Re: [PATCH v2 2/2] papr/scm: Add bad memory ranges to nvdimm bad ranges

[Christophe Leroy]

Le 09/07/2020 à 15:51, Santosh Sivaraj a écrit :

Subscribe to the MCE notification and add the physical address which
generated a memory error to nvdimm bad range.

Reviewed-by: Mahesh Salgaonkar <mah...@linux.ibm.com>
Signed-off-by: Santosh Sivaraj <sant...@fossix.org>

Reviewed-by: Christophe Leroy <christophe.le...@csgroup.eu>

---
  arch/powerpc/platforms/pseries/papr_scm.c | 96 ++++++++++++++++++++++-
  1 file changed, 95 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/papr_scm.c 
b/arch/powerpc/platforms/pseries/papr_scm.c
index 9c569078a09fd..90729029ca010 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -13,9 +13,11 @@
  #include <linux/platform_device.h>
  #include <linux/delay.h>
  #include <linux/seq_buf.h>
+#include <linux/nd.h>

#include <asm/plpar_wrappers.h>

  #include <asm/papr_pdsm.h>
+#include <asm/mce.h>

#define BIND_ANY_ADDR (~0ul) @@ -80,6 +82,7 @@ struct papr_scm_priv {

        struct resource res;
        struct nd_region *region;
        struct nd_interleave_set nd_set;
+       struct list_head region_list;

/* Protect dimm health data from concurrent read/writes */

        struct mutex health_mutex;
@@ -91,6 +94,9 @@ struct papr_scm_priv {
        u64 health_bitmap;
  };

+LIST_HEAD(papr_nd_regions);

+DEFINE_MUTEX(papr_ndr_lock);
+
  static int drc_pmem_bind(struct papr_scm_priv *p)
  {
        unsigned long ret[PLPAR_HCALL_BUFSIZE];
@@ -759,6 +765,10 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
                dev_info(dev, "Region registered with target node %d and online node 
%d",
                         target_nid, online_nid);

+ mutex_lock(&papr_ndr_lock);

+       list_add_tail(&p->region_list, &papr_nd_regions);
+       mutex_unlock(&papr_ndr_lock);
+
        return 0;

err: nvdimm_bus_unregister(p->bus);

@@ -766,6 +776,68 @@ err:       nvdimm_bus_unregister(p->bus);
        return -ENXIO;
  }

+static void papr_scm_add_badblock(struct nd_region *region,

+                                 struct nvdimm_bus *bus, u64 phys_addr)
+{
+       u64 aligned_addr = ALIGN_DOWN(phys_addr, L1_CACHE_BYTES);
+
+       if (nvdimm_bus_add_badrange(bus, aligned_addr, L1_CACHE_BYTES)) {
+               pr_err("Bad block registration for 0x%llx failed\n", phys_addr);
+               return;
+       }
+
+       pr_debug("Add memory range (0x%llx - 0x%llx) as bad range\n",
+                aligned_addr, aligned_addr + L1_CACHE_BYTES);
+
+       nvdimm_region_notify(region, NVDIMM_REVALIDATE_POISON);
+}
+
+static int handle_mce_ue(struct notifier_block *nb, unsigned long val,
+                        void *data)
+{
+       struct machine_check_event *evt = data;
+       struct papr_scm_priv *p;
+       u64 phys_addr;
+       bool found = false;
+
+       if (evt->error_type != MCE_ERROR_TYPE_UE)
+               return NOTIFY_DONE;
+
+       if (list_empty(&papr_nd_regions))
+               return NOTIFY_DONE;
+
+       /*
+        * The physical address obtained here is PAGE_SIZE aligned, so get the
+        * exact address from the effective address
+        */
+       phys_addr = evt->u.ue_error.physical_address +
+                       (evt->u.ue_error.effective_address & ~PAGE_MASK);
+
+       if (!evt->u.ue_error.physical_address_provided ||
+           !is_zone_device_page(pfn_to_page(phys_addr >> PAGE_SHIFT)))
+               return NOTIFY_DONE;
+
+       /* mce notifier is called from a process context, so mutex is safe */
+       mutex_lock(&papr_ndr_lock);
+       list_for_each_entry(p, &papr_nd_regions, region_list) {
+               if (phys_addr >= p->res.start && phys_addr <= p->res.end) {
+                       found = true;
+                       break;
+               }
+       }
+
+       if (found)
+               papr_scm_add_badblock(p->region, p->bus, phys_addr);
+
+       mutex_unlock(&papr_ndr_lock);
+
+       return found ? NOTIFY_OK : NOTIFY_DONE;
+}
+
+static struct notifier_block mce_ue_nb = {
+       .notifier_call = handle_mce_ue
+};
+
  static int papr_scm_probe(struct platform_device *pdev)
  {
        struct device_node *dn = pdev->dev.of_node;
@@ -866,6 +938,10 @@ static int papr_scm_remove(struct platform_device *pdev)
  {
        struct papr_scm_priv *p = platform_get_drvdata(pdev);

+ mutex_lock(&papr_ndr_lock);

+       list_del(&p->region_list);
+       mutex_unlock(&papr_ndr_lock);
+
        nvdimm_bus_unregister(p->bus);
        drc_pmem_unbind(p);
        kfree(p->bus_desc.provider_name);
@@ -888,7 +964,25 @@ static struct platform_driver papr_scm_driver = {
        },
  };

-module_platform_driver(papr_scm_driver);

+static int __init papr_scm_init(void)
+{
+       int ret;
+
+       ret = platform_driver_register(&papr_scm_driver);
+       if (!ret)
+               mce_register_notifier(&mce_ue_nb);
+
+       return ret;
+}
+module_init(papr_scm_init);
+
+static void __exit papr_scm_exit(void)
+{
+       mce_unregister_notifier(&mce_ue_nb);
+       platform_driver_unregister(&papr_scm_driver);
+}
+module_exit(papr_scm_exit);
+
  MODULE_DEVICE_TABLE(of, papr_scm_match);
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("IBM Corporation");