linux-dev/kernel/gcov/Kconfig, branch master

gcov: Remove compiler version check

2021-12-02T08:25:21Z

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 Reviewed-by: Miguel Ojeda Reviewed-by: Mark Brown Reviewed-by: Nick Desaulniers Reviewed-by: Kees Cook Signed-off-by: Masahiro Yamada

Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR

2021-06-22T18:07:18Z

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 Link: https://lore.kernel.org/lkml/YMTn9yjuemKFLbws@hirez.programming.kicks-ass.net/ Link: https://lore.kernel.org/lkml/YMcssV%2Fn5IBGv4f0@hirez.programming.kicks-ass.net/ Suggested-by: Nathan Chancellor Suggested-by: Peter Zijlstra Signed-off-by: Nick Desaulniers Reviewed-by: Peter Oberparleiter Reviewed-by: Nathan Chancellor Acked-by: Mark Rutland Acked-by: Heiko Carstens Acked-by: Peter Zijlstra (Intel) Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20210621231822.2848305-4-ndesaulniers@google.com

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

2021-05-07T07:26:32Z

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/20210312224132.3413602-3-ndesaulniers@google.com Link: https://lkml.kernel.org/r/20210413183113.2977432-1-ndesaulniers@google.com Signed-off-by: Nick Desaulniers Suggested-by: Nathan Chancellor Acked-by: Peter Oberparleiter Reviewed-by: Nathan Chancellor Reviewed-by: Fangrui Song Cc: Prasad Sodagudi Cc: Johannes Berg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

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

2021-02-05T19:03:47Z

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 Reviewed-by: Peter Oberparleiter Cc: Arnd Bergmann Cc: Jessica Yu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

gcov: add support for GCC 10.1

2020-09-11T16:33:54Z

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

gcov: Disable gcov build with GCC 10

2020-09-04T16:19:49Z

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

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

2020-06-13T16:57:21Z

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

gcov: Remove old GCC 3.4 support

2020-04-16T11:28:35Z

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 Reviewed-by: Nick Desaulniers Signed-off-by: Will Deacon

Revert "um: Enable CONFIG_CONSTRUCTORS"

2020-01-19T21:42:06Z

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: stable@vger.kernel.org [5.4+] Fixes: 786b2384bf1c ("um: Enable CONFIG_CONSTRUCTORS") Reported-by: Anton Ivanov Signed-off-by: Johannes Berg Acked-by: Anton Ivanov Signed-off-by: Richard Weinberger

um: Enable CONFIG_CONSTRUCTORS

2019-09-15T19:37:13Z

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 Signed-off-by: Richard Weinberger