Devel July 2017

devel@sel4.systems

17 participants
13 discussions

L4Re IPC share memory that share file in one Linux filesystem and be visible to other Linuxes
by Joyce Peng(彭美僑) 05 Jul '17

05 Jul '17

Hi L4, I want to share a file in one Linux filesystem and be visible to other Linuxes that all run on top Fiasco.OC. It seems an IPC communication between L4re vm tasks. And access a file in Linux filesystem is a mechanism with kernel block device driver. But I only notice two char device drivers that use L4re library l4shmc in L4linux. It is l4ser_shm and l4shmnet. May you give some information about this work how to work. Thanks. Joyce Peng(彭美僑)

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malloc & errno
by Fabrizio Bertocci 05 Jul '17

05 Jul '17

Hi all, I am facing a puzzling problem related to muslc. While running some tests with the ia32 simulator (qemu), have noticed that whenever I call malloc() and I run out of memory (because my morecore buffer is too small), I am getting some kernel crash. I have traced the issue to the place where errno is set to -ENOMEM. Referencing to errno is platform-dependent and end up calling a function that retrieve the struct pthread associated and access errno as one of the field of the struct pthread. What is the correct process to set up a heap from the root task in such a way that we can call malloc() and correctly handle error conditions through errno? I am pretty sure I am doing something wrong in my initialization code (I have based my main(0 on the code from the tutorials), because I am also having other problems with malloc(). (even after I increase my heap area). For example, in some cases a call to malloc() end up calling a cascade of functions that eventually (from inside muslc) end up calling again malloc(). As consequence it enters in an infinite loop that stop only after it exhaust the initial stack. I could not find any clear example that show how to correctly set up a system to use muslc. Can anyone point me to a good example that shows how to bootstrap a system for the 5.2.0 branch? Regards, Fabrizio Bertocci Real-Time Innovations, Inc. Sunnyvale, CA

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make: stack: Command not found
by tj5527 04 Jul '17

04 Jul '17

A newbie question. I follow the link [1] trying to build sel4 with qemu. But when `make`ing the binary, it throws error message `make: stack: Command not found`. I `apt-get install stacks` but it still fails with the same error. What packages should I install for making sel4 with Ubuntu 16.04 LTS, GNU Make 4.1, and gcc version 5.4.0 20160609? Thanks [Error Message] -- Build files have been written to: /path/to/sel4/stage/x86/pc99/accelerator ninja: no work to do. [apps/vm] building... [HEADERS] [STAGE] autoconf.h [apps/vm] done. [parse-capDL] building... make: Entering directory '/path/to/sel4/projects/capdl/capDL-tool' stack setup make: stack: Command not found Makefile:39: recipe for target 'sandbox' failed make: *** [sandbox] Error 127 make: Leaving directory '/path/to/sel4/projects/capdl/capDL-tool' Makefile:53: recipe for target '/path/to/sel4/stage/x86/pc99/parse-capDL/parse-capDL' failed make: *** [/path/to/sel4/stage/x86/pc99/parse-capDL/parse-capDL] Error 2 [1] https://wiki.sel4.systems/Hardware/Qemu

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Devel July 2017