**** BEGIN LOGGING AT Wed Mar 17 02:59:57 2010 Mar 17 13:09:36 ogra_cmpc, lool, we recently added CRAMFS to builtin i think for at least one of our arm bracches... what was the reason again? initrd support perhaps? Mar 17 13:09:56 apw: Yes; and it didn't help Mar 17 13:10:01 apw: And I don't know what the issue is Mar 17 13:10:06 apw: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/524893 Mar 17 13:10:09 Launchpad bug 524893 in qemu-kvm (Ubuntu Lucid) (and 3 other projects) "versatile: Can't boot initramfses (affects: 1)" [Low,In progress] Mar 17 13:10:21 lool ... ok thank Mar 17 13:10:37 apw: You can try with the images at http://ports.ubuntu.com/ubuntu-ports/dists/lucid/main/installer-armel/current/images/versatile/netboot/ and qemu-system-arm -m 256 -M versatilepb -cpu cortex-a8 -kernel vmlinuz -initrd initrd.gz Mar 17 13:10:46 apw: Happy if you have any idea what's going on Mar 17 13:12:21 looking at it whether it needs to built in for another branch, seems not, so good Mar 17 13:15:27 ok Mar 17 13:15:49 dmart: Could it be that ldr is causing SIGILL under qemu but it's really a SIGBUS? Mar 17 13:16:40 dmart: disassemble shows that it's a "ldr r0, [pc, #24]"; I'm not sure what can go wrong here, I guess only the fact that it's not 4-bytes aligned? Mar 17 13:27:19 lool: hi, are we talking qemu-kvm or valgrind here? Mar 17 13:30:31 pc is rounded down to a multiple of 4 when used as a base in ldr in Thumb Mar 17 13:56:28 dmart: It's under qemu-system-arm that I test, but it's a valgrind SIGILL AFAICT Mar 17 13:56:46 dmart: Not sure what would cause the SIGILL then Mar 17 13:56:56 Hi, I posted another patch. Mar 17 13:56:59 dmart: I have a debug session open here if it helps Mar 17 13:57:14 It looks like the code at _start is executed as ARM, not Thumb, so it's a real SIGILL Mar 17 13:57:21 lool, could you pop your head into #ubuntu+1, and glare at thiebaude, and then leave again? Mar 17 13:57:42 The _start symbol needs to be properly tagged to solve this (as for ARM/Thumb interworking generally) Mar 17 13:59:37 cwillu_at_work: thiebaude? Mar 17 13:59:44 yes Mar 17 13:59:53 he's using your name in vain Mar 17 14:00:12 ah, he's gone now anyway Mar 17 14:00:17 dmart: Oh so it's executing random instructions because it jumps into an assembly which was built as Thumb (our default) but is executed as ARM because it was not annotated properly as such; ok Mar 17 14:00:27 dmart: This ARM/Thumb stuff is tricky Mar 17 14:00:36 lool: Yes, it looks like there is also some wrong code in m_syswrap/syswrap-arm-linux.c causing another SIGILL... I have a meeting now though. Mar 17 14:00:47 I didn't quite grasp how the various memory locations are ARM or Thumb yet Mar 17 14:00:55 Normally you don't need to worry about the instruction set for the program entry point 'cause that's in crt*.o Mar 17 14:01:07 cwillu_at_work: Mar 17 14:01:11 cwillu_at_work: As in lol? Mar 17 14:01:22 don't mind me, I'm goofy at this hour Mar 17 14:01:27 (yes) Mar 17 14:02:27 lool: "I didn't quite grasp how ..." neither does the CPU ;) so you need to tell it when you jump into code. The toolchain tracks this by setting the bottom bit of the address of Thumb symbols, but proper tagging is needed to enable this. Mar 17 14:07:54 dmart: Wee! Mar 17 14:07:58 dmart: Doesn't SIGILL anymore Mar 17 14:08:02 I get helpful output Mar 17 14:08:12 Now need to start qemu-system-arm as qemu-arm wont cut it Mar 17 14:21:28 dmart: Ok; after another similar fix than yours, I'm hitting "unhandled instruction" Mar 17 15:18:24 unhandled instruction: yeah, that would probably be the real "valrgind doesn't support Thumb-2" problems Mar 17 15:19:11 Unless you can eliminate *all* Thumb code (including crt*.o and friends and all libraries including libgcc), this will happen Mar 17 22:25:55 hi **** ENDING LOGGING AT Thu Mar 18 02:59:56 2010