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| author | Marco Elver <elver@google.com> | 2022-01-19 18:10:31 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-01-20 08:52:55 +0200 |
| commit | bece04b5b41dd7730dd06aec0d6b15c53d1fbb5a (patch) | |
| tree | 80e2c0030164cc60b37aff27866f922067315081 /lib/Kconfig.debug | |
| parent | bbd2e05fad3e692ff2495895975bd0fce02bdbae (diff) | |
| download | lwn-bece04b5b41dd7730dd06aec0d6b15c53d1fbb5a.tar.gz lwn-bece04b5b41dd7730dd06aec0d6b15c53d1fbb5a.zip | |
kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR
Until recent versions of GCC and Clang, it was not possible to disable
KCOV instrumentation via a function attribute. The relevant function
attribute was introduced in 540540d06e9d9 ("kcov: add
__no_sanitize_coverage to fix noinstr for all architectures").
x86 was the first architecture to want a working noinstr, and at the
time no compiler support for the attribute existed yet. Therefore,
commit 0f1441b44e823 ("objtool: Fix noinstr vs KCOV") introduced the
ability to NOP __sanitizer_cov_*() calls in .noinstr.text.
However, this doesn't work for other architectures like arm64 and s390
that want a working noinstr per ARCH_WANTS_NO_INSTR.
At the time of 0f1441b44e823, we didn't yet have ARCH_WANTS_NO_INSTR,
but now we can move the Kconfig dependency checks to the generic KCOV
option. KCOV will be available if:
- architecture does not care about noinstr, OR
- we have objtool support (like on x86), OR
- GCC is 12.0 or newer, OR
- Clang is 13.0 or newer.
Link: https://lkml.kernel.org/r/20211201152604.3984495-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/Kconfig.debug')
| -rw-r--r-- | lib/Kconfig.debug | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 666e070feeb6..1a5d168c388b 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1979,6 +1979,8 @@ config KCOV bool "Code coverage for fuzzing" depends on ARCH_HAS_KCOV depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS + depends on !ARCH_WANTS_NO_INSTR || STACK_VALIDATION || \ + GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 select DEBUG_FS select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC help |