Devel June 2016

devel@sel4.systems

24 participants
20 discussions

IA32 syscall bindings
by Norman Feske 26 Aug '16

26 Aug '16

Dear seL4 developers, first, I'd like to thank you for publishing seL4 under GPL. I am very happy that I can finally get my hands dirty with working with the kernel of your group. :-) Currently, I am taking the first baby steps to bring the Genode OS framework (http://genode.org) to seL4. For reference, I am using the experimental branch. The first smallish issue I stumbled upon stems from the fact that Genode is written in C++. By compiling the seL4 syscall bindings with a C++ compiler, I got the following error: error: inconsistent operand constraints in an ‘asm’ It can be reproduced by putting the following code snippet into a cc file and compiling it with 'g++ -m32 -c' (tested with the Genode tool chain as well as with GCC 4.8.1): typedef enum { seL4_SysDebugPutChar = -9, _enum_pad_seL4_Syscall_ID = (1U << ((sizeof(int)*8) - 1)) } seL4_Syscall_ID; void seL4_DebugPutChar(char c) { asm volatile ( "pushl %%ebp \n" "movl %%esp, %%ecx \n" "leal 1f, %%edx \n" "1: \n" "sysenter \n" "popl %%ebp \n" : : "a" (seL4_SysDebugPutChar), "b" (c) : "%ecx", "%edx", "%esi", "%edi", "memory" ); } When compiling the same code snippet with 'gcc' instead of 'g++', everything is fine. It turns out that the C++ compiler does not like the enum value to be specified as input argument. I found the following ways to circumvent this problem: * Changing the enum value 'SysDebugPutChar' to a positive value, * Removing the definition of '_enum_pad_seL4_Syscall_ID', * Casting 'seL4_SysDebugPutChar' to an integer: : "a" ((int)seL4_SysDebugPutChar), In any case, I seem to have to change the bindings. Do you see a way around it? If not, would you consider one of the solutions above for the seL4 headers? On another note, I noticed that the bindings use the EBX register. Unfortunately, this makes it impossible to compile seL4 userland software as position-independent code (PIC). E.g., when compiling the above code snippet via 'g++ -m32 -fPIC -c', the following error occurs: error: inconsistent operand constraints in an ‘asm’ However, PIC is required in order to use shared libraries. The solution would be to not use EBX to pass arguments to the 'asm' statements, save EBX on the stack prior moving the respective kernel argument to the register, and, of course, restoring it after sysenter returns. Before I start changing the bindings, I'd like to know: is there anyone else working on the same problem? Would you be open to accept a change of the bindings to become PIC compliant on the costs of a few added instructions? Or do you have another suggestion how I should go about it? Best regards Norman -- Dr.-Ing. Norman Feske Genode Labs http://www.genode-labs.com · http://genode.org Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth

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[sel4] persistent storage / file system
by rahul mahadev 06 Jul '16

06 Jul '16

Hi, I wanted to know if persistent storage/ file system have been tried on sel4 before ,if so can I have more details on it. Regards , Rahul S Mahadev

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Get real time clock data (and timer) from I.MX6
by Norrathep Rattanavipanon 30 Jun '16

30 Jun '16

Hi, I was wondering if there's any real time clock implementation for I.MX6 in sel4. And if there isnt any, what would be the best way to use a timer in sel4 (since I saw many implementations of those)? through sel4platsupport_get_default_timer? Best, Oak -- Norrathep (Oak) Rattanavipanon M.S. in Computer Science University of California - Irvine

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ARM Hypervisor extensions in master
by Adrian Danis 28 Jun '16

28 Jun '16

The ARM hypervisor extensions are now supported in the master seL4 kernel. This support has existed on a public development branch (arm_hyp) for some time, but this marks the beginning of proper support and a verification target. What is done: * Hypervisor extensions supported on odroid-xu and Jetson TK1 platforms * SystemMMU supported on Jetson TK1 platform Limitations: * Currently any usage of hyp extensions or SystemMMU is *not* verified * SystemMMU contains work around currently for the VMM to map in large amounts of memory (fix for this relies on a kernel change currently being verified) You can use the manifest https://github.com/seL4proj/camkes-arm-vm-manifest to get the project https://github.com/seL4proj/camkes-arm-vm and then use one of the two default configs for the TK1 and odroid-xu platforms. Adrian ________________________________ The information in this e-mail may be confidential and subject to legal professional privilege and/or copyright. National ICT Australia Limited accepts no liability for any damage caused by this email or its attachments.

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camkes-VM with QEMU and virutal PCI device
by Samuel Weiser 28 Jun '16

28 Jun '16

Hi again, I'm playing around with camkes-vm in QEMU+KVM. I want to add a virtual PCI device to Linux, which is running as vm0 on top of seL4. However, I got stuck with some errors during system boot. My setup is as follows: QEMU is configured to share a 1MB memory region between the host and the QEMU guest (seL4). Here's what QEMU sets up: (qemu): info mtree ... 00000000fe000000-00000000fe0fffff (prio 1, RW): ivshmem-bar2-container 00000000fe000000-00000000fe0fffff (prio 0, RW): ivshmem.bar2 00000000febf1000-00000000febf10ff (prio 1, RW): ivshmem-mmio ... (qemu): info pci ... Bus 0, device 4, function 0: RAM controller: PCI device 1af4:1110 IRQ 11. BAR0: 32 bit memory at 0xfebf1000 [0xfebf10ff]. BAR2: 64 bit prefetchable memory at 0xfe000000 [0xfe0fffff]. id "" ... I adapted a previously working configuration (optiplex9020.camkes) accordingly with what I thought should be correct. Especially, I added vm0_config.pci_devices_iospace and vm0_config.pci_devices as well as the PCI irq. Here's the configuration: configuration { VM_CONFIGURATION_DEF() VM_PER_VM_CONFIG_DEF(0, 2) vm0.simple_untyped24_pool = 12; vm0.heap_size = 0; vm0.guest_ram_mb = 1536; vm0.kernel_cmdline = VM_GUEST_CMDLINE; vm0.kernel_image = C162_KERNEL_IMAGE; vm0.kernel_relocs = C162_KERNEL_IMAGE; vm0.initrd_image = C162_ROOTFS; vm0.iospace_domain = 0x00; vm0_config.ram = [ [ 0x20800000, 23 ], [ 0x21000000, 24 ], [ 0x22000000, 25 ], [ 0x24000000, 26], [ 0x28000000, 27], [0x30000000, 28], [0x40000000, 29] , [0x60000000, 30], [0xa0000000, 28]]; vm0_config.ioports = [ {"start":0x2f8, "end":0x2ff, "pci_device":0, "name":"COM2 Serial Port"}, {"start":0x2e8, "end":0x2ef, "pci_device":0, "name":"COM4 Serial Port"} ]; vm0_config.irqs = [ {"name":"Serial", "source":3, "level_trig":0, "active_low":0, "dest":3}, {"name":"PCI", "source":11, "level_trig":1, "active_low":1, "dest":11} ]; vm0_config.pci_devices_iospace = 1; vm0_config.pci_devices = [ {"name":"PCI", "bus":0, "dev":0x04, "fun":0, "irq":"PCI", "memory":[ {"paddr":0xfe000000, "size":0x100000, "page_bits":12}, ], }, ]; } However, after creating the MMIO frames and doing some other stuff, the boot process fails, as shown below. The error also occurs if I change or completely remove just the "memory" definition of my PCI device. I also tried different values for "iospace_domain" (QEMU should use 0 as default PCI domain). Thanks in advance for any hints and ideas! Best, Sammey Starting Loader... Parsing bootinfo... 1041793 free cap slots, from 6783 to 1048576 Untyped memory (24) 0x0000000000100000 - 0x0000000000108000 0x0000000000108000 - 0x0000000000109000 0x0000000003000000 - 0x0000000004000000 0x0000000004000000 - 0x0000000008000000 0x0000000008000000 - 0x0000000010000000 0x0000000010000000 - 0x0000000018000000 0x0000000018000000 - 0x000000001c000000 0x000000001c000000 - 0x000000001e000000 0x000000001e000000 - 0x000000001f000000 0x000000001f000000 - 0x000000001f800000 0x000000001f800000 - 0x000000001fc00000 0x0000000001b6b000 - 0x0000000001b6c000 0x0000000001b6c000 - 0x0000000001b70000 0x0000000001b70000 - 0x0000000001b80000 0x0000000001b80000 - 0x0000000001c00000 0x0000000001c00000 - 0x0000000001e00000 0x0000000001e00000 - 0x0000000001f00000 0x0000000001f00000 - 0x0000000001f80000 0x0000000001f80000 - 0x0000000001fc0000 0x0000000001fc0000 - 0x0000000001fe0000 0x0000000001fe0000 - 0x0000000001ff0000 0x0000000001ff0000 - 0x0000000001ff2000 0x0000000001ff2000 - 0x0000000001ff3000 0x0000000001ff3000 - 0x0000000001ff3800 Loader is running in domain 0 Device untyped memory (30) 0x0000000000001000 - 0x0000000000002000 0x0000000000002000 - 0x0000000000004000 0x0000000000004000 - 0x0000000000008000 0x0000000000008000 - 0x0000000000010000 0x0000000000010000 - 0x0000000000020000 0x0000000000020000 - 0x0000000000040000 0x0000000000040000 - 0x0000000000080000 0x0000000000080000 - 0x0000000000100000 0x000000001fc00000 - 0x0000000020000000 0x0000000020001000 - 0x0000000020002000 0x0000000020002000 - 0x0000000020004000 0x0000000020004000 - 0x0000000020008000 0x0000000020008000 - 0x0000000020010000 0x0000000020010000 - 0x0000000020020000 0x0000000020020000 - 0x0000000020040000 0x0000000020040000 - 0x0000000020080000 0x0000000020080000 - 0x0000000020100000 0x0000000020100000 - 0x0000000020200000 0x0000000020200000 - 0x0000000020400000 0x0000000020400000 - 0x0000000020800000 0x0000000020800000 - 0x0000000021000000 0x0000000021000000 - 0x0000000022000000 0x0000000022000000 - 0x0000000024000000 0x0000000024000000 - 0x0000000028000000 0x0000000028000000 - 0x0000000030000000 0x0000000030000000 - 0x0000000040000000 0x0000000040000000 - 0x0000000060000000 0x0000000060000000 - 0x00000000a0000000 0x00000000a0000000 - 0x00000000e0000000 0x00000000e0000000 - 0x0000000000000000 Sorting untypeds... Untyped 0 (cptr=1a39) is of size 15. Placing in slot 17... Untyped 1 (cptr=1a3a) is of size 12. Placing in slot 20... Untyped 2 (cptr=1a3b) is of size 24. Placing in slot 5... Untyped 3 (cptr=1a3c) is of size 26. Placing in slot 2... Untyped 4 (cptr=1a3d) is of size 27. Placing in slot 0... Untyped 5 (cptr=1a3e) is of size 27. Placing in slot 1... Untyped 6 (cptr=1a3f) is of size 26. Placing in slot 3... Untyped 7 (cptr=1a40) is of size 25. Placing in slot 4... Untyped 8 (cptr=1a41) is of size 24. Placing in slot 6... Untyped 9 (cptr=1a42) is of size 23. Placing in slot 7... Untyped 10 (cptr=1a43) is of size 22. Placing in slot 8... Untyped 11 (cptr=1a44) is of size 12. Placing in slot 21... Untyped 12 (cptr=1a45) is of size 14. Placing in slot 18... Untyped 13 (cptr=1a46) is of size 16. Placing in slot 15... Untyped 14 (cptr=1a47) is of size 19. Placing in slot 11... Untyped 15 (cptr=1a48) is of size 21. Placing in slot 9... Untyped 16 (cptr=1a49) is of size 20. Placing in slot 10... Untyped 17 (cptr=1a4a) is of size 19. Placing in slot 12... Untyped 18 (cptr=1a4b) is of size 18. Placing in slot 13... Untyped 19 (cptr=1a4c) is of size 17. Placing in slot 14... Untyped 20 (cptr=1a4d) is of size 16. Placing in slot 16... Untyped 21 (cptr=1a4e) is of size 13. Placing in slot 19... Untyped 22 (cptr=1a4f) is of size 12. Placing in slot 22... Untyped 23 (cptr=1a50) is of size 11. Placing in slot 23... Creating objects... ... Creating object conn1_mmio_frame_4261412864 in slot 6808, from untyped 1a3c... device frame, paddr = 0xfe000000, size = 12 bits Creating object conn1_mmio_frame_4261416960 in slot 6809, from untyped 1a3c... device frame, paddr = 0xfe001000, size = 12 bits Creating object conn1_mmio_frame_4261421056 in slot 6810, from untyped 1a3c... device frame, paddr = 0xfe002000, size = 12 bits ... Creating object vm_vm0_pre_init_ep in slot 10275, from untyped 1a3c... Creating object conn1_iospace_32 in slot 10276, from untyped 1a3c... <=== This is ignored! Creating object conn4_iport_760_767 in slot 10276, from untyped 1a3c... ... Populating slot 21 with cap to conn1_iospace_32... minting (with badge/guard 0x20)... <<seL4 [decodeCNodeInvocation/107 T0xe1ff3900 "rootserver" @804a911]: CNode Copy/Mint/Move/Mutate: Source slot invalid or empty.>> capDL-loader :: << Error: init_cnode_slot:1689: seL4_FailedLookup >>

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Autocorres Error.
by Dan DaCosta 24 Jun '16

24 Jun '16

seL4 Developers: I apologize in advance if this is not the correct place for this email. I am experimenting with Autocorres as an intern at Rockwell Collin's Advanced Technology Center in Minnesota. My latest experiment is in building a small verified library for manipulation and analysis of adjacency lists. My initial work towards this end generated the following error: exception CTERM raised (line 948 of "~/development/rockwellcollins/verification/l4v/tools/autocorres/utils.ML"): autocorres: Internal var uu_::"int" is exposed. Please notify the AutoCorres maintainers of this failure. In the meantime, use "autocorres [keep_going]" to ignore the failure. I am using the latest version of Autocorres and Isabelle. The c and theory file that generated this error can be found here: https://github.com/chaosape/autocorresexperiments/tree/master/graph Thanks! Dan DaCosta

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Resolving issue using camkes-vm with qemu
by Samuel Weiser 20 Jun '16

20 Jun '16

Hi, I just want to share some information which I needed to run camkes-vm with qemu, especially addressing one issue which prevented the guest vm to boot. I basically follow the recommendations of Adrian in [1] and only focus on the simple case without vt-d. 1. use the 'optiplex9020_onevm' configuration as it basically just specifies physical RAM. 2. enable nested KVM [2,3] 3. run QEMU with enough RAM: qemu-system-i386 -nographic \ -m 3GB \ -enable-kvm \ -cpu host \ -kernel images/kernel-ia32-pc99 -initrd images/capdl-loader-experimental-image-ia32-pc99 Following the above steps gives you a booting camkes vmm, however it fails to eventually activate Intel vt-x, needed to run the guest vm. The reason for that is that the seL4 kernel requires the IA32_FEATURE_CONTROL MSR to have VMXON enabled (bit 2) and locked (bit 0) (i.e. a value of 5). Normally, it's the job of the BIOS to do so, however I couldn't find an appropriate QEMU BIOS ROM which does so. The quick workaround is to enable VMXON within the seL4 kernel itself. The corresponding diff is attached. With this minor change, the recompiled kernel works like a charm. PS: One could consider making a separate option in Kconfig for that purpose. Best, Sammey [1] https://sel4.systems/pipermail/devel/2016-March/000717.html [2] http://www.rdoxenham.com/?p=275 [3] https://wiki.archlinux.org/index.php/QEMU#Enabling_KVM

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Rust application support
by Kent.Mcleod＠data61.csiro.au 20 Jun '16

20 Jun '16

Using rust (https://www.rust-lang.org) in user applications on top of seL4 with existing C libaries and apps now has limited support. See here for more information: https://wiki.sel4.systems/Rust What you can do: + Build system support for using a rust cargo project as a library or app on seL4 + Use most core libraries (core, alloc, collections, rustc_unicode, and a limited std) + Use rust dependencies from crates.io on seL4 + Use rust to implement camkes components + Using rust's FFI support it is possible to call rust from C and C from rust. Two sample apps are located here: https://github.com/SEL4PROJ/rust-camkes-samples Instructions for building and running are on the wiki page. Has been tested on x86 i386 and arm kzm both in qemu and hardware. Caveats: + Rust's libstd functionality is limited by which muslc syscalls are supported on seL4. + Rust's libstd requires muslc thread local storage support which is not currently available on seL4. We currently use a muslc branch called rust that uses a global TLS struct. Kent McLeod Kernel engineer / Thesis Student DATA61 | CSIRO

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WIll seL4 support any Unikernel
by XilongPei 16 Jun '16

16 Jun '16

Hi, According to wikipedia.org, Unikernels are specialised, single address space machine images constructed by using library operating systems. A developer selects, from a modular stack, the minimal set of libraries which correspond to the OS constructs required for their application to run. These libraries are then compiled with the application and configuration code to build sealed, fixed-purpose images (unikernels) which run directly on a hypervisor or hardware without an intervening OS such as Linux or Windows. Will seL4 support any unikernel, such as Drawbridge or MirageOS, in the future? Xilong Pei Tongji University Shanghai, China 2016/6/13

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Beaglebone black/CAmkES issue
by Julien Delange 16 Jun '16

16 Jun '16

I am using the second serial interface of the beaglebone black. According to the source code (in libsel4platsupport/plat_include/am335x/sel4platsupport/plat/hw/soc_AM335x.h), the address is 0x48022000). The following line is found in the source #define SOC_UART_1_REGS (0x48022000) So, in CAmkES, I configure the hardware component that represents the serial hardware component with the following attributes: drv.mem_attributes = "0x48022000:0x1000"; The application compiles fine. However, when launching the image on the target, I have the following issue. Any idea about how to solve this? Does anybody successfully used UART1 on the beaglebone black? Or have any idea/suggestion to investigate? Thanks. Julien. Creating object conn1_frame__timer_0 in slot 728, from untyped 29b... device frame, paddr = 0x48040000, size = 12 bits Creating object conn2_frame__Cons_PingMe_0 in slot 729, from untyped 29b... device frame, paddr = 0x48022000, size = 12 bits capDL-loader :: << Error: Failed to find device frame at paddr = 0x48022000 >> Ignoring call to sys_rt_sigprocmask Ignoring call to sys_gettid sys_tkill assuming self kill

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Devel June 2016