[PATCH v2 10/22] alpha: select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

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 <mattst88@gmail.com>
Tested-by: Magnus Lindholm <linmag7@gmail.com>
Reviewed-by: Magnus Lindholm <linmag7@gmail.com>
---
 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