From: Catalin Marinas <catalin.marinas@arm.com>
To: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: linux-arm-kernel@lists.infradead.org, keescook@chromium.org,
dave.martin@arm.com, will@kernel.org
Subject: Re: [PATCH v4 1/2] arm64: Support execute-only permissions with Enhanced PAN
Date: Fri, 26 Mar 2021 11:04:45 +0000 [thread overview]
Message-ID: <20210326110444.GB5126@arm.com> (raw)
In-Reply-To: <20210312173811.58284-2-vladimir.murzin@arm.com>
On Fri, Mar 12, 2021 at 05:38:10PM +0000, Vladimir Murzin wrote:
> @@ -992,6 +995,18 @@ static inline bool arch_wants_old_prefaulted_pte(void)
> }
> #define arch_wants_old_prefaulted_pte arch_wants_old_prefaulted_pte
>
> +static inline pgprot_t arch_filter_pgprot(pgprot_t prot)
> +{
> + if (cpus_have_const_cap(ARM64_HAS_EPAN))
> + return prot;
> +
> + if (pgprot_val(prot) != pgprot_val(PAGE_EXECONLY))
> + return prot;
> +
> + return PAGE_READONLY_EXEC;
> +}
Just a thought: we could allow exec-only permissions if
!system_uses_hw_pan(), though not sure it's worth it. We'd have 8.0 CPUs
with exec-only then a gap up to 8.7 when we add it back in (since most
kernels will turn PAN on).
--
Catalin
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next prev parent reply other threads:[~2021-03-26 11:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-12 17:38 [PATCH v4 0/2] arm64: Support Enhanced PAN Vladimir Murzin
2021-03-12 17:38 ` [PATCH v4 1/2] arm64: Support execute-only permissions with " Vladimir Murzin
2021-03-25 19:06 ` Will Deacon
2021-03-26 11:04 ` Catalin Marinas [this message]
2021-03-30 8:47 ` Geert Uytterhoeven
2021-03-30 9:30 ` Catalin Marinas
2021-03-30 9:34 ` Geert Uytterhoeven
2021-03-12 17:38 ` [PATCH v4 2/2] arm64: Introduce HWCAPS2_EXECONLY Vladimir Murzin
2021-03-25 19:00 ` Will Deacon
2021-03-26 9:35 ` Catalin Marinas
2021-03-29 8:53 ` Will Deacon
2021-03-26 11:05 ` (subset) [PATCH v4 0/2] arm64: Support Enhanced PAN Catalin Marinas
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