Angelo, My most frustrating experience with uClinux was with the memory allocator. Linux uses a "buddy" system power-of-2 allocator. It is VERY easy to fragment memory such that no more can be allocated. Usually I received an error message, which you say does not happen for you. Perhaps that is because in my case, the memory allocation failure occurs during program loading, while yours occurs during program execution (C++ startup vs. a plain C program?).
The current memory free list is in /proc/buddyinfo. Memory is organized into blocks by powers-of-2. The first one is the 2^0 * PAGESIZE. PAGESIZE is 4096 on x86 systems. To find out the PAGESIZE, try "getconf PAGESIZE" or "getconf PAGE_SIZE" (unless someone on the list knows what it is for a coldfire mcf5307). Even if there are, for example, 6 MB free memory and your program only needs 5 MB, you won't be able to run your program, because the next higher power-of-2 is 8 MB. Maybe this is what is happening to you. I moved on to using SoC ARM chips with lots more RAM and MMUs because I was wasting so much time trying to squeeze a program to fit in an uClinux system. Larry Baker US Geological Survey 650-329-5608 ba...@usgs.gov On 23 Jan 2014, at 2:31 PM, Angelo Dureghello wrote: > Dear Larry, > > many thanks for the very useful info, unfortunately i have still not solved. > > Original stack size in the header was 4096, i set it up growing until 65535, > same result, program block and paralize the uclinux system without any > wanring. > > I have some doubt, > 1) for example about the fact that i see that ti have compiled uclinux with > CodeSourcery toolchain (i did it some time ago don't remember exactly the > reason now), can this be an issue ? Anyway, actually i am compiling my c++ > program with this same toolchain (gcc 4.6.1). > 2) could i have some uclinux configuration issues ? In particular i have > doubt on general setup and processor > > General Setup: > [*] Prompt for development and/or incomplete code/drivers > () Cross-compiler tool prefix > () Local version - append to kernel release > [*] Automatically append version information to the version string > [*] System V IPC > [ ] POSIX Message Queues > [ ] BSD Process Accounting > [ ] Export task/process statistics through netlink (EXPERIMENTAL) > [ ] Auditing support > RCU Subsystem ---> > [ ] Kernel .config support > (14) Kernel log buffer size (16 => 64KB, 17 => 128KB) > [ ] enable deprecated sysfs features to support old userspace tools > [ ] Kernel->user space relay support (formerly relayfs) > [ ] Namespaces support > [ ] Initial RAM filesystem and RAM disk (initramfs/initrd) support > [ ] Optimize for size > [*] Configure standard kernel features (for small systems) ---> > Kernel Performance Events And Counters ---> > [ ] Enable VM event counters for /proc/vmstat > [*] Enable SLUB debugging support > [*] Disable heap randomization > Choose SLAB allocator (SLUB (Unqueued Allocator)) ---> > [ ] Allow mmapped anonymous memory to be uninitialized > [ ] Profiling support > GCOV-based kernel profiling ---> > > CPU (MCF5307) ---> > [*] Enable setting the CPU clock frequency > (90000000) Set the core clock frequency > (2) Set the core/bus clock divide ratio > [ ] Old mask 5307 (1H55J) silicon > *** Platform *** > [*] Sysam AMCORE board support > [ ] Arnewsh 5307 board support > [ ] Motorola M5307C3 board support > [ ] SnapGear SecureEdge/MP3 platform support > [ ] Feith CLEOPATRA board support > [ ] SecureEdge/NETtel board support > [*] Support for U-Boot command line parameters > [*] Use 4Kb for kernel stacks instead of 8Kb > *** RAM configuration *** > (0) Address of the base of RAM > (0x1000000) Size of RAM (in bytes), or 0 for automatic > (0x0) Address of the base of system vectors > (0x20000) Address of the base of kernel code > RAM bus width (AUTO) ---> > *** ROM configuration *** > [ ] Specify ROM linker regions > Kernel executes from (RAM) ---> > Preemption Model (No Forced Preemption (Server)) ---> > Memory model (Flat Memory) ---> > (1) Turn on mmap() excess space trimming before booting > > Do you see something strange here ? > > I go on investingating, > > Many thanks, > angelo > > > > On 23/01/2014 19:49, Larry Baker wrote: >> Angelo, >> >> This sounds like your application stack size is too small and you are >> overflowing the stack. Remember, uClinux has no MMU to protect for that. >> Try increasing the stack size. Ted Ma told me once the application flthdr >> can manipulate the stack size in the executable's header: >> >>> Hi Larry, >>> flthdr is the utility to manipulate the header >>> ==== >>> The flat format also defines the stack size for an application as a field >>> in the flat header. To increase the stack allocated to an application, a >>> simple change of this field is all that is required. This can be done with >>> the flthdr command, like this: >>> flthdr -s flat-executable >>> >>> The flat format also allows two compression options. The entire executable >>> can be compressed, providing maximum ROM savings. It also offers the often >>> useful side effect that the application is loaded entirely into a >>> contiguous RAM block. You also may choose data-segment-only compression. >>> This is important if you want to save ROM space but still want the option >>> to utilize XIP. The following: >>> >>> flthdr -z flat-executable >>> creates a fully compressed executable, and >>> >>> flthdr -d flat-executable >>> compresses only the data segment. >>> ==== >>> ...MaTed >> >> >> Larry Baker >> US Geological Survey >> 650-329-5608 >> ba...@usgs.gov >> >> >> >> On 23 Jan 2014, at 1:15 AM, Angelo Dureghello wrote: >> >>> Dear all, >>> >>> i have a small board with a coldfire mcf5307, 4 MB flash and 16MB sdram. >>> >>> I have loaded on it this ucLinux: >>> >>> ~ # cat /proc/version >>> uClinux version 2.6.36.2 (angelo@angel3) (gcc version 4.6.1 (Sourcery >>> CodeBench Lite 2011.09-23) ) #122 Fri Dec 14 23:52:01 CET 2012 >>> >>> I am now trying to upload and run a simple c++ program, with just 3 simple >>> classes, >>> and a main(). >>> >>> Fist issue, >>> >>> I tried to use the most recent uclinux.org supplied toolchanin >>> (m68k-uclinux-20101118), >>> i get : >>> >>> make >>> /usr/local/bin/m68k-uclinux-g++ -O2 --pipe -m5307 -Iinclude -Wall -c -o >>> obj/base64.o src/base64.cc >>> /usr/local/bin/m68k-uclinux-g++ -O2 --pipe -m5307 -Iinclude -Wall -c -o >>> obj/main.o src/main.cc >>> /usr/local/bin/m68k-uclinux-g++ -O2 --pipe -m5307 -Iinclude -Wall -c -o >>> obj/sha256.o src/sha256.cc >>> /usr/local/bin/m68k-uclinux-g++ obj/base64.o obj/main.o obj/sha256.o -m5307 >>> -o bin/cfbm -Wl,-Map,bin/cfbm.map >>> ERROR: text=0x1c100 overlaps data=0x0 ? >>> collect2: ld returned 1 exit status >>> make: *** [bin/cfbm] Error 1 >>> >>> Surfing the net, i don't find any good explaination to this, and the common >>> workaround >>> suggested is to use the CodeSourcery toolchain. >>> So as a first thing i was wondering if the uclinux "user" folder does >>> contain some cpp >>> projects, how do they compile ? >>> >>> Then i moved to the CodeSourcery toolchain, that i copied from an old hard >>> disk, since >>> seems is not free to download anymore, is it ? Are there any alternative ? >>> >>> >>> With this toolchain strange things happen, until a certain point, adding >>> code, everything >>> works fine, program is correctly compiled on my host and executed on the >>> board. Then, >>> strangely, as the code increase, the program execution crash (without >>> errors on console) >>> and paralize the system. As i remove (comment out) some lines, ini random >>> places, program >>> start to work correctly again. >>> So for now, also the CodeSourcery toolchain solution is not helping me. >>> >>> I have now the suspect that uClinux itself has not been correctly >>> configured, or that i am >>> suffering for my 16MB of ram, even if i see 6,8MB still free before >>> executing. >>> >>> ~ # cat /proc/meminfo >>> MemTotal: 13684 kB >>> MemFree: 6984 kB >>> Buffers: 16 kB >>> Cached: 144 kB >>> SwapCached: 0 kB >>> Active: 64 kB >>> Inactive: 48 kB >>> Active(anon): 0 kB >>> Inactive(anon): 0 kB >>> Active(file): 64 kB >>> Inactive(file): 48 kB >>> Unevictable: 0 kB >>> Mlocked: 0 kB >>> MmapCopy: 412 kB >>> SwapTotal: 0 kB >>> SwapFree: 0 kB >>> Dirty: 40 kB >>> Writeback: 0 kB >>> AnonPages: 0 kB >>> Mapped: 0 kB >>> Shmem: 0 kB >>> Slab: 1292 kB >>> SReclaimable: 64 kB >>> SUnreclaim: 1228 kB >>> KernelStack: 108 kB >>> PageTables: 0 kB >>> NFS_Unstable: 0 kB >>> Bounce: 0 kB >>> WritebackTmp: 0 kB >>> CommitLimit: 6840 kB >>> Committed_AS: 0 kB >>> VmallocTotal: 0 kB >>> VmallocUsed: 0 kB >>> VmallocChunk: 0 kB >>> >>> >>> I don't know actually how to move, every help is accepted. >>> >>> Many thanks, >>> angelo >>> >>> >>> >>> >>> >>> >>> _______________________________________________ >>> uClinux-dev mailing list >>> uClinux-dev@uclinux.org >>> http://mailman.uclinux.org/mailman/listinfo/uclinux-dev >>> This message was resent by uclinux-dev@uclinux.org >>> To unsubscribe see: >>> http://mailman.uclinux.org/mailman/options/uclinux-dev >> >
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