July 2017 - Devel - lists.sel4.systems

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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