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From: Sami Tolvanen <samitolvanen@google.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Kees Cook <keescook@chromium.org>,
	 Josh Poimboeuf <jpoimboe@redhat.com>, X86 ML <x86@kernel.org>,
	 Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	 Mark Rutland <mark.rutland@arm.com>,
	Nathan Chancellor <nathan@kernel.org>,
	 Nick Desaulniers <ndesaulniers@google.com>,
	Joao Moreira <joao@overdrivepizza.com>,
	 Sedat Dilek <sedat.dilek@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	 linux-hardening@vger.kernel.org,
	 linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	llvm@lists.linux.dev
Subject: Re: [RFC PATCH 16/21] objtool: Add support for CONFIG_CFI_CLANG
Date: Fri, 29 Apr 2022 18:00:03 -0700	[thread overview]
Message-ID: <CABCJKufNUoJJPcraG-o2AvTBSWmFEQAzg0z-Z=xLohBqsMA3KQ@mail.gmail.com> (raw)
In-Reply-To: <Ymx1JcO36h7YqLa0@hirez.programming.kicks-ass.net>

On Fri, Apr 29, 2022 at 4:30 PM Peter Zijlstra <peterz@infradead.org> wrote:
> Urgh, what does this do for decode speed? This is a hash-lookup for
> every single instruction.

Two actually, since .kcfi_traps only contains compiler-emitted
locations and we also have to check for manual type annotations. I
haven't measured performance yet, but I also didn't notice a
significant impact here.

> Is that kcfi location array sorted by the compiler? Because then you can
> keep a running iterator and replace the whole lookup with a simple
> equality comparison.

The compiler generates a separate .kcfi_types section for each text
section and the entries are emitted in order, so this should be
doable.

Sami

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  reply	other threads:[~2022-04-30  1:02 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-29 20:36 [RFC PATCH 00/21] KCFI support Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 01/21] efi/libstub: Filter out CC_FLAGS_CFI Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 02/21] arm64/vdso: " Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 03/21] kallsyms: Ignore __kcfi_typeid_ Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 04/21] cfi: Remove CONFIG_CFI_CLANG_SHADOW Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 05/21] cfi: Drop __CFI_ADDRESSABLE Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 06/21] cfi: Switch to -fsanitize=kcfi Sami Tolvanen
2022-04-30  9:09   ` Peter Zijlstra
2022-04-29 20:36 ` [RFC PATCH 07/21] cfi: Add type helper macros Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 08/21] arm64/crypto: Add types to indirect called assembly functions Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 09/21] arm64: Add CFI error handling Sami Tolvanen
2022-05-05 15:44   ` Mark Rutland
2022-05-05 16:23     ` Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 10/21] treewide: Drop function_nocfi Sami Tolvanen
2022-05-05 16:30   ` Mark Rutland
2022-05-05 16:51     ` Sami Tolvanen
2022-05-05 18:03       ` Mark Rutland
2022-04-29 20:36 ` [RFC PATCH 11/21] treewide: Drop WARN_ON_FUNCTION_MISMATCH Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 12/21] treewide: Drop __cficanonical Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 13/21] cfi: Add the cfi_unchecked macro Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 14/21] treewide: static_call: Pass call arguments to the macro Sami Tolvanen
2022-04-29 23:21   ` Peter Zijlstra
2022-04-30  0:49     ` Sami Tolvanen
2022-05-02  7:46       ` Peter Zijlstra
2022-04-29 20:36 ` [RFC PATCH 15/21] static_call: Use cfi_unchecked Sami Tolvanen
2022-04-29 23:23   ` Peter Zijlstra
2022-04-29 20:36 ` [RFC PATCH 16/21] objtool: Add support for CONFIG_CFI_CLANG Sami Tolvanen
2022-04-29 23:30   ` Peter Zijlstra
2022-04-30  1:00     ` Sami Tolvanen [this message]
2022-04-29 20:36 ` [RFC PATCH 17/21] x86/tools/relocs: Ignore __kcfi_typeid_ relocations Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 18/21] x86: Add types to indirect called assembly functions Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 19/21] x86/purgatory: Disable CFI Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 20/21] x86/vdso: " Sami Tolvanen
2022-04-29 20:36 ` [RFC PATCH 21/21] x86: Add support for CONFIG_CFI_CLANG Sami Tolvanen
2022-04-30  9:24   ` Peter Zijlstra
2022-05-02 15:20     ` Sami Tolvanen
2022-04-29 22:53 ` [RFC PATCH 00/21] KCFI support Kees Cook
2022-04-30  9:02   ` Peter Zijlstra
2022-05-02 15:22     ` Sami Tolvanen
2022-05-02 19:55       ` Peter Zijlstra
2022-05-03 22:35         ` Peter Collingbourne
2022-05-04  7:34           ` Peter Zijlstra
2022-04-30 16:07 ` Kenton Groombridge
2022-05-02 15:31   ` Sami Tolvanen
2022-05-04 16:17 ` Mark Rutland
2022-05-04 16:41   ` Sami Tolvanen
2022-05-04 20:17     ` Sami Tolvanen
2022-05-05 12:36       ` Mark Rutland
2022-05-05 16:00         ` Sami Tolvanen
2022-05-05 17:14           ` Mark Rutland

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