xen: Re-upload processor PM data to hypervisor after S3 resume (v2)

Upon resume, it was found that ACPI C-states were missing from non-boot CPUs.
This change registers a syscore_ops handler for this case, and re-uploads the
PM information to the hypervisor to properly reset the C-state on these
processors.

v2:
v1 did not go through the check_acpi_ids() code-path, and missed some cases when
xen was running with the dom0_max_vcpus= command line parameter.

Signed-Off-By: Ben Guthro <benjamin.guthro@citrix.com>
[v3: Ate some tabs, s/printk/pr_info/]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 53 insertions, 25 deletions

diff --git a/drivers/xen/xen-acpi-processor.c b/drivers/xen/xen-acpi-processor.c
index 90e34ac7e522..e2a53337725d 100644
--- a/drivers/xen/xen-acpi-processor.c
+++ b/drivers/xen/xen-acpi-processor.c
@@ -25,6 +25,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/types.h>
+#include <linux/syscore_ops.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
 #include <acpi/processor.h>
@@ -51,9 +52,9 @@ static DEFINE_MUTEX(acpi_ids_mutex);
 /* Which ACPI ID we have processed from 'struct acpi_processor'. */
 static unsigned long *acpi_ids_done;
 /* Which ACPI ID exist in the SSDT/DSDT processor definitions. */
-static unsigned long __initdata *acpi_id_present;
+static unsigned long *acpi_id_present;
 /* And if there is an _CST definition (or a PBLK) for the ACPI IDs */
-static unsigned long __initdata *acpi_id_cst_present;
+static unsigned long *acpi_id_cst_present;
 
 static int push_cxx_to_hypervisor(struct acpi_processor *_pr)
 {
@@ -390,6 +391,10 @@ static int __init check_acpi_ids(struct acpi_processor *pr_backup)
         if (!pr_backup)
                 return -ENODEV;
 
+        if (acpi_id_present && acpi_id_cst_present)
+                /* OK, done this once .. skip to uploading */
+                goto upload;
+
         /* All online CPUs have been processed at this stage. Now verify
          * whether in fact "online CPUs" == physical CPUs.
          */
@@ -408,6 +413,7 @@ static int __init check_acpi_ids(struct acpi_processor *pr_backup)
                             read_acpi_id, NULL, NULL, NULL);
         acpi_get_devices("ACPI0007", read_acpi_id, NULL, NULL);
 
+upload:
         if (!bitmap_equal(acpi_id_present, acpi_ids_done, nr_acpi_bits)) {
                 unsigned int i;
                 for_each_set_bit(i, acpi_id_present, nr_acpi_bits) {
@@ -417,10 +423,7 @@ static int __init check_acpi_ids(struct acpi_processor *pr_backup)
                         (void)upload_pm_data(pr_backup);
                 }
         }
-        kfree(acpi_id_present);
-        acpi_id_present = NULL;
-        kfree(acpi_id_cst_present);
-        acpi_id_cst_present = NULL;
+
         return 0;
 }
 static int __init check_prereq(void)
@@ -467,10 +470,47 @@ static void free_acpi_perf_data(void)
         free_percpu(acpi_perf_data);
 }
 
-static int __init xen_acpi_processor_init(void)
+static int xen_upload_processor_pm_data(void)
 {
         struct acpi_processor *pr_backup = NULL;
         unsigned int i;
+        int rc = 0;
+
+        pr_info(DRV_NAME "Uploading Xen processor PM info\n");
+
+        for_each_possible_cpu(i) {
+                struct acpi_processor *_pr;
+                _pr = per_cpu(processors, i /* APIC ID */);
+                if (!_pr)
+                        continue;
+
+                if (!pr_backup) {
+                        pr_backup = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
+                        if (pr_backup)
+                                memcpy(pr_backup, _pr, sizeof(struct acpi_processor));
+                }
+                (void)upload_pm_data(_pr);
+        }
+
+        rc = check_acpi_ids(pr_backup);
+        kfree(pr_backup);
+
+        return rc;
+}
+
+static void xen_acpi_processor_resume(void)
+{
+        bitmap_zero(acpi_ids_done, nr_acpi_bits);
+        xen_upload_processor_pm_data();
+}
+
+static struct syscore_ops xap_syscore_ops = {
+        .resume = xen_acpi_processor_resume,
+};
+
+static int __init xen_acpi_processor_init(void)
+{
+        unsigned int i;
         int rc = check_prereq();
 
         if (rc)
@@ -514,27 +554,12 @@ static int __init xen_acpi_processor_init(void)
                         goto err_out;
         }
 
-        for_each_possible_cpu(i) {
-                struct acpi_processor *_pr;
-                _pr = per_cpu(processors, i /* APIC ID */);
-                if (!_pr)
-                        continue;
-
-                if (!pr_backup) {
-                        pr_backup = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
-                        if (pr_backup)
-                                memcpy(pr_backup, _pr, sizeof(struct acpi_processor));
-                }
-                (void)upload_pm_data(_pr);
-        }
-        rc = check_acpi_ids(pr_backup);
-
-        kfree(pr_backup);
-        pr_backup = NULL;
-
+        rc = xen_upload_processor_pm_data();
         if (rc)
                 goto err_unregister;
 
+        register_syscore_ops(&xap_syscore_ops);
+
         return 0;
 err_unregister:
         for_each_possible_cpu(i) {
@@ -552,7 +577,10 @@ static void __exit xen_acpi_processor_exit(void)
 {
         int i;
 
+        unregister_syscore_ops(&xap_syscore_ops);
         kfree(acpi_ids_done);
+        kfree(acpi_id_present);
+        kfree(acpi_id_cst_present);
         for_each_possible_cpu(i) {
                 struct acpi_processor_performance *perf;
                 perf = per_cpu_ptr(acpi_perf_data, i);