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From: Catalin Marinas <catalin.marinas@arm.com>
To: Amit Daniel Kachhap <amit.kachhap@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Kees Cook <keescook@chromium.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Richard Henderson <richard.henderson@linaro.org>,
	Kristina Martsenko <kristina.martsenko@arm.com>,
	James Morse <james.morse@arm.com>,
	Ramana Radhakrishnan <ramana.radhakrishnan@arm.com>,
	Mark Brown <Mark.Brown@arm.com>,
	Vincenzo Frascino <Vincenzo.Frascino@arm.com>,
	Will Deacon <will@kernel.org>, Dave Martin <Dave.Martin@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 06/16] arm64: enable ptrauth earlier
Date: Thu, 16 Jan 2020 16:24:14 +0000	[thread overview]
Message-ID: <20200116162414.GF10277@arrakis.emea.arm.com> (raw)
In-Reply-To: <1576486038-9899-7-git-send-email-amit.kachhap@arm.com>

On Mon, Dec 16, 2019 at 02:17:08PM +0530, Amit Daniel Kachhap wrote:
> diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
> index 5aaf1bb..c59c28f 100644
> --- a/arch/arm64/kernel/head.S
> +++ b/arch/arm64/kernel/head.S
> @@ -13,6 +13,7 @@
>  #include <linux/init.h>
>  #include <linux/irqchip/arm-gic-v3.h>
>  
> +#include <asm/alternative.h>
>  #include <asm/assembler.h>
>  #include <asm/boot.h>
>  #include <asm/ptrace.h>
> @@ -713,6 +714,7 @@ secondary_startup:
>  	 * Common entry point for secondary CPUs.
>  	 */
>  	bl	__cpu_secondary_check52bitva
> +	bl	__cpu_secondary_checkptrauth
>  	mov	x0, #ARM64_CPU_BOOT_LATE
>  	bl	__cpu_setup			// initialise processor
>  	adrp	x1, swapper_pg_dir
> @@ -831,6 +833,24 @@ __no_granule_support:
>  	early_park_cpu CPU_STUCK_REASON_NO_GRAN
>  ENDPROC(__no_granule_support)
>  
> +ENTRY(__cpu_secondary_checkptrauth)
> +#ifdef CONFIG_ARM64_PTR_AUTH
> +	/* Check if the CPU supports ptrauth */
> +	mrs	x2, id_aa64isar1_el1
> +	ubfx	x2, x2, #ID_AA64ISAR1_APA_SHIFT, #8
> +	cbnz	x2, 1f
> +alternative_if ARM64_HAS_ADDRESS_AUTH
> +	mov	x3, 1
> +alternative_else
> +	mov	x3, 0
> +alternative_endif
> +	cbz	x3, 1f
> +	/* Park the mismatched secondary CPU */
> +	early_park_cpu CPU_STUCK_REASON_NO_PTRAUTH
> +#endif
> +1:	ret
> +ENDPROC(__cpu_secondary_checkptrauth)

Do we actually need to park secondary CPUs early? Let's say a secondary
CPU doesn't have PAC, __cpu_setup won't set the corresponding SCTLR_EL1
bits and the instructions are NOPs. Wouldn't the cpufeature framework
park it later anyway?

-- 
Catalin

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  parent reply	other threads:[~2020-01-16 16:24 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-16  8:47 [PATCH v3 00/16] arm64: return address signing Amit Daniel Kachhap
2019-12-16  8:47 ` [PATCH v3 01/16] arm64: cpufeature: add pointer auth meta-capabilities Amit Daniel Kachhap
2020-01-15 12:26   ` Catalin Marinas
2020-01-15 13:52     ` Suzuki Kuruppassery Poulose
2020-01-15 16:01       ` Catalin Marinas
2020-01-16 12:35         ` Amit Kachhap
2019-12-16  8:47 ` [PATCH v3 02/16] arm64: rename ptrauth key structures to be user-specific Amit Daniel Kachhap
2020-01-15 16:42   ` Catalin Marinas
2019-12-16  8:47 ` [PATCH v3 03/16] arm64: install user ptrauth keys at kernel exit time Amit Daniel Kachhap
2020-01-15 17:02   ` Catalin Marinas
2020-01-16 12:39     ` Amit Kachhap
2019-12-16  8:47 ` [PATCH v3 04/16] arm64: create macro to park cpu in an infinite loop Amit Daniel Kachhap
2020-01-07 11:13   ` Suzuki Kuruppassery Poulose
2020-01-15 17:03   ` Catalin Marinas
2019-12-16  8:47 ` [PATCH v3 05/16] arm64: ptrauth: Add bootup/runtime flags for __cpu_setup Amit Daniel Kachhap
2020-01-07 11:18   ` Suzuki Kuruppassery Poulose
2020-01-09  8:33     ` Amit Kachhap
2020-01-15 17:30   ` Catalin Marinas
2020-01-16 12:40     ` Amit Kachhap
2019-12-16  8:47 ` [PATCH v3 06/16] arm64: enable ptrauth earlier Amit Daniel Kachhap
2020-01-07 11:35   ` Suzuki Kuruppassery Poulose
2020-01-09  8:29     ` Amit Kachhap
2020-01-10 10:18       ` Suzuki Kuruppassery Poulose
2020-01-16 16:24   ` Catalin Marinas [this message]
2020-01-17 10:43     ` Amit Kachhap
2020-01-17 12:00       ` Catalin Marinas
2020-01-20 14:27         ` Amit Kachhap
2019-12-16  8:47 ` [PATCH v3 07/16] arm64: initialize and switch ptrauth kernel keys Amit Daniel Kachhap
2020-01-16 18:00   ` Catalin Marinas
2019-12-16  8:47 ` [PATCH v3 08/16] arm64: initialize ptrauth keys for kernel booting task Amit Daniel Kachhap
2020-01-16 17:59   ` Catalin Marinas
2020-01-20 10:50     ` Amit Kachhap
2019-12-16  8:47 ` [PATCH v3 09/16] arm64: mask PAC bits of __builtin_return_address Amit Daniel Kachhap
2020-01-17 10:14   ` Catalin Marinas
2020-01-20 14:20     ` Amit Kachhap
2020-01-21 16:52       ` Catalin Marinas
2019-12-16  8:47 ` [PATCH v3 10/16] arm64: unwind: strip PAC from kernel addresses Amit Daniel Kachhap
2020-01-17 10:22   ` Catalin Marinas
2019-12-16  8:47 ` [PATCH v3 11/16] arm64: __show_regs: strip PAC from lr in printk Amit Daniel Kachhap
2020-01-17 10:25   ` Catalin Marinas
2019-12-16  8:47 ` [PATCH v3 12/16] arm64: suspend: restore the kernel ptrauth keys Amit Daniel Kachhap
2020-01-17 10:31   ` Catalin Marinas
2019-12-16  8:47 ` [PATCH v3 13/16] arm64: kprobe: disable probe of ptrauth instruction Amit Daniel Kachhap
2020-01-17 11:16   ` Catalin Marinas
2020-01-20 14:24     ` Amit Kachhap
2019-12-16  8:47 ` [PATCH v3 14/16] kconfig: Add support for 'as-option' Amit Daniel Kachhap
2019-12-17 11:43   ` Masahiro Yamada
2020-01-17 11:33   ` Catalin Marinas
2020-01-17 17:51     ` Masahiro Yamada
2020-01-20 10:26     ` Vincenzo Frascino
2019-12-16  8:47 ` [PATCH v3 15/16] arm64: compile the kernel with ptrauth return address signing Amit Daniel Kachhap
2020-01-17 11:49   ` Catalin Marinas
2020-01-21 14:37     ` Amit Kachhap
2020-01-21 14:46       ` Vincenzo Frascino
2020-01-21 16:50       ` Catalin Marinas
2019-12-16  8:47 ` [PATCH v3 16/16] lkdtm: arm64: test kernel pointer authentication Amit Daniel Kachhap
2020-01-17 11:53   ` Catalin Marinas
2019-12-16  9:35 ` [RESEND PATCH v3 00/16] arm64: return address signing Amit Daniel Kachhap
2019-12-30 19:09 ` [PATCH " Kees Cook
2020-01-07 11:07   ` Amit Kachhap

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