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From: Ard Biesheuvel <ardb+git@google.com>
To: 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>
Subject: [RFC PATCH 2/8] arm64: Kconfig: fix ARCH_MMAP_RND_BITS_MAX for 52-bit virtual addressing
Date: Wed, 30 Oct 2024 11:18:06 +0100	[thread overview]
Message-ID: <20241030101803.2037606-12-ardb+git@google.com> (raw)
In-Reply-To: <20241030101803.2037606-10-ardb+git@google.com>

From: Ard Biesheuvel <ardb@kernel.org>

The default values for ARCH_MMAP_RND_BITS_MAX fail to take into account
that we now have support for 52-bit virtual addressing. As these configs
are compatible with hardware that is incapable of 52-bit virtual
addressing, use the same value we use for 47/48-bit virtual addressing.
(For the sake of simplicity, use the same value for 47 and 48 bit
virtual addressing for 16k pages)

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/Kconfig | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index ec218ef22f2b..ac8e7550430b 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -324,13 +324,9 @@ config ARCH_MMAP_RND_BITS_MAX
 	default 19 if ARM64_VA_BITS=36
 	default 24 if ARM64_VA_BITS=39
 	default 27 if ARM64_VA_BITS=42
-	default 30 if ARM64_VA_BITS=47
-	default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
-	default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
-	default 33 if ARM64_VA_BITS=48
-	default 14 if ARM64_64K_PAGES
-	default 16 if ARM64_16K_PAGES
-	default 18
+	default 29 if ARM64_64K_PAGES
+	default 30 if ARM64_16K_PAGES
+	default 33
 
 config ARCH_MMAP_RND_COMPAT_BITS_MIN
 	default 7 if ARM64_64K_PAGES
-- 
2.47.0.163.g1226f6d8fa-goog



  parent reply	other threads:[~2024-10-30 10:23 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-30 10:18 [RFC PATCH 0/8] arm64: Simplify VA space configurations Ard Biesheuvel
2024-10-30 10:18 ` [RFC PATCH 1/8] arm64: Kconfig: force ARM64_PAN=y when enabling TTBR0 sw PAN Ard Biesheuvel
2024-10-30 10:18 ` Ard Biesheuvel [this message]
2024-10-30 10:18 ` [RFC PATCH 3/8] arm64: Kconfig: eliminate 64k/48-bit VA combination Ard Biesheuvel
2024-10-30 10:18 ` [RFC PATCH 4/8] arm64: Kconfig: eliminate 4k/48-bit " Ard Biesheuvel
2024-10-30 10:18 ` [RFC PATCH 5/8] arm64/Kconfig: Drop support for 47-bit virtual addressing Ard Biesheuvel
2024-10-30 10:18 ` [RFC PATCH 6/8] arm64/Kconfig: Drop support for 48-bit " Ard Biesheuvel
2024-10-30 10:18 ` [RFC PATCH 7/8] arm64/mm: Use reduced VA sizes (36/39/42 bits) only for user space Ard Biesheuvel
2024-10-30 12:44   ` Marc Zyngier
2024-10-30 13:25     ` Ard Biesheuvel
2024-10-30 10:18 ` [RFC PATCH 8/8] arm64/mm: Account for reduced VA sizes in T0SZ and skip the levels Ard Biesheuvel

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