I am developing a kernel for an operating system. In order to execute it, I've decided to use GRUB. Currently, I have a script attached to GRUB's stage1, stage2, a pad file and the kernel itself together which makes it bootable. The only problem is that when I run it, you have to let GRUB know where the kernel is and how big it is manually and then boot it, like this:
kernel 200+KERNELSIZE
boot
KERNELSIZE is the size of the kernel in blocks. This is fine and alright for a start, but is it possible to get these values in the binary and make GRUB boot the kernel automatically? Any suggestions on how to accomplish that?
http://www.gnu.org/software/grub/manual/grub.html#Embedded-data gives some general information about block list storage in GRUB. Most importantly, it mentions that block lists are stored in well defined locations in stage2.
You will probably want to look at the GRUB source code to figure out the exact location.
I would imagine you could just make your own menu.lst conf file, load that at the grub shell with "configfile /path/to/menu.lst" and then do "setup (hd0)" replacing values as needed. I'm just guessing though.. no telling what the differences are on your custom setup.
Related
I am trying out this MCU / SoC emulator, Renode.
I loaded their existing model template under platforms/cpus/stm32l072.repl, which just includes the repl file for stm32l071 and adds one little thing.
When I then load & run a program binary built with STM32CubeIDE and ST's LL library, and the code hits the initial function of SystemClock_Config(), where the Flash:ACR register is being probed in a loop, to observe an expected change in value, it gets stuck there, as the Renode Monitor window is outputting:
[WARNING] sysbus: Read from an unimplemented register Flash:ACR (0x40022000), returning a value from SVD: 0x0
This seems to be expected, not all existing templates model nearly everything out of the box. I also found that the stm32L071 model is missing some of the USARTs and NVIC channels. I saw how, probably, the latter might be added, but there seems to be not a single among the default models defining that Flash:ACR register that I could use as example.
How would one add such a missing register for this particular MCU model?
Note1: For this test, I'm using a STM32 firmware binary which works as intended on actual hardware, e.g. a devboard for this MCU.
Note2:
The stated advantage of Renode over QEMU, which does apparently not emulate peripherals, is also allowing to stick together a more complex system, out of mocked external e.g. I2C and other devices (apparently C# modules, not yet looked into it).
They say "use the same binary as on the real system".
Which is my reason for trying this out - sounds like a lot of potential for implementing systems where the hardware is not yet fully available, and also automatted testing.
So the obvious thing, commenting out a lot of parts in init code, to only test some hardware-independent code while sidestepping such issues, would defeat the purpose here.
If you want to just provide the ACR register for the flash to pass your init, use a tag.
You can either provide it via REPL (recommended, like here https://github.com/renode/renode/blob/master/platforms/cpus/stm32l071.repl#L175) or via RESC.
Assuming that your software would like to read value 0xDEADBEEF. In the repl you'd use:
sysbus:
init:
Tag <0x40022000, 0x40022003> "ACR" 0xDEADBEEF
In the resc or in the Monitor it would be just:
sysbus Tag <0x40022000, 0x40022003> "ACR" 0xDEADBEEF
If you want more complex logic, you can use a Python peripheral, as described in the docs (https://renode.readthedocs.io/en/latest/basic/using-python.html#python-peripherals-in-a-platform-description):
flash: Python.PythonPeripheral # sysbus 0x40022000
size: 0x1000
initable: false
filename: "script_with_complex_python_logic.py"
```
If you really need advanced implementation, then you need to create a complete C# model.
As you correctly mentioned, we do not want you to modify your binary. But we're ok with mocking some parts we're not interested in for a particular use case if the software passes with these mocks.
Disclaimer: I'm one of the Renode developers.
I've been investigating a change to some embedded software inasmuch as we want U-Boot to be able to pass specific command-line parameters to the kernel, ones that aren't necessarily known in advance.
This is so that the kernel can tell which U-Boot partition it was started by (we have two copies, one in /dev/mmc3boot0 and /dev/mmc3boot1, and they both share a single (redundant) environment space, so we can't use that alone to uniquely identify the instance).
One thought was to simply have each U-Boot write its ID to the shared environment when it boots but that has the downside that there are variants out there that do not currently do this. So, if we boot from one that does, it will write its ID and, if we then boot from one that doesn't, it will not change the ID back to blank, leading to incorrect information if we rely on that.
This is why we thought to use a kernel parameter - since older style U-Boot instances never supply an ID, we know it's running in boot0. The newer style would provide their actual ID so we could then search the two boot partitions to see which one it was in.
To that end, I've modified U-Boot so that it sets up ATAGs to pass through the extra parameter needed. Specifically:
I've define CONFIG_SYS_BOOT_GET_CMDLINE in arch\arm\include\asm\config.h so that boot_get_cmdline() is called.
I've modified that boot_get_cmdline() function so that it sets up a specific parameter before appending the normal parameters. In other words, rather than just plugh=xyzzy, we now get uboot_instance=42 plugh=xyzzy.
This all compiles fine and U-Boot successfully starts the kernel but the extra information is not being reflected in the Linux kernel, which has its kernel parameters set to the regular plugh=xyzzy.
On further research, it appears that we are falling afoul of the two possible ways to invoke the kernel. One of these is with ATAGs and one is with a flattened device tree (FDT), and they appear to be mutually exclusive (the kernel startup code selects one or the other based on signatures passed in with the pointer referencing either the ATAGs or FDT structure).
So my question is this. Given that the device tree is meant to be a fixed structure for the device you're describing, how do you pass arbitrary kernel command line parameters (calculated at runtime) when the bootloader is invoking the kernel?
You can use a dummy environment variable for your platform in include/configs/<board>.h.
For example, assume you have the following (simplified) UBoot environment variables for booting:
bootcmd=run mmcargs
run loadimage loadfdt
bootz ${loadaddr} - ${fdt_addr}
mmcargs=setenv bootargs blah=blah
This uses mmcargs to set up the kernel command line to use. What we need to do is to insert that dummy environment variable in a way that current UBoot instances supply nothing and new ones supply the actual ID. This is done simply with the following change:
mmcargs=setenv bootargs ${uboot_id_stanza} blah=blah
Then, during the initialization of the board, you can set this variable using env_set API, specifically by writing your own custom board_late_init of the board init code in board/<vendor>/<init_code>.c.
The following line should be placed at the end of the board_late_init function:
setenv("uboot_id_stanza", "uboot_id=<uniqueId>");
That way, the uboot_id variable setting is added to the kernel command line but, since you didn't do a saveenv, it doesn't become persistent. Every UBoot instance will set the correct ID (including old ones that don't set an ID).
Since a couple of days, I constantly receive the same error while using MATLAB which happens at some point with dlopen. I am pretty new to MATLAB, and that is why I don't know what to do. Google doesn't seem to be helping me either. When I try to make an eigenvector, I get this:
Error using eig
LAPACK loading error:
dlopen: cannot load any more object with static TLS
I also get this while making a multiplication:
Error using *
BLAS loading error:
dlopen: cannot load any more object with static TLS
I did of course look for the solutions to this problem, but I don't understand too much and don't know what to do. These are threads I found:
How do I use the BLAS library provided by MATLAB?
http://www.mathworks.de/de/help/matlab/matlab_external/calling-lapack-and-blas-functions-from-mex-files.html
Can someone help me please?
Examples of function calls demonstrating this error
>> randn(3,3)
ans =
2.7694 0.7254 -0.2050
-1.3499 -0.0631 -0.1241
3.0349 0.7147 1.4897
>> eig(ans)
Error using eig
LAPACK loading error:
dlopen: cannot load any more object with static TLS
That's bug no 961964 of MATLAB known since R2012b (8.0). MATLAB dynamically loads some libs with static TLS (thread local storage, e.g. see gcc compiler flag -ftls-model). Loading too many such libs => no space left.
Until now mathwork's only workaround is to load the important(!) libs first by using them early (they suggest to put "ones(10)*ones(10);" in startup.m). I better don't comment on this "solution strategy".
Since R2013b (8.2.0.701) with Linux x86_64 my experience is: Don't use "doc" (the graphical help system)! I think this doc-utility (libxul, etc.) is using a lot of static TLS memory.
Here is an update (2013/12/31)
All the following tests were done with Fedora 20 (with glibc-2.18-11.fc20) and Matlab 8.3.0.73043 (R2014a Prerelease).
For more information on TLS, see
Ulrich Drepper, ELF handling For Thread-Local Storage, Version 0.21, 2013,
currently available at Akkadia and Redhat.
What happens exactly?
MATLAB dynamically (with dlopen) loads several libraries that need tls initialization. All those libs need a slot in the dtv (dynamic thread vector). Because MATLAB loads several of these libs dynamically at runtime at compile/link time the linker (at mathworks) had no chance to count the slots needed (that's the important part). Now it's the task of the dynamic lib loader to handle such a case at runtime. But this is not easy. To cite dl-open.c:
For static TLS we have to allocate the memory here and
now. This includes allocating memory in the DTV. But we
cannot change any DTV other than our own. So, if we
cannot guarantee that there is room in the DTV we don't
even try it and fail the load.
There is a compile time constant (called DTV_SURPLUS, see glibc-source/sysdeps/generic/ldsodefs.h) in the glibc's dynamic lib loader for reserving a number of additional slots for such a mess (dynamically loading libs with static TLS in a multithreading program). In the glibc-Version of Fedora 20 this value is 14.
Here are the first libs (running MATLAB) that needed dtv slots in my case:
matlabroot/bin/glnxa64/libut.so
/lib64/libstdc++.so.6
/lib64/libpthread.so.0
matlabroot/bin/glnxa64/libunwind.so.8
/lib64/libuuid.so.1
matlabroot/sys/java/jre/glnxa64/jre/lib/amd64/server/libjvm.so
matlabroot/sys/java/jre/glnxa64/jre/lib/amd64/libfontmanager.so
matlabroot/sys/java/jre/glnxa64/jre/lib/amd64/libt2k.so
matlabroot/bin/glnxa64/mkl.so
matlabroot/sys/os/glnxa64/libiomp5.so
/lib64/libasound.so.2
matlabroot/sys/jxbrowser/glnxa64/xulrunner/xulrunner-linux-64/libxul.so
/lib64/libselinux.so.1
/lib64/libpixman-1.so.0
/lib64/libEGL.so.1
/lib64/libGL.so.1
/lib64/libglapi.so.0
Yes more than 14 => too many => no slot left in the dtv. That's what the error message tries to tell us and especially mathworks.
For the record: In order not to violate MATLAB's license I didn't debug, decompile or disassemble any part of the binaries shipped with MATLAB. I only debugged the free and open glibc-binaries of Fedora 20 that MATLAB were using to dynamically load the libs.
What can be done, to solve this problem?
There are 3 options:
(a)
Rebuild MATLAB and do not dynamically load those libs
(with initial-exec tls model) instead link against them (then the linker
can count the required slots!)
(b)
Rebuild those libs and ensure they are NOT using the initial-exec tls model.
(c)
Rebuild glibc and increase DTV_SURPLUS in
glibc/sysdeps/generic/ldsodefs.h
Obviously options (a) and (b) can only be done by mathworks.
For option (c) no source of MATLAB is needed and thus can be done without mathworks.
What is the status at mathworks?
I really tried to explain this to the "MathWorks Technical Support Department". But my impression is: they don't understand me. They closed my support ticket and suggested a telephone(!) conversation in January 2014 with a technical support manager.
I'll do my very best to explain this, but to be honest: I'm not very confident.
Update (2014/01/10): Currently mathworks is trying option (b).
Update (2014/03/19): For the file libiomp5.so you can download a newly compiled version (without static TLS) at mathworks, bug report 961964. And the other libs? No improvement there. So don't be suprised to get "dlopen: cannot load any more object with static TLS" with "doc", e.g. see bug report 1003952.
Restarting Matlab solved the problem for me.
long story short: in the directory that you start matlab from create a file
startup.m with content ones(10)*ones(10);. Restart matlab and it will be taken care of.
This is, as I find, an age-old problem yet unsolved by MathWorks.
Here are my two cents, which worked for me (when I wanted IT++ external libraries, with MEX).
Let the library that you found to be the cause of the problem be "libXYZ.so", and that you know where it lies on your system.
The solution is to inform MATLAB to load the specific library at the earliest of its startup. The reason for this error is apparently due to the lack of slots for this thread local storage aka tls purpose (due to they already been filled-up).
Because the latest compilations suddenly required a new library that was not loaded earlier during its startup, MATLAB throws up this error.
Pity that MATLAB never cared to resolve this problem so long.
Fortunately, the solution is a single, very simple terminal command.
Typical steps on a linux-machine should be as follows:
Open command prompt (Ctrl+Alt+T in Ubuntu)
Issue the following command
export LD_PRELOAD=<PATH-TO-libxyz.so>
e.g.: export LD_PRELOAD=/usr/local/lib/libitpp.so
Start matlab from the same terminal
matlab &
Running your program now should resolve the issue, as it is for my case.
Good luck!
Reference:
[1] http://au.mathworks.com/matlabcentral/answers/125117-openmp-mex-files-static-tls-problem
http://www.mathworks.de/support/bugreports/961964 has been updated on 30/01/2014.
There is a zip file attached with libiomp5.so
I tested it on Mageia 4 x86_64 with Matlab R2013b.
I can now use the Documentation of Matlab to open a demo without any problem.
I had the same problem and I think I just solved it.
When installing matlab use the custom installation (I did not do this the first time). Choose to create symbolic links to matlab scripts in the predefined folder (/usr/local/bin). This did the trick for me!
I had the same problem with both Matlab 2013b and Matlab 2014a. The fix provided by mathworks for libiomp5.so only removed the problem of LAPACK not working. However, I could not use external libraries which are using OpenMp (such as VL_FEAT): I still get the error
"dlopen: cannot load any more object with static TLS."
The only thing which worked for me was downgrading to Matlab 2012b.
I came across this problem after "bar" (for bar plots) with a an array gives me just a single blue block, with no errors thrown. Reboot at first solved the problem. But after a memory error (after processing a very large file), I just cannot get past this blue block problem.
Using "hist" on a matrix input gives me the "BLAS loading error" problem and led me to this thread. The Mathwork workaround fixed the hist and bar problems.
Just wanted to bring recognition to the extent of this bug's influence.
I had the same problem and solved it by increasing my Java Heap memory. Go to Preferences > General > Java-Heap Memory, and increase the allocated memory.
Increasing Java heap memory (to 512 mb) also worked for me on R2013b/Ubuntu 12.04. The "BLAS loading error" began when I processed an 11 GB file (with 16 GB RAM), and has not recurred after increasing java heap memory and restarting matlab.
Basically, when my system is running, I would like the user to ftp some new code to the SD card, and dynamically load the new function and create a task to run in the system. This is normal for Linux. For example, I can compile a SO, and dynamically load into the memory.
How to do it in uC/OS II or III?
This is not a service uC/OS-II or uC/OS-III can provide by itself.
You would need a program loader that is able to read an ELF file, copy its relevant sections (ex .text, .rodata, etc.) in memory according to load addresses specified and allocate memory for uninitialized memory sections. You would then be able to create a new uC/OS task and pass it the function pointer that corresponds to the ELF entry point.
Most embedded systems don't have a Memory Management Unit (MMU) and thus you would need to pay special care to the linking process to make sure any of those sections don't overlap with any code that would already running on your target. Depending on your toolchain, that would most likely involve carefully crafting your linker script.
Another option that would avoid the problem of potential overlapping of the memory space would be to use a toolchain that can produce position independent code and load the ELF in the heap of your main application or in any other allocated and available memory space that is allocated by your main application.
Yet another option would be to produce relocatable code and use or build a program linker that is able to process relocations at runtime, when you want to load the uploaded code.
Since a couple of days, I constantly receive the same error while using MATLAB which happens at some point with dlopen. I am pretty new to MATLAB, and that is why I don't know what to do. Google doesn't seem to be helping me either. When I try to make an eigenvector, I get this:
Error using eig
LAPACK loading error:
dlopen: cannot load any more object with static TLS
I also get this while making a multiplication:
Error using *
BLAS loading error:
dlopen: cannot load any more object with static TLS
I did of course look for the solutions to this problem, but I don't understand too much and don't know what to do. These are threads I found:
How do I use the BLAS library provided by MATLAB?
http://www.mathworks.de/de/help/matlab/matlab_external/calling-lapack-and-blas-functions-from-mex-files.html
Can someone help me please?
Examples of function calls demonstrating this error
>> randn(3,3)
ans =
2.7694 0.7254 -0.2050
-1.3499 -0.0631 -0.1241
3.0349 0.7147 1.4897
>> eig(ans)
Error using eig
LAPACK loading error:
dlopen: cannot load any more object with static TLS
That's bug no 961964 of MATLAB known since R2012b (8.0). MATLAB dynamically loads some libs with static TLS (thread local storage, e.g. see gcc compiler flag -ftls-model). Loading too many such libs => no space left.
Until now mathwork's only workaround is to load the important(!) libs first by using them early (they suggest to put "ones(10)*ones(10);" in startup.m). I better don't comment on this "solution strategy".
Since R2013b (8.2.0.701) with Linux x86_64 my experience is: Don't use "doc" (the graphical help system)! I think this doc-utility (libxul, etc.) is using a lot of static TLS memory.
Here is an update (2013/12/31)
All the following tests were done with Fedora 20 (with glibc-2.18-11.fc20) and Matlab 8.3.0.73043 (R2014a Prerelease).
For more information on TLS, see
Ulrich Drepper, ELF handling For Thread-Local Storage, Version 0.21, 2013,
currently available at Akkadia and Redhat.
What happens exactly?
MATLAB dynamically (with dlopen) loads several libraries that need tls initialization. All those libs need a slot in the dtv (dynamic thread vector). Because MATLAB loads several of these libs dynamically at runtime at compile/link time the linker (at mathworks) had no chance to count the slots needed (that's the important part). Now it's the task of the dynamic lib loader to handle such a case at runtime. But this is not easy. To cite dl-open.c:
For static TLS we have to allocate the memory here and
now. This includes allocating memory in the DTV. But we
cannot change any DTV other than our own. So, if we
cannot guarantee that there is room in the DTV we don't
even try it and fail the load.
There is a compile time constant (called DTV_SURPLUS, see glibc-source/sysdeps/generic/ldsodefs.h) in the glibc's dynamic lib loader for reserving a number of additional slots for such a mess (dynamically loading libs with static TLS in a multithreading program). In the glibc-Version of Fedora 20 this value is 14.
Here are the first libs (running MATLAB) that needed dtv slots in my case:
matlabroot/bin/glnxa64/libut.so
/lib64/libstdc++.so.6
/lib64/libpthread.so.0
matlabroot/bin/glnxa64/libunwind.so.8
/lib64/libuuid.so.1
matlabroot/sys/java/jre/glnxa64/jre/lib/amd64/server/libjvm.so
matlabroot/sys/java/jre/glnxa64/jre/lib/amd64/libfontmanager.so
matlabroot/sys/java/jre/glnxa64/jre/lib/amd64/libt2k.so
matlabroot/bin/glnxa64/mkl.so
matlabroot/sys/os/glnxa64/libiomp5.so
/lib64/libasound.so.2
matlabroot/sys/jxbrowser/glnxa64/xulrunner/xulrunner-linux-64/libxul.so
/lib64/libselinux.so.1
/lib64/libpixman-1.so.0
/lib64/libEGL.so.1
/lib64/libGL.so.1
/lib64/libglapi.so.0
Yes more than 14 => too many => no slot left in the dtv. That's what the error message tries to tell us and especially mathworks.
For the record: In order not to violate MATLAB's license I didn't debug, decompile or disassemble any part of the binaries shipped with MATLAB. I only debugged the free and open glibc-binaries of Fedora 20 that MATLAB were using to dynamically load the libs.
What can be done, to solve this problem?
There are 3 options:
(a)
Rebuild MATLAB and do not dynamically load those libs
(with initial-exec tls model) instead link against them (then the linker
can count the required slots!)
(b)
Rebuild those libs and ensure they are NOT using the initial-exec tls model.
(c)
Rebuild glibc and increase DTV_SURPLUS in
glibc/sysdeps/generic/ldsodefs.h
Obviously options (a) and (b) can only be done by mathworks.
For option (c) no source of MATLAB is needed and thus can be done without mathworks.
What is the status at mathworks?
I really tried to explain this to the "MathWorks Technical Support Department". But my impression is: they don't understand me. They closed my support ticket and suggested a telephone(!) conversation in January 2014 with a technical support manager.
I'll do my very best to explain this, but to be honest: I'm not very confident.
Update (2014/01/10): Currently mathworks is trying option (b).
Update (2014/03/19): For the file libiomp5.so you can download a newly compiled version (without static TLS) at mathworks, bug report 961964. And the other libs? No improvement there. So don't be suprised to get "dlopen: cannot load any more object with static TLS" with "doc", e.g. see bug report 1003952.
Restarting Matlab solved the problem for me.
long story short: in the directory that you start matlab from create a file
startup.m with content ones(10)*ones(10);. Restart matlab and it will be taken care of.
This is, as I find, an age-old problem yet unsolved by MathWorks.
Here are my two cents, which worked for me (when I wanted IT++ external libraries, with MEX).
Let the library that you found to be the cause of the problem be "libXYZ.so", and that you know where it lies on your system.
The solution is to inform MATLAB to load the specific library at the earliest of its startup. The reason for this error is apparently due to the lack of slots for this thread local storage aka tls purpose (due to they already been filled-up).
Because the latest compilations suddenly required a new library that was not loaded earlier during its startup, MATLAB throws up this error.
Pity that MATLAB never cared to resolve this problem so long.
Fortunately, the solution is a single, very simple terminal command.
Typical steps on a linux-machine should be as follows:
Open command prompt (Ctrl+Alt+T in Ubuntu)
Issue the following command
export LD_PRELOAD=<PATH-TO-libxyz.so>
e.g.: export LD_PRELOAD=/usr/local/lib/libitpp.so
Start matlab from the same terminal
matlab &
Running your program now should resolve the issue, as it is for my case.
Good luck!
Reference:
[1] http://au.mathworks.com/matlabcentral/answers/125117-openmp-mex-files-static-tls-problem
http://www.mathworks.de/support/bugreports/961964 has been updated on 30/01/2014.
There is a zip file attached with libiomp5.so
I tested it on Mageia 4 x86_64 with Matlab R2013b.
I can now use the Documentation of Matlab to open a demo without any problem.
I had the same problem and I think I just solved it.
When installing matlab use the custom installation (I did not do this the first time). Choose to create symbolic links to matlab scripts in the predefined folder (/usr/local/bin). This did the trick for me!
I had the same problem with both Matlab 2013b and Matlab 2014a. The fix provided by mathworks for libiomp5.so only removed the problem of LAPACK not working. However, I could not use external libraries which are using OpenMp (such as VL_FEAT): I still get the error
"dlopen: cannot load any more object with static TLS."
The only thing which worked for me was downgrading to Matlab 2012b.
I came across this problem after "bar" (for bar plots) with a an array gives me just a single blue block, with no errors thrown. Reboot at first solved the problem. But after a memory error (after processing a very large file), I just cannot get past this blue block problem.
Using "hist" on a matrix input gives me the "BLAS loading error" problem and led me to this thread. The Mathwork workaround fixed the hist and bar problems.
Just wanted to bring recognition to the extent of this bug's influence.
I had the same problem and solved it by increasing my Java Heap memory. Go to Preferences > General > Java-Heap Memory, and increase the allocated memory.
Increasing Java heap memory (to 512 mb) also worked for me on R2013b/Ubuntu 12.04. The "BLAS loading error" began when I processed an 11 GB file (with 16 GB RAM), and has not recurred after increasing java heap memory and restarting matlab.