From mboxrd@z Thu Jan 1 00:00:00 1970 From: xhpohanka@gmail.com (Jan Pohanka) Date: Tue, 02 Aug 2011 10:13:45 +0200 Subject: kernel debugging (KGDB or JTAG) Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Dear all, I'd like to ask if anyone has working setup for kernel debugging on arm target. I have tried two boards (one with at91sam9g20, second with freescale i.mx27) with Segger j-link and kgdb with similar and not very useful results. I have Ubuntu 11.04 as development host and latest codesourcery arm-none-(linux-gnu)eabi toolchain. Using 2.6.39 I was able to compile the sources with KGDB enabled. I'm also able to enter kdb terminal and connect with arm-none-eabi-gdb. Setting and triggering breakpoints works well, but single stepping (which is essential to me) does not. Here is the example Breakpoint 1, 0xc00e40d4 in sys_sync () at /home/honza/_dev/kernel/linux-2.6.39.y/fs/sync.c:190 190 } (gdb) list 185 ret = err; 186 mutex_unlock(&mapping->host->i_mutex); 187 188 out: 189 return ret; 190 } 191 EXPORT_SYMBOL(vfs_fsync_range); 192 193 /** 194 * vfs_fsync - perform a fsync or fdatasync on a file (gdb) s Sending packet: $Hc148#48...Ack Packet received: OK Sending packet: $s#73...Ack Packet received: warning: Invalid remote reply: ... now gdb hangs forever Using j-ling JTAG probe from segger I can't start debug session at all. When JLinkGDBServer connects it resets the board and I'm not able to resume the execution. I have found e.g. this howto http://www.timesys.com/embedded-linux/docs/Debug_Linux_kernel_with_a_JTAG_from_Segger but as I said it is not working for me. Here is the log from JLinkGDBServer J-Link connected Firmware: J-Link ARM V8 compiled Jul 5 2011 20:48:23 Hardware: V8.00 S/N: 58004787 J-Link found 2 JTAG devices, Total IRLen = 8 JTAG ID: 0x07926121 (ARM9) Connected to 127.0.0.1 Reading all registers WARNING: Failed to read cacheable memory @ address 0x00000000 Read 4 bytes @ address 0x00000000 (Data = 0x00000000) Starting target CPU... Any advice will be greatly appreciated... with best regards Jan -- Tato zpr?va byla vytvo?ena p?evratn?m po?tovn?m klientem Opery: http://www.opera.com/mail/