[PATCH v13 1/2] ACPI / APEI: Add a notifier chain for unknown (vendor) CPER records

Shiju Jose
2020-07-22T10:43:57Z

CPER records describing a firmware-first error are identified by GUID.
The ghes driver currently logs, but ignores any unknown CPER records.
This prevents describing errors that can't be represented by a standard
entry, that would otherwise allow a driver to recover from an error.
The UEFI spec calls these 'Non-standard Section Body' (N.2.3 of
version 2.8).

Add a notifier chain for these non-standard/vendor-records. Callers
must identify their type of records by GUID.

Record data is copied to memory from the ghes_estatus_pool to allow
us to keep it until after the notifier has run.

Co-developed-by: James Morse <james.morse@arm.com>
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
---
drivers/acpi/apei/ghes.c | 63 ++++++++++++++++++++++++++++++++++++++++
include/acpi/ghes.h | 27 +++++++++++++++++
2 files changed, 90 insertions(+)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 81bf71b10d44..99df00f64306 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -79,6 +79,12 @@
((struct acpi_hest_generic_status *) \
((struct ghes_estatus_node *)(estatus_node) + 1))

+#define GHES_VENDOR_ENTRY_LEN(gdata_len) \
+ (sizeof(struct ghes_vendor_record_entry) + (gdata_len))
+#define GHES_GDATA_FROM_VENDOR_ENTRY(vendor_entry) \
+ ((struct acpi_hest_generic_data *) \
+ ((struct ghes_vendor_record_entry *)(vendor_entry) + 1))
+
/*
* NMI-like notifications vary by architecture, before the compiler can prune
* unused static functions it needs a value for these enums.
@@ -123,6 +129,12 @@ static DEFINE_MUTEX(ghes_list_mutex);
*/
static DEFINE_SPINLOCK(ghes_notify_lock_irq);

+struct ghes_vendor_record_entry {
+ struct work_struct work;
+ int error_severity;
+ char vendor_record[];
+};
+
static struct gen_pool *ghes_estatus_pool;
static unsigned long ghes_estatus_pool_size_request;

@@ -511,6 +523,56 @@ static void ghes_handle_aer(struct acpi_hest_generic_data *gdata)
#endif
}

+static BLOCKING_NOTIFIER_HEAD(vendor_record_notify_list);
+
+int ghes_register_vendor_record_notifier(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_register(&vendor_record_notify_list, nb);
+}
+EXPORT_SYMBOL_GPL(ghes_register_vendor_record_notifier);
+
+void ghes_unregister_vendor_record_notifier(struct notifier_block *nb)
+{
+ blocking_notifier_chain_unregister(&vendor_record_notify_list, nb);
+}
+EXPORT_SYMBOL_GPL(ghes_unregister_vendor_record_notifier);
+
+static void ghes_vendor_record_work_func(struct work_struct *work)
+{
+ struct ghes_vendor_record_entry *entry;
+ struct acpi_hest_generic_data *gdata;
+ u32 len;
+
+ entry = container_of(work, struct ghes_vendor_record_entry, work);
+ gdata = GHES_GDATA_FROM_VENDOR_ENTRY(entry);
+
+ blocking_notifier_call_chain(&vendor_record_notify_list,
+ entry->error_severity, gdata);
+
+ len = GHES_VENDOR_ENTRY_LEN(acpi_hest_get_record_size(gdata));
+ gen_pool_free(ghes_estatus_pool, (unsigned long)entry, len);
+}
+
+static void ghes_defer_non_standard_event(struct acpi_hest_generic_data *gdata,
+ int sev)
+{
+ struct acpi_hest_generic_data *copied_gdata;
+ struct ghes_vendor_record_entry *entry;
+ u32 len;
+
+ len = GHES_VENDOR_ENTRY_LEN(acpi_hest_get_record_size(gdata));
+ entry = (void *)gen_pool_alloc(ghes_estatus_pool, len);
+ if (!entry)
+ return;
+
+ copied_gdata = GHES_GDATA_FROM_VENDOR_ENTRY(entry);
+ memcpy(copied_gdata, gdata, acpi_hest_get_record_size(gdata));
+ entry->error_severity = sev;
+
+ INIT_WORK(&entry->work, ghes_vendor_record_work_func);
+ schedule_work(&entry->work);
+}
+
static bool ghes_do_proc(struct ghes *ghes,
const struct acpi_hest_generic_status *estatus)
{
@@ -549,6 +611,7 @@ static bool ghes_do_proc(struct ghes *ghes,
} else {
void *err = acpi_hest_get_payload(gdata);

+ ghes_defer_non_standard_event(gdata, sev);
log_non_standard_event(sec_type, fru_id, fru_text,
sec_sev, err,
gdata->error_data_length);
diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h
index 517a5231cc1b..491bd8c6d600 100644
--- a/include/acpi/ghes.h
+++ b/include/acpi/ghes.h
@@ -53,6 +53,33 @@ enum {
GHES_SEV_PANIC = 0x3,
};

+#ifdef CONFIG_ACPI_APEI_GHES
+/**
+ * ghes_register_vendor_record_notifier - register a notifier for vendor
+ * records that the kernel would otherwise ignore.
+ * @nb: pointer to the notifier_block structure of the event handler.
+ *
+ * return 0 : SUCCESS, non-zero : FAIL
+ */
+int ghes_register_vendor_record_notifier(struct notifier_block *nb);
+
+/**
+ * ghes_unregister_vendor_record_notifier - unregister the previously
+ * registered vendor record notifier.
+ * @nb: pointer to the notifier_block structure of the vendor record handler.
+ */
+void ghes_unregister_vendor_record_notifier(struct notifier_block *nb);
+#else
+static inline int ghes_register_vendor_record_notifier(struct notifier_block *nb)
+{
+ return -ENODEV;
+}
+
+static inline void ghes_unregister_vendor_record_notifier(struct notifier_block *nb)
+{
+}
+#endif
+
int ghes_estatus_pool_init(int num_ghes);

/* From drivers/edac/ghes_edac.c */
--
2.17.1