May 2019 - Devel - lists.sel4.systems

Stuck during invalidate local TLB in Tx2
by Muneeswaran Rajendran 16 Oct '24

16 Oct '24

Hi seL4 Dev team, Can someone explain the reason (share the reference) to invalidate the local TLB during kernel vspace activation as part CPU initialisation. The Tx2 board stuck while performing this operation. As per my understanding both Tx1 and Tx2 are using same A57 core. so the TLB initialisation and invalidation remain same for Tx2 and should not stuck during invalidation.Please correct me if anything wrong here. I understand from that instruction (tlbi vmalle1) which is invalidating stage 1 entries associated to the current VMID. Also from arm mmu code the seL4 setting up (TCR_EL1) TCR register addressing space as 48bit, ASID as 16bit and page table setup 4k granular size. I am using MRS macro to dump the spsr_el1 and dspsr_el0 register to see the state of processor but its throwing synchronous exception. Do we have any other option to dump all the register content to see the state of processor like we have one in 'sel4debug_dump_registers' which is used in sel4test code. Regards, Muneeswaran R

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Questions about Memory Management in seL4
by Daniel Wang 19 May '23

19 May '23

Hi all, Sorry to bother, I have some basic questions about seL4 memory management. Can someone help me? 1. where is the kernel’s address space? I know there are basically three methods: a) separate virtual address space, e.g. through changing page tables on entry into privileged mode to access b) physical space, e.g. through disable automatic hardware translation of virtual addresses on entry into privilege mode c) privilege region in each process’s virtual address space, e.g. through page table to map kernel address into use-mode process. My question is which of this is being used by seL4 microkernel? 2. Objects like CSpace, VSpace, CNode, TCB, Endpoint, etc. are called kernel objects, but it seems all dynamically allocated in thread running/creating time. Are those objects (e.g. Figure 3.3 in seL4 manual) in kernel space or in user space? 3. I read that after the kernel boot up, it passes all resources, untyped memory to the first thread. Are those untyped memory physical memory or virtual memory in a single page? The reason I ask is I’m learning the code of the UNSW AOS project (two of the assignment projects are implementing frame and papers). I’m confused that before the implementation of frames and pages what kind of memory is passed to the the first thread? I saw int AOS project, it uses ut_table_init(), ut_steal_mem(), I wonder what kind of memory it operates on? Thanks -Dan

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TLB issue
by Stefan Kalkowski 15 Nov '19

15 Nov '19

Dear sel4 community, yesterday I've started to develop a low-level platform test to stress several multi-processor aspects on top of the Genode API. Thereby, I've recognized that on sel4/x86_64 the TLB is practically not always cleaned properly in SMP systems. The test spawns threads of one protection domain on each available cpu. Each thread accesses one of the first words of a shared dataspace. Afterwards the main thread on CPU 0 detaches and destroys the dataspace. Unfortunately, the threads on other CPUs still successfully access the corresponding memory instead of triggering a fault. To be able to reproduce the problem, you might investigate the simple test case here: https://github.com/skalk/genode/commit/2d2d7f982555f551227ad5dcbf9df46705d7… My colleague Alexander Boettcher already investigated the problem in part, and might share his insights with you. Best regards Stefan -- Stefan Kalkowski Genode labs https://github.com.skalk | https://genode.org

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Sel4 for quadcore riscv64imafd
by Sreenadh S 03 Oct '19

03 Oct '19

I want to build sel4 for quadcore riscv64imafd and run the test programs, how to do that? Regards, Sreenadh S, CDAC, Trivandrum, India

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seL4_FailedLookup in vmware
by KAP Benjamin 03 Oct '19

03 Oct '19

Hello I set up VMware according to this guide https://docs.sel4.systems/Hardware/VMware/ (using serial output to file) and compiled the picoserver CAmkES application (for x86_64) to run inside the VMware machine. However, I do encounter a seL4_FailedLookup error. I understand the error message but cannot figure out why it occurs nor how to fix it (probably my pci configuration is wrong). Attached you find the serial_output file. For the ethernet configuration I used linux in the same VM to figure out the details: 1) ip addr: 2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN group default qlen 1000 link/ether 00:0c:29:90:a7:4a brd ff:ff:ff:ff:ff:ff 2) lspci -vvv: 02:00.0 Ethernet controller: Advanced Micro Devices, Inc. [AMD] 79c970 [PCnet32 LANCE] (rev 10) Subsystem: Advanced Micro Devices, Inc. [AMD] PCnet - Fast 79C971 Physical Slot: 32 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 64 (1500ns min, 63750ns max) Interrupt: pin A routed to IRQ 18 Region 0: I/O ports at 2000 [size=128] [virtual] Expansion ROM at fd500000 [disabled] [size=64K] Kernel driver in use: pcnet32 Kernel modules: pcnet32 3) dmesg | grep "02:00.0": ... [ 0.378516] pci 0000:02:00.0: BAR 6: assigned [mem 0xfd500000-0xfd50ffff pref] ... 4) lspci -nn: 02:00.0 Ethernet controller [0200]: Advanced Micro Devices, Inc. [AMD] 79c970 [PCnet32 LANCE] [1022:2000] (rev 10) And here the configuration part inside picoserver.camkes (anything else NOT pasted here is unmodified): picoserver.ethdriver_mac = [0x00, 0x0c, 0x29, 0x90, 0xa7, 0x4a]; .... hwethdriver.mmio_paddr = 0xfd500000 hwethdriver.mmio_size = 0x10000 hwethdriver.irq_irq_type = "pci"; hwethdriver.irq_irq_ioapic = 0; hwethdriver.irq_irq_ioapic_pin = 18; hwethdriver.irq_irq_vector = 18; ethdriver.iospaces = "0x0:0x02:0x00:0"; ethdriver.iospace_id = 0x0200; ethdriver.pci_bdf = "0x02:0x00.0"; I am sorry to bother you with this; I am fairly new to low level stuff. Any help would be very much appreciated. Best regards, Benjamin

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回复: Devel Digest, Vol 60, Issue 18
by KIM MK 03 Jun '19

03 Jun '19

Hello Sel4 developer, Thanks for your support. Aditya and me are debugging physical memory sel4. Is there visual tool or analysis module or anything to debugging that physical memory to virtual mapping table. If you have any question, please let me know. BR, MK

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Multicore for 64-bit ARM
by Rutherford, Luke 24 May '19

24 May '19

I see this on your roadmap: https://sel4.systems/Info/Roadmap/ planned Multicore for 64-bit ARM and x64 master Do you have any updates on when this will be implemented?

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How to add conditional compilation in .Camkes files
by yogidk 21 May '19

21 May '19

Hi, I try to add support for UART on one platform and disable this UART for another platform. As my application is Camkes based, I need to define the UART connections (Dataport, Interface functions etc) between the 2 Camkes components. However I need to use the same application on another platform without UART support. How can this be got in .Camkes files ? I already tried including a .h file where I define something like this In main.h #ifdef PLATFORM_X #define UART 1 #else #define UART 0 #endif Then include main.h file in Camkes files using a .idl4 file . However it did not work. .Camkes file is not able to see these defines to use it further for conditional compilation in .camkes files to enable or disable UART between the two components. Is there any way to get it done ? Regards yk

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Compiling seL4
by Yousif Kako 21 May '19

21 May '19

Hello, I am a student researcher, I am trying to compile seL4 using the Configuring and building an seL4 project guidelines on your website ( https://docs.sel4.systems/Developing/Building/Using) And on the site, it says that after the command "ninja", I will be given binaries in the folder "images". But, I do not get such folder nor any images. I tried re-configuring some settings using cmake-gui but still nothing. I am want to write a user-level application but I am not sure if I am going about this the right way. If you have any suggestions or if you can point me in the right direction, that would be great. Thank You

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Compilation Errors for the MCS tutorial
by Zeyu Mi 21 May '19

21 May '19

Hi, I was trying the MCS tutorial but encountered a few compilation errors which I cannot resolve. And the previous tutorials can be compiled normally. The building environment is based on Docker, as recommended by the tutorials. Steps: 1. cd kernel 2. git fetch seL4 mcs-tutorials 3. git checkout mcs-tutorials 4. cd .. && ./init --tut mcs 5. cd mcs && ninja Compilation output about the errors: [79/161] Building C object projects/seL4_libs/libsel4utils/CMakeFiles/sel4utils.dir/src/elf.c.obj FAILED: projects/seL4_libs/libsel4utils/CMakeFiles/sel4utils.dir/src/elf.c.obj ccache /usr/bin/gcc --sysroot=/host/mcs_build -DHAVE_AUTOCONF -I../projects/seL4_libs/libsel4utils/include -I../projects/seL4_libs/libsel4utils/sel4_arch_include/x86_64 -I../projects/seL4_libs/libsel4utic ../projects/seL4_libs/libsel4utils/src/elf.c: In function ‘rights_from_elf’: ../projects/seL4_libs/libsel4utils/src/elf.c:35:12: error: too many arguments to function ‘seL4_CapRights_new’ return seL4_CapRights_new(false, false, canRead, canWrite); In file included from ../kernel/libsel4/include/sel4/types.h:30:0, from ../kernel/libsel4/include/sel4/sel4.h:16, from ../projects/seL4_libs/libsel4utils/src/elf.c:15: libsel4/include/sel4/shared_types_gen.h:317:1: note: declared here seL4_CapRights_new(seL4_Uint64 capAllowGrant, seL4_Uint64 capAllowRead, seL4_Uint64 capAllowWrite) [82/161] Building C object projects/seL4_libs/libsel4utils/CMakeFiles/sel4utils.dir/src/vspace/bootstrap.c.obj FAILED: projects/seL4_libs/libsel4utils/CMakeFiles/sel4utils.dir/src/vspace/bootstrap.c.obj ccache /usr/bin/gcc --sysroot=/host/mcs_build -DHAVE_AUTOCONF -I../projects/seL4_libs/libsel4utils/include -I../projects/seL4_libs/libsel4utils/sel4_arch_include/x86_64 -I../projects/seL4_libs/libsel4utic In file included from ../projects/seL4_libs/libsel4utils/src/vspace/bootstrap.c:20:0: ../projects/seL4_libs/libsel4utils/src/vspace/bootstrap.c: In function ‘common_init_post_bootstrap’: ../projects/seL4_libs/libsel4utils/include/sel4utils/vspace.h:43:43: error: ‘seL4_UserTop’ undeclared (first use in this function) #define KERNEL_RESERVED_START (ALIGN_DOWN(seL4_UserTop, PAGE_SIZE_4K)) Thanks in advance. Zeyu

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