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Fri, 03 Apr 2026 08:03:07 -0700 (PDT) Received: from localhost ([76.195.202.134]) by smtp.gmail.com with UTF8SMTPSA id 956f58d0204a3-6503a9b6285sm2472521d50.17.2026.04.03.08.03.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Apr 2026 08:03:07 -0700 (PDT) From: Matt Turner To: Magnus Lindholm Cc: linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, Matt Turner Subject: [PATCH] alpha: Select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE Date: Fri, 3 Apr 2026 11:03:03 -0400 Message-ID: <20260403150304.489061-1-mattst88@gmail.com> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 --- arch/alpha/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git ./arch/alpha/Kconfig ./arch/alpha/Kconfig index d870529fa251..394e49328cb6 100644 --- ./arch/alpha/Kconfig +++ ./arch/alpha/Kconfig @@ -5,6 +5,7 @@ config ALPHA select ARCH_32BIT_USTAT_F_TINODE select ARCH_HAS_CURRENT_STACK_POINTER select ARCH_HAS_DMA_OPS if PCI + select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE select ARCH_MIGHT_HAVE_PC_PARPORT select ARCH_MIGHT_HAVE_PC_SERIO select ARCH_MODULE_NEEDS_WEAK_PER_CPU if SMP --=20 2.52.0