[PATCH] 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 <[email protected]>
---
 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
-- 
2.52.0