1 # SPDX-License-Identifier: GPL-2.0-only 1 # SPDX-License-Identifier: GPL-2.0-only
2 menu "GCOV-based kernel profiling" 2 menu "GCOV-based kernel profiling"
3 3
4 config GCOV_KERNEL 4 config GCOV_KERNEL
5 bool "Enable gcov-based kernel profili 5 bool "Enable gcov-based kernel profiling"
6 depends on DEBUG_FS 6 depends on DEBUG_FS
7 depends on !ARCH_WANTS_NO_INSTR || CC_ !! 7 select CONSTRUCTORS if !UML
8 select CONSTRUCTORS <<
9 default n 8 default n
10 help !! 9 ---help---
11 This option enables gcov-based code pr 10 This option enables gcov-based code profiling (e.g. for code coverage
12 measurements). 11 measurements).
13 12
14 If unsure, say N. 13 If unsure, say N.
15 14
16 Additionally specify CONFIG_GCOV_PROFI 15 Additionally specify CONFIG_GCOV_PROFILE_ALL=y to get profiling data
17 for the entire kernel. To enable profi 16 for the entire kernel. To enable profiling for specific files or
18 directories, add a line similar to the 17 directories, add a line similar to the following to the respective
19 Makefile: 18 Makefile:
20 19
21 For a single file (e.g. main.o): 20 For a single file (e.g. main.o):
22 GCOV_PROFILE_main.o := y 21 GCOV_PROFILE_main.o := y
23 22
24 For all files in one directory: 23 For all files in one directory:
25 GCOV_PROFILE := y 24 GCOV_PROFILE := y
26 25
27 To exclude files from being profiled e 26 To exclude files from being profiled even when CONFIG_GCOV_PROFILE_ALL
28 is specified, use: 27 is specified, use:
29 28
30 GCOV_PROFILE_main.o := n 29 GCOV_PROFILE_main.o := n
31 and: 30 and:
32 GCOV_PROFILE := n 31 GCOV_PROFILE := n
33 32
34 Note that the debugfs filesystem has t 33 Note that the debugfs filesystem has to be mounted to access
35 profiling data. 34 profiling data.
36 35
37 config ARCH_HAS_GCOV_PROFILE_ALL 36 config ARCH_HAS_GCOV_PROFILE_ALL
38 def_bool n 37 def_bool n
39 38
40 config GCOV_PROFILE_ALL 39 config GCOV_PROFILE_ALL
41 bool "Profile entire Kernel" 40 bool "Profile entire Kernel"
42 depends on !COMPILE_TEST 41 depends on !COMPILE_TEST
43 depends on GCOV_KERNEL 42 depends on GCOV_KERNEL
44 depends on ARCH_HAS_GCOV_PROFILE_ALL 43 depends on ARCH_HAS_GCOV_PROFILE_ALL
45 default n 44 default n
46 help !! 45 ---help---
47 This options activates profiling for t 46 This options activates profiling for the entire kernel.
48 47
49 If unsure, say N. 48 If unsure, say N.
50 49
51 Note that a kernel compiled with profi 50 Note that a kernel compiled with profiling flags will be significantly
52 larger and run slower. Also be sure to 51 larger and run slower. Also be sure to exclude files from profiling
53 which are not linked to the kernel ima 52 which are not linked to the kernel image to prevent linker errors.
>> 53
>> 54 choice
>> 55 prompt "Specify GCOV format"
>> 56 depends on GCOV_KERNEL
>> 57 depends on CC_IS_GCC
>> 58 ---help---
>> 59 The gcov format is usually determined by the GCC version, and the
>> 60 default is chosen according to your GCC version. However, there are
>> 61 exceptions where format changes are integrated in lower-version GCCs.
>> 62 In such a case, change this option to adjust the format used in the
>> 63 kernel accordingly.
>> 64
>> 65 config GCOV_FORMAT_3_4
>> 66 bool "GCC 3.4 format"
>> 67 depends on GCC_VERSION < 40700
>> 68 ---help---
>> 69 Select this option to use the format defined by GCC 3.4.
>> 70
>> 71 config GCOV_FORMAT_4_7
>> 72 bool "GCC 4.7 format"
>> 73 ---help---
>> 74 Select this option to use the format defined by GCC 4.7.
>> 75
>> 76 endchoice
54 77
55 endmenu 78 endmenu
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