![Johannes Berg](/assets/img/avatar_default.png)
We do need to call the constructors for *modules*, and at least for KASAN in the future, we must call even the kernel constructors only later when the kernel has been initialized. Instead of relying on libc to call them, emit an empty section for libc and let the kernel's CONSTRUCTORS code do the rest of the job. Tested that it indeed doesn't work in modules, and does work after the fixes in both, with a few functions with __attribute__((constructor)) in both dynamic and static builds. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
79 lines
2 KiB
Plaintext
79 lines
2 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
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menu "GCOV-based kernel profiling"
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config GCOV_KERNEL
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bool "Enable gcov-based kernel profiling"
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depends on DEBUG_FS
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select CONSTRUCTORS
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default n
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---help---
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This option enables gcov-based code profiling (e.g. for code coverage
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measurements).
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If unsure, say N.
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Additionally specify CONFIG_GCOV_PROFILE_ALL=y to get profiling data
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for the entire kernel. To enable profiling for specific files or
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directories, add a line similar to the following to the respective
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Makefile:
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For a single file (e.g. main.o):
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GCOV_PROFILE_main.o := y
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For all files in one directory:
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GCOV_PROFILE := y
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To exclude files from being profiled even when CONFIG_GCOV_PROFILE_ALL
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is specified, use:
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GCOV_PROFILE_main.o := n
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and:
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GCOV_PROFILE := n
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Note that the debugfs filesystem has to be mounted to access
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profiling data.
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config ARCH_HAS_GCOV_PROFILE_ALL
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def_bool n
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config GCOV_PROFILE_ALL
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bool "Profile entire Kernel"
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depends on !COMPILE_TEST
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depends on GCOV_KERNEL
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depends on ARCH_HAS_GCOV_PROFILE_ALL
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default n
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---help---
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This options activates profiling for the entire kernel.
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If unsure, say N.
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Note that a kernel compiled with profiling flags will be significantly
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larger and run slower. Also be sure to exclude files from profiling
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which are not linked to the kernel image to prevent linker errors.
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choice
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prompt "Specify GCOV format"
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depends on GCOV_KERNEL
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depends on CC_IS_GCC
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---help---
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The gcov format is usually determined by the GCC version, and the
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default is chosen according to your GCC version. However, there are
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exceptions where format changes are integrated in lower-version GCCs.
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In such a case, change this option to adjust the format used in the
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kernel accordingly.
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config GCOV_FORMAT_3_4
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bool "GCC 3.4 format"
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depends on GCC_VERSION < 40700
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---help---
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Select this option to use the format defined by GCC 3.4.
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config GCOV_FORMAT_4_7
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bool "GCC 4.7 format"
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---help---
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Select this option to use the format defined by GCC 4.7.
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endchoice
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endmenu
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