From: Marco Elver <elver@google.com>
To: elver@google.com, Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kasan-dev@googlegroups.com,
Peter Zijlstra <peterz@infradead.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Nathan Chancellor <nathan@kernel.org>,
Dmitry Vyukov <dvyukov@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH] kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR
Date: Wed, 1 Dec 2021 16:26:04 +0100 [thread overview]
Message-ID: <20211201152604.3984495-1-elver@google.com> (raw)
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,
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.
Signed-off-by: Marco Elver <elver@google.com>
---
arch/x86/Kconfig | 2 +-
lib/Kconfig.debug | 2 ++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 95dd1ee01546..c030b2ee93b3 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -78,7 +78,7 @@ config X86
select ARCH_HAS_FILTER_PGPROT
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
- select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION
+ select ARCH_HAS_KCOV if X86_64
select ARCH_HAS_MEM_ENCRYPT
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 9ef7ce18b4f5..589c8aaa2d5b 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1977,6 +1977,8 @@ 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
--
2.34.0.rc2.393.gf8c9666880-goog
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WARNING: multiple messages have this Message-ID (diff)
From: Marco Elver <elver@google.com>
To: elver@google.com, Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kasan-dev@googlegroups.com,
Peter Zijlstra <peterz@infradead.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Nathan Chancellor <nathan@kernel.org>,
Dmitry Vyukov <dvyukov@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH] kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR
Date: Wed, 1 Dec 2021 16:26:04 +0100 [thread overview]
Message-ID: <20211201152604.3984495-1-elver@google.com> (raw)
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,
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.
Signed-off-by: Marco Elver <elver@google.com>
---
arch/x86/Kconfig | 2 +-
lib/Kconfig.debug | 2 ++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 95dd1ee01546..c030b2ee93b3 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -78,7 +78,7 @@ config X86
select ARCH_HAS_FILTER_PGPROT
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
- select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION
+ select ARCH_HAS_KCOV if X86_64
select ARCH_HAS_MEM_ENCRYPT
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 9ef7ce18b4f5..589c8aaa2d5b 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1977,6 +1977,8 @@ 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
--
2.34.0.rc2.393.gf8c9666880-goog
next reply other threads:[~2021-12-01 15:27 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-01 15:26 Marco Elver [this message]
2021-12-01 15:26 ` [PATCH] kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR Marco Elver
2021-12-01 15:57 ` Mark Rutland
2021-12-01 15:57 ` Mark Rutland
2021-12-01 16:10 ` Marco Elver
2021-12-01 16:10 ` Marco Elver
2021-12-01 17:46 ` Mark Rutland
2021-12-01 17:46 ` Mark Rutland
2021-12-01 18:16 ` Marco Elver
2021-12-01 18:16 ` Marco Elver
2021-12-01 18:28 ` Mark Rutland
2021-12-01 18:28 ` Mark Rutland
2021-12-01 17:16 ` Nathan Chancellor
2021-12-01 17:16 ` Nathan Chancellor
2021-12-02 14:50 ` Peter Zijlstra
2021-12-02 14:50 ` Peter Zijlstra
2021-12-02 17:38 ` Marco Elver
2021-12-02 17:38 ` Marco Elver
2021-12-02 17:56 ` Peter Zijlstra
2021-12-02 17:56 ` Peter Zijlstra
2021-12-09 10:00 ` Marco Elver
2021-12-09 10:00 ` Marco Elver
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