arm64: Make cpu_logical_map() take unsigned int

CPU index should never be negative. Change the signature of
(set_)cpu_logical_map to take an unsigned int.

This still works even if the users treat the CPU index as an int,
and will allow the hypervisor's implementation to check that the index
is valid with a single upper-bound check.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-8-dbrazdil@google.com

arch/arm64/include/asm/smp.h

@@ -46,9 +46,9 @@ DECLARE_PER_CPU_READ_MOSTLY(int, cpu_number);
  * Logical CPU mapping.
  */
 extern u64 __cpu_logical_map[NR_CPUS];
-extern u64 cpu_logical_map(int cpu);
+extern u64 cpu_logical_map(unsigned int cpu);
 
-static inline void set_cpu_logical_map(int cpu, u64 hwid)
+static inline void set_cpu_logical_map(unsigned int cpu, u64 hwid)
 {
 	__cpu_logical_map[cpu] = hwid;
 }

arch/arm64/kernel/setup.c

@@ -276,7 +276,7 @@ arch_initcall(reserve_memblock_reserved_regions);
 
 u64 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID_HWID };
 
-u64 cpu_logical_map(int cpu)
+u64 cpu_logical_map(unsigned int cpu)
 {
 	return __cpu_logical_map[cpu];
 }