[PATCH 4.7 019/143] ACPI: CPPC: Return error if _CPC is invalid on a CPU

[Greg Kroah-Hartman]

4.7-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hoan Tran <hotran@xxxxxxx>

commit 8343c40d3de32ebfe8f48b043964e4ba0e7701f7 upstream.

Based on 8.4.7.1 section of ACPI 6.1 specification, if the platform
supports CPPC, the _CPC object must exist under all processor objects.
If cpc_desc_ptr pointer is invalid on any CPUs, acpi_get_psd_map()
should return error and CPPC cpufreq driver can not be registered.

Signed-off-by: Hoan Tran <hotran@xxxxxxx>
Reviewed-by: Prashanth Prakash <pprakash@xxxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/acpi/cppc_acpi.c |   18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -299,8 +299,10 @@ int acpi_get_psd_map(struct cpudata **al
 			continue;
 
 		cpc_ptr = per_cpu(cpc_desc_ptr, i);
-		if (!cpc_ptr)
-			continue;
+		if (!cpc_ptr) {
+			retval = -EFAULT;
+			goto err_ret;
+		}
 
 		pdomain = &(cpc_ptr->domain_info);
 		cpumask_set_cpu(i, pr->shared_cpu_map);
@@ -322,8 +324,10 @@ int acpi_get_psd_map(struct cpudata **al
 				continue;
 
 			match_cpc_ptr = per_cpu(cpc_desc_ptr, j);
-			if (!match_cpc_ptr)
-				continue;
+			if (!match_cpc_ptr) {
+				retval = -EFAULT;
+				goto err_ret;
+			}
 
 			match_pdomain = &(match_cpc_ptr->domain_info);
 			if (match_pdomain->domain != pdomain->domain)
@@ -353,8 +357,10 @@ int acpi_get_psd_map(struct cpudata **al
 				continue;
 
 			match_cpc_ptr = per_cpu(cpc_desc_ptr, j);
-			if (!match_cpc_ptr)
-				continue;
+			if (!match_cpc_ptr) {
+				retval = -EFAULT;
+				goto err_ret;
+			}
 
 			match_pdomain = &(match_cpc_ptr->domain_info);
 			if (match_pdomain->domain != pdomain->domain)