acpi: Fix broken error check in map_processor()

[Thomas Gleixner]

map_processor() checks the cpuid value returned by acpi_map_cpuid() for -1
but acpi_map_cpuid() returns -EINVAL in case of error.

As a consequence the error is ignored and the following access into percpu
data with that negative cpuid results in a boot crash.

This happens always when NR_CPUS/nr_cpu_ids is smaller than the number of
processors listed in the ACPI tables.

Use a proper error check for id < 0 so the function returns instead of
trying to map CPU#(-EINVAL).

Reported-by: Ingo Molnar <mingo@xxxxxxxxxx>
Fixes: dc6db24d2476 ("x86/acpi: Set persistent cpuid <-> nodeid mapping when booting")
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
 drivers/acpi/processor_core.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -284,7 +284,7 @@ EXPORT_SYMBOL_GPL(acpi_get_cpuid);
 static bool __init
 map_processor(acpi_handle handle, phys_cpuid_t *phys_id, int *cpuid)
 {
-	int type;
+	int type, id;
 	u32 acpi_id;
 	acpi_status status;
 	acpi_object_type acpi_type;
@@ -320,10 +320,11 @@ map_processor(acpi_handle handle, phys_c
 	type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0;
 
 	*phys_id = __acpi_get_phys_id(handle, type, acpi_id, false);
-	*cpuid = acpi_map_cpuid(*phys_id, acpi_id);
-	if (*cpuid == -1)
-		return false;
+	id = acpi_map_cpuid(*phys_id, acpi_id);
 
+	if (id < 0)
+		return false;
+	*cpuid = id;
 	return true;
 }