From: Nick Chan <towinchenmi@gmail.com>
To: Ard Biesheuvel <ardb+git@google.com>,
linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Ryan Roberts <ryan.roberts@arm.com>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Kees Cook <keescook@chromium.org>,
Quentin Perret <qperret@google.com>,
asahi@lists.linux.dev
Subject: Re: [PATCH v3 6/6] arm64/mm: Drop configurable 48-bit physical address space limit
Date: Sun, 22 Dec 2024 20:05:28 +0800 [thread overview]
Message-ID: <bf93c563-f331-43c0-a145-1abf143bd0eb@gmail.com> (raw)
In-Reply-To: <20241212081841.2168124-14-ardb+git@google.com>
Hi Ard,
On 12/12/2024 16:18, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@kernel.org>
>
> Currently, the maximum supported physical address space can be
> configured as either 48 bits or 52 bits. The only remaining difference
> between these in practice is that the former omits the masking and
> shifting required to construct TTBR and PTE values, which carry bits #48
> and higher disjoint from the rest of the physical address.
>
> The overhead of performing these additional calculations is negligible,
> and so there is little reason to retain support for two different
> configurations, and we can simply support whatever the hardware
> supports.
I am seeing a boot failure on Apple iPad 7 which uses
CONFIG_ARM64_16K=y after this change in linux-next as commit
32d053d6f5e9, with nothing appearing on serial console with
earlycon enabled unless I set CONFIG_ARM64_VA_BITS_52=y. Reverting
this patch makes the kernel work again.
Nick Chan
next prev parent reply other threads:[~2024-12-22 12:05 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-12 8:18 [PATCH v3 0/6] arm64: Clean up and simplify PA space size handling Ard Biesheuvel
2024-12-12 8:18 ` [PATCH v3 1/6] arm64/mm: Reduce PA space to 48 bits when LPA2 is not enabled Ard Biesheuvel
2024-12-12 8:18 ` [PATCH v3 2/6] arm64/mm: Override PARange for !LPA2 and use it consistently Ard Biesheuvel
2024-12-12 8:18 ` [PATCH v3 3/6] arm64/kvm: Configure HYP TCR.PS/DS based on host stage1 Ard Biesheuvel
2024-12-12 8:18 ` [PATCH v3 4/6] arm64/kvm: Avoid invalid physical addresses to signal owner updates Ard Biesheuvel
2024-12-12 11:33 ` Quentin Perret
2024-12-12 11:44 ` Ard Biesheuvel
2024-12-12 12:27 ` Quentin Perret
2024-12-12 8:18 ` [PATCH v3 5/6] arm64: Kconfig: force ARM64_PAN=y when enabling TTBR0 sw PAN Ard Biesheuvel
2024-12-12 8:18 ` [PATCH v3 6/6] arm64/mm: Drop configurable 48-bit physical address space limit Ard Biesheuvel
2024-12-20 23:39 ` Klara Modin
2024-12-20 23:41 ` Ard Biesheuvel
2024-12-21 0:29 ` Nathan Chancellor
2024-12-21 12:10 ` Will Deacon
2024-12-22 12:05 ` Nick Chan [this message]
2024-12-22 15:35 ` Ard Biesheuvel
2024-12-19 17:11 ` [PATCH v3 0/6] arm64: Clean up and simplify PA space size handling Marc Zyngier
2024-12-19 19:47 ` Will Deacon
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