* [RFC PATCH 01/20] coverage: move gcov and kcov under kernel/coverage/
2026-10-28 11:59 [RFC PATCH 00/20] Unify code coverage and add Clang source-based coverage with MC/DC Sasha Levin
@ 2026-10-28 11:59 ` Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 02/20] kbuild: unify static coverage instrumentation as COVERAGE_PROFILE Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 20/20] Documentation: dev-tools: document the common code coverage interface Sasha Levin
2 siblings, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2026-10-28 11:59 UTC (permalink / raw)
To: linux-kernel
Cc: Alexander Potapenko, Andrew Morton, Andrey Konovalov, Ben Segall,
Bill Wendling, Chuck Wolber, Dietmar Eggemann, Dmitry Vyukov,
Ingo Molnar, Juri Lelli, Justin Stitt, kasan-dev, K Prateek Nayak,
linux-doc, llvm, Marco Elver, Masami Hiramatsu,
Mauro Carvalho Chehab, Mel Gorman, Nathan Chancellor,
Nick Desaulniers, Peter Oberparleiter, Peter Zijlstra,
Steven Rostedt, Thomas Gleixner, Valentin Schneider,
Vincent Guittot
The kernel carries more than one code coverage implementation, each
with its own directory, Kconfig menu, build plumbing and debugfs
interface. Start consolidating them by moving the existing
implementations next to each other:
kernel/gcov/ -> kernel/coverage/gcov/
kernel/kcov.c -> kernel/coverage/kcov.c
Both are configured from a new "Code coverage" menu in
kernel/coverage/Kconfig, which is sourced from "Kernel Testing and
Coverage" where the KCOV options used to live. The gcov options move
there from "General architecture-dependent options".
No functional change: the Kconfig symbols and their dependencies are
unchanged, and so are the per-object compiler flags of kcov.o, which
move to kernel/coverage/Makefile.
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
MAINTAINERS | 8 +++-
arch/Kconfig | 2 -
include/linux/sched.h | 2 +-
kernel/Makefile | 15 +------
kernel/coverage/Kconfig | 65 +++++++++++++++++++++++++++
kernel/coverage/Makefile | 16 +++++++
kernel/{ => coverage}/gcov/Kconfig | 0
kernel/{ => coverage}/gcov/Makefile | 0
kernel/{ => coverage}/gcov/base.c | 0
kernel/{ => coverage}/gcov/clang.c | 2 +-
kernel/{ => coverage}/gcov/fs.c | 0
kernel/{ => coverage}/gcov/gcc_4_7.c | 0
kernel/{ => coverage}/gcov/gcc_base.c | 0
kernel/{ => coverage}/gcov/gcov.h | 0
kernel/{ => coverage}/kcov.c | 0
lib/Kconfig.debug | 59 +-----------------------
tools/unittests/test_cmatch.py | 2 +-
17 files changed, 92 insertions(+), 79 deletions(-)
create mode 100644 kernel/coverage/Kconfig
create mode 100644 kernel/coverage/Makefile
rename kernel/{ => coverage}/gcov/Kconfig (100%)
rename kernel/{ => coverage}/gcov/Makefile (100%)
rename kernel/{ => coverage}/gcov/base.c (100%)
rename kernel/{ => coverage}/gcov/clang.c (99%)
rename kernel/{ => coverage}/gcov/fs.c (100%)
rename kernel/{ => coverage}/gcov/gcc_4_7.c (100%)
rename kernel/{ => coverage}/gcov/gcc_base.c (100%)
rename kernel/{ => coverage}/gcov/gcov.h (100%)
rename kernel/{ => coverage}/kcov.c (100%)
diff --git a/MAINTAINERS b/MAINTAINERS
index 1ed6d81ed2f6b..2e0a98ceed3e7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11129,7 +11129,9 @@ GCOV BASED KERNEL PROFILING
M: Peter Oberparleiter <oberpar@linux.ibm.com>
S: Maintained
F: Documentation/dev-tools/gcov.rst
-F: kernel/gcov/
+F: kernel/coverage/Kconfig
+F: kernel/coverage/Makefile
+F: kernel/coverage/gcov/
GDB KERNEL DEBUGGING HELPER SCRIPTS
M: Jan Kiszka <jan.kiszka@siemens.com>
@@ -14350,7 +14352,9 @@ B: https://bugzilla.kernel.org/buglist.cgi?component=Sanitizers&product=Memory%2
F: Documentation/dev-tools/kcov.rst
F: include/linux/kcov.h
F: include/uapi/linux/kcov.h
-F: kernel/kcov.c
+F: kernel/coverage/Kconfig
+F: kernel/coverage/Makefile
+F: kernel/coverage/kcov.c
F: scripts/Makefile.kcov
KCSAN
diff --git a/arch/Kconfig b/arch/Kconfig
index 50601c0301e84..f4b24649f039c 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1777,8 +1777,6 @@ config ARCH_VMLINUX_NEEDS_RELOCS
config HAVE_GENERIC_TIF_BITS
bool
-source "kernel/gcov/Kconfig"
-
source "scripts/gcc-plugins/Kconfig"
config FUNCTION_ALIGNMENT_4B
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1c93da75226e3..aa71fe45a6ae1 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1536,7 +1536,7 @@ struct task_struct {
#endif /* CONFIG_TRACING */
#ifdef CONFIG_KCOV
- /* See kernel/kcov.c for more details. */
+ /* See kernel/coverage/kcov.c for more details. */
/* Coverage collection mode enabled for this task (0 if disabled): */
unsigned int kcov_mode;
diff --git a/kernel/Makefile b/kernel/Makefile
index 4ff92e24680c5..50bf37a26bae3 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -35,18 +35,6 @@ KCSAN_SANITIZE_softirq.o = n
# and produce insane amounts of uninteresting coverage.
KCOV_INSTRUMENT_extable.o := n
KCOV_INSTRUMENT_stacktrace.o := n
-# Don't self-instrument.
-KCOV_INSTRUMENT_kcov.o := n
-# If sanitizers detect any issues in kcov, it may lead to recursion
-# via printk, etc.
-KASAN_SANITIZE_kcov.o := n
-KCSAN_SANITIZE_kcov.o := n
-UBSAN_SANITIZE_kcov.o := n
-KMSAN_SANITIZE_kcov.o := n
-
-CONTEXT_ANALYSIS_kcov.o := y
-CFLAGS_kcov.o := $(call cc-option, -fno-conserve-stack) -fno-stack-protector
-
obj-y += sched/
obj-y += locking/
obj-y += power/
@@ -96,8 +84,7 @@ obj-$(CONFIG_IKHEADERS) += kheaders.o
obj-$(CONFIG_SMP) += stop_machine.o
obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
obj-$(CONFIG_AUDITSYSCALL) += auditsc.o audit_watch.o audit_fsnotify.o audit_tree.o
-obj-$(CONFIG_GCOV_KERNEL) += gcov/
-obj-$(CONFIG_KCOV) += kcov.o
+obj-y += coverage/
obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_FAIL_FUNCTION) += fail_function.o
obj-$(CONFIG_KGDB) += debug/
diff --git a/kernel/coverage/Kconfig b/kernel/coverage/Kconfig
new file mode 100644
index 0000000000000..dd90b6a61ae65
--- /dev/null
+++ b/kernel/coverage/Kconfig
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "Code coverage"
+
+source "kernel/coverage/gcov/Kconfig"
+
+config ARCH_HAS_KCOV
+ bool
+ help
+ An architecture should select this when it can successfully
+ build and run with CONFIG_KCOV. This typically requires
+ disabling instrumentation for some early boot code.
+
+config KCOV
+ bool "Code coverage for fuzzing"
+ depends on ARCH_HAS_KCOV
+ depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
+ GCC_VERSION >= 120000 || CC_IS_CLANG
+ select DEBUG_FS
+ select OBJTOOL if HAVE_NOINSTR_HACK
+ help
+ KCOV exposes kernel code coverage information in a form suitable
+ for coverage-guided fuzzing (randomized testing).
+
+ For more details, see Documentation/dev-tools/kcov.rst.
+
+config KCOV_ENABLE_COMPARISONS
+ bool "Enable comparison operands collection by KCOV"
+ depends on KCOV
+ depends on $(cc-option,-fsanitize-coverage=trace-cmp)
+ help
+ KCOV also exposes operands of every comparison in the instrumented
+ code along with operand sizes and PCs of the comparison instructions.
+ These operands can be used by fuzzing engines to improve the quality
+ of fuzzing coverage.
+
+config KCOV_INSTRUMENT_ALL
+ bool "Instrument all code by default"
+ depends on KCOV
+ default y
+ help
+ If you are doing generic system call fuzzing (like e.g. syzkaller),
+ then you will want to instrument the whole kernel and you should
+ say y here. If you are doing more targeted fuzzing (like e.g.
+ filesystem fuzzing with AFL) then you will want to enable coverage
+ for more specific subsets of files, and should say n here.
+
+config KCOV_IRQ_AREA_SIZE
+ hex "Size of interrupt coverage collection area in words"
+ depends on KCOV
+ range 0x80 0x1000000
+ default 0x40000
+ help
+ KCOV uses preallocated areas to collect coverage from soft
+ interrupts. This specifies the size of those areas in the
+ number of unsigned long words.
+
+config KCOV_SELFTEST
+ bool "Perform short selftests on boot"
+ depends on KCOV
+ help
+ Run short KCOV coverage collection selftests on boot.
+ On test failure, causes the kernel to panic. Recommended to be
+ enabled, ensuring critical functionality works as intended.
+
+endmenu
diff --git a/kernel/coverage/Makefile b/kernel/coverage/Makefile
new file mode 100644
index 0000000000000..a4cd8cc18d9bc
--- /dev/null
+++ b/kernel/coverage/Makefile
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_GCOV_KERNEL) += gcov/
+obj-$(CONFIG_KCOV) += kcov.o
+
+# Don't self-instrument.
+KCOV_INSTRUMENT_kcov.o := n
+# If sanitizers detect any issues in kcov, it may lead to recursion
+# via printk, etc.
+KASAN_SANITIZE_kcov.o := n
+KCSAN_SANITIZE_kcov.o := n
+UBSAN_SANITIZE_kcov.o := n
+KMSAN_SANITIZE_kcov.o := n
+
+CONTEXT_ANALYSIS_kcov.o := y
+CFLAGS_kcov.o := $(call cc-option, -fno-conserve-stack) -fno-stack-protector
diff --git a/kernel/gcov/Kconfig b/kernel/coverage/gcov/Kconfig
similarity index 100%
rename from kernel/gcov/Kconfig
rename to kernel/coverage/gcov/Kconfig
diff --git a/kernel/gcov/Makefile b/kernel/coverage/gcov/Makefile
similarity index 100%
rename from kernel/gcov/Makefile
rename to kernel/coverage/gcov/Makefile
diff --git a/kernel/gcov/base.c b/kernel/coverage/gcov/base.c
similarity index 100%
rename from kernel/gcov/base.c
rename to kernel/coverage/gcov/base.c
diff --git a/kernel/gcov/clang.c b/kernel/coverage/gcov/clang.c
similarity index 99%
rename from kernel/gcov/clang.c
rename to kernel/coverage/gcov/clang.c
index fd98ced0e51d2..e979e8983dce8 100644
--- a/kernel/gcov/clang.c
+++ b/kernel/coverage/gcov/clang.c
@@ -1,7 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2019 Google, Inc.
- * modified from kernel/gcov/gcc_4_7.c
+ * modified from kernel/coverage/gcov/gcc_4_7.c
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
diff --git a/kernel/gcov/fs.c b/kernel/coverage/gcov/fs.c
similarity index 100%
rename from kernel/gcov/fs.c
rename to kernel/coverage/gcov/fs.c
diff --git a/kernel/gcov/gcc_4_7.c b/kernel/coverage/gcov/gcc_4_7.c
similarity index 100%
rename from kernel/gcov/gcc_4_7.c
rename to kernel/coverage/gcov/gcc_4_7.c
diff --git a/kernel/gcov/gcc_base.c b/kernel/coverage/gcov/gcc_base.c
similarity index 100%
rename from kernel/gcov/gcc_base.c
rename to kernel/coverage/gcov/gcc_base.c
diff --git a/kernel/gcov/gcov.h b/kernel/coverage/gcov/gcov.h
similarity index 100%
rename from kernel/gcov/gcov.h
rename to kernel/coverage/gcov/gcov.h
diff --git a/kernel/kcov.c b/kernel/coverage/kcov.c
similarity index 100%
rename from kernel/kcov.c
rename to kernel/coverage/kcov.c
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 6759087154edd..41a5925e4568b 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2192,64 +2192,7 @@ config FAULT_INJECTION_STACKTRACE_FILTER
help
Provide stacktrace filter for fault-injection capabilities
-config ARCH_HAS_KCOV
- bool
- help
- An architecture should select this when it can successfully
- build and run with CONFIG_KCOV. This typically requires
- disabling instrumentation for some early boot code.
-
-config KCOV
- bool "Code coverage for fuzzing"
- depends on ARCH_HAS_KCOV
- depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
- GCC_VERSION >= 120000 || CC_IS_CLANG
- select DEBUG_FS
- select OBJTOOL if HAVE_NOINSTR_HACK
- help
- KCOV exposes kernel code coverage information in a form suitable
- for coverage-guided fuzzing (randomized testing).
-
- For more details, see Documentation/dev-tools/kcov.rst.
-
-config KCOV_ENABLE_COMPARISONS
- bool "Enable comparison operands collection by KCOV"
- depends on KCOV
- depends on $(cc-option,-fsanitize-coverage=trace-cmp)
- help
- KCOV also exposes operands of every comparison in the instrumented
- code along with operand sizes and PCs of the comparison instructions.
- These operands can be used by fuzzing engines to improve the quality
- of fuzzing coverage.
-
-config KCOV_INSTRUMENT_ALL
- bool "Instrument all code by default"
- depends on KCOV
- default y
- help
- If you are doing generic system call fuzzing (like e.g. syzkaller),
- then you will want to instrument the whole kernel and you should
- say y here. If you are doing more targeted fuzzing (like e.g.
- filesystem fuzzing with AFL) then you will want to enable coverage
- for more specific subsets of files, and should say n here.
-
-config KCOV_IRQ_AREA_SIZE
- hex "Size of interrupt coverage collection area in words"
- depends on KCOV
- range 0x80 0x1000000
- default 0x40000
- help
- KCOV uses preallocated areas to collect coverage from soft
- interrupts. This specifies the size of those areas in the
- number of unsigned long words.
-
-config KCOV_SELFTEST
- bool "Perform short selftests on boot"
- depends on KCOV
- help
- Run short KCOV coverage collection selftests on boot.
- On test failure, causes the kernel to panic. Recommended to be
- enabled, ensuring critical functionality works as intended.
+source "kernel/coverage/Kconfig"
menuconfig RUNTIME_TESTING_MENU
bool "Runtime Testing"
diff --git a/tools/unittests/test_cmatch.py b/tools/unittests/test_cmatch.py
index 109141cd2ab8d..06f9c61572e2e 100755
--- a/tools/unittests/test_cmatch.py
+++ b/tools/unittests/test_cmatch.py
@@ -706,7 +706,7 @@ class TestSubWithLocalXforms(TestCaseDiff):
def test_struct_kcov(self):
"""
- Test a struct from kernel/kcov.c.
+ Test a struct from kernel/coverage/kcov.c.
"""
line = """
struct kcov {
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [RFC PATCH 02/20] kbuild: unify static coverage instrumentation as COVERAGE_PROFILE
2026-10-28 11:59 [RFC PATCH 00/20] Unify code coverage and add Clang source-based coverage with MC/DC Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 01/20] coverage: move gcov and kcov under kernel/coverage/ Sasha Levin
@ 2026-10-28 11:59 ` Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 20/20] Documentation: dev-tools: document the common code coverage interface Sasha Levin
2 siblings, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2026-10-28 11:59 UTC (permalink / raw)
To: linux-kernel
Cc: Alexander Potapenko, Andrew Morton, Andrey Konovalov,
Chuck Wolber, Dmitry Vyukov, Jonathan Corbet, kasan-dev,
linux-doc, linux-kbuild, Marco Elver, Masami Hiramatsu,
Nathan Chancellor, Nicolas Schier, Peter Oberparleiter,
Peter Zijlstra, Randy Dunlap, Shuah Khan, Thomas Gleixner,
workflows
The gcov plumbing is written for a single coverage implementation: the
per-object and per-directory knobs are called GCOV_PROFILE, the flags
are CFLAGS_GCOV, and every dependency on "coverage instrumentation is
present" spells it as GCOV_KERNEL. Make this generic so that further
coverage implementations can share it instead of growing parallel
copies:
- The coverage implementation becomes a choice ("Code coverage
measurement"), with gcov as its only member besides "None" for now.
COVERAGE_KERNEL is set whenever one is selected. allyesconfig and
allmodconfig keep selecting gcov through a COMPILE_TEST default.
- GCOV_PROFILE_ALL becomes COVERAGE_PROFILE_ALL. The old symbol is
kept as a transitional one so that existing configurations keep
profiling the entire kernel.
- GCOV_PROFILE[_obj.o] becomes COVERAGE_PROFILE[_obj.o] tree-wide,
with unchanged precedence (object, then directory, then
COVERAGE_PROFILE_ALL). Out-of-tree modules that use GCOV_PROFILE
need the same rename.
- The compiler flags move from the top-level Makefile to
scripts/Makefile.gcov, which sets CFLAGS_COVERAGE and is only
included when gcov is enabled. This also stops running the
-fprofile-update=prefer-atomic probe on every GCC build.
- The per-subsystem opt-ins GCOV_PROFILE_{NETFILTER,IPSET,IPVS,RDS,
AMDGPU,URING,FTRACE} become COVERAGE_PROFILE_*, again with the old
names kept as transitional symbols. The rds selftest is updated.
- Dependencies that are about instrumented code rather than about
gcov (LTO, the KCFI integer normalization workaround, the longest
symbol KUnit test, the per-subsystem opt-ins and objtool's
--no-unreachable) now use COVERAGE_KERNEL.
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
Documentation/dev-tools/gcov.rst | 18 +--
.../translations/zh_CN/dev-tools/gcov.rst | 16 +--
.../translations/zh_TW/dev-tools/gcov.rst | 16 +--
MAINTAINERS | 1 +
Makefile | 22 +---
arch/Kconfig | 6 +-
arch/alpha/boot/compressed/Makefile | 2 +-
arch/parisc/kernel/vdso32/Makefile | 2 +-
arch/parisc/kernel/vdso64/Makefile | 2 +-
arch/powerpc/kernel/Makefile | 6 +-
arch/powerpc/kernel/trace/Makefile | 4 +-
arch/powerpc/kexec/Makefile | 2 +-
arch/powerpc/xmon/Makefile | 2 +-
arch/s390/boot/Makefile | 2 +-
arch/s390/kernel/Makefile | 2 +-
arch/sh/mm/Makefile | 2 +-
arch/x86/coco/sev/Makefile | 2 +-
arch/x86/platform/efi/Makefile | 2 +-
arch/xtensa/boot/lib/Makefile | 2 +-
drivers/gpu/drm/amd/amdgpu/Kconfig | 12 +-
drivers/gpu/drm/amd/amdgpu/Makefile | 4 +-
.../gpu/drm/amd/display/amdgpu_dm/Makefile | 2 +-
drivers/gpu/drm/i915/Makefile | 2 +-
drivers/gpu/drm/xe/Makefile | 2 +-
drivers/s390/char/Makefile | 2 +-
init/Kconfig | 9 +-
io_uring/Makefile | 4 +-
kernel/coverage/Kconfig | 103 +++++++++++++++++-
kernel/coverage/gcov/Kconfig | 55 ----------
kernel/trace/Kconfig | 9 +-
kernel/trace/Makefile | 4 +-
lib/Kconfig.debug | 2 +-
lib/Makefile | 2 +-
lib/crypto/Makefile | 2 +-
net/bridge/Makefile | 8 +-
net/bridge/netfilter/Makefile | 4 +-
net/ipv4/Makefile | 4 +-
net/ipv4/netfilter/Makefile | 4 +-
net/ipv6/Makefile | 4 +-
net/ipv6/netfilter/Makefile | 4 +-
net/netfilter/Kconfig | 9 +-
net/netfilter/Makefile | 4 +-
net/netfilter/ipset/Kconfig | 9 +-
net/netfilter/ipset/Makefile | 4 +-
net/netfilter/ipvs/Kconfig | 9 +-
net/netfilter/ipvs/Makefile | 4 +-
net/rds/Kconfig | 9 +-
net/rds/Makefile | 4 +-
scripts/Makefile.gcov | 22 ++++
scripts/Makefile.lib | 14 +--
scripts/Makefile.modfinal | 2 +-
scripts/sbom/sbom/environment.py | 2 +-
tools/testing/selftests/net/rds/config.sh | 9 +-
tools/testing/selftests/net/rds/rds_run.sh | 8 +-
54 files changed, 259 insertions(+), 203 deletions(-)
delete mode 100644 kernel/coverage/gcov/Kconfig
create mode 100644 scripts/Makefile.gcov
diff --git a/Documentation/dev-tools/gcov.rst b/Documentation/dev-tools/gcov.rst
index 075df6a4598d8..b6910c3fc00dd 100644
--- a/Documentation/dev-tools/gcov.rst
+++ b/Documentation/dev-tools/gcov.rst
@@ -36,10 +36,10 @@ Configure the kernel with::
and to get coverage data for the entire kernel::
- CONFIG_GCOV_PROFILE_ALL=y
+ CONFIG_COVERAGE_PROFILE_ALL=y
Note that kernels compiled with profiling flags will be significantly
-larger and run slower. Also CONFIG_GCOV_PROFILE_ALL may not be supported
+larger and run slower. Also CONFIG_COVERAGE_PROFILE_ALL may not be supported
on all architectures.
Profiling data will only become accessible once debugfs has been
@@ -56,20 +56,20 @@ similar to the following to the respective kernel Makefile:
- For a single file (e.g. main.o)::
- GCOV_PROFILE_main.o := y
+ COVERAGE_PROFILE_main.o := y
- For all files in one directory::
- GCOV_PROFILE := y
+ COVERAGE_PROFILE := y
-To exclude files from being profiled even when CONFIG_GCOV_PROFILE_ALL
+To exclude files from being profiled even when CONFIG_COVERAGE_PROFILE_ALL
is specified, use::
- GCOV_PROFILE_main.o := n
+ COVERAGE_PROFILE_main.o := n
and::
- GCOV_PROFILE := n
+ COVERAGE_PROFILE := n
Only files which are linked to the main kernel image or are compiled as
kernel modules are supported by this mechanism.
@@ -80,7 +80,7 @@ Module specific configs
Gcov kernel configs for specific modules are described below:
-CONFIG_GCOV_PROFILE_RDS:
+CONFIG_COVERAGE_PROFILE_RDS:
Enables GCOV profiling on RDS for checking which functions or
lines are executed. This config is used by the rds selftest to
generate coverage reports. If left unset the report is omitted.
@@ -207,7 +207,7 @@ Cause
Solution
Exclude affected source files from profiling by specifying
- ``GCOV_PROFILE := n`` or ``GCOV_PROFILE_basename.o := n`` in the
+ ``COVERAGE_PROFILE := n`` or ``COVERAGE_PROFILE_basename.o := n`` in the
corresponding Makefile.
Problem
diff --git a/Documentation/translations/zh_CN/dev-tools/gcov.rst b/Documentation/translations/zh_CN/dev-tools/gcov.rst
index ea8f94852f417..47064c4d5ff98 100644
--- a/Documentation/translations/zh_CN/dev-tools/gcov.rst
+++ b/Documentation/translations/zh_CN/dev-tools/gcov.rst
@@ -39,7 +39,7 @@ gcov分析核心支持在Linux内核中启用GCC的覆盖率测试工具 gcov_
获取整个内核的覆盖率数据，还需要打开::
- CONFIG_GCOV_PROFILE_ALL=y
+ CONFIG_COVERAGE_PROFILE_ALL=y
需要注意的是，整个内核开启覆盖率统计会造成内核镜像文件尺寸的增大，
同时内核运行也会变慢一些。
@@ -58,20 +58,20 @@ gcov分析核心支持在Linux内核中启用GCC的覆盖率测试工具 gcov_
- 单独统计单个文件（例如main.o）::
- GCOV_PROFILE_main.o := y
+ COVERAGE_PROFILE_main.o := y
- 单独统计某一个路径::
- GCOV_PROFILE := y
+ COVERAGE_PROFILE := y
-如果要在整个内核的覆盖率统计（开启CONFIG_GCOV_PROFILE_ALL）中单独排除
+如果要在整个内核的覆盖率统计（开启CONFIG_COVERAGE_PROFILE_ALL）中单独排除
某一个文件或者路径，可以使用如下的方法::
- GCOV_PROFILE_main.o := n
+ COVERAGE_PROFILE_main.o := n
和::
- GCOV_PROFILE := n
+ COVERAGE_PROFILE := n
此机制仅支持链接到内核镜像或编译为内核模块的文件。
@@ -186,8 +186,8 @@ kconfig会根据编译工具链的检查自动选择合适的gcov格式。
分析标志指定在了源文件但是没有链接到主内核，或者客制化了链接程序
解决方法
- 通过在相应的Makefile中使用 ``GCOV_PROFILE := n``
- 或者 ``GCOV_PROFILE_basename.o := n`` 来将链接报错的文件排除掉
+ 通过在相应的Makefile中使用 ``COVERAGE_PROFILE := n``
+ 或者 ``COVERAGE_PROFILE_basename.o := n`` 来将链接报错的文件排除掉
可能出现的问题2
从sysfs复制的文件显示为空或不完整
diff --git a/Documentation/translations/zh_TW/dev-tools/gcov.rst b/Documentation/translations/zh_TW/dev-tools/gcov.rst
index 39ac3fff44cdb..7d36a5460ce12 100644
--- a/Documentation/translations/zh_TW/dev-tools/gcov.rst
+++ b/Documentation/translations/zh_TW/dev-tools/gcov.rst
@@ -39,7 +39,7 @@ gcov分析核心支持在Linux內核中啓用GCC的覆蓋率測試工具 gcov_
獲取整個內核的覆蓋率數據，還需要打開::
- CONFIG_GCOV_PROFILE_ALL=y
+ CONFIG_COVERAGE_PROFILE_ALL=y
需要注意的是，整個內核開啓覆蓋率統計會造成內核鏡像文件尺寸的增大，
同時內核運行也會變慢一些。
@@ -58,20 +58,20 @@ gcov分析核心支持在Linux內核中啓用GCC的覆蓋率測試工具 gcov_
- 單獨統計單個文件（例如main.o）::
- GCOV_PROFILE_main.o := y
+ COVERAGE_PROFILE_main.o := y
- 單獨統計某一個路徑::
- GCOV_PROFILE := y
+ COVERAGE_PROFILE := y
-如果要在整個內核的覆蓋率統計（開啓CONFIG_GCOV_PROFILE_ALL）中單獨排除
+如果要在整個內核的覆蓋率統計（開啓CONFIG_COVERAGE_PROFILE_ALL）中單獨排除
某一個文件或者路徑，可以使用如下的方法::
- GCOV_PROFILE_main.o := n
+ COVERAGE_PROFILE_main.o := n
和::
- GCOV_PROFILE := n
+ COVERAGE_PROFILE := n
此機制僅支持鏈接到內核鏡像或編譯爲內核模塊的文件。
@@ -186,8 +186,8 @@ kconfig會根據編譯工具鏈的檢查自動選擇合適的gcov格式。
分析標誌指定在了源文件但是沒有鏈接到主內核，或者客製化了鏈接程序
解決方法
- 通過在相應的Makefile中使用 ``GCOV_PROFILE := n``
- 或者 ``GCOV_PROFILE_basename.o := n`` 來將鏈接報錯的文件排除掉
+ 通過在相應的Makefile中使用 ``COVERAGE_PROFILE := n``
+ 或者 ``COVERAGE_PROFILE_basename.o := n`` 來將鏈接報錯的文件排除掉
可能出現的問題2
從sysfs複製的文件顯示爲空或不完整
diff --git a/MAINTAINERS b/MAINTAINERS
index 2e0a98ceed3e7..3cedde9ecaac3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11132,6 +11132,7 @@ F: Documentation/dev-tools/gcov.rst
F: kernel/coverage/Kconfig
F: kernel/coverage/Makefile
F: kernel/coverage/gcov/
+F: scripts/Makefile.gcov
GDB KERNEL DEBUGGING HELPER SCRIPTS
M: Jan Kiszka <jan.kiszka@siemens.com>
diff --git a/Makefile b/Makefile
index 77caa3b0e9925..cb34eb7e1b790 100644
--- a/Makefile
+++ b/Makefile
@@ -1183,27 +1183,6 @@ endif
# Ensure compilers do not transform certain loops into calls to wcslen()
KBUILD_CFLAGS += -fno-builtin-wcslen
-CFLAGS_GCOV := -fprofile-arcs -ftest-coverage
-ifdef CONFIG_CC_IS_GCC
-CFLAGS_GCOV += -fno-tree-loop-im
-# Use atomic counter updates to avoid concurrent-access crashes in GCOV.
-# Only enable if -fprofile-update=prefer-atomic does not introduce new
-# undefined symbols (e.g. libatomic calls that the kernel cannot link).
-CFLAGS_GCOV += $(call try-run,\
- echo 'long long x; void f(void){x++;}' | \
- $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -w -fprofile-arcs \
- -ftest-coverage -x c - -c -o "$$TMP.base" && \
- echo 'long long x; void f(void){x++;}' | \
- $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -w -fprofile-arcs \
- -ftest-coverage -fprofile-update=prefer-atomic \
- -x c - -c -o "$$TMP" && \
- $(NM) "$$TMP.base" | grep ' U ' > "$$TMP.ubase" || true ; \
- $(NM) "$$TMP" | grep ' U ' > "$$TMP.utest" || true ; \
- cmp -s "$$TMP.ubase" "$$TMP.utest",\
- -fprofile-update=prefer-atomic)
-endif
-export CFLAGS_GCOV
-
# change __FILE__ to the relative path to the source directory
ifdef building_out_of_srctree
CFLAGS_PREFIX_MAP := -fmacro-prefix-map=$(srcroot)/=
@@ -1223,6 +1202,7 @@ include-$(CONFIG_KASAN) += scripts/Makefile.kasan
include-$(CONFIG_KCSAN) += scripts/Makefile.kcsan
include-$(CONFIG_KMSAN) += scripts/Makefile.kmsan
include-$(CONFIG_UBSAN) += scripts/Makefile.ubsan
+include-$(CONFIG_GCOV_KERNEL) += scripts/Makefile.gcov
include-$(CONFIG_KCOV) += scripts/Makefile.kcov
include-$(CONFIG_RANDSTRUCT) += scripts/Makefile.randstruct
include-$(CONFIG_KSTACK_ERASE) += scripts/Makefile.kstack_erase
diff --git a/arch/Kconfig b/arch/Kconfig
index f4b24649f039c..5fc66af346eda 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -819,7 +819,7 @@ config HAS_LTO_CLANG
depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
depends on ARCH_SUPPORTS_LTO_CLANG
depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
- depends on !GCOV_KERNEL
+ depends on !COVERAGE_KERNEL
help
The compiler and Kconfig options support building with Clang's
LTO.
@@ -985,7 +985,7 @@ config HAVE_CFI_ICALL_NORMALIZE_INTEGERS
def_bool y
depends on $(cc-option,-fsanitize=kcfi -fsanitize-cfi-icall-experimental-normalize-integers)
# With GCOV/KASAN we need this fix: https://github.com/llvm/llvm-project/pull/104826
- depends on CLANG_VERSION >= 190103 || (!GCOV_KERNEL && !KASAN_GENERIC && !KASAN_SW_TAGS)
+ depends on CLANG_VERSION >= 190103 || (!COVERAGE_KERNEL && !KASAN_GENERIC && !KASAN_SW_TAGS)
config HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC
def_bool y
@@ -993,7 +993,7 @@ config HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC
depends on ARM64 || X86_64
# With GCOV/KASAN we need this fix: https://github.com/rust-lang/rust/pull/129373
depends on RUSTC_LLVM_VERSION >= 190103 || \
- (!GCOV_KERNEL && !KASAN_GENERIC && !KASAN_SW_TAGS)
+ (!COVERAGE_KERNEL && !KASAN_GENERIC && !KASAN_SW_TAGS)
config CFI_PERMISSIVE
bool "Use CFI in permissive mode"
diff --git a/arch/alpha/boot/compressed/Makefile b/arch/alpha/boot/compressed/Makefile
index eb930f01b4be4..26c3f62075a90 100644
--- a/arch/alpha/boot/compressed/Makefile
+++ b/arch/alpha/boot/compressed/Makefile
@@ -28,7 +28,7 @@ KBUILD_AFLAGS := -D__ASSEMBLY__ $(KBUILD_CFLAGS)
# built with the kernel's instrumentation and -mcpu=, so build private
# copies of the library routines the stub needs instead of linking it.
UBSAN_SANITIZE := n
-GCOV_PROFILE := n
+COVERAGE_PROFILE := n
$(obj)/memcpy.o: $(srctree)/arch/alpha/lib/memcpy.c FORCE
$(call if_changed_dep,cc_o_c)
diff --git a/arch/parisc/kernel/vdso32/Makefile b/arch/parisc/kernel/vdso32/Makefile
index 4ee8d17da229b..e884795da088d 100644
--- a/arch/parisc/kernel/vdso32/Makefile
+++ b/arch/parisc/kernel/vdso32/Makefile
@@ -4,7 +4,7 @@ include $(srctree)/lib/vdso/Makefile.include
KCOV_INSTRUMENT := n
# Disable gcov profiling, ubsan and kasan for VDSO code
-GCOV_PROFILE := n
+COVERAGE_PROFILE := n
UBSAN_SANITIZE := n
KASAN_SANITIZE := n
KCSAN_SANITIZE := n
diff --git a/arch/parisc/kernel/vdso64/Makefile b/arch/parisc/kernel/vdso64/Makefile
index c63f4069170f4..42b8b0d167e1a 100644
--- a/arch/parisc/kernel/vdso64/Makefile
+++ b/arch/parisc/kernel/vdso64/Makefile
@@ -4,7 +4,7 @@ include $(srctree)/lib/vdso/Makefile.include
KCOV_INSTRUMENT := n
# Disable gcov profiling, ubsan and kasan for VDSO code
-GCOV_PROFILE := n
+COVERAGE_PROFILE := n
UBSAN_SANITIZE := n
KASAN_SANITIZE := n
KCSAN_SANITIZE := n
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 7bf6b16b2d93c..a38e82894130c 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -169,15 +169,15 @@ obj-$(CONFIG_PPC_SECURE_BOOT) += secure_boot.o ima_arch.o secvar-ops.o
obj-$(CONFIG_PPC_SECVAR_SYSFS) += secvar-sysfs.o
# Disable GCOV, KCOV & sanitizers in odd or sensitive code
-GCOV_PROFILE_prom_init.o := n
+COVERAGE_PROFILE_prom_init.o := n
KCOV_INSTRUMENT_prom_init.o := n
KCSAN_SANITIZE_prom_init.o := n
UBSAN_SANITIZE_prom_init.o := n
-GCOV_PROFILE_kprobes.o := n
+COVERAGE_PROFILE_kprobes.o := n
KCOV_INSTRUMENT_kprobes.o := n
KCSAN_SANITIZE_kprobes.o := n
UBSAN_SANITIZE_kprobes.o := n
-GCOV_PROFILE_kprobes-ftrace.o := n
+COVERAGE_PROFILE_kprobes-ftrace.o := n
KCOV_INSTRUMENT_kprobes-ftrace.o := n
KCSAN_SANITIZE_kprobes-ftrace.o := n
UBSAN_SANITIZE_kprobes-ftrace.o := n
diff --git a/arch/powerpc/kernel/trace/Makefile b/arch/powerpc/kernel/trace/Makefile
index d6c3885453bda..e5d3b15f82018 100644
--- a/arch/powerpc/kernel/trace/Makefile
+++ b/arch/powerpc/kernel/trace/Makefile
@@ -24,11 +24,11 @@ obj-$(CONFIG_PPC64) += $(obj64-y)
obj-$(CONFIG_PPC32) += $(obj32-y)
# Disable GCOV, KCOV & sanitizers in odd or sensitive code
-GCOV_PROFILE_ftrace.o := n
+COVERAGE_PROFILE_ftrace.o := n
KCOV_INSTRUMENT_ftrace.o := n
KCSAN_SANITIZE_ftrace.o := n
UBSAN_SANITIZE_ftrace.o := n
-GCOV_PROFILE_ftrace_64_pg.o := n
+COVERAGE_PROFILE_ftrace_64_pg.o := n
KCOV_INSTRUMENT_ftrace_64_pg.o := n
KCSAN_SANITIZE_ftrace_64_pg.o := n
UBSAN_SANITIZE_ftrace_64_pg.o := n
diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
index ec7a0eed75dc5..d9e7a387d058c 100644
--- a/arch/powerpc/kexec/Makefile
+++ b/arch/powerpc/kexec/Makefile
@@ -12,7 +12,7 @@ obj-$(CONFIG_VMCORE_INFO) += vmcore_info.o
obj-$(CONFIG_CRASH_DUMP) += crash.o
# Disable GCOV, KCOV & sanitizers in odd or sensitive code
-GCOV_PROFILE_core_$(BITS).o := n
+COVERAGE_PROFILE_core_$(BITS).o := n
KCOV_INSTRUMENT_core_$(BITS).o := n
UBSAN_SANITIZE_core_$(BITS).o := n
KASAN_SANITIZE_core.o := n
diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile
index d74b147126b7a..b2ad38d5ec8d8 100644
--- a/arch/powerpc/xmon/Makefile
+++ b/arch/powerpc/xmon/Makefile
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
# Makefile for xmon
-GCOV_PROFILE := n
+COVERAGE_PROFILE := n
KCOV_INSTRUMENT := n
UBSAN_SANITIZE := n
KASAN_SANITIZE := n
diff --git a/arch/s390/boot/Makefile b/arch/s390/boot/Makefile
index e8e43ae80dd52..8dea682626462 100644
--- a/arch/s390/boot/Makefile
+++ b/arch/s390/boot/Makefile
@@ -5,7 +5,7 @@
# Tooling runtimes are unavailable and cannot be linked for early boot code
KCOV_INSTRUMENT := n
-GCOV_PROFILE := n
+COVERAGE_PROFILE := n
UBSAN_SANITIZE := n
KASAN_SANITIZE := n
KCSAN_SANITIZE := n
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index f84b8fb41331b..8642db1c1f234 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -18,7 +18,7 @@ CFLAGS_REMOVE_unwind_bc.o = $(CC_FLAGS_FTRACE)
endif
-GCOV_PROFILE_early.o := n
+COVERAGE_PROFILE_early.o := n
KCOV_INSTRUMENT_early.o := n
UBSAN_SANITIZE_early.o := n
KASAN_SANITIZE_ipl.o := n
diff --git a/arch/sh/mm/Makefile b/arch/sh/mm/Makefile
index f69ddc70b1465..8752d3a0c1ea5 100644
--- a/arch/sh/mm/Makefile
+++ b/arch/sh/mm/Makefile
@@ -42,4 +42,4 @@ obj-$(CONFIG_IOREMAP_FIXED) += ioremap_fixed.o
obj-$(CONFIG_UNCACHED_MAPPING) += uncached.o
obj-$(CONFIG_HAVE_SRAM_POOL) += sram.o
-GCOV_PROFILE_pmb.o := n
+COVERAGE_PROFILE_pmb.o := n
diff --git a/arch/x86/coco/sev/Makefile b/arch/x86/coco/sev/Makefile
index 3111a2ee67221..be4785d766ec1 100644
--- a/arch/x86/coco/sev/Makefile
+++ b/arch/x86/coco/sev/Makefile
@@ -9,4 +9,4 @@ UBSAN_SANITIZE_noinstr.o := n
KASAN_SANITIZE_noinstr.o := n
KCSAN_SANITIZE_noinstr.o := n
-GCOV_PROFILE_noinstr.o := n
+COVERAGE_PROFILE_noinstr.o := n
diff --git a/arch/x86/platform/efi/Makefile b/arch/x86/platform/efi/Makefile
index 500cab4a7f7c6..b0b891f776bfb 100644
--- a/arch/x86/platform/efi/Makefile
+++ b/arch/x86/platform/efi/Makefile
@@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
KASAN_SANITIZE := n
-GCOV_PROFILE := n
+COVERAGE_PROFILE := n
obj-$(CONFIG_EFI) += memmap.o quirks.o efi.o efi_$(BITS).o \
efi_stub_$(BITS).o
diff --git a/arch/xtensa/boot/lib/Makefile b/arch/xtensa/boot/lib/Makefile
index 0378a22a08e33..b42c7fab56a5e 100644
--- a/arch/xtensa/boot/lib/Makefile
+++ b/arch/xtensa/boot/lib/Makefile
@@ -18,7 +18,7 @@ endif
KASAN_SANITIZE := n
KCSAN_SANITIZE := n
KCOV_INSTRUMENT := n
-GCOV_PROFILE := n
+COVERAGE_PROFILE := n
CFLAGS_REMOVE_inflate.o += -fstack-protector -fstack-protector-strong
CFLAGS_REMOVE_zmem.o += -fstack-protector -fstack-protector-strong
diff --git a/drivers/gpu/drm/amd/amdgpu/Kconfig b/drivers/gpu/drm/amd/amdgpu/Kconfig
index 12e4a41bf1f04..aaebfdfc31a12 100644
--- a/drivers/gpu/drm/amd/amdgpu/Kconfig
+++ b/drivers/gpu/drm/amd/amdgpu/Kconfig
@@ -103,16 +103,16 @@ config DRM_AMDGPU_WERROR
Only enable this if you are warning code for amdgpu.ko.
-config GCOV_PROFILE_AMDGPU
- bool "Enable GCOV profiling on amdgpu"
+config COVERAGE_PROFILE_AMDGPU
+ bool "Enable code coverage profiling on amdgpu"
depends on DRM_AMDGPU
- depends on GCOV_KERNEL
- default n
+ depends on COVERAGE_KERNEL
+ default GCOV_PROFILE_AMDGPU
help
- Enable GCOV profiling on the amdgpu driver for checking which
+ Enable code coverage profiling on the amdgpu driver for checking which
functions/lines are executed during testing. This adds compiler
instrumentation flags to all amdgpu source files, producing
- .gcda/.gcno coverage data accessible via debugfs.
+ coverage data accessible via debugfs.
This increases the amdgpu module size by ~50% and adds ~2-5%
runtime overhead on GPU submission paths.
diff --git a/drivers/gpu/drm/amd/amdgpu/Makefile b/drivers/gpu/drm/amd/amdgpu/Makefile
index 55b5d11f19382..dc408e24f5bc6 100644
--- a/drivers/gpu/drm/amd/amdgpu/Makefile
+++ b/drivers/gpu/drm/amd/amdgpu/Makefile
@@ -27,8 +27,8 @@ FULL_AMD_PATH=$(src)/..
DISPLAY_FOLDER_NAME=display
FULL_AMD_DISPLAY_PATH = $(FULL_AMD_PATH)/$(DISPLAY_FOLDER_NAME)
-ifdef CONFIG_GCOV_PROFILE_AMDGPU
-GCOV_PROFILE := y
+ifdef CONFIG_COVERAGE_PROFILE_AMDGPU
+COVERAGE_PROFILE := y
endif
ccflags-y := -I$(FULL_AMD_PATH)/include/asic_reg \
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/Makefile b/drivers/gpu/drm/amd/display/amdgpu_dm/Makefile
index d1faf2d8370ff..3cd62d0be68e7 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/Makefile
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/Makefile
@@ -71,5 +71,5 @@ ifneq ($(CONFIG_DRM_AMD_DC_KUNIT_TEST),)
obj-y += $(AMDDALPATH)/amdgpu_dm/tests/
# Enable gcov for amdgpu_dm KUnit builds
-GCOV_PROFILE := y
+COVERAGE_PROFILE := y
endif
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index d4e7764621e18..20675723fee4a 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -456,7 +456,7 @@ always-$(CONFIG_DRM_I915_WERROR) += \
$(shell cd $(src) && find * -name '*.h')))
quiet_cmd_hdrtest = HDRTEST $(patsubst %.hdrtest,%.h,$@)
- cmd_hdrtest = $(CC) $(filter-out $(CFLAGS_GCOV), $(c_flags)) -S -o /dev/null -x c /dev/null -include $<; \
+ cmd_hdrtest = $(CC) $(filter-out $(CFLAGS_COVERAGE), $(c_flags)) -S -o /dev/null -x c /dev/null -include $<; \
$(KERNELDOC) -none -Werror $<; touch $@
$(obj)/%.hdrtest: $(src)/%.h FORCE
diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
index 563c2f859361f..c0f4e684268cf 100644
--- a/drivers/gpu/drm/xe/Makefile
+++ b/drivers/gpu/drm/xe/Makefile
@@ -392,7 +392,7 @@ always-$(CONFIG_DRM_XE_WERROR) += \
$(patsubst %.h,%.hdrtest, $(shell cd $(src) && find * -name '*.h' $(hdrtest_find_args)))
quiet_cmd_hdrtest = HDRTEST $(patsubst %.hdrtest,%.h,$@)
- cmd_hdrtest = $(CC) $(filter-out $(CFLAGS_GCOV), $(c_flags)) -S -o /dev/null -x c /dev/null -include $< -include $<; \
+ cmd_hdrtest = $(CC) $(filter-out $(CFLAGS_COVERAGE), $(c_flags)) -S -o /dev/null -x c /dev/null -include $< -include $<; \
$(srctree)/scripts/kernel-doc -none -Werror $<; touch $@
$(obj)/%.hdrtest: $(src)/%.h FORCE
diff --git a/drivers/s390/char/Makefile b/drivers/s390/char/Makefile
index 0ad960d000a2f..0d4c144cbd994 100644
--- a/drivers/s390/char/Makefile
+++ b/drivers/s390/char/Makefile
@@ -10,7 +10,7 @@ ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_sclp_early_core.o = $(CC_FLAGS_FTRACE)
endif
-GCOV_PROFILE_sclp_early_core.o := n
+COVERAGE_PROFILE_sclp_early_core.o := n
KCOV_INSTRUMENT_sclp_early_core.o := n
UBSAN_SANITIZE_sclp_early_core.o := n
KASAN_SANITIZE_sclp_early_core.o := n
diff --git a/init/Kconfig b/init/Kconfig
index b31aa298c4fe5..9ec5def26d1b8 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1780,11 +1780,12 @@ config IO_URING
applications to submit and complete IO through submission and
completion rings that are shared between the kernel and application.
-config GCOV_PROFILE_URING
- bool "Enable GCOV profiling on the io_uring subsystem"
- depends on IO_URING && GCOV_KERNEL
+config COVERAGE_PROFILE_URING
+ bool "Enable code coverage profiling on the io_uring subsystem"
+ depends on IO_URING && COVERAGE_KERNEL
+ default GCOV_PROFILE_URING
help
- Enable GCOV profiling on the io_uring subsystem, to facilitate
+ Enable code coverage profiling on the io_uring subsystem, to facilitate
code coverage testing.
If unsure, say N.
diff --git a/io_uring/Makefile b/io_uring/Makefile
index 965bb60e9f7b1..cb27f1f8b59fb 100644
--- a/io_uring/Makefile
+++ b/io_uring/Makefile
@@ -2,8 +2,8 @@
#
# Makefile for io_uring
-ifdef CONFIG_GCOV_PROFILE_URING
-GCOV_PROFILE := y
+ifdef CONFIG_COVERAGE_PROFILE_URING
+COVERAGE_PROFILE := y
endif
obj-$(CONFIG_IO_URING) += io_uring.o opdef.o kbuf.o rsrc.o notif.o \
diff --git a/kernel/coverage/Kconfig b/kernel/coverage/Kconfig
index dd90b6a61ae65..62a6fa94bd308 100644
--- a/kernel/coverage/Kconfig
+++ b/kernel/coverage/Kconfig
@@ -1,7 +1,108 @@
# SPDX-License-Identifier: GPL-2.0-only
menu "Code coverage"
-source "kernel/coverage/gcov/Kconfig"
+config ARCH_HAS_GCOV_PROFILE_ALL
+ def_bool n
+
+choice
+ prompt "Code coverage measurement"
+ default GCOV_KERNEL if COMPILE_TEST
+ default COVERAGE_NONE
+ help
+ Instrument the kernel to measure which parts of it get executed.
+ Each mechanism produces data in the format of its toolchain, so
+ only one of them can be enabled at a time.
+
+ KCOV, which collects coverage for fuzzers, is configured
+ separately and can be combined with any of them.
+
+ The instrumentation of a single file or of all files in a
+ directory can be controlled from the respective Makefile:
+
+ For a single file (e.g. main.o):
+ COVERAGE_PROFILE_main.o := y
+
+ For all files in one directory:
+ COVERAGE_PROFILE := y
+
+ To exclude files from being profiled even when
+ CONFIG_COVERAGE_PROFILE_ALL is specified, use:
+
+ COVERAGE_PROFILE_main.o := n
+ and:
+ COVERAGE_PROFILE := n
+
+ Note that the debugfs filesystem has to be mounted to access
+ the coverage data.
+
+config COVERAGE_NONE
+ bool "None"
+
+config GCOV_KERNEL
+ bool "gcov-based kernel profiling"
+ depends on DEBUG_FS
+ depends on !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR
+ select CONSTRUCTORS
+ help
+ This option enables gcov-based code profiling (e.g. for code coverage
+ measurements), with GCC or Clang. The coverage data of the kernel
+ and its modules is exported in gcov's format in /sys/kernel/debug/gcov,
+ see Documentation/dev-tools/gcov.rst.
+
+endchoice
+
+config COVERAGE_KERNEL
+ def_bool GCOV_KERNEL
+
+config GCOV_PROFILE_ALL
+ bool
+ transitional
+ help
+ Transitional config for GCOV_PROFILE_ALL to COVERAGE_PROFILE_ALL
+ migration.
+
+config COVERAGE_PROFILE_ALL
+ bool "Profile entire kernel"
+ depends on !COMPILE_TEST
+ depends on GCOV_KERNEL && ARCH_HAS_GCOV_PROFILE_ALL
+ default GCOV_PROFILE_ALL
+ help
+ This option activates coverage instrumentation for the entire kernel.
+
+ If unsure, say N.
+
+ Note that a kernel compiled with profiling flags will be significantly
+ larger and run slower. Also be sure to exclude files from profiling
+ which are not linked to the kernel image to prevent linker errors.
+
+# The per-subsystem COVERAGE_PROFILE_* options used to be GCOV_PROFILE_*.
+config GCOV_PROFILE_AMDGPU
+ bool
+ transitional
+
+config GCOV_PROFILE_URING
+ bool
+ transitional
+
+config GCOV_PROFILE_FTRACE
+ bool
+ transitional
+
+config GCOV_PROFILE_NETFILTER
+ bool
+ transitional
+
+config GCOV_PROFILE_IPSET
+ bool
+ transitional
+
+config GCOV_PROFILE_IPVS
+ bool
+ transitional
+
+config GCOV_PROFILE_RDS
+ bool
+ transitional
config ARCH_HAS_KCOV
bool
diff --git a/kernel/coverage/gcov/Kconfig b/kernel/coverage/gcov/Kconfig
deleted file mode 100644
index 04f4ebdc3cf59..0000000000000
--- a/kernel/coverage/gcov/Kconfig
+++ /dev/null
@@ -1,55 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0-only
-menu "GCOV-based kernel profiling"
-
-config GCOV_KERNEL
- bool "Enable gcov-based kernel profiling"
- depends on DEBUG_FS
- depends on !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR
- select CONSTRUCTORS
- default n
- help
- This option enables gcov-based code profiling (e.g. for code coverage
- measurements).
-
- If unsure, say N.
-
- Additionally specify CONFIG_GCOV_PROFILE_ALL=y to get profiling data
- for the entire kernel. To enable profiling for specific files or
- directories, add a line similar to the following to the respective
- Makefile:
-
- For a single file (e.g. main.o):
- GCOV_PROFILE_main.o := y
-
- For all files in one directory:
- GCOV_PROFILE := y
-
- To exclude files from being profiled even when CONFIG_GCOV_PROFILE_ALL
- is specified, use:
-
- GCOV_PROFILE_main.o := n
- and:
- GCOV_PROFILE := n
-
- Note that the debugfs filesystem has to be mounted to access
- profiling data.
-
-config ARCH_HAS_GCOV_PROFILE_ALL
- def_bool n
-
-config GCOV_PROFILE_ALL
- bool "Profile entire Kernel"
- depends on !COMPILE_TEST
- depends on GCOV_KERNEL
- depends on ARCH_HAS_GCOV_PROFILE_ALL
- default n
- help
- This options activates profiling for the entire kernel.
-
- If unsure, say N.
-
- Note that a kernel compiled with profiling flags will be significantly
- larger and run slower. Also be sure to exclude files from profiling
- which are not linked to the kernel image to prevent linker errors.
-
-endmenu
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index d8faeb659cfc9..4d88deda4ef8a 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -1110,11 +1110,12 @@ config RING_BUFFER_RECORD_RECURSION
This will add more overhead to cases that have recursion.
-config GCOV_PROFILE_FTRACE
- bool "Enable GCOV profiling on ftrace subsystem"
- depends on GCOV_KERNEL
+config COVERAGE_PROFILE_FTRACE
+ bool "Enable code coverage profiling on ftrace subsystem"
+ depends on COVERAGE_KERNEL
+ default GCOV_PROFILE_FTRACE
help
- Enable GCOV profiling on ftrace subsystem for checking
+ Enable code coverage profiling on ftrace subsystem for checking
which functions/lines are tested.
If unsure, say N.
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 1f925cd1b9f89..02d57906f13f5 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -44,8 +44,8 @@ KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
endif
# for GCOV coverage profiling
-ifdef CONFIG_GCOV_PROFILE_FTRACE
-GCOV_PROFILE := y
+ifdef CONFIG_COVERAGE_PROFILE_FTRACE
+COVERAGE_PROFILE := y
endif
# Functions in these files can run from IRQ entry before hardirq context
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 41a5925e4568b..fa68fc92e543c 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -3048,7 +3048,7 @@ config FORTIFY_KUNIT_TEST
config LONGEST_SYM_KUNIT_TEST
tristate "Test the longest symbol possible" if !KUNIT_ALL_TESTS
depends on KUNIT && KPROBES
- depends on !CALL_PADDING && !CFI && !GCOV_KERNEL
+ depends on !CALL_PADDING && !CFI && !COVERAGE_KERNEL
default KUNIT_ALL_TESTS
help
Tests the longest symbol possible
diff --git a/lib/Makefile b/lib/Makefile
index a2afe954805cb..6e80cd0023e8e 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -88,7 +88,7 @@ obj-$(CONFIG_TEST_DYNAMIC_DEBUG) += test_dynamic_debug.o
obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o
ifeq ($(CONFIG_CC_IS_CLANG)$(CONFIG_KASAN),yy)
# FIXME: Clang breaks test_bitmap_const_eval when KASAN and GCOV are enabled
-GCOV_PROFILE_test_bitmap.o := n
+COVERAGE_PROFILE_test_bitmap.o := n
endif
obj-$(CONFIG_TEST_XARRAY) += test_xarray.o
diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile
index 832d170cab941..4d7b265c023a1 100644
--- a/lib/crypto/Makefile
+++ b/lib/crypto/Makefile
@@ -143,7 +143,7 @@ obj-$(CONFIG_CRYPTO_LIB_CURVE25519) += libcurve25519.o
libcurve25519-y := curve25519.o
# Disable GCOV in odd or sensitive code
-GCOV_PROFILE_curve25519.o := n
+COVERAGE_PROFILE_curve25519.o := n
ifeq ($(CONFIG_ARCH_SUPPORTS_INT128),y)
libcurve25519-$(CONFIG_CRYPTO_LIB_CURVE25519_GENERIC) += curve25519-hacl64.o
diff --git a/net/bridge/Makefile b/net/bridge/Makefile
index 1203dc19e15c9..79e07925c9322 100644
--- a/net/bridge/Makefile
+++ b/net/bridge/Makefile
@@ -30,8 +30,8 @@ bridge-$(CONFIG_BRIDGE_MRP) += br_mrp_switchdev.o br_mrp.o br_mrp_netlink.o
bridge-$(CONFIG_BRIDGE_CFM) += br_cfm.o br_cfm_netlink.o
-ifdef CONFIG_GCOV_PROFILE_NETFILTER
-GCOV_PROFILE_br_nf_core.o := y
-GCOV_PROFILE_br_netfilter_hooks.o := y
-GCOV_PROFILE_br_netfilter_ipv6.o := y
+ifdef CONFIG_COVERAGE_PROFILE_NETFILTER
+COVERAGE_PROFILE_br_nf_core.o := y
+COVERAGE_PROFILE_br_netfilter_hooks.o := y
+COVERAGE_PROFILE_br_netfilter_ipv6.o := y
endif
diff --git a/net/bridge/netfilter/Makefile b/net/bridge/netfilter/Makefile
index af0c903aa4ace..46af78735a5c5 100644
--- a/net/bridge/netfilter/Makefile
+++ b/net/bridge/netfilter/Makefile
@@ -39,6 +39,6 @@ obj-$(CONFIG_BRIDGE_EBT_SNAT) += ebt_snat.o
obj-$(CONFIG_BRIDGE_EBT_LOG) += ebt_log.o
obj-$(CONFIG_BRIDGE_EBT_NFLOG) += ebt_nflog.o
-ifdef CONFIG_GCOV_PROFILE_NETFILTER
-GCOV_PROFILE := y
+ifdef CONFIG_COVERAGE_PROFILE_NETFILTER
+COVERAGE_PROFILE := y
endif
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index e8a0e9605b901..23f68b7fb3498 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -74,6 +74,6 @@ obj-$(CONFIG_BPF_SYSCALL) += bpf_tcp_ca.o
obj-$(CONFIG_CGROUP_BPF) += bpf_tcp_ops.o
endif
-ifdef CONFIG_GCOV_PROFILE_NETFILTER
-GCOV_PROFILE_netfilter.o := y
+ifdef CONFIG_COVERAGE_PROFILE_NETFILTER
+COVERAGE_PROFILE_netfilter.o := y
endif
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index dbfb1c4739a87..c4c0dfeef382c 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -52,6 +52,6 @@ obj-$(CONFIG_IP_NF_ARPFILTER) += arptable_filter.o
obj-$(CONFIG_NF_DUP_IPV4) += nf_dup_ipv4.o
-ifdef CONFIG_GCOV_PROFILE_NETFILTER
-GCOV_PROFILE := y
+ifdef CONFIG_COVERAGE_PROFILE_NETFILTER
+COVERAGE_PROFILE := y
endif
diff --git a/net/ipv6/Makefile b/net/ipv6/Makefile
index cf5e01f83ce3d..3c7e993fefcc1 100644
--- a/net/ipv6/Makefile
+++ b/net/ipv6/Makefile
@@ -55,6 +55,6 @@ obj-y += mcast_snoop.o ndisc_snoop.o
obj-$(CONFIG_TCP_AO) += tcp_ao.o
endif
-ifdef CONFIG_GCOV_PROFILE_NETFILTER
-GCOV_PROFILE_netfilter.o := y
+ifdef CONFIG_COVERAGE_PROFILE_NETFILTER
+COVERAGE_PROFILE_netfilter.o := y
endif
diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile
index 72902d8005ad9..e49f0dd9526ac 100644
--- a/net/ipv6/netfilter/Makefile
+++ b/net/ipv6/netfilter/Makefile
@@ -44,6 +44,6 @@ obj-$(CONFIG_IP6_NF_TARGET_NPT) += ip6t_NPT.o
obj-$(CONFIG_IP6_NF_TARGET_REJECT) += ip6t_REJECT.o
obj-$(CONFIG_IP6_NF_TARGET_SYNPROXY) += ip6t_SYNPROXY.o
-ifdef CONFIG_GCOV_PROFILE_NETFILTER
-GCOV_PROFILE := y
+ifdef CONFIG_COVERAGE_PROFILE_NETFILTER
+COVERAGE_PROFILE := y
endif
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 09874c26fd135..9470494ee760a 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -1649,11 +1649,12 @@ config NETFILTER_XT_MATCH_U32
endif # NETFILTER_XTABLES
-config GCOV_PROFILE_NETFILTER
- bool "Enable GCOV profiling for netfilter"
- depends on GCOV_KERNEL
+config COVERAGE_PROFILE_NETFILTER
+ bool "Enable code coverage profiling for netfilter"
+ depends on COVERAGE_KERNEL
+ default GCOV_PROFILE_NETFILTER
help
- Enable GCOV profiling for netfilter to check which functions/lines
+ Enable code coverage profiling for netfilter to check which functions/lines
are executed.
If unsure, say N.
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 6bf74d488a292..f84c622e3a70d 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -241,6 +241,6 @@ obj-$(CONFIG_IP_VS) += ipvs/
# lwtunnel
obj-$(CONFIG_LWTUNNEL) += nf_hooks_lwtunnel.o
-ifdef CONFIG_GCOV_PROFILE_NETFILTER
-GCOV_PROFILE := y
+ifdef CONFIG_COVERAGE_PROFILE_NETFILTER
+COVERAGE_PROFILE := y
endif
diff --git a/net/netfilter/ipset/Kconfig b/net/netfilter/ipset/Kconfig
index 6c4d547581067..e8f05c1df8e0f 100644
--- a/net/netfilter/ipset/Kconfig
+++ b/net/netfilter/ipset/Kconfig
@@ -175,11 +175,12 @@ config IP_SET_LIST_SET
To compile it as a module, choose M here. If unsure, say N.
-config GCOV_PROFILE_IPSET
- bool "Enable GCOV profiling for ipset"
- depends on GCOV_KERNEL
+config COVERAGE_PROFILE_IPSET
+ bool "Enable code coverage profiling for ipset"
+ depends on COVERAGE_KERNEL
+ default GCOV_PROFILE_IPSET
help
- Enable GCOV profiling for ipset to check which functions/lines
+ Enable code coverage profiling for ipset to check which functions/lines
are executed.
If unsure, say N.
diff --git a/net/netfilter/ipset/Makefile b/net/netfilter/ipset/Makefile
index 4f48df5406cd3..b4991815f44bb 100644
--- a/net/netfilter/ipset/Makefile
+++ b/net/netfilter/ipset/Makefile
@@ -29,6 +29,6 @@ obj-$(CONFIG_IP_SET_HASH_NETPORTNET) += ip_set_hash_netportnet.o
# list types
obj-$(CONFIG_IP_SET_LIST_SET) += ip_set_list_set.o
-ifdef CONFIG_GCOV_PROFILE_IPSET
-GCOV_PROFILE := y
+ifdef CONFIG_COVERAGE_PROFILE_IPSET
+COVERAGE_PROFILE := y
endif
diff --git a/net/netfilter/ipvs/Kconfig b/net/netfilter/ipvs/Kconfig
index 7724cb44e6dea..959e5832be874 100644
--- a/net/netfilter/ipvs/Kconfig
+++ b/net/netfilter/ipvs/Kconfig
@@ -349,11 +349,12 @@ config IP_VS_PE_SIP
help
Allow persistence based on the SIP Call-ID
-config GCOV_PROFILE_IPVS
- bool "Enable GCOV profiling for IPVS"
- depends on GCOV_KERNEL
+config COVERAGE_PROFILE_IPVS
+ bool "Enable code coverage profiling for IPVS"
+ depends on COVERAGE_KERNEL
+ default GCOV_PROFILE_IPVS
help
- Enable GCOV profiling for IPVS to check which functions/lines
+ Enable code coverage profiling for IPVS to check which functions/lines
are executed.
If unsure, say N.
diff --git a/net/netfilter/ipvs/Makefile b/net/netfilter/ipvs/Makefile
index 8e4cc67ad39d5..6cf42a7350904 100644
--- a/net/netfilter/ipvs/Makefile
+++ b/net/netfilter/ipvs/Makefile
@@ -43,6 +43,6 @@ obj-$(CONFIG_IP_VS_FTP) += ip_vs_ftp.o
# IPVS connection template retrievers
obj-$(CONFIG_IP_VS_PE_SIP) += ip_vs_pe_sip.o
-ifdef CONFIG_GCOV_PROFILE_IPVS
-GCOV_PROFILE := y
+ifdef CONFIG_COVERAGE_PROFILE_IPVS
+COVERAGE_PROFILE := y
endif
diff --git a/net/rds/Kconfig b/net/rds/Kconfig
index f007730aa2bb6..9c35cb18a3f93 100644
--- a/net/rds/Kconfig
+++ b/net/rds/Kconfig
@@ -27,11 +27,12 @@ config RDS_DEBUG
depends on RDS
default n
-config GCOV_PROFILE_RDS
- bool "Enable GCOV profiling on RDS"
- depends on GCOV_KERNEL
+config COVERAGE_PROFILE_RDS
+ bool "Enable code coverage profiling on RDS"
+ depends on COVERAGE_KERNEL
+ default GCOV_PROFILE_RDS
help
- Enable GCOV profiling on RDS for checking which functions/lines
+ Enable code coverage profiling on RDS for checking which functions/lines
are executed.
If unsure, say N.
diff --git a/net/rds/Makefile b/net/rds/Makefile
index 3af1ca1d965ce..84c1eb77369f5 100644
--- a/net/rds/Makefile
+++ b/net/rds/Makefile
@@ -17,6 +17,6 @@ rds_tcp-y := tcp.o tcp_connect.o tcp_listen.o tcp_recv.o \
ccflags-$(CONFIG_RDS_DEBUG) := -DRDS_DEBUG
# for GCOV coverage profiling
-ifdef CONFIG_GCOV_PROFILE_RDS
-GCOV_PROFILE := y
+ifdef CONFIG_COVERAGE_PROFILE_RDS
+COVERAGE_PROFILE := y
endif
diff --git a/scripts/Makefile.gcov b/scripts/Makefile.gcov
new file mode 100644
index 0000000000000..1620b81398eaa
--- /dev/null
+++ b/scripts/Makefile.gcov
@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: GPL-2.0
+
+CFLAGS_COVERAGE := -fprofile-arcs -ftest-coverage
+ifdef CONFIG_CC_IS_GCC
+CFLAGS_COVERAGE += -fno-tree-loop-im
+# Use atomic counter updates to avoid concurrent-access crashes in GCOV.
+# Only enable if -fprofile-update=prefer-atomic does not introduce new
+# undefined symbols (e.g. libatomic calls that the kernel cannot link).
+CFLAGS_COVERAGE += $(call try-run,\
+ echo 'long long x; void f(void){x++;}' | \
+ $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -w -fprofile-arcs \
+ -ftest-coverage -x c - -c -o "$$TMP.base" && \
+ echo 'long long x; void f(void){x++;}' | \
+ $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -w -fprofile-arcs \
+ -ftest-coverage -fprofile-update=prefer-atomic \
+ -x c - -c -o "$$TMP" && \
+ $(NM) "$$TMP.base" | grep ' U ' > "$$TMP.ubase" || true ; \
+ $(NM) "$$TMP" | grep ' U ' > "$$TMP.utest" || true ; \
+ cmp -s "$$TMP.ubase" "$$TMP.utest",\
+ -fprofile-update=prefer-atomic)
+endif
+export CFLAGS_COVERAGE
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 19e96b30a122f..e0dc21e009522 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -38,14 +38,14 @@ _a_flags = $(filter-out $(AFLAGS_REMOVE_$(target-stem).o), \
_cpp_flags = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(target-stem).lds)
#
-# Enable gcov profiling flags for a file, directory or for all files depending
-# on variables GCOV_PROFILE_obj.o, GCOV_PROFILE and CONFIG_GCOV_PROFILE_ALL
-# (in this order)
+# Enable code coverage instrumentation for a file, directory or for all files
+# depending on variables COVERAGE_PROFILE_obj.o, COVERAGE_PROFILE and
+# CONFIG_COVERAGE_PROFILE_ALL (in this order)
#
-ifeq ($(CONFIG_GCOV_KERNEL),y)
+ifeq ($(CONFIG_COVERAGE_KERNEL),y)
_c_flags += $(if $(patsubst n%,, \
- $(GCOV_PROFILE_$(target-stem).o)$(GCOV_PROFILE)$(if $(is-kernel-object),$(CONFIG_GCOV_PROFILE_ALL))), \
- $(CFLAGS_GCOV))
+ $(COVERAGE_PROFILE_$(target-stem).o)$(COVERAGE_PROFILE)$(if $(is-kernel-object),$(CONFIG_COVERAGE_PROFILE_ALL))), \
+ $(CFLAGS_COVERAGE))
endif
#
@@ -206,7 +206,7 @@ objtool-args-$(CONFIG_MITIGATION_SLS) += --sls
objtool-args-$(CONFIG_STACK_VALIDATION) += --stackval
objtool-args-$(CONFIG_HAVE_STATIC_CALL_INLINE) += --static-call
objtool-args-$(CONFIG_HAVE_UACCESS_VALIDATION) += --uaccess
-objtool-args-$(or $(CONFIG_GCOV_KERNEL),$(CONFIG_KCOV)) += --no-unreachable
+objtool-args-$(or $(CONFIG_COVERAGE_KERNEL),$(CONFIG_KCOV)) += --no-unreachable
objtool-args-$(CONFIG_OBJTOOL_WERROR) += --werror
objtool-args = $(objtool-args-y) \
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index 01a37ec872b90..2ca03eccbe291 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -19,7 +19,7 @@ __modfinal: $(modules:%.o=%.ko)
# modname and part-of-module are set to make c_flags define proper module flags
modname = $(notdir $(@:.mod.o=))
part-of-module = y
-GCOV_PROFILE := n
+COVERAGE_PROFILE := n
ccflags-remove-y := $(CC_FLAGS_CFI)
%.mod.o: %.mod.c FORCE
diff --git a/scripts/sbom/sbom/environment.py b/scripts/sbom/sbom/environment.py
index 4304066fe974e..a74c96ddfe593 100644
--- a/scripts/sbom/sbom/environment.py
+++ b/scripts/sbom/sbom/environment.py
@@ -18,7 +18,7 @@ KERNEL_BUILD_VARIABLES_ALLOWLIST = [
"CC",
"CC_FLAGS_FPU",
"CC_FLAGS_NO_FPU",
- "CFLAGS_GCOV",
+ "CFLAGS_COVERAGE",
"CFLAGS_KERNEL",
"CFLAGS_MODULE",
"CHECK",
diff --git a/tools/testing/selftests/net/rds/config.sh b/tools/testing/selftests/net/rds/config.sh
index 2df2226310efe..bb854f49e464d 100755
--- a/tools/testing/selftests/net/rds/config.sh
+++ b/tools/testing/selftests/net/rds/config.sh
@@ -43,13 +43,14 @@ scripts/config "${FLAGS[@]}" --enable CONFIG_RDS_TCP
if [ "$GENERATE_GCOV_REPORT" -eq 1 ]; then
# instrument RDS and only RDS
+ scripts/config "${FLAGS[@]}" --disable CONFIG_COVERAGE_NONE
scripts/config "${FLAGS[@]}" --enable CONFIG_GCOV_KERNEL
- scripts/config "${FLAGS[@]}" --disable GCOV_PROFILE_ALL
- scripts/config "${FLAGS[@]}" --enable GCOV_PROFILE_RDS
+ scripts/config "${FLAGS[@]}" --disable COVERAGE_PROFILE_ALL
+ scripts/config "${FLAGS[@]}" --enable COVERAGE_PROFILE_RDS
else
scripts/config "${FLAGS[@]}" --disable CONFIG_GCOV_KERNEL
- scripts/config "${FLAGS[@]}" --disable GCOV_PROFILE_ALL
- scripts/config "${FLAGS[@]}" --disable GCOV_PROFILE_RDS
+ scripts/config "${FLAGS[@]}" --disable COVERAGE_PROFILE_ALL
+ scripts/config "${FLAGS[@]}" --disable COVERAGE_PROFILE_RDS
fi
# need network namespaces to run tests with veth network interfaces
diff --git a/tools/testing/selftests/net/rds/rds_run.sh b/tools/testing/selftests/net/rds/rds_run.sh
index cdf487ec97dcc..25bb65d048abe 100755
--- a/tools/testing/selftests/net/rds/rds_run.sh
+++ b/tools/testing/selftests/net/rds/rds_run.sh
@@ -70,16 +70,16 @@ check_gcov_env()
# Check to see if the kconfig has the required configs to generate a coverage report
check_gcov_conf()
{
- if ! grep -x "CONFIG_GCOV_PROFILE_RDS=y" "$kconfig" > /dev/null 2>&1; then
- echo "# INFO: CONFIG_GCOV_PROFILE_RDS should be enabled for coverage reports"
+ if ! grep -x "CONFIG_COVERAGE_PROFILE_RDS=y" "$kconfig" > /dev/null 2>&1; then
+ echo "# INFO: CONFIG_COVERAGE_PROFILE_RDS should be enabled for coverage reports"
GENERATE_GCOV_REPORT=0
fi
if ! grep -x "CONFIG_GCOV_KERNEL=y" "$kconfig" > /dev/null 2>&1; then
echo "# INFO: CONFIG_GCOV_KERNEL should be enabled for coverage reports"
GENERATE_GCOV_REPORT=0
fi
- if grep -x "CONFIG_GCOV_PROFILE_ALL=y" "$kconfig" > /dev/null 2>&1; then
- echo "# INFO: CONFIG_GCOV_PROFILE_ALL should be disabled for coverage reports"
+ if grep -x "CONFIG_COVERAGE_PROFILE_ALL=y" "$kconfig" > /dev/null 2>&1; then
+ echo "# INFO: CONFIG_COVERAGE_PROFILE_ALL should be disabled for coverage reports"
GENERATE_GCOV_REPORT=0
fi
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [RFC PATCH 20/20] Documentation: dev-tools: document the common code coverage interface
2026-10-28 11:59 [RFC PATCH 00/20] Unify code coverage and add Clang source-based coverage with MC/DC Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 01/20] coverage: move gcov and kcov under kernel/coverage/ Sasha Levin
2026-10-28 11:59 ` [RFC PATCH 02/20] kbuild: unify static coverage instrumentation as COVERAGE_PROFILE Sasha Levin
@ 2026-10-28 11:59 ` Sasha Levin
2 siblings, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2026-10-28 11:59 UTC (permalink / raw)
To: linux-kernel
Cc: Alexander Potapenko, Andrey Konovalov, Bill Wendling,
Chuck Wolber, Dmitry Vyukov, Jonathan Corbet, Justin Stitt,
kasan-dev, linux-doc, llvm, Marco Elver, Masami Hiramatsu,
Nathan Chancellor, Nick Desaulniers, Peter Oberparleiter,
Peter Zijlstra, Randy Dunlap, Shuah Khan, Thomas Gleixner,
workflows
Describe the code coverage implementations and what they share: the
Kconfig options, the COVERAGE_PROFILE annotations, the
/sys/kernel/debug/coverage/ interface, MC/DC measurement, and how they
deal with noinstr code. Point to it from the gcov and KCOV
documentation, and document gcov's MC/DC support.
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
Documentation/dev-tools/coverage.rst | 158 +++++++++++++++++++++++++++
Documentation/dev-tools/gcov.rst | 28 +++++
Documentation/dev-tools/index.rst | 1 +
Documentation/dev-tools/kcov.rst | 3 +
MAINTAINERS | 1 +
5 files changed, 191 insertions(+)
create mode 100644 Documentation/dev-tools/coverage.rst
diff --git a/Documentation/dev-tools/coverage.rst b/Documentation/dev-tools/coverage.rst
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@@ -0,0 +1,158 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=============
+Code coverage
+=============
+
+The kernel can be instrumented to find out which parts of it get executed.
+This serves two different purposes:
+
+* Measuring code coverage, e.g. to assess and improve a test suite, or to
+ show the structural coverage required by safety standards. This is done by
+ one of the code coverage measurement implementations described below.
+
+* Guiding fuzzers. This is done by KCOV, which collects coverage per task;
+ see Documentation/dev-tools/kcov.rst.
+
+All of them are configured in the "Kernel hacking -> Kernel Testing and
+Coverage -> Code coverage" menu, live in ``kernel/coverage/``, and share the
+``/sys/kernel/debug/coverage/`` debugfs directory.
+
+
+Code coverage measurement
+=========================
+
+The implementation is selected by the "Code coverage measurement" choice:
+
+============================ ============== ================================
+Option Compilers Data
+============================ ============== ================================
+``CONFIG_GCOV_KERNEL`` GCC, Clang gcov ``.gcda`` files, see
+ Documentation/dev-tools/gcov.rst
+``CONFIG_LLVM_COV_KERNEL`` Clang 19 and LLVM raw profile of the kernel
+ later image (``.profraw``)
+============================ ============== ================================
+
+The instrumentation and the format of the data are defined by the toolchain,
+so only one implementation can be used at a time. Both only instrument C
+code.
+
+Clang's source-based code coverage (``CONFIG_LLVM_COV_KERNEL``) instruments
+the code in the compiler front end. Its data therefore maps back to the source
+code exactly, regardless of the optimizations applied, and it can show the
+coverage of every condition of a decision. It only instruments code built into
+the kernel image. gcov also supports modules.
+
+
+Selecting the code to instrument
+--------------------------------
+
+``CONFIG_COVERAGE_PROFILE_ALL`` instruments the entire kernel. On architectures
+that don't support it, or to instrument only parts of the kernel, add a line
+like the following to the respective Makefile.
+
+For a single file (e.g. main.o)::
+
+ COVERAGE_PROFILE_main.o := y
+
+For all files in one directory::
+
+ COVERAGE_PROFILE := y
+
+To exclude files from being instrumented even when
+``CONFIG_COVERAGE_PROFILE_ALL`` is enabled, use::
+
+ COVERAGE_PROFILE_main.o := n
+
+and::
+
+ COVERAGE_PROFILE := n
+
+The per-file setting takes precedence over the per-directory one, which takes
+precedence over ``CONFIG_COVERAGE_PROFILE_ALL``.
+
+Only exclude code that can't work when instrumented, for example because it
+runs before the kernel is relocated or is copied elsewhere. Code that must not
+be instrumented for correctness reasons, such as the entry code, is annotated
+``noinstr`` instead; see `noinstr`_.
+
+
+Interface
+---------
+
+``/sys/kernel/debug/coverage/`` contains:
+
+``backend``
+ The name of the selected implementation, ``gcov`` or ``llvm``, followed by
+ ``mcdc`` when MC/DC is measured.
+
+``reset``
+ Writing to this file resets all coverage data of the selected
+ implementation. It does not affect KCOV.
+
+``gcov``
+ A symlink to ``/sys/kernel/debug/gcov``, where gcov keeps its data (see
+ Documentation/dev-tools/gcov.rst).
+
+``llvm/profraw``
+ The raw profile of the kernel image, for Clang's source-based code
+ coverage.
+
+``kcov``
+ A symlink to ``/sys/kernel/debug/kcov`` (see
+ Documentation/dev-tools/kcov.rst).
+
+The instrumented code updates the coverage data without synchronizing with
+readers, so reading the data while other CPUs execute instrumented code
+doesn't give an atomic snapshot, and the same applies to a reset.
+
+With Clang's source-based code coverage, convert the raw profile and create a
+report with the ``llvm-profdata`` and ``llvm-cov`` tools of the LLVM version
+that built the kernel, since the raw profile format changes between releases::
+
+ # cp /sys/kernel/debug/coverage/llvm/profraw vmlinux.profraw
+ $ llvm-profdata merge vmlinux.profraw -o vmlinux.profdata
+ $ llvm-cov report -instr-profile=vmlinux.profdata vmlinux
+ $ llvm-cov show -instr-profile=vmlinux.profdata vmlinux kernel/fork.c
+
+
+MC/DC
+-----
+
+Modified condition/decision coverage (MC/DC) verifies that each condition of a
+boolean decision has been shown to independently affect the outcome of the
+decision. It is required by safety standards such as DO-178C (avionics) and
+ISO 26262 (automotive). Enable it with ``CONFIG_COVERAGE_MCDC``:
+
+* With Clang's source-based code coverage, decisions with more than
+ ``CONFIG_LLVM_COV_MCDC_MAX_CONDITIONS`` conditions are not measured. Show
+ the results with ``llvm-cov show -show-mcdc`` and
+ ``llvm-cov report -show-mcdc-summary``.
+
+* With gcov, GCC 14 or later is required, and decisions with more than 64
+ conditions are not measured. Show the results with ``gcov --conditions``.
+
+The compiler warns about every decision it doesn't instrument.
+
+
+noinstr
+=======
+
+Code annotated ``noinstr`` must not be instrumented; this includes the code
+running on kernel entry and exit, and in NMI context. Outside of
+``instrumentation_begin()``/``instrumentation_end()`` sections, ``noinstr``
+functions may only call other ``noinstr`` functions and ``__always_inline``
+functions.
+
+The code coverage measurement implementations insert their instrumentation
+before functions get inlined, which would carry the instrumentation of an
+``__always_inline`` function into the ``noinstr`` code it is inlined into. To
+avoid that, ``__always_inline`` functions are not instrumented when one of them
+is enabled, and as a consequence they don't show up in the coverage data.
+
+With ``CONFIG_NOINSTR_VALIDATION``, objtool reports coverage counters that get
+updated by ``noinstr`` code outside of such sections.
+
+KCOV instruments the code after inlining and honours ``noinstr`` through the
+``no_sanitize_coverage`` attribute with Clang and GCC 12 or later; with older
+GCC, objtool removes its calls from ``noinstr`` code.
diff --git a/Documentation/dev-tools/gcov.rst b/Documentation/dev-tools/gcov.rst
index b6910c3fc00dd..d2950070f3ca4 100644
--- a/Documentation/dev-tools/gcov.rst
+++ b/Documentation/dev-tools/gcov.rst
@@ -22,6 +22,9 @@ Possible uses:
* minimizing kernel configurations (do I need this option if the
associated code is never run?)
+See Documentation/dev-tools/coverage.rst for the options and interfaces shared
+with the other code coverage implementations.
+
.. _gcov: https://gcc.gnu.org/onlinedocs/gcc/Gcov.html
.. _lcov: https://github.com/linux-test-project/lcov
@@ -180,6 +183,31 @@ b) gcov is run on the BUILD machine
[user@build] gcov -o /tmp/coverage/tmp/out/init main.c
+MC/DC Coverage
+--------------
+
+When using GCC 14 or later with ``CONFIG_COVERAGE_MCDC=y``, Modified
+Condition/Decision Coverage (MC/DC) data is collected alongside standard
+branch coverage. MC/DC verifies that each condition in a decision
+independently affects the decision's outcome.
+
+To view MC/DC data, use::
+
+ gcov --conditions -o /sys/kernel/debug/gcov/path/to/dir file.c
+
+MC/DC coverage is required by safety standards such as DO-178C
+(avionics) and ISO 26262 (automotive).
+
+GCC's condition coverage implementation has a limit of 64 conditions per
+boolean expression, due to the use of 64-bit bitmasks internally.
+Expressions exceeding this limit cannot be instrumented and will produce
+a compiler warning. This does not affect the correctness of the kernel;
+those expressions simply will not have MC/DC coverage data.
+
+Note that MC/DC instrumentation increases binary size and execution
+overhead compared to standard gcov profiling.
+
+
Note on compilers
-----------------
diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst
index 59cbb77b33ff4..d670c1398e495 100644
--- a/Documentation/dev-tools/index.rst
+++ b/Documentation/dev-tools/index.rst
@@ -23,6 +23,7 @@ Documentation/process/debugging/index.rst
coccinelle
context-analysis
sparse
+ coverage
kcov
gcov
kasan
diff --git a/Documentation/dev-tools/kcov.rst b/Documentation/dev-tools/kcov.rst
index 1a739290c8ecc..98a30a1a3f88a 100644
--- a/Documentation/dev-tools/kcov.rst
+++ b/Documentation/dev-tools/kcov.rst
@@ -12,6 +12,9 @@ To achieve this goal, it does not collect coverage in soft/hard interrupts
(unless remove coverage collection is enabled, see below) and from some
inherently non-deterministic parts of the kernel (e.g. scheduler, locking).
+KCOV is configured next to the other code coverage implementations, see
+Documentation/dev-tools/coverage.rst.
+
Besides collecting code coverage, KCOV can also collect comparison operands.
See the "Comparison operands collection" section for details.
diff --git a/MAINTAINERS b/MAINTAINERS
index 506f25cfc3e85..ff9b355c2fc0d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6592,6 +6592,7 @@ F: drivers/media/platform/chips-media/coda
CODE COVERAGE
M: Sasha Levin <sashal@kernel.org>
S: Maintained
+F: Documentation/dev-tools/coverage.rst
F: kernel/coverage/Kconfig
F: kernel/coverage/Makefile
F: kernel/coverage/core.c
--
2.53.0
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