I am new to this and just learning about the kernel, and I am trying to add a custom call to kernel 4.20.4. This is the steps that I did.
First I create the file (kernel/printmsg.c) that contains the code.
#include <linux/kernel.h>
#include <linux/syscalls.h>
SYSCALL_DEFINE1(printmsg, int, i)
{
printk(KERN_DEBUG, "TESTING %d", i);
return 1;
}
Next, I add this file to the kernel/Makefile
obj-y = fork.o exec_domain.o panic.o \
// A few more lines
obj-y += printmsg.o // I added this line
Finally, I add the system call to the syscall table on arch/x86/entry/syscalls/syscall_64.tbl(I'm building this on a 64-bit Ubuntu) by appending this line:
548 64 printmsg sys_printmsg
Now, I proceed to run make. However, it has this error:
arch/x86/entry/syscall_64.o:(.rodata+0x1120): undefined reference to `sys_printmsg'
Makefile:1034: recipe for target 'vmlinux' failed
make: *** [vmlinux] Error 1
I've been scratching my head for a long time for this but I can't seem to realised what went wrong.
Hope that anyone that managed to find a problem can help out a poor soul. Thanks in advance!
Okay, after hours of trial and error, I have finally found the problem. From linux kernel v4.17 onwards, x86_64 system calls may begin with "__x64_sys".
So, instead of using 548 64 printmsg sys_printmsg, I changed it to 548 64 printmsg __x64_sys_printmsg. Then everything works.
Hoped this helped everyone that might have this problem.
Related
(firstly I'm a chinese, so there might be some syntax errors. I'm sorry for that)
So yesterday I just update my VulkanSDK version to the newest (version 1.3.216.0) as well as VMA, but there's a runtime error occured when I try to run the code which was like : 'Entry Point Not Found'(The picture's chinese)
So I try to clean the Project and Regenerate it but no progress, then I re-installed VulkanSDK and restart my computer but still nothing helped. Later I find that this is a Vulkan error which probably originate from vk_mem_alloc.h (VMA). But I debugged for a few days but still don't understand why "vkGetDeviceImageRequirements" is not find while there seems nothing wrong with "vkGetDeviceBufferMemoryRequirements" which was actually fetched earlier
#if VMA_VULKAN_VERSION >= 1003000
if(m_VulkanApiVersion >= VK_MAKE_VERSION(1, 3, 0))
{
VMA_FETCH_DEVICE_FUNC(vkGetDeviceBufferMemoryRequirements, PFN_vkGetDeviceBufferMemoryRequirements, "vkGetDeviceBufferMemoryRequirements");
VMA_FETCH_DEVICE_FUNC(vkGetDeviceImageMemoryRequirements, PFN_vkGetDeviceImageMemoryRequirements, "vkGetDeviceImageMemoryRequirements");
}
#endif
And here is my base.h:
#pragma once
#include <glad/glad.h>
#define GLFW_INCLUDE_VULKAN
#include <GLFW/glfw3.h>
#include <vulkan/vulkan.hpp>
#include <shaderc/shaderc.hpp>
#include <vma/vk_mem_alloc.h>
This is my CKake list:
cmake_minimum_required(VERSION 3.21)
project(FFEngine_Project)
set(CMAKE_CXX_STANDARD 20)
file(GLOB copyResources "./assets" "./thirdParty/libs/assimp/assimp-vc143-mtd.dll")
file(COPY ${copyResources} DESTINATION ${CMAKE_BINARY_DIR})
include_directories(
SYSTEM ${CMAKE_CURRENT_SOURCE_DIR}/thirdParty/include)
include_directories(
SYSTEM D:/Vulkan/VulkanSDK/1.3.216.0/Include)
link_directories(
SYSTEM ${CMAKE_CURRENT_SOURCE_DIR}/thirdParty/libs/glfw
SYSTEM ${CMAKE_CURRENT_SOURCE_DIR}/thirdParty/libs/assimp
SYSTEM D:/Vulkan/VulkanSDK/1.3.216.0/Lib
)
add_subdirectory(ff)
add_executable(triangle "examples/triangle.cpp")
target_link_libraries(triangle ff_lib glfw3.lib vulkan-1.lib shaderc_sharedd.lib assimp-vc143-mtd.lib)
This error has been confusing me for days, I'm really pissed off... If any more details or codes are needed, ask me, and I'll reply
I'm brand new to Linux programming and I'm trying to implement a simple system call loosely following this guide: https://medium.com/anubhav-shrimal/adding-a-hello-world-system-call-to-linux-kernel-dad32875872. In my linux kernel directory, I created a new directory called my_syscall. Within that directory, I created my_syscall.c. Here is my_syscall.c
#include <linux/syscalls.h>
#include <linux/kernel.h>
asmlinkage long sys_my_syscall(int i) {
prink(KERN_INFO "This is the system call.");
return(0);
}
I then created a Makefile in the my_syscall directory with a single line:
obj-y := my_syscall.o
I then edited this line in the Makefile in the kernel directory to be:
core-y += kernel/ certs/ mm/ fs/ ipc/ security/ crypto/ block/ my_syscall/
Then, in the directory linux-5.4.15/arch/x86/entry/syscalls, I edited the syscall_64.tbl to include the following line at the very end:
548 64 my_syscall sys_my_syscall
Finally, in the directory linux-5.4.15/include/linux, I edited the syscalls.h file to include this line before the #endif:
asmlinkage long sys_my_syscall(int i);
Now, when I run the command sudo make, I run into the following error soon after:
./arch/x86/include/generated/asm/syscalls_64.h:2664:19: error: conflicting types for 'sys_my_syscall'
__SYSCALL_64(548, sys_my_syscall, )
arch/x86/entry/syscall_64.c:18:60: note: in definition of macro '__SYSCALL-64'
#define __SYSCALL_64(nr, sym, qual) extern asmlinkage long sym(const struct pt_regs *);
In file included from arch/x86/entry/syscall_64.c:7:0:
./include/linux/syscalls.h:1423:17: note: previous declaration of 'sys_my_syscall' was here
asmlinkage long sys_my_syscall(int i);
^
make[3]: *** [arch/x86/entry/syscall_64.o] Error 1
make[2]: *** [arch/x86/entry] Error 2
make[1]: *** [arch/x86] Error 2
make: *** [sub-make] Error 2
I have no idea how to approach this error. With a conflicting types error, I would think I declared the syscall differently in someplace, but in both my_syscall.c and the syscalls.h files, the declaration is the same. These were the only two files where the syscall is declared, but it is also named within syscall_64.tbl and it seems like this is where linux is trying to point me towards. However, I don't see what's wrong with how I declared it in the table as I followed the guide directly. Any help with this would be greatly appreciated!
Info:
Kernel version: 5.4.15
Linux Distribution: Ubuntu 14
I just changed the location where the syscall number is defined in syscall_64.tbl.
Instead of this:
548 64 my_syscall sys_my_syscall
I wrote this:
436 common my_syscall __x64_sys_my_syscall
Screen Capture of my configuration
It worked out.
I'm doing something similar and got the exact same error.
What fixed the error for me is changing the last part of the syscall_64.tbl table entry from "sys_my_syscall" to "__x64_sys_my_syscall". If you scroll up, other entries have the same prefix. The kernel started compiling after I made that change.
I eventually gave up on trying to implement this in kernel 5. Unfortunately, none of the other solutions resulted in my kernel compiling. I rolled back my kernel and followed the steps here. This resulted in the system call working correctly. I'm not sure how to make this function in kernel 5+.
#include <linux/syscalls.h>
#include <linux/kernel.h>
SYSCALL_DEFINE1(my_syscall, int, i)
{
printk(KERN_INFO "This is the system call (param %d).\n", i);
return(0);
}
For kernel 5, try deleting "sys_" before "my_syscall" and try. It worked for me
Some architectures (including x86-64) use syscall wrappers to call the real syscall handler. To define the real syscall handler and its wrappers (for architectures that use syscall wrappers), use one of the SYSCALL_DEFINE<n> macros before the body of the syscall handler. The parameters of the SYSCALL_DEFINE<n> macros are the function name, followed by <n> pairs of ``type, param'' for the function parameters.
Your sys_my_syscall syscall handler function has one parameter, so use the SYSCALL_DEFINE1 macro before the body of the function:
#include <linux/syscalls.h>
#include <linux/kernel.h>
SYSCALL_DEFINE1(sys_my_syscall, int, i)
{
printk(KERN_INFO "This is the system call (param %d).\n", i);
return(0);
}
I have build environment to run code in a Docker container. One of the components is OpenMPI, which I think is the source of problem or manifest it.
When I run code using MPI I getting message,
Unexpected end of /proc/mounts line `overlay / overlay rw,relatime,lowerdir=/var/lib/docker/overlay2/l/NHW6L2TB73FPMK4A52XDP6SO2V:/var/lib/docker/overlay2/l/MKAGUDHZZTJF4KNSUM73QGVRUD:/var/lib/docker/overlay2/l/4PFRG6M47TX5TYVHKQQO2KCG7Q:/var/lib/docker/overlay2/l/4UR3OEP3IW5ZTADZ6OKT77ZBEU:/var/lib/docker/overlay2/l/LGBMK7HFUCHRTM2MMITMD6ILMG:/var/lib/docker/overlay2/l/ODJ2DJIGYGWRXEJZ6ECSLG7VDJ:/var/lib/docker/overlay2/l/JYQIR5JVEUVQPHEF452BRDVC23:/var/lib/docker/overlay2/l/AUDTRIBKXDZX62ANXO75LD3DW5:/var/lib/docker/overlay2/l/RFFN2MQPDHS2Z'
Unexpected end of /proc/mounts line `KNEJCAQH6YG5S:/var/lib/docker/overlay2/l/7LZSAIYKPQ56QB6GEIB2KZTDQA:/var/lib/docker/overlay2/l/CP2WSFS5347GXQZMXFTPWU4F3J:/var/lib/docker/overlay2/l/SJHIWRVQO5IENQFYDG6R5VF7EB:/var/lib/docker/overlay2/l/ICNNZZ4KB64VEFSKEQZUF7XI63:/var/lib/docker/overlay2/l/SOHRMEBEIIP4MRKRRUWMFTXMU2:/var/lib/docker/overlay2/l/DL4GM7DYQUV4RQE4Z6H5XWU2AB:/var/lib/docker/overlay2/l/JNEAR5ISUKIBKQKKZ6GEH6T6NP:/var/lib/docker/overlay2/l/LIAK7F7Q4SSOJBKBFY4R66J2C3:/var/lib/docker/overlay2/l/MYL6XNGBKKZO5CR3PG3HIB475X:/var/lib/do'
That message is printed for code line
MPI_Init(&argc,&argv);
To make the problem more complex to understand, a warning message is printed only when the host machine is mac os x, for linux host all is ok.
Except for warning message all works fine. I do not know how OpenMPI and docker well enough how this can be fixed.
This is likely due to your /proc/mount file having a line in it greater than 512 characters, causing the hwloc module of OpenMPI to fail to parse it correctly. Docker has a tendency to put very long lines into /proc/mounts. You can see the bug in openmpi-1.10.7/opal/mca/hwloc/hwloc191/hwloc/src/topology-linux.c:1677:
static void
hwloc_find_linux_cpuset_mntpnt(char **cgroup_mntpnt, char **cpuset_mntpnt, int fsroot_fd)
{
#define PROC_MOUNT_LINE_LEN 512
char line[PROC_MOUNT_LINE_LEN];
FILE *fd;
*cgroup_mntpnt = NULL;
*cpuset_mntpnt = NULL;
/* ideally we should use setmntent, getmntent, hasmntopt and endmntent,
* but they do not support fsroot_fd.
*/
fd = hwloc_fopen("/proc/mounts", "r", fsroot_fd);
if (!fd)
return;
This can be fixed by increasing the value of PROC_MOUNT_LINE_LEN, although that should be considered a temporary workaround.
This issue should be fixed in hwloc since 1.11.3 (released 2 years ago). You can either upgrade to OpenMPI 3.0 which contains a hwloc 1.11.7 >= 1.11.3. Or recompile OpenMPI to use an external hwloc instead of the old embedded one.
I want load resources from c++ code. And try repeat this way. But when i try build it, i get:
E:\Android\Samples\android-ndk-assets\project>e:\Android\android-ndk-r8b\ndk-build
Gdbserver : [arm-linux-androideabi-4.6] libs/armeabi/gdbserver
Gdbsetup : libs/armeabi/gdb.setup
"Compile thumb : png <= pngrtran.c
jni/libpng/pngrtran.c: In function 'png_do_expand':
jni/libpng/pngrtran.c:3790:1: internal compiler error: in reload, at reload1.c:1061
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
make: *** [obj/local/armeabi/objs-debug/png/pngrtran.o] Error 1
I just ran into this problem as well. Another workaround is to build the library as ARM code instead of Thumb code by adding the following line to your makefile:
LOCAL_ARM_MODE := arm
There should be no problem using ARM mode... ARM instructions require twice the space of Thumb instructions but are also much more sophisticated and capable of accomplishing a lot more in a single instruction, so depending on the cleverness of the compiler the resultant code may be bigger or smaller as well as more efficient or less efficient, but should execute with the same results.
I had the same error in android-ndk-r8b.
Looks like the bug in GCC. Do you submit bug report already?
I found the code which make error:
if (*(sp - 5) == red_high &&
*(sp - 4) == red_low &&
*(sp - 3) == green_high && //this line make error
*(sp - 2) == green_low && //this line make error
*(sp - 1) == blue_high &&
*(sp ) == blue_low)
{
*dp-- = 0;
*dp-- = 0;
}
I have a similar error in android-ndk-r8b as well. It occurs when calling ndk-build with the NDK_DEBUG flag set:
ndk-build NDK_DEBUG=1 <--- error
Try setting the NDK_BUILD flag to 0. It should compile. Of course it won't be debuggable :(
ndk-build NDK_DEBUG=0 <--- no error
Today one of our devs had "error 9009" from my subwcrev post-build command. It worked fine in the command line. What fixed it was restarting Visual Studio. A couple of other people found that updating SVN and/or ensuring it's on the path were the culprits;
http://forum.battleclinic.com/index.php?topic=42617.0;Building-problems
http://www.autismcollaborative.org/wiki/index.php?title=Troubleshooting
I was surprised not to see a list of SubWcRev's error code's and their meanings. Does anyone know where to find that? thank you!
You can find the error codes in the source.
// Internal error codes
#define ERR_SYNTAX 1 // Syntax error
#define ERR_FNF 2 // File/folder not found
#define ERR_OPEN 3 // File open error
#define ERR_ALLOC 4 // Memory allocation error
#define ERR_READ 5 // File read/write/size error
#define ERR_SVN_ERR 6 // SVN error
// Documented error codes
#define ERR_SVN_MODS 7 // Local mods found (-n)
#define ERR_SVN_MIXED 8 // Mixed rev WC found (-m)
#define ERR_OUT_EXISTS 9 // Output file already exists (-d)
#define ERR_NOWC 10 // the path is not a working copy or part of one
Remove it from: Project--> Properties ---> Build Event --> Pre build event command line
subwcrev "$(SolutionDir)." "$(ProjectDir)Properties\AssemblyInfoTemplate.cs" "$(ProjectDir)Properties\AssemblyInfo.cs" -f
Then build the project