gcov-kernel - a gcov infrastructure for the Linux kernel

About gcov-kernel

gcov-kernel enables code coverage measurements for the Linux kernel and kernel modules. It is based on GCC's gcov tool. gcov-kernel is available as a set of patches for Linux kernels 2.6.4 to 2.6.30. Starting with Linux kernel 2.6.31, gcov-kernel is part of the Linux kernel and can be used without extra patches.

Using gcov-kernel (Linux 2.6.31 and above)

Example: (assumes that Linux source code is installed in directory /tmp/linux)

1. Obtain the Linux kernel source code
2. Enable the gcov-kernel configuration options:

   CONFIG_GCOV_KERNEL=y
   CONFIG_GCOV_PROFILE_ALL=y

3. Compile, install and boot the kernel
4. Mount the debugfs file system at mount point /sys/kernel/debug

   [root@host]# mount -t debugfs none /sys/kernel/debug

5. Change to the kernel source tree

   [root@host]# cd /tmp/linux

6. Run the gcov tool on a source code file

   [root@host]# gcov kernel/gcov/base.c -o /sys/kernel/debug/gcov/tmp/linux/kernel/gcov/
   File 'kernel/gcov/base.c'
   Lines executed:52.17% of 46
   kernel/gcov/base.c:creating 'base.c.gcov'
   

7. Code coverage information for the specified source file can be found in the files created by gcov. Alternatively, use LCOV to obtain the information automatically.

Using gcov-kernel (Linux 2.6.30 and below)

Example: (assumes that Linux source code is installed in directory /tmp/linux)

1. Obtain the Linux kernel source code
2. Obtain and apply the corresponding gcov-kernel patch
3. Enable the gcov-kernel configuration options:

   CONFIG_GCOV_PROFILE=y
   CONFIG_GCOV_ALL=y
   CONFIG_GCOV_PROC=y

4. Compile, install and boot the kernel
5. Change to the kernel source tree

   [root@host]# cd /tmp/linux

6. Run the gcov tool on a source code file

   [root@host]# gcov lib/sort.c -o /proc/gcov/module/tmp/linux/lib/
   File '/tmp/linux/lib/sort.c'
   Lines executed:84.85% of 33
   /tmp/linux/lib/sort.c:creating 'sort.c.gcov'

Code coverage information for the specified source file can be found in the files created by gcov. Alternatively, use LCOV to obtain the information automatically.

Download

Source code: gcov-kernel is released under the GPL license. The latest patch versions can be found in the LTP CVS repository.

• CVS access: module name "utils", directory "utils/analysis/gcov-kernel"
• Browse CVS

Comments And Questions

For comments and questions contact: ltp-coverage@lists.sourceforge.net