linux-stable.git/kernel/gcov/Kconfig, branch v5.2

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46+00:00

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 
Signed-off-by: Greg Kroah-Hartman

gcov: clang support

2019-05-15T02:52:51+00:00

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().

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20190417225328.208129-1-trong@android.com
Signed-off-by: Greg Hackmann 
Signed-off-by: Nick Desaulniers 
Signed-off-by: Tri Vo 
Co-developed-by: Nick Desaulniers 
Co-developed-by: Tri Vo 
Tested-by: Trilok Soni 
Tested-by: Prasad Sodagudi 
Tested-by: Tri Vo 
Tested-by: Daniel Mentz 
Tested-by: Petri Gynther 
Reviewed-by: Peter Oberparleiter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT

2018-06-08T09:56:02+00:00

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 
Acked-by: Peter Oberparleiter 
Reviewed-by: Kees Cook

gcov: disable for COMPILE_TEST

2016-05-10T15:12:49+00:00

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 
Acked-by: Peter Oberparleiter 
Signed-off-by: Michal Marek

gcov: enable GCOV_PROFILE_ALL from ARCH Kconfigs

2014-12-13T20:42:51+00:00

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 
Cc: Peter Oberparleiter 
Cc: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gcov: add ARM64 to GCOV_PROFILE_ALL

2014-10-29T23:33:14+00:00

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 
Acked-by: Peter Oberparleiter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

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

2014-09-26T13:39:57+00:00

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 
Cc: Naresh Kamboju 
Acked-by: Arnd Bergmann 
Signed-off-by: Riku Voipio 
Signed-off-by: Vincent Sanders 
Signed-off-by: Russell King

gcov: compile specific gcov implementation based on gcc version

2013-11-13T03:09:34+00:00

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

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

kernel/gcov: remove depends on CONFIG_EXPERIMENTAL

2013-01-11T19:39:33+00:00

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 
Signed-off-by: Kees Cook 
Acked-by: Peter Oberparleiter

gcov: disable CONSTRUCTORS for UML

2011-07-26T23:49:45+00:00

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 
Cc: Peter Oberparleiter 
Acked-by: Richard Weinberger 
Acked-by: WANG Cong 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds