gcov: Remove compiler version check

The minimum supported version of LLVM has been raised to 11.0.0, meaning
this check is always true, so it can be dropped.

Signed-off-by: Nathan Chancellor <natha

gcov: Remove compiler version check

The minimum supported version of LLVM has been raised to 11.0.0, meaning
this check is always true, so it can be dropped.

Signed-off-by: Nathan Chancellor <[email protected]>
Reviewed-by: Miguel Ojeda <[email protected]>
Reviewed-by: Mark Brown <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>

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Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR

We don't want compiler instrumentation to touch noinstr functions,
which are annotated with the no_profile_instrument_function fu

Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR

We don't want compiler instrumentation to touch noinstr functions,
which are annotated with the no_profile_instrument_function function
attribute. Add a Kconfig test for this and make GCOV depend on it, and
in the future, PGO.

If an architecture is using noinstr, it should denote that via this
Kconfig value. That makes Kconfigs that depend on noinstr able to express
dependencies in an architecturally agnostic way.

Cc: Masahiro Yamada <[email protected]>
Link: https://lore.kernel.org/lkml/[email protected]/
Link: https://lore.kernel.org/lkml/YMcssV%[email protected]/
Suggested-by: Nathan Chancellor <[email protected]>
Suggested-by: Peter Zijlstra <[email protected]>
Signed-off-by: Nick Desaulniers <[email protected]>
Reviewed-by: Peter Oberparleiter <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Acked-by: Heiko Carstens <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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gcov: clang: drop support for clang-10 and older

LLVM changed the expected function signatures for llvm_gcda_start_file()
and llvm_gcda_emit_function() in the clang-11 release. Drop the older
imple

gcov: clang: drop support for clang-10 and older

LLVM changed the expected function signatures for llvm_gcda_start_file()
and llvm_gcda_emit_function() in the clang-11 release. Drop the older
implementations and require folks to upgrade their compiler if they're
interested in GCOV support.

Link: https://reviews.llvm.org/rGcdd683b516d147925212724b09ec6fb792a40041
Link: https://reviews.llvm.org/rG13a633b438b6500ecad9e4f936ebadf3411d0f44
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Nick Desaulniers <[email protected]>
Suggested-by: Nathan Chancellor <[email protected]>
Acked-by: Peter Oberparleiter <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
Reviewed-by: Fangrui Song <[email protected]>
Cc: Prasad Sodagudi <[email protected]>
Cc: Johannes Berg <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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init/gcov: allow CONFIG_CONSTRUCTORS on UML to fix module gcov

On ARCH=um, loading a module doesn't result in its constructors getting
called, which breaks module gcov since the debugfs files are ne

init/gcov: allow CONFIG_CONSTRUCTORS on UML to fix module gcov

On ARCH=um, loading a module doesn't result in its constructors getting
called, which breaks module gcov since the debugfs files are never
registered. On the other hand, in-kernel constructors have already been
called by the dynamic linker, so we can't call them again.

Get out of this conundrum by allowing CONFIG_CONSTRUCTORS to be
selected, but avoiding the in-kernel constructor calls.

Also remove the "if !UML" from GCOV selecting CONSTRUCTORS now, since we
really do want CONSTRUCTORS, just not kernel binary ones.

Link: https://lkml.kernel.org/r/20210120172041.c246a2cac2fb.I1358f584b76f1898373adfed77f4462c8705b736@changeid
Signed-off-by: Johannes Berg <[email protected]>
Reviewed-by: Peter Oberparleiter <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Jessica Yu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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gcov: add support for GCC 10.1

Using gcov to collect coverage data for kernels compiled with GCC 10.1
causes random malfunctions and kernel crashes. This is the result of a
changed GCOV_COUNTERS va

gcov: add support for GCC 10.1

Using gcov to collect coverage data for kernels compiled with GCC 10.1
causes random malfunctions and kernel crashes. This is the result of a
changed GCOV_COUNTERS value in GCC 10.1 that causes a mismatch between
the layout of the gcov_info structure created by GCC profiling code and
the related structure used by the kernel.

Fix this by updating the in-kernel GCOV_COUNTERS value. Also re-enable
config GCOV_KERNEL for use with GCC 10.

Reported-by: Colin Ian King <[email protected]>
Reported-by: Leon Romanovsky <[email protected]>
Signed-off-by: Peter Oberparleiter <[email protected]>
Tested-by: Leon Romanovsky <[email protected]>
Tested-and-Acked-by: Colin Ian King <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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gcov: Disable gcov build with GCC 10

GCOV built with GCC 10 doesn't initialize n_function variable. This
produces different kernel panics as was seen by Colin in Ubuntu and me
in FC 32.

As a worka

gcov: Disable gcov build with GCC 10

GCOV built with GCC 10 doesn't initialize n_function variable. This
produces different kernel panics as was seen by Colin in Ubuntu and me
in FC 32.

As a workaround, let's disable GCOV build for broken GCC 10 version.

Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1891288
Link: https://lore.kernel.org/lkml/[email protected]
Link: https://lore.kernel.org/lkml/CAHk-=whbijeSdSvx-Xcr0DPMj0BiwhJ+uiNnDSVZcr_h_kg7UA@mail.gmail.com/
Cc: Colin Ian King <[email protected]>
Signed-off-by: Leon Romanovsky <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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treewide: replace '---help---' in Kconfig files with 'help'

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasi

treewide: replace '---help---' in Kconfig files with 'help'

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'

Signed-off-by: Masahiro Yamada <[email protected]>

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gcov: Remove old GCC 3.4 support

The kernel requires at least GCC 4.8 in order to build, and so there is
no need to cater for the pre-4.7 gcov format.

Remove the obsolete code.

Acked-by: Peter Obe

gcov: Remove old GCC 3.4 support

The kernel requires at least GCC 4.8 in order to build, and so there is
no need to cater for the pre-4.7 gcov format.

Remove the obsolete code.

Acked-by: Peter Oberparleiter <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Signed-off-by: Will Deacon <[email protected]>

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Revert "um: Enable CONFIG_CONSTRUCTORS"

This reverts commit 786b2384bf1c ("um: Enable CONFIG_CONSTRUCTORS").

There are two issues with this commit, uncovered by Anton in tests
on some (Debian) syst

Revert "um: Enable CONFIG_CONSTRUCTORS"

This reverts commit 786b2384bf1c ("um: Enable CONFIG_CONSTRUCTORS").

There are two issues with this commit, uncovered by Anton in tests
on some (Debian) systems:

1) I completely forgot to call any constructors if CONFIG_CONSTRUCTORS
isn't set. Don't recall now if it just wasn't needed on my system, or
if I never tested this case.

2) With that fixed, it works - with CONFIG_CONSTRUCTORS *unset*. If I
set CONFIG_CONSTRUCTORS, it fails again, which isn't totally
unexpected since whatever wanted to run is likely to have to run
before the kernel init etc. that calls the constructors in this case.

Basically, some constructors that gcc emits (libc has?) need to run
very early during init; the failure mode otherwise was that the ptrace
fork test already failed:

----------------------
$ ./linux mem=512M
Core dump limits :
soft - 0
hard - NONE
Checking that ptrace can change system call numbers...check_ptrace : child exited with exitcode 6, while expecting 0; status 0x67f
Aborted
----------------------

Thinking more about this, it's clear that we simply cannot support
CONFIG_CONSTRUCTORS in UML. All the cases we need now (gcov, kasan)
involve not use of the __attribute__((constructor)), but instead
some constructor code/entry generated by gcc. Therefore, we cannot
distinguish between kernel constructors and system constructors.

Thus, revert this commit.

Cc: [email protected] [5.4+]
Fixes: 786b2384bf1c ("um: Enable CONFIG_CONSTRUCTORS")
Reported-by: Anton Ivanov <[email protected]>
Signed-off-by: Johannes Berg <[email protected]>
Acked-by: Anton Ivanov <[email protected]>

Signed-off-by: Richard Weinberger <[email protected]>

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um: Enable CONFIG_CONSTRUCTORS

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

um: Enable CONFIG_CONSTRUCTORS

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 <[email protected]>
Signed-off-by: Richard Weinberger <[email protected]>

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treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project

treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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gcov: clang support

LLVM uses profiling data that's deliberately similar to GCC, but has a
very different way of exporting that data. LLVM calls llvm_gcov_init()
once per module, and provides a cou

gcov: clang support

LLVM uses profiling data that's deliberately similar to GCC, but has a
very different way of exporting that data. LLVM calls llvm_gcov_init()
once per module, and provides a couple of callbacks that we can use to
ask for more data.

We care about the "writeout" callback, which in turn calls back into
compiler-rt/this module to dump all the gathered coverage data to disk:

llvm_gcda_start_file()
llvm_gcda_emit_function()
llvm_gcda_emit_arcs()
llvm_gcda_emit_function()
llvm_gcda_emit_arcs()
[... repeats for each function ...]
llvm_gcda_summary_info()
llvm_gcda_end_file()

This design is much more stateless and unstructured than gcc's, and is
intended to run at process exit. This forces us to keep some local
state about which module we're dealing with at the moment. On the other
hand, it also means we don't depend as much on how LLVM represents
profiling data internally.

See LLVM's lib/Transforms/Instrumentation/GCOVProfiling.cpp for more
details on how this works, particularly GCOVProfiler::emitProfileArcs(),
GCOVProfiler::insertCounterWriteout(), and GCOVProfiler::insertFlush().

[[email protected]: coding-style fixes]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Greg Hackmann <[email protected]>
Signed-off-by: Nick Desaulniers <[email protected]>
Signed-off-by: Tri Vo <[email protected]>
Co-developed-by: Nick Desaulniers <[email protected]>
Co-developed-by: Tri Vo <[email protected]>
Tested-by: Trilok Soni <[email protected]>
Tested-by: Prasad Sodagudi <[email protected]>
Tested-by: Tri Vo <[email protected]>
Tested-by: Daniel Mentz <[email protected]>
Tested-by: Petri Gynther <[email protected]>
Reviewed-by: Peter Oberparleiter <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT

CONFIG_GCOV_FORMAT_AUTODETECT compiles either gcc_3_4.c or gcc_4_7.c
according to your GCC version.

We can achieve the equivalent behavior by setting reas

gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT

CONFIG_GCOV_FORMAT_AUTODETECT compiles either gcc_3_4.c or gcc_4_7.c
according to your GCC version.

We can achieve the equivalent behavior by setting reasonable dependency
with the knowledge of the compiler version.

If GCC older than 4.7 is used, GCOV_FORMAT_3_4 is the default, but users
are still allowed to select GCOV_FORMAT_4_7 in case the newer format is
back-ported.

On the other hand, If GCC 4.7 or newer is used, there is no reason to
use GCOV_FORMAT_3_4, so it should be hidden.

If you downgrade the compiler to GCC 4.7 or older, oldconfig/syncconfig
will display a prompt for the choice because GCOV_FORMAT_3_4 becomes
visible as a new symbol.

Signed-off-by: Masahiro Yamada <[email protected]>
Acked-by: Peter Oberparleiter <[email protected]>
Reviewed-by: Kees Cook <[email protected]>

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gcov: disable for COMPILE_TEST

Enabling gcov is counterproductive to compile testing: it significantly
increases the kernel image size, compile time, and it produces lots
of false positive "may be u

gcov: disable for COMPILE_TEST

Enabling gcov is counterproductive to compile testing: it significantly
increases the kernel image size, compile time, and it produces lots
of false positive "may be used uninitialized" warnings as the result
of missed optimizations.

This is in line with how UBSAN_SANITIZE_ALL and PROFILE_ALL_BRANCHES
work, both of which have similar problems.

With an ARM allmodconfig kernel, I see the build time drop from
283 minutes CPU time to 225 minutes, and the vmlinux size drops
from 43MB to 26MB.

Signed-off-by: Arnd Bergmann <[email protected]>
Acked-by: Peter Oberparleiter <[email protected]>
Signed-off-by: Michal Marek <[email protected]>

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gcov: enable GCOV_PROFILE_ALL from ARCH Kconfigs

Following the suggestions from Andrew Morton and Stephen Rothwell,
Dont expand the ARCH list in kernel/gcov/Kconfig. Instead,
define a ARCH_HAS_GCOV_

gcov: enable GCOV_PROFILE_ALL from ARCH Kconfigs

Following the suggestions from Andrew Morton and Stephen Rothwell,
Dont expand the ARCH list in kernel/gcov/Kconfig. Instead,
define a ARCH_HAS_GCOV_PROFILE_ALL bool which architectures
can enable.

set ARCH_HAS_GCOV_PROFILE_ALL on Architectures where it was
previously allowed + ARM64 which I tested.

Signed-off-by: Riku Voipio <[email protected]>
Cc: Peter Oberparleiter <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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gcov: add ARM64 to GCOV_PROFILE_ALL

Following up the arm testing of gcov, turns out gcov on ARM64 works fine
as well. Only change needed is adding ARM64 to Kconfig depends.

Tested with qemu and ma

gcov: add ARM64 to GCOV_PROFILE_ALL

Following up the arm testing of gcov, turns out gcov on ARM64 works fine
as well. Only change needed is adding ARM64 to Kconfig depends.

Tested with qemu and mach-virt

Signed-off-by: Riku Voipio <[email protected]>
Acked-by: Peter Oberparleiter <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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ARM: 8153/1: Enable gcov support on the ARM architecture

Enable gcov support for ARM based on original patches by David
Singleton and George G. Davis

Riku - updated to patch to current mainline ker

ARM: 8153/1: Enable gcov support on the ARM architecture

Enable gcov support for ARM based on original patches by David
Singleton and George G. Davis

Riku - updated to patch to current mainline kernel. The patch
has been submitted in 2010, 2012 - for symmetry, now in 2014 too.

https://lwn.net/Articles/390419/
http://marc.info/?l=linux-arm-kernel&m=133823081813044

v2: remove arch/arm/kernel from gcov disabled files

Cc: Andrey Ryabinin <[email protected]>
Cc: Naresh Kamboju <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Signed-off-by: Riku Voipio <[email protected]>
Signed-off-by: Vincent Sanders <[email protected]>
Signed-off-by: Russell King <[email protected]>

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gcov: compile specific gcov implementation based on gcc version

Compile the correct gcov implementation file for the specific gcc version.

Signed-off-by: Frantisek Hrbata <[email protected]>
Cc: J

gcov: compile specific gcov implementation based on gcc version

Compile the correct gcov implementation file for the specific gcc version.

Signed-off-by: Frantisek Hrbata <[email protected]>
Cc: Jan Stancek <[email protected]>
Cc: Kees Cook <[email protected]>
Acked-by: Peter Oberparleiter <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Andy Gospodarek <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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kernel/gcov: remove depends on CONFIG_EXPERIMENTAL

The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
while now and is almost always enabled by default. As agreed during the
Linu

kernel/gcov: remove depends on CONFIG_EXPERIMENTAL

The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
while now and is almost always enabled by default. As agreed during the
Linux kernel summit, remove it from any "depends on" lines in Kconfigs.

Cc: WANG Cong <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Acked-by: Peter Oberparleiter <[email protected]>

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gcov: disable CONSTRUCTORS for UML

Selecting GCOV for UML causing configuration mismatch:

warning: (GCOV_KERNEL) selects CONSTRUCTORS which has unmet direct dependencies (!UML)

Constructors are

gcov: disable CONSTRUCTORS for UML

Selecting GCOV for UML causing configuration mismatch:

warning: (GCOV_KERNEL) selects CONSTRUCTORS which has unmet direct dependencies (!UML)

Constructors are not needed for UML.

Signed-off-by: Vitaliy Ivanov <[email protected]>
Cc: Peter Oberparleiter <[email protected]>
Acked-by: Richard Weinberger <[email protected]>
Acked-by: WANG Cong <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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gcov: disable CONFIG_CONSTRUCTORS when not needed by CONFIG_GCOV_KERNEL

CONFIG_CONSTRUCTORS controls support for running constructor functions at
kernel init time. According to commit b99b87f70c778

gcov: disable CONFIG_CONSTRUCTORS when not needed by CONFIG_GCOV_KERNEL

CONFIG_CONSTRUCTORS controls support for running constructor functions at
kernel init time. According to commit b99b87f70c7785ab ("kernel:
constructor support"), gcov (CONFIG_GCOV_KERNEL) needs this. However,
CONFIG_CONSTRUCTORS currently defaults to y, with no option to disable it,
and CONFIG_GCOV_KERNEL depends on it. Instead, default it to n and have
CONFIG_GCOV_KERNEL select it, so that the normal case of
CONFIG_GCOV_KERNEL=n will result in CONFIG_CONSTRUCTORS=n.

Observed in the short list of =y values in a minimal kernel configuration.

Signed-off-by: Josh Triplett <[email protected]>
Acked-by: WANG Cong <[email protected]>
Acked-by: Peter Oberparleiter <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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sh: Enable CONFIG_GCOV_PROFILE_ALL for sh

This patch enables gcov kernel profiling over the whole kernel for sh.
Profiling of specific files individually already worked. A handful of
files have to b

sh: Enable CONFIG_GCOV_PROFILE_ALL for sh

This patch enables gcov kernel profiling over the whole kernel for sh.
Profiling of specific files individually already worked. A handful of
files have to be explicitly excluded from the profiling to avoid
breaking things, notably pmb.c.

Signed-off-by: Chris Smith <[email protected]>
Signed-off-by: Stuart Menefy <[email protected]>
Signed-off-by: Paul Mundt <[email protected]>

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microblaze: Enable GCOV_PROFILE_ALL

Signed-off-by: Michal Simek <[email protected]>

powerpc: Enable GCOV

Make it possible to enable GCOV code coverage measurement on powerpc.

Lightly tested on 64-bit, seems to work as expected.

Signed-off-by: Michael Ellerman <[email protected]

powerpc: Enable GCOV

Make it possible to enable GCOV code coverage measurement on powerpc.

Lightly tested on 64-bit, seems to work as expected.

Signed-off-by: Michael Ellerman <[email protected]>
Signed-off-by: Benjamin Herrenschmidt <[email protected]>

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gcov: enable GCOV_PROFILE_ALL for x86_64

Enable gcov profiling of the entire kernel on x86_64. Required changes
include disabling profiling for:

* arch/kernel/acpi/realmode and arch/kernel/boot/com

gcov: enable GCOV_PROFILE_ALL for x86_64

Enable gcov profiling of the entire kernel on x86_64. Required changes
include disabling profiling for:

* arch/kernel/acpi/realmode and arch/kernel/boot/compressed:
not linked to main kernel
* arch/vdso, arch/kernel/vsyscall_64 and arch/kernel/hpet:
profiling causes segfaults during boot (incompatible context)

Signed-off-by: Peter Oberparleiter <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Huang Ying <[email protected]>
Cc: Li Wei <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: WANG Cong <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Jeff Dike <[email protected]>
Cc: Al Viro <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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