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Date:   Sat, 23 Jul 2022 13:21:33 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Sami Tolvanen <samitolvanen@google.com>
Cc:     linux-kernel@vger.kernel.org, Kees Cook <keescook@chromium.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>, 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@lists.infradead.org, llvm@lists.linux.dev
Subject: Re: [RFC PATCH v3 20/20] x86: Add support for CONFIG_CFI_CLANG
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References: <20220610233513.1798771-1-samitolvanen@google.com>
 <20220610233513.1798771-21-samitolvanen@google.com>
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On Fri, Jun 10, 2022 at 04:35:13PM -0700, Sami Tolvanen wrote:

> +#ifdef CONFIG_CFI_CLANG
> +#define __CFI_TYPE(name)					\
> +	.fill 7, 1, 0xCC ASM_NL					\
> +	SYM_START(__cfi_##name, SYM_L_LOCAL, SYM_A_NONE)	\
> +	int3 ASM_NL						\
> +	int3 ASM_NL						\
> +	mov __kcfi_typeid_##name, %eax ASM_NL			\
> +	int3 ASM_NL						\
> +	int3 ASM_NL						\
> +	SYM_FUNC_END(__cfi_##name)
> +#endif

Like said on IRC yesterday, this doesn't generate the right mov
encoding.

	.byte 0xb8 ; .long __kcfi_typeid_##name ;		\

works. Your LLVM tree already has the ZExt patch you gave me yesterday
to fix up the linker fallout from this change.