSB0