Elf debugging

Elf debugging

[maybedoo]

Hi,

I want to debug an elf binary. Compiling with the debugging symbols works
fine, but when I'm connected with gdb, after loading it, it can't find my
source files. I've set the path to the src with "directory" but the same.
How can I find out what files are loaded and how can I load my file I need
for a breakpoint?

Regards,

May
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Re: Elf debugging

[Michael Snyder]

maybedoo wrote:
> Hi,
> 
> I want to debug an elf binary. Compiling with the debugging symbols works
> fine, but when I'm connected with gdb, after loading it, it can't find my
> source files. I've set the path to the src with "directory" but the same.
> How can I find out what files are loaded and how can I load my file I need
> for a breakpoint?

It should work.  What compiler are you using?

Re: Elf debugging

[maybedoo]

I'm using GCC 4, that's why I'm wondering that it isn't working.


Michael Snyder-6 wrote:
> 
> maybedoo wrote:
>> Hi,
>> 
>> I want to debug an elf binary. Compiling with the debugging symbols works
>> fine, but when I'm connected with gdb, after loading it, it can't find my
>> source files. I've set the path to the src with "directory" but the same.
>> How can I find out what files are loaded and how can I load my file I
>> need
>> for a breakpoint?
> 
> It should work.  What compiler are you using?
> 
> 
> 
> 

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Re: Elf debugging

[Paul Pluzhnikov]

On Tue, Jun 2, 2009 at 10:15 AM, maybedoo <maybedoo@gmx.de> wrote:
>
> I'm using GCC 4, that's why I'm wondering that it isn't working.

You have supplied so little relevant info, it's a wonder anyone responded
to you at all.

What are your host and target? What does 'gcc --version' say?
What command line did you use to compile and link your executable?
What does 'readelf -w exename' say?
What commands did you execute to debug it?
What version of GDB did use? How was that GDB built?

Please provide log of your entire GDB interaction, and someone may be able
to help you.

Cheers,
-- 
Paul Pluzhnikov

Re: Elf debugging

[maybedoo]

Hi, I'm sorry this is the first time I'm posting here.

Host is a Linux Debian Lenny System and target also the same machine.

 - gcc version: gcc (Debian 4.3.2-1.1) 4.3.2
 - gdb version: GNU gdb 6.8-debian

The gdb is the preinstalled on the system.

To compile the elf I've used make with the following command: 

makedefine CFLAGS := $(CPU_OPT) $(DISTRO_CFLAGS) $(CPPFLAGS) -O2 -g
-nostdinc -nostdlib -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs
-Werror-implicit-function-declaration -Wstrict-aliasing -Wshadow -fno-common
-ffreestanding -fno-builtin -fomit-frame-pointer

Here is the log how I connected to the elf:

(gdb) file
/home/sphinx/coreboot/coreboot-v2/targets/emulation/qemu-x86/qemu-x86/normal/coreboot_ram
Reading symbols from
/home/sphinx/coreboot/coreboot-v2/targets/emulation/qemu-x86/qemu-x86/normal/coreboot_ram...done.
(gdb) target remote localhost:1234
Remote debugging using localhost:1234
0x0000fff0 in pci_conf1_read_config32 (pbus=0x0, bus=0, devfn=0, where=0)
    at /home/sphinx/coreboot/coreboot-v2/src/arch/i386/include/arch/io.h:58
58              __asm__ __volatile__ ("outl %0, %w1" : : "a" (value), "Nd"
(port));
(gdb) search elfboot
Expression not found
(gdb) break elfboot.c:20
No source file named elfboot.c.
Make breakpoint pending on future shared library load? (y or [n]) n

I've attached the readelf log, hopefully it says something to you.

Thanks for your help Paul.

Regards,

May


http://www.nabble.com/file/p23849811/readelf.txt readelf.txt 

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Re: Elf debugging

[Paul Pluzhnikov]

On Wed, Jun 3, 2009 at 4:31 AM, maybedoo <maybedoo@gmx.de> wrote:

> (gdb) break elfboot.c:20
> No source file named elfboot.c.

Are you sure this isn't a "pilot error"?
I see that you have selfboot.c, but no elfboot.c.

Here are the files which have debug info (and which you shouldn't have
problems setting breakpoints in):

$ grep 'DW_AT_name.*\.c' readelf.txt  | sed -e 's/.*: //' -e 's:.*//::'

src/southbridge/intel/i82371eb/i82371eb_smbus.c
src/console/uart8250_console.c
src/southbridge/intel/i82371eb/i82371eb.c
src/southbridge/intel/i82371eb/i82371eb_usb.c
src/southbridge/intel/i82371eb/i82371eb_reset.c
src/southbridge/intel/i82371eb/i82371eb_isa.c
src/southbridge/intel/i82371eb/i82371eb_ide.c
src/mainboard/emulation/qemu-x86/mainboard.c
src/arch/i386/lib/exception.c
src/devices/root_device.c
src/lib/uart8250.c
src/console/printk.c
src/pc80/mc146818rtc.c
src/boot/hardwaremain.c
src/devices/pci_device.c
src/lib/version.c
src/devices/cardbus_device.c
src/pc80/keyboard.c
src/devices/pciexp_device.c
src/devices/pci_ops.c
src/console/console.c
src/devices/hypertransport.c
src/devices/device.c
src/lib/malloc.c
src/devices/device_util.c
src/devices/../../util/x86emu/x86.c
src/pc80/isa-dma.c
src/lib/memmove.c
src/lib/memcpy.c
src/lib/memset.c
src/console/vtxprintf.c
static.c
src/arch/i386/boot/tables.c
src/boot/selfboot.c
src/devices/pci_rom.c
src/arch/i386/boot/coreboot_table.c
src/devices/pcix_device.c
src/cpu/emulation/qemu-x86/northbridge.c
src/mainboard/emulation/qemu-x86/irq_tables.c
src/devices/../../util/x86emu/x86_interrupts.c
src/arch/i386/boot/boot.c
src/lib/delay.c
src/arch/i386/lib/pci_ops_auto.c
src/console/vsprintf.c
src/arch/i386/lib/pci_ops_conf2.c
src/lib/cbfs.c
option_table.c
src/lib/compute_ip_checksum.c
src/lib/fallback_boot.c
src/arch/i386/boot/pirq_routing.c
src/arch/i386/boot/multiboot.c
src/lib/lzma.c
src/arch/i386/lib/pci_ops_conf1.c

Cheers,
-- 
Paul Pluzhnikov

Re: Elf debugging

[maybedoo]

Hmm it's strange that i've no debug information in elfboot.c?

Here is the ls from the src directory:

may@debian:~/coreboot/coreboot-v2/src/boot$ ls
Config.lb  elfboot.c  filo.c  hardwaremain.c  selfboot.c


Problem is that I need elfboot.c for a breakpoint.

Thanks for your help Paul with readelf. Didn't know that and how to use it.

Regards,

May


Paul Pluzhnikov-4 wrote:
> 
> On Wed, Jun 3, 2009 at 4:31 AM, maybedoo <maybedoo@gmx.de> wrote:
> 
>> (gdb) break elfboot.c:20
>> No source file named elfboot.c.
> 
> Are you sure this isn't a "pilot error"?
> I see that you have selfboot.c, but no elfboot.c.
> 
> Here are the files which have debug info (and which you shouldn't have
> problems setting breakpoints in):
> 
> $ grep 'DW_AT_name.*\.c' readelf.txt  | sed -e 's/.*: //' -e 's:.*//::'
> 
> src/southbridge/intel/i82371eb/i82371eb_smbus.c
> src/console/uart8250_console.c
> src/southbridge/intel/i82371eb/i82371eb.c
> src/southbridge/intel/i82371eb/i82371eb_usb.c
> src/southbridge/intel/i82371eb/i82371eb_reset.c
> src/southbridge/intel/i82371eb/i82371eb_isa.c
> src/southbridge/intel/i82371eb/i82371eb_ide.c
> src/mainboard/emulation/qemu-x86/mainboard.c
> src/arch/i386/lib/exception.c
> src/devices/root_device.c
> src/lib/uart8250.c
> src/console/printk.c
> src/pc80/mc146818rtc.c
> src/boot/hardwaremain.c
> src/devices/pci_device.c
> src/lib/version.c
> src/devices/cardbus_device.c
> src/pc80/keyboard.c
> src/devices/pciexp_device.c
> src/devices/pci_ops.c
> src/console/console.c
> src/devices/hypertransport.c
> src/devices/device.c
> src/lib/malloc.c
> src/devices/device_util.c
> src/devices/../../util/x86emu/x86.c
> src/pc80/isa-dma.c
> src/lib/memmove.c
> src/lib/memcpy.c
> src/lib/memset.c
> src/console/vtxprintf.c
> static.c
> src/arch/i386/boot/tables.c
> src/boot/selfboot.c
> src/devices/pci_rom.c
> src/arch/i386/boot/coreboot_table.c
> src/devices/pcix_device.c
> src/cpu/emulation/qemu-x86/northbridge.c
> src/mainboard/emulation/qemu-x86/irq_tables.c
> src/devices/../../util/x86emu/x86_interrupts.c
> src/arch/i386/boot/boot.c
> src/lib/delay.c
> src/arch/i386/lib/pci_ops_auto.c
> src/console/vsprintf.c
> src/arch/i386/lib/pci_ops_conf2.c
> src/lib/cbfs.c
> option_table.c
> src/lib/compute_ip_checksum.c
> src/lib/fallback_boot.c
> src/arch/i386/boot/pirq_routing.c
> src/arch/i386/boot/multiboot.c
> src/lib/lzma.c
> src/arch/i386/lib/pci_ops_conf1.c
> 
> Cheers,
> -- 
> Paul Pluzhnikov
> 
> 

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Re: Elf debugging

[maybedoo]

OK I found it. It was a pilot error :(. In the config file is a construction
whether the CB File System should be loaded or not. If yes selfboot.c is
needed, else elfboot.c

Thanks again for all your help and time you spent Paul.

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