linux.git/kernel/gcov/Kconfig, branch v4.9.262

gcov: add support for GCC 10.1

2020-09-23T06:46:14+00:00

[ Upstream commit 40249c6962075c040fd071339acae524f18bfac9 ]

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 
Reported-by: Leon Romanovsky 
Signed-off-by: Peter Oberparleiter 
Tested-by: Leon Romanovsky 
Tested-and-Acked-by: Colin Ian King 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

gcov: Disable gcov build with GCC 10

2020-09-23T06:46:10+00:00

[ Upstream commit cfc905f158eaa099d6258031614d11869e7ef71c ]

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/20200827133932.3338519-1-leon@kernel.org
Link: https://lore.kernel.org/lkml/CAHk-=whbijeSdSvx-Xcr0DPMj0BiwhJ+uiNnDSVZcr_h_kg7UA@mail.gmail.com/
Cc: Colin Ian King 
Signed-off-by: Leon Romanovsky 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

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

gcov: disable CONFIG_CONSTRUCTORS when not needed by CONFIG_GCOV_KERNEL

2011-06-16T03:04:01+00:00

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