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Sat, 05 Sep 2026 12:29:48 -0700 (PDT) Received: from localhost ([2600:1702:7a90:6f9f:8bc4:8aec:108d:7a04]) by smtp.gmail.com with ESMTPSA id 956f58d0204a3-66fb48ee9easm4992431d50.8.2026.09.05.12.29.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 05 Sep 2026 12:29:46 -0700 (PDT) From: Matt Turner Date: Sat, 05 Sep 2026 15:29:31 -0400 Subject: [PATCH v2 10/22] alpha: select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE Precedence: bulk X-Mailing-List: linux-alpha@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260905-arch-kconfig-options-v2-v2-10-83e8245761a2@gmail.com> References: <20260905-arch-kconfig-options-v2-v2-0-83e8245761a2@gmail.com> In-Reply-To: <20260905-arch-kconfig-options-v2-v2-0-83e8245761a2@gmail.com> To: Richard Henderson , Magnus Lindholm , Kees Cook , Marco Elver , Andrey Konovalov , Andrey Ryabinin , Jonathan Corbet , Shuah Khan , Randy Dunlap Cc: linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-hardening@vger.kernel.org, linux-doc@vger.kernel.org, Matt Turner X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=1116; i=mattst88@gmail.com; h=from:subject:message-id; bh=lVWPvO4U0PzjUNH5kaTEpUlpvE87Z4wloLcJMNvypDE=; b=owGbwMvMwCW25rVmCc8sv+mMp9WSGLLm5E72ChM4a7tjV7n9C2Wll7PuLNjEbPTkS+LHy+In3 4eFbN20t+MjC4MYF8NMMUWWuPWKLLPadiz1OS39C2YOKxPIEGmRBgYgYGHgy03MKzXSMdIz1TbU MwQydIziIXJ6DBqZxcWlqUW6aQVFDnn5JYklmfl5xXr5Bal5BekFemmZaSUZGflFxalAI/TyUkt MXR3djAwNTCwdLcycLBxNTZydnQyd3BwdnV2djCzNTQycLR1NXC3NGbg4BWCuKfdjZNg++Uq7IJ +0QtGSyhc3Jn8IOXPqKfsLiYT+L6pr31xpTM1nZJi+2JDPrXXGUavglK1Ja5e3bSgOvlj51OJwW NrHa/N5WXkA X-Developer-Key: i=mattst88@gmail.com; a=openpgp; fpr=3BB639E56F861FA2E86505690FDD682D974CA72A Alpha has a clean split between user and kernel address spaces: user space occupies 0x0000000000000000-0x000003ffffffffff (TASK_SIZE), while kernel space uses KSEG and vmalloc regions near the top of the 64-bit address space. These are strictly non-overlapping. This enables optimizations in BPF and tracing that can skip address range checks when user and kernel pointers are distinguishable by address alone. Assisted-by: Claude:claude-opus-4-6 Signed-off-by: Matt Turner Tested-by: Magnus Lindholm Reviewed-by: Magnus Lindholm --- arch/alpha/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig index 237ef0c214dd..8f97d6e22b28 100644 --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -9,6 +9,7 @@ config ALPHA select ARCH_HAS_DMA_OPS if PCI select ARCH_HAS_FAST_MULTIPLIER select ARCH_HAS_GCOV_PROFILE_ALL + select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE select ARCH_HAS_UBSAN select ARCH_MIGHT_HAVE_PC_PARPORT select ARCH_MIGHT_HAVE_PC_SERIO -- 2.54.0