[PATCH] ACPI: CPPC: Return error if _CPC is invalid on a CPU

From: Hoan Tran
Date: Fri Jun 17 2016 - 18:16:54 EST


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

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 85fd8f7..2e98173 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -299,8 +299,10 @@ int acpi_get_psd_map(struct cpudata **all_cpu_data)
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 **all_cpu_data)
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 **all_cpu_data)
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)
--
1.9.1