[RFC PATCH 3/5] cxl/core: introduce cxl_mem_report_poison()

[Shiyang Ruan]

If poison is detected(reported from cxl memdev), OS should be notified to
handle it.  Introduce this function:
  1. translate DPA to HPA;
  2. construct a MCE instance; (TODO: more details need to be filled)
  3. log it into MCE event queue;

After that, MCE mechanism can walk over its notifier chain to execute
specific handlers.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
 arch/x86/kernel/cpu/mce/core.c |  1 +
 drivers/cxl/core/mbox.c        | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index bc39252bc54f..a64c0aceb7e0 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -131,6 +131,7 @@ void mce_setup(struct mce *m)
        m->ppin = cpu_data(m->extcpu).ppin;
        m->microcode = boot_cpu_data.microcode;
 }
+EXPORT_SYMBOL_GPL(mce_setup);
 
 DEFINE_PER_CPU(struct mce, injectm);
 EXPORT_PER_CPU_SYMBOL_GPL(injectm);
diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 27166a411705..f9b6f50fbe80 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -4,6 +4,7 @@
 #include <linux/debugfs.h>
 #include <linux/ktime.h>
 #include <linux/mutex.h>
+#include <asm/mce.h>
 #include <asm/unaligned.h>
 #include <cxlpci.h>
 #include <cxlmem.h>
@@ -1290,6 +1291,38 @@ int cxl_set_timestamp(struct cxl_memdev_state *mds)
 }
 EXPORT_SYMBOL_NS_GPL(cxl_set_timestamp, CXL);
 
+static void cxl_mem_report_poison(struct cxl_memdev *cxlmd,
+                                 struct cxl_poison_record *poison)
+{
+       struct mce m;
+       u64 dpa = le64_to_cpu(poison->address) & CXL_POISON_START_MASK;
+       u64 len = le64_to_cpu(poison->length), i;
+       phys_addr_t phys_addr = cxl_memdev_dpa_to_hpa(cxlmd, dpa);
+
+       if (phys_addr)
+               return;
+
+       /*
+        * Initialize struct mce.  Call preempt_disable() to avoid
+        * "BUG: using smp_processor_id() in preemptible" for now, not sure
+        * if this is a correct way.
+        */
+       preempt_disable();
+       mce_setup(&m);
+       preempt_enable();
+
+       m.bank = -1;
+       /* Fake a memory read error with unknown channel */
+       m.status = MCI_STATUS_VAL | MCI_STATUS_EN | MCI_STATUS_ADDRV |
+                  MCI_STATUS_MISCV | 0x9f;
+       m.misc = (MCI_MISC_ADDR_PHYS << 6);
+
+       for (i = 0; i < len; i++) {
+               m.addr = phys_addr++;
+               mce_log(&m);
+       }
+}
+
 int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
                       struct cxl_region *cxlr)
 {
-- 
2.34.1