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From: Peter Zijlstra <peterz@infradead.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Jason Baron <jbaron@akamai.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ard Biesheuvel <ardb@kernel.org>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Sami Tolvanen <samitolvanen@google.com>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Will McVicker <willmcvicker@google.com>,
	Kees Cook <keescook@chromium.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 08/11] arm64/static_call: Fix static call CFI violations
Date: Wed, 22 Mar 2023 15:19:33 +0100	[thread overview]
Message-ID: <20230322141933.GD2357380@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <ZBry75KS3F+a0VM0@FVFF77S0Q05N>

On Wed, Mar 22, 2023 at 12:22:07PM +0000, Mark Rutland wrote:
> On Tue, Mar 21, 2023 at 09:00:14PM -0700, Josh Poimboeuf wrote:

> > +++ b/arch/arm64/include/asm/static_call.h
> > @@ -0,0 +1,29 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _ASM_ARM64_STATIC_CALL_H
> > +#define _ASM_ARM64_STATIC_CALL_H
> > +
> > +/*
> > + * Make a dummy reference to a function pointer in C to force the compiler to
> > + * emit a __kcfi_typeid_ symbol for asm to use.
> > + */
> > +#define GEN_CFI_SYM(func)						\
> > +	static typeof(func) __used __section(".discard.cfi") *__UNIQUE_ID(cfi) = func
> > +
> > +
> > +/* Generate a CFI-compliant static call NOP function */
> > +#define __ARCH_DEFINE_STATIC_CALL_CFI(name, insns)			\
> > +	asm(".align 4						\n"	\

Should this ^ be:

	__ALIGN_STR "\n" \

> > +	    ".word __kcfi_typeid_" name "			\n"	\
> > +	    ".globl " name "					\n"	\
> > +	    name ":						\n"	\
> > +	    "bti c						\n"	\
> > +	    insns "						\n"	\
> > +	    "ret						\n"	\
> > +	    ".type " name ", @function				\n"	\
> > +	    ".size " name ", . - " name "			\n")

Also, Mark, I think you can remove __ALIGN and __ALIGN_STR from
arch/arm64/include/linkage.h they're very similar to the generic one.

  reply	other threads:[~2023-03-22 14:20 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-22  4:00 [PATCH v2 00/11] static_call: Improve NULL/ret0 handling Josh Poimboeuf
2023-03-22  4:00 ` [PATCH v2 01/11] static_call: Improve key type abstraction Josh Poimboeuf
2023-03-22  4:53   ` Josh Poimboeuf
2023-03-22  5:02   ` [PATCH v2.1 " Josh Poimboeuf
2023-03-22  4:00 ` [PATCH v2 02/11] static_call: Flip key type union bit Josh Poimboeuf
2023-03-22  5:03   ` [PATCH v2.1 " Josh Poimboeuf
2023-03-22  4:00 ` [PATCH v2 03/11] static_call: Remove static_call_mod_init() declaration Josh Poimboeuf
2023-03-22  4:00 ` [PATCH v2 04/11] static_call: Remove static_call.h dependency on cpu.h Josh Poimboeuf
2023-03-22  4:00 ` [PATCH v2 05/11] static_call: Make ARCH_ADD_TRAMP_KEY() generic Josh Poimboeuf
2023-03-22  4:00 ` [PATCH v2 06/11] static_call: "EXPORT_STATIC_CALL_TRAMP" -> "EXPORT_STATIC_CALL_RO" Josh Poimboeuf
2023-03-22  4:00 ` [PATCH v2 07/11] static_call: Reorganize static call headers Josh Poimboeuf
2023-03-22  4:00 ` [PATCH v2 08/11] arm64/static_call: Fix static call CFI violations Josh Poimboeuf
2023-03-22 12:22   ` Mark Rutland
2023-03-22 14:19     ` Peter Zijlstra [this message]
2023-03-22 18:26       ` Josh Poimboeuf
2023-03-22 18:09     ` Josh Poimboeuf
2023-03-22 18:07   ` Sami Tolvanen
2023-03-22 18:33     ` Josh Poimboeuf
2023-03-22  4:00 ` [PATCH v2 09/11] static_call: Make NULL static calls consistent Josh Poimboeuf
2023-03-22 14:45   ` Peter Zijlstra
2023-03-22 14:59   ` Peter Zijlstra
2023-03-22 18:35     ` Josh Poimboeuf
2023-03-22 15:04   ` Christophe Leroy
2023-03-22  4:00 ` [PATCH v2 10/11] static_call: Remove static_call_cond() Josh Poimboeuf
2023-03-22  4:00 ` [PATCH v2 11/11] static_call: Remove DEFINE_STATIC_CALL_RET0() Josh Poimboeuf
2023-03-22 15:04   ` Christophe Leroy
2023-03-22 18:50     ` Josh Poimboeuf
2023-03-22 15:15   ` Peter Zijlstra
2023-03-22 18:45     ` Josh Poimboeuf

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