[PATCH v6 17/36] powernv/fadump: reset metadata address during clean up

[Hari Bathini]

During kexec boot, metadata address needs to be reset to avoid running
into errors interpreting stale metadata address, in case the kexec'ed
kernel crashes before metadata address could be setup again.

Signed-off-by: Hari Bathini <hbath...@linux.ibm.com>
---

Changes in v6:
  * Drop shallow rtas_fadump_cleanup() callback definition. Instead, check
    before using the callback.


 arch/powerpc/include/asm/fadump-internal.h   |    1 +
 arch/powerpc/kernel/fadump.c                 |    6 ++++++
 arch/powerpc/platforms/powernv/opal-fadump.c |   10 ++++++++++
 3 files changed, 17 insertions(+)

diff --git a/arch/powerpc/include/asm/fadump-internal.h 
b/arch/powerpc/include/asm/fadump-internal.h
index 5262c76..0c2c4f5 100644
--- a/arch/powerpc/include/asm/fadump-internal.h
+++ b/arch/powerpc/include/asm/fadump-internal.h
@@ -117,6 +117,7 @@ struct fadump_ops {
        int     (*fadump_register)(struct fw_dump *fadump_conf);
        int     (*fadump_unregister)(struct fw_dump *fadump_conf);
        int     (*fadump_invalidate)(struct fw_dump *fadump_conf);
+       void    (*fadump_cleanup)(struct fw_dump *fadump_conf);
        int     (*fadump_process)(struct fw_dump *fadump_conf);
        void    (*fadump_region_show)(struct fw_dump *fadump_conf,
                                      struct seq_file *m);
diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 7e70563..aab9b4d 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -965,6 +965,9 @@ static int register_fadump(void)
 
 void fadump_cleanup(void)
 {
+       if (!fw_dump.fadump_supported)
+               return;
+
        /* Invalidate the registration only if dump is active. */
        if (fw_dump.dump_active) {
                pr_debug("Invalidating firmware-assisted dump registration\n");
@@ -974,6 +977,9 @@ void fadump_cleanup(void)
                fw_dump.ops->fadump_unregister(&fw_dump);
                free_crash_memory_ranges();
        }
+
+       if (fw_dump.ops->fadump_cleanup)
+               fw_dump.ops->fadump_cleanup(&fw_dump);
 }
 
 static void fadump_free_reserved_memory(unsigned long start_pfn,
diff --git a/arch/powerpc/platforms/powernv/opal-fadump.c 
b/arch/powerpc/platforms/powernv/opal-fadump.c
index 21de832..871a129 100644
--- a/arch/powerpc/platforms/powernv/opal-fadump.c
+++ b/arch/powerpc/platforms/powernv/opal-fadump.c
@@ -105,6 +105,15 @@ static int opal_fadump_invalidate(struct fw_dump 
*fadump_conf)
        return -EIO;
 }
 
+static void opal_fadump_cleanup(struct fw_dump *fadump_conf)
+{
+       s64 ret;
+
+       ret = opal_mpipl_register_tag(OPAL_MPIPL_TAG_KERNEL, 0);
+       if (ret != OPAL_SUCCESS)
+               pr_warn("Could not reset (%llu) kernel metadata tag!\n", ret);
+}
+
 static int __init opal_fadump_process(struct fw_dump *fadump_conf)
 {
        return -EINVAL;
@@ -145,6 +154,7 @@ static struct fadump_ops opal_fadump_ops = {
        .fadump_register                = opal_fadump_register,
        .fadump_unregister              = opal_fadump_unregister,
        .fadump_invalidate              = opal_fadump_invalidate,
+       .fadump_cleanup                 = opal_fadump_cleanup,
        .fadump_process                 = opal_fadump_process,
        .fadump_region_show             = opal_fadump_region_show,
        .fadump_trigger                 = opal_fadump_trigger,