From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Marco Elver <elver@google.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>,
Alexander Potapenko <glider@google.com>,
Boqun Feng <boqun.feng@gmail.com>, Borislav Petkov <bp@alien8.de>,
Dmitry Vyukov <dvyukov@google.com>,
Ingo Molnar <mingo@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Waiman Long <longman@redhat.com>, Will Deacon <will@kernel.org>,
kasan-dev@googlegroups.com, linux-arch@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kbuild@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org
Subject: Re: [PATCH v2 23/23] objtool, kcsan: Remove memory barrier instrumentation from noinstr
Date: Fri, 19 Nov 2021 12:31:35 -0800 [thread overview]
Message-ID: <20211119203135.clplwzh3hyo5xddg@treble> (raw)
In-Reply-To: <20211118081027.3175699-24-elver@google.com>
On Thu, Nov 18, 2021 at 09:10:27AM +0100, Marco Elver wrote:
> @@ -1071,12 +1071,7 @@ static void annotate_call_site(struct objtool_file *file,
> return;
> }
>
> - /*
> - * Many compilers cannot disable KCOV with a function attribute
> - * so they need a little help, NOP out any KCOV calls from noinstr
> - * text.
> - */
> - if (insn->sec->noinstr && sym->kcov) {
> + if (insn->sec->noinstr && sym->removable_instr) {
> if (reloc) {
> reloc->type = R_NONE;
> elf_write_reloc(file->elf, reloc);
I'd love to have a clearer name than 'removable_instr', though I'm
having trouble coming up with something.
'profiling_func'?
Profiling isn't really accurate but maybe it gets the point across. I'm
definitely open to other suggestions.
Also, the above code isn't very self-evident so there still needs to be
a comment there, like:
/*
* Many compilers cannot disable KCOV or sanitizer calls with a
* function attribute so they need a little help, NOP out any
* such calls from noinstr text.
*/
> @@ -1991,6 +1986,32 @@ static int read_intra_function_calls(struct objtool_file *file)
> return 0;
> }
>
> +static bool is_removable_instr(const char *name)
> +{
> + /*
> + * Many compilers cannot disable KCOV with a function attribute so they
> + * need a little help, NOP out any KCOV calls from noinstr text.
> + */
> + if (!strncmp(name, "__sanitizer_cov_", 16))
> + return true;
A comment is good here, but the NOP-ing bit seems out of place.
--
Josh
next prev parent reply other threads:[~2021-11-19 20:31 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-18 8:10 [PATCH v2 00/23] kcsan: Support detecting a subset of missing memory barriers Marco Elver
2021-11-18 8:10 ` [PATCH v2 01/23] kcsan: Refactor reading of instrumented memory Marco Elver
2021-11-18 11:08 ` Mark Rutland
2021-11-18 8:10 ` [PATCH v2 02/23] kcsan: Remove redundant zero-initialization of globals Marco Elver
2021-11-18 11:09 ` Mark Rutland
2021-11-18 8:10 ` [PATCH v2 03/23] kcsan: Avoid checking scoped accesses from nested contexts Marco Elver
2021-11-29 8:47 ` Boqun Feng
2021-11-29 10:57 ` Marco Elver
2021-11-29 14:26 ` Boqun Feng
2021-11-29 14:42 ` Marco Elver
2021-11-18 8:10 ` [PATCH v2 04/23] kcsan: Add core support for a subset of weak memory modeling Marco Elver
2021-11-18 8:10 ` [PATCH v2 05/23] kcsan: Add core memory barrier instrumentation functions Marco Elver
2021-11-18 8:10 ` [PATCH v2 06/23] kcsan, kbuild: Add option for barrier instrumentation only Marco Elver
2021-11-18 8:10 ` [PATCH v2 07/23] kcsan: Call scoped accesses reordered in reports Marco Elver
2021-11-18 8:10 ` [PATCH v2 08/23] kcsan: Show location access was reordered to Marco Elver
2021-11-18 8:10 ` [PATCH v2 09/23] kcsan: Document modeling of weak memory Marco Elver
2021-11-18 8:10 ` [PATCH v2 10/23] kcsan: test: Match reordered or normal accesses Marco Elver
2021-11-18 8:10 ` [PATCH v2 11/23] kcsan: test: Add test cases for memory barrier instrumentation Marco Elver
2021-11-18 8:10 ` [PATCH v2 12/23] kcsan: Ignore GCC 11+ warnings about TSan runtime support Marco Elver
2021-11-18 8:10 ` [PATCH v2 13/23] kcsan: selftest: Add test case to check memory barrier instrumentation Marco Elver
2021-11-18 8:10 ` [PATCH v2 14/23] locking/barriers, kcsan: Add instrumentation for barriers Marco Elver
2021-11-18 8:10 ` [PATCH v2 15/23] locking/barriers, kcsan: Support generic instrumentation Marco Elver
2021-11-18 8:10 ` [PATCH v2 16/23] locking/atomics, kcsan: Add instrumentation for barriers Marco Elver
2021-11-18 8:10 ` [PATCH v2 17/23] asm-generic/bitops, " Marco Elver
2021-11-18 8:10 ` [PATCH v2 18/23] x86/barriers, kcsan: Use generic instrumentation for non-smp barriers Marco Elver
2021-11-18 8:10 ` [PATCH v2 19/23] x86/qspinlock, kcsan: Instrument barrier of pv_queued_spin_unlock() Marco Elver
2021-11-18 8:10 ` [PATCH v2 20/23] mm, kcsan: Enable barrier instrumentation Marco Elver
2021-11-18 8:10 ` [PATCH v2 21/23] sched, kcsan: Enable memory " Marco Elver
2021-11-18 8:10 ` [PATCH v2 22/23] objtool, kcsan: Add memory barrier instrumentation to whitelist Marco Elver
2021-11-18 8:10 ` [PATCH v2 23/23] objtool, kcsan: Remove memory barrier instrumentation from noinstr Marco Elver
2021-11-19 20:31 ` Josh Poimboeuf [this message]
2021-11-19 21:31 ` Marco Elver
2021-11-23 11:29 ` Marco Elver
2021-11-24 17:53 ` Josh Poimboeuf
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