linux-kernel - [RFC PATCH 4/8] arm64: Kconfig: eliminate 4k/48-bit VA combination

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Message-ID: <20241030101803.2037606-14-ardb+git@google.com>
Date: Wed, 30 Oct 2024 11:18:08 +0100
From: Ard Biesheuvel <ardb+git@...gle.com>
To: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org, Ard Biesheuvel <ardb@...nel.org>, 
	Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, Ryan Roberts <ryan.roberts@....com>, 
	Anshuman Khandual <anshuman.khandual@....com>, Kees Cook <keescook@...omium.org>
Subject: [RFC PATCH 4/8] arm64: Kconfig: eliminate 4k/48-bit VA combination

From: Ard Biesheuvel <ardb@...nel.org>

Now that LPA2 is supported seamlessly, using alternatives patching where
appropriate to fall back to 48-bit virtual addressing when running with
4k page size on hardware that lacks LPA support, there is no longer a
need to keep the separate 48-bit VA size configurations. Note that LPA2
support can be overridden at boot time by passing arm64.nolva on the
command line, and given that no LPA2 hardware exists yet in the field,
now is a good time to make this change.

Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
---
 arch/arm64/Kconfig | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6a73fd61b4aa..099b1a825b9f 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -382,9 +382,8 @@ config PGTABLE_LEVELS
 	default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
 	default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
 	default 3 if ARM64_64K_PAGES
-	default 4 if ARM64_16K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52)
-	default 4 if ARM64_VA_BITS_48
-	default 5 if ARM64_4K_PAGES && ARM64_VA_BITS_52
+	default 4 if ARM64_16K_PAGES
+	default 5 if ARM64_4K_PAGES
 
 config ARCH_SUPPORTS_UPROBES
 	def_bool y
@@ -1361,7 +1360,7 @@ config ARM64_VA_BITS_47
 
 config ARM64_VA_BITS_48
 	bool "48-bit"
-	depends on !PAGE_SIZE_64KB
+	depends on PAGE_SIZE_16KB
 
 config ARM64_VA_BITS_52
 	bool "52-bit"
-- 
2.47.0.163.g1226f6d8fa-goog