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From: Peter Zijlstra <peterz@infradead.org>
To: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
	aruna.ramakrishna@oracle.com, broonie@kernel.org,
	catalin.marinas@arm.com, dave.hansen@linux.intel.com,
	jannh@google.com, jeffxu@chromium.org, joey.gouly@arm.com,
	kees@kernel.org, maz@kernel.org, pierre.langlois@arm.com,
	qperret@google.com, ryan.roberts@arm.com, will@kernel.org,
	linux-arm-kernel@lists.infradead.org, x86@kernel.org
Subject: Re: [RFC PATCH 08/16] mm: Introduce kernel_pgtables_set_pkey()
Date: Mon, 9 Dec 2024 11:03:35 +0100	[thread overview]
Message-ID: <20241209100335.GH21636@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20241206101110.1646108-9-kevin.brodsky@arm.com>

On Fri, Dec 06, 2024 at 10:11:02AM +0000, Kevin Brodsky wrote:
> kernel_pgtables_set_pkey() allows setting the pkey of all page table
> pages in swapper_pg_dir, recursively. This will be needed by
> kpkeys_hardened_pgtables, as it relies on all PTPs being mapped with
> a non-default pkey. Those initial kernel page tables cannot
> practically be assigned a non-default pkey right when they are
> allocated, so mutating them during (early) boot is required.
> 
> Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
> ---
> 
> It feels that some sort of locking is called for in
> kernel_pgtables_set_pkey(), but I couldn't figure out what would be
> appropriate.

init_mm.page_table_lock is typically the one used to serialize kernel
page tables IIRC.


  reply	other threads:[~2024-12-09 10:28 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-06 10:10 [RFC PATCH 00/16] pkeys-based page table hardening Kevin Brodsky
2024-12-06 10:10 ` [RFC PATCH 01/16] mm: Introduce kpkeys Kevin Brodsky
2024-12-06 10:10 ` [RFC PATCH 02/16] set_memory: Introduce set_memory_pkey() stub Kevin Brodsky
2024-12-06 10:10 ` [RFC PATCH 03/16] arm64: mm: Enable overlays for all EL1 indirect permissions Kevin Brodsky
2024-12-06 10:10 ` [RFC PATCH 04/16] arm64: Introduce por_set_pkey_perms() helper Kevin Brodsky
2024-12-06 10:10 ` [RFC PATCH 05/16] arm64: Implement asm/kpkeys.h using POE Kevin Brodsky
2024-12-06 10:11 ` [RFC PATCH 06/16] arm64: set_memory: Implement set_memory_pkey() Kevin Brodsky
2024-12-06 10:11 ` [RFC PATCH 07/16] arm64: Enable kpkeys Kevin Brodsky
2024-12-06 10:11 ` [RFC PATCH 08/16] mm: Introduce kernel_pgtables_set_pkey() Kevin Brodsky
2024-12-09 10:03   ` Peter Zijlstra [this message]
2024-12-10  9:27     ` Kevin Brodsky
2024-12-06 10:11 ` [RFC PATCH 09/16] mm: Introduce kpkeys_hardened_pgtables Kevin Brodsky
2024-12-06 10:11 ` [RFC PATCH 10/16] mm: Map page tables with privileged pkey Kevin Brodsky
2024-12-06 10:11 ` [RFC PATCH 11/16] arm64: kpkeys: Support KPKEYS_LVL_PGTABLES Kevin Brodsky
2024-12-06 10:11 ` [RFC PATCH 12/16] arm64: mm: Map p4d/pgd with privileged pkey Kevin Brodsky
2024-12-09 10:24   ` Peter Zijlstra
2024-12-10  9:27     ` Kevin Brodsky
2024-12-10 12:23       ` Peter Zijlstra
2024-12-11 13:35         ` Kevin Brodsky
2024-12-06 10:11 ` [RFC PATCH 13/16] arm64: mm: Reset pkey in __tlb_remove_table() Kevin Brodsky
2024-12-09 10:29   ` Peter Zijlstra
2024-12-10  9:28     ` Kevin Brodsky
2024-12-10 12:27       ` Peter Zijlstra
2024-12-11 13:37         ` Kevin Brodsky
2024-12-06 10:11 ` [RFC PATCH 14/16] arm64: mm: Guard page table writes with kpkeys Kevin Brodsky
2024-12-06 10:11 ` [RFC PATCH 15/16] arm64: Enable kpkeys_hardened_pgtables support Kevin Brodsky
2024-12-06 10:11 ` [RFC PATCH 16/16] mm: Add basic tests for kpkeys_hardened_pgtables Kevin Brodsky
2024-12-06 19:14 ` [RFC PATCH 00/16] pkeys-based page table hardening Jann Horn
2024-12-09 12:57   ` Kevin Brodsky

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