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 09/16] arm64: mask PAC bits of __builtin_return_address
Date: Fri, 17 Jan 2020 10:14:32 +0000 [thread overview]
Message-ID: <20200117101432.GA26090@arrakis.emea.arm.com> (raw)
In-Reply-To: <1576486038-9899-10-git-send-email-amit.kachhap@arm.com>
On Mon, Dec 16, 2019 at 02:17:11PM +0530, Amit Daniel Kachhap wrote:
> diff --git a/arch/arm64/include/asm/compiler.h b/arch/arm64/include/asm/compiler.h
> new file mode 100644
> index 0000000..3cb06f9
> --- /dev/null
> +++ b/arch/arm64/include/asm/compiler.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef __ASM_COMPILER_H
> +#define __ASM_COMPILER_H
> +
> +#if defined(CONFIG_ARM64_PTR_AUTH)
> +
> +/*
> + * The EL0/EL1 pointer bits used by a pointer authentication code.
> + * This is dependent on TBI0/TBI1 being enabled, or bits 63:56 would also apply.
> + */
> +#define ptrauth_user_pac_mask() GENMASK_ULL(54, vabits_actual)
That's the current behaviour but I guess we could extend the mask to 63
here without breaking anything since we don't expect instruction
addresses to be tagged. I also think we should turn TCR_EL1.TBID0 on
when we have PAC present (in a separate patch for both the mask change
and the TCR_EL1 bit as this may be slightly more controversial, a
theoretical ABI change).
> +#define ptrauth_kernel_pac_mask() (GENMASK_ULL(63, 56) | GENMASK_ULL(54, VA_BITS))
I think the kernel mask should be GENMASK_ULL(63, vabits_actual), no
need to skip bit 55 since it's 1 already.
With regards to VA_BITS (a constant), I'm not sure that's correct.
ARMv8.2-LVA (52-bit VA) is an optional feature and I don't think PAC in
8.3 mandates it.
--
Catalin
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next prev parent reply other threads:[~2020-01-17 10:15 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
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 [this message]
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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