From: Catalin Marinas <catalin.marinas@arm.com>
To: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: keescook@chromium.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 2/2] arm64: Expose EPAN support via HWCAPS2_EPAN
Date: Tue, 17 Nov 2020 16:59:37 +0000 [thread overview]
Message-ID: <X7QBefooa2VbMS47@trantor> (raw)
In-Reply-To: <20201113152023.102855-3-vladimir.murzin@arm.com>
On Fri, Nov 13, 2020 at 03:20:23PM +0000, Vladimir Murzin wrote:
> So user have a clue whether exec-only permissions will work.
I do think we should tell user the PROT_EXEC actually gives execute-only
permission.
> --- a/arch/arm64/include/uapi/asm/hwcap.h
> +++ b/arch/arm64/include/uapi/asm/hwcap.h
> @@ -75,5 +75,6 @@
> #define HWCAP2_RNG (1 << 16)
> #define HWCAP2_BTI (1 << 17)
> #define HWCAP2_MTE (1 << 18)
> +#define HWCAP2_EPAN (1 << 19)
However, I wonder whether EPAN is meaningful to the user. PAN is a
kernel protection that doesn't say much from a user perspective. Maybe
something like HWCAP2_EXECONLY?
That said, we do have a precedent on 32-bit where we exposed HWCAP_LPAE
to the user meaning that 64-bit atomics are available.
--
Catalin
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next prev parent reply other threads:[~2020-11-17 17:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-13 15:20 [RFC PATCH 0/2] arm64: Support Enhanced PAN Vladimir Murzin
2020-11-13 15:20 ` [RFC PATCH 1/2] arm64: Support execute-only permissions with " Vladimir Murzin
2020-11-17 16:47 ` Catalin Marinas
2020-11-18 12:37 ` Vladimir Murzin
2020-11-18 16:04 ` Catalin Marinas
2020-11-19 13:39 ` Vladimir Murzin
2020-11-13 15:20 ` [RFC PATCH 2/2] arm64: Expose EPAN support via HWCAPS2_EPAN Vladimir Murzin
2020-11-17 16:59 ` Catalin Marinas [this message]
2020-11-18 12:43 ` Vladimir Murzin
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