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From: Catalin Marinas <catalin.marinas@arm.com>
To: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v6 4/4] arm64: Use a variable to store non-global mappings decision
Date: Wed, 6 Nov 2019 10:24:28 +0000	[thread overview]
Message-ID: <20191106102428.GE21133@arrakis.emea.arm.com> (raw)
In-Reply-To: <20191105214854.30725-5-broonie@kernel.org>

On Tue, Nov 05, 2019 at 09:48:54PM +0000, Mark Brown wrote:
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 60c929f3683b..8462a358a1dc 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -679,6 +679,13 @@ void __init paging_init(void)
>  	cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
>  	init_mm.pgd = swapper_pg_dir;
>  
> +        /*
> +         * If know now we are going to need KPTI then use non-global
> +         * mappings from the start, avoiding the cost of rewriting
> +         * everything later.
> +         */
> +        arm64_use_ng_mappings = kaslr_requires_kpti();

This really needs to be done before map_kernel() and map_mem() in
paging_init(). Tested this series and most of the linear map does not
have the nG bit when it should (/sys/kernel/debug/kernel_page_tables).

-- 
Catalin

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  reply	other threads:[~2019-11-06 10:24 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-05 21:48 [PATCH v6 0/4] E0PD support Mark Brown
2019-11-05 21:48 ` [PATCH v6 1/4] arm64: Add initial support for E0PD Mark Brown
2019-11-05 21:48 ` [PATCH v6 2/4] arm64: Factor out checks for KASLR in KPTI code into separate function Mark Brown
2019-11-05 21:48 ` [PATCH v6 3/4] arm64: Don't use KPTI where we have E0PD Mark Brown
2019-11-05 21:48 ` [PATCH v6 4/4] arm64: Use a variable to store non-global mappings decision Mark Brown
2019-11-06 10:24   ` Catalin Marinas [this message]
2019-11-06 12:12     ` Mark Brown

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