perf/x86/uncore: Handle pci_read_config_dword() errors

This, beyond handling corner cases, also fixes some build warnings:

 arch/x86/kernel/cpu/perf_event_intel_uncore.c: In function ‘snbep_uncore_pci_disable_box’:
 arch/x86/kernel/cpu/perf_event_intel_uncore.c:124:9: warning: ‘config’ is used uninitialized in this function [-Wuninitialized]
 arch/x86/kernel/cpu/perf_event_intel_uncore.c: In function ‘snbep_uncore_pci_enable_box’:
 arch/x86/kernel/cpu/perf_event_intel_uncore.c:135:9: warning: ‘config’ is used uninitialized in this function [-Wuninitialized]
 arch/x86/kernel/cpu/perf_event_intel_uncore.c: In function ‘snbep_uncore_pci_read_counter’:
 arch/x86/kernel/cpu/perf_event_intel_uncore.c:164:2: warning: ‘count’ is used uninitialized in this function [-Wuninitialized]

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Cc: a.p.zijlstra@chello.nl
Link: http://lkml.kernel.org/r/1351068140-13456-1-git-send-email-zheng.z.yan@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 28 insertions, 15 deletions

diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
index 5df8d32ba91e..6f874771ee65 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
@@ -118,22 +118,24 @@ static void snbep_uncore_pci_disable_box(struct intel_uncore_box *box)
 {
         struct pci_dev *pdev = box->pci_dev;
         int box_ctl = uncore_pci_box_ctl(box);
-        u32 config;
+        u32 config = 0;
 
-        pci_read_config_dword(pdev, box_ctl, &config);
-        config |= SNBEP_PMON_BOX_CTL_FRZ;
-        pci_write_config_dword(pdev, box_ctl, config);
+        if (!pci_read_config_dword(pdev, box_ctl, &config)) {
+                config |= SNBEP_PMON_BOX_CTL_FRZ;
+                pci_write_config_dword(pdev, box_ctl, config);
+        }
 }
 
 static void snbep_uncore_pci_enable_box(struct intel_uncore_box *box)
 {
         struct pci_dev *pdev = box->pci_dev;
         int box_ctl = uncore_pci_box_ctl(box);
-        u32 config;
+        u32 config = 0;
 
-        pci_read_config_dword(pdev, box_ctl, &config);
-        config &= ~SNBEP_PMON_BOX_CTL_FRZ;
-        pci_write_config_dword(pdev, box_ctl, config);
+        if (!pci_read_config_dword(pdev, box_ctl, &config)) {
+                config &= ~SNBEP_PMON_BOX_CTL_FRZ;
+                pci_write_config_dword(pdev, box_ctl, config);
+        }
 }
 
 static void snbep_uncore_pci_enable_event(struct intel_uncore_box *box, struct perf_event *event)
@@ -156,7 +158,7 @@ static u64 snbep_uncore_pci_read_counter(struct intel_uncore_box *box, struct pe
 {
         struct pci_dev *pdev = box->pci_dev;
         struct hw_perf_event *hwc = &event->hw;
-        u64 count;
+        u64 count = 0;
 
         pci_read_config_dword(pdev, hwc->event_base, (u32 *)&count);
         pci_read_config_dword(pdev, hwc->event_base + 4, (u32 *)&count + 1);
@@ -603,11 +605,12 @@ static struct pci_driver snbep_uncore_pci_driver = {
 /*
  * build pci bus to socket mapping
  */
-static void snbep_pci2phy_map_init(void)
+static int snbep_pci2phy_map_init(void)
 {
         struct pci_dev *ubox_dev = NULL;
         int i, bus, nodeid;
-        u32 config;
+        int err = 0;
+        u32 config = 0;
 
         while (1) {
                 /* find the UBOX device */
@@ -618,10 +621,14 @@ static void snbep_pci2phy_map_init(void)
                         break;
                 bus = ubox_dev->bus->number;
                 /* get the Node ID of the local register */
-                pci_read_config_dword(ubox_dev, 0x40, &config);
+                err = pci_read_config_dword(ubox_dev, 0x40, &config);
+                if (err)
+                        break;
                 nodeid = config;
                 /* get the Node ID mapping */
-                pci_read_config_dword(ubox_dev, 0x54, &config);
+                err = pci_read_config_dword(ubox_dev, 0x54, &config);
+                if (err)
+                        break;
                 /*
                  * every three bits in the Node ID mapping register maps
                  * to a particular node.
@@ -633,7 +640,11 @@ static void snbep_pci2phy_map_init(void)
                         }
                 }
         };
-        return;
+
+        if (ubox_dev)
+                pci_dev_put(ubox_dev);
+
+        return err ? pcibios_err_to_errno(err) : 0;
 }
 /* end of Sandy Bridge-EP uncore support */
 
@@ -2578,9 +2589,11 @@ static int __init uncore_pci_init(void)
 
         switch (boot_cpu_data.x86_model) {
         case 45: /* Sandy Bridge-EP */
+                ret = snbep_pci2phy_map_init();
+                if (ret)
+                        return ret;
                 pci_uncores = snbep_pci_uncores;
                 uncore_pci_driver = &snbep_uncore_pci_driver;
-                snbep_pci2phy_map_init();
                 break;
         default:
                 return 0;