[merged] kcov-fix-generic-kconfig-dependencies-if-arch_wants_no_instr.patch removed from -mm tree

[akpm@linux-foundation.org]

The patch titled
     Subject: kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR
has been removed from the -mm tree.  Its filename was
     kcov-fix-generic-kconfig-dependencies-if-arch_wants_no_instr.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Marco Elver <elver@google.com>
Subject: 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,
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: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/x86/Kconfig  |    2 +-
 lib/Kconfig.debug |    2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

--- a/arch/x86/Kconfig~kcov-fix-generic-kconfig-dependencies-if-arch_wants_no_instr
+++ a/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
--- a/lib/Kconfig.debug~kcov-fix-generic-kconfig-dependencies-if-arch_wants_no_instr
+++ a/lib/Kconfig.debug
@@ -1985,6 +1985,8 @@ 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
_

Patches currently in -mm which might be from elver@google.com are

lib-stackdepot-always-do-filter_irq_stacks-in-stack_depot_save.patch