1 files changed, 55 insertions, 3 deletions

diff --git a/drivers/acpi/apei/hest.c b/drivers/acpi/apei/hest.c
index 277f00b288d1..20d757687e3d 100644
--- a/drivers/acpi/apei/hest.c
+++ b/drivers/acpi/apei/hest.c
@@ -37,6 +37,20 @@ EXPORT_SYMBOL_GPL(hest_disable);
 
 static struct acpi_table_hest *__read_mostly hest_tab;
 
+/*
+ * Since GHES_ASSIST is not supported, skip initialization of GHES_ASSIST
+ * structures for MCA.
+ * During HEST parsing, detected MCA error sources are cached from early
+ * table entries so that the Flags and Source Id fields from these cached
+ * values are then referred to in later table entries to determine if the
+ * encountered GHES_ASSIST structure should be initialized.
+ */
+static struct {
+	struct acpi_hest_ia_corrected *cmc;
+	struct acpi_hest_ia_machine_check *mc;
+	struct acpi_hest_ia_deferred_check *dmc;
+} mces;
+
 static const int hest_esrc_len_tab[ACPI_HEST_TYPE_RESERVED] = {
 	[ACPI_HEST_TYPE_IA32_CHECK] = -1,	/* need further calculation */
 	[ACPI_HEST_TYPE_IA32_CORRECTED_CHECK] = -1,
@@ -70,23 +84,57 @@ static int hest_esrc_len(struct acpi_hest_header *hest_hdr)
 		cmc = (struct acpi_hest_ia_corrected *)hest_hdr;
 		len = sizeof(*cmc) + cmc->num_hardware_banks *
 			sizeof(struct acpi_hest_ia_error_bank);
+		mces.cmc = cmc;
 	} else if (hest_type == ACPI_HEST_TYPE_IA32_CHECK) {
 		struct acpi_hest_ia_machine_check *mc;
 		mc = (struct acpi_hest_ia_machine_check *)hest_hdr;
 		len = sizeof(*mc) + mc->num_hardware_banks *
 			sizeof(struct acpi_hest_ia_error_bank);
+		mces.mc = mc;
 	} else if (hest_type == ACPI_HEST_TYPE_IA32_DEFERRED_CHECK) {
 		struct acpi_hest_ia_deferred_check *mc;
 		mc = (struct acpi_hest_ia_deferred_check *)hest_hdr;
 		len = sizeof(*mc) + mc->num_hardware_banks *
 			sizeof(struct acpi_hest_ia_error_bank);
+		mces.dmc = mc;
 	}
 	BUG_ON(len == -1);
 
 	return len;
 };
 
-int apei_hest_parse(apei_hest_func_t func, void *data)
+/*
+ * GHES and GHESv2 structures share the same format, starting from
+ * Source Id and ending in Error Status Block Length (inclusive).
+ */
+static bool is_ghes_assist_struct(struct acpi_hest_header *hest_hdr)
+{
+	struct acpi_hest_generic *ghes;
+	u16 related_source_id;
+
+	if (hest_hdr->type != ACPI_HEST_TYPE_GENERIC_ERROR &&
+	    hest_hdr->type != ACPI_HEST_TYPE_GENERIC_ERROR_V2)
+		return false;
+
+	ghes = (struct acpi_hest_generic *)hest_hdr;
+	related_source_id = ghes->related_source_id;
+
+	if (mces.cmc && mces.cmc->flags & ACPI_HEST_GHES_ASSIST &&
+	    related_source_id == mces.cmc->header.source_id)
+		return true;
+	if (mces.mc && mces.mc->flags & ACPI_HEST_GHES_ASSIST &&
+	    related_source_id == mces.mc->header.source_id)
+		return true;
+	if (mces.dmc && mces.dmc->flags & ACPI_HEST_GHES_ASSIST &&
+	    related_source_id == mces.dmc->header.source_id)
+		return true;
+
+	return false;
+}
+
+typedef int (*apei_hest_func_t)(struct acpi_hest_header *hest_hdr, void *data);
+
+static int apei_hest_parse(apei_hest_func_t func, void *data)
 {
 	struct acpi_hest_header *hest_hdr;
 	int i, rc, len;
@@ -112,6 +160,11 @@ int apei_hest_parse(apei_hest_func_t func, void *data)
 			return -EINVAL;
 		}
 
+		if (is_ghes_assist_struct(hest_hdr)) {
+			hest_hdr = (void *)hest_hdr + len;
+			continue;
+		}
+
 		rc = func(hest_hdr, data);
 		if (rc)
 			return rc;
@@ -121,7 +174,6 @@ int apei_hest_parse(apei_hest_func_t func, void *data)
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(apei_hest_parse);
 
 /*
  * Check if firmware advertises firmware first mode. We need FF bit to be set
@@ -223,7 +275,7 @@ err:
 static int __init setup_hest_disable(char *str)
 {
 	hest_disable = HEST_DISABLED;
-	return 0;
+	return 1;
 }
 
 __setup("hest_disable", setup_hest_disable);