[RFC PATCH 15/31] x86/resctrl: Parse ACPI MMRC table

[Chen Yu]

The MMRC table is used to provide Memory Bandwidth Monitor Register
information. Its register addresses are mapped, and the MMRC pointer
is saved in the corresponding domain information entry.

Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx>
---
 arch/x86/kernel/cpu/resctrl/erdt.c     | 51 ++++++++++++++++++++++++++
 arch/x86/kernel/cpu/resctrl/internal.h |  6 ++-
 2 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/resctrl/erdt.c b/arch/x86/kernel/cpu/resctrl/erdt.c
index 5f9377c80be6..a14de9eb8b88 100644
--- a/arch/x86/kernel/cpu/resctrl/erdt.c
+++ b/arch/x86/kernel/cpu/resctrl/erdt.c
@@ -24,6 +24,7 @@ static bool erdt_enabled;
 
 #define ERDT_VALID_VERSION		1
 #define CMRC_SUPPORTED_INDEX_FN		1
+#define MMRC_SUPPORTED_INDEX_FN		1
 #define RMDD_FLAG_CPU_L3_DOMAIN		BIT(0)
 
 /* Set in a monitoring counter when it holds no valid data to report. */
@@ -141,6 +142,7 @@ static void cleanup_one_domain(struct erdt_domain_info *d)
 {
 	erdt_iounmap_domain(d);
 	kfree(d->cmrc);
+	kfree(d->mmrc);
 	kfree(d);
 }
 
@@ -211,6 +213,49 @@ static __init int cmrc_init(struct acpi_subtbl_hdr_16 *subtbl,
 	return 0;
 }
 
+static __init int mmrc_init(struct acpi_subtbl_hdr_16 *subtbl,
+			    struct erdt_domain_info *domain_info)
+{
+	struct acpi_erdt_mmrc *mmrc = (struct acpi_erdt_mmrc *)subtbl;
+
+	if (subtbl->length < sizeof(*mmrc)) {
+		pr_warn(FW_BUG "Truncated MMRC subtable\n");
+		return -EIO;
+	}
+
+	if (mmrc->index_fn != MMRC_SUPPORTED_INDEX_FN) {
+		pr_info("Unsupported MMRC index function %d\n", mmrc->index_fn);
+		return -EIO;
+	}
+
+	/*
+	 * The correction factor list is a trailing flexible array, so it is
+	 * not covered by the sizeof(*mmrc) check above. Firmware could claim
+	 * more entries than the sub-table actually carries, so only trust the
+	 * length the sub-table can back.
+	 */
+	if (subtbl->length < struct_size(mmrc, corr_factor_list,
+					 mmrc->corr_factor_list_len)) {
+		pr_warn(FW_BUG "MMRC correction factor list of %u entries exceeds sub-table\n",
+			mmrc->corr_factor_list_len);
+		return -EIO;
+	}
+
+	domain_info->base[ERDT_MMIO_MMRC_BASE] =
+		erdt_ioremap(mmrc->reg_base, mmrc->reg_size, "MMRC base");
+	if (!domain_info->base[ERDT_MMIO_MMRC_BASE])
+		return -EIO;
+
+	domain_info->mmrc = kmemdup(mmrc, subtbl->length, GFP_KERNEL);
+	if (!domain_info->mmrc) {
+		iounmap(domain_info->base[ERDT_MMIO_MMRC_BASE]);
+		domain_info->base[ERDT_MMIO_MMRC_BASE] = NULL;
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
 static inline struct acpi_subtbl_hdr_16 *rmdd_subtbl(struct acpi_erdt_rmdd *rmdd)
 {
 	return (void *)rmdd + sizeof(*rmdd);
@@ -287,6 +332,12 @@ static __init bool parse_rmdd_table(struct acpi_subtbl_hdr_16 *rmdd_hdr)
 			    !cmrc_init(subtbl, domain_info))
 				subtbl_mask |= BIT(ACPI_ERDT_TYPE_CMRC);
 
+			break;
+		case ACPI_ERDT_TYPE_MMRC:
+			if (!(subtbl_mask & BIT(ACPI_ERDT_TYPE_MMRC)) &&
+			    !mmrc_init(subtbl, domain_info))
+				subtbl_mask |= BIT(ACPI_ERDT_TYPE_MMRC);
+
 			break;
 		default:
 			break;
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index c175d8884516..4bbe0c80c9e6 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -25,11 +25,13 @@
  * Index into erdt_domain_info::base[] for each MMIO region.
  * @ERDT_MMIO_RMDD_CREG: RMDD control register base address
  * @ERDT_MMIO_CMRC_BASE: CMRC monitoring register base address
+ * @ERDT_MMIO_MMRC_BASE: MMRC monitoring register base address
  */
 enum erdt_mmio_type {
 	ERDT_MMIO_RMDD_CREG,
 	ERDT_MMIO_CMRC_BASE,
-	ERDT_MMIO_LAST = ERDT_MMIO_CMRC_BASE
+	ERDT_MMIO_MMRC_BASE,
+	ERDT_MMIO_LAST = ERDT_MMIO_MMRC_BASE
 };
 
 #define ERDT_MMIO_NUM_TYPES	(ERDT_MMIO_LAST + 1)
@@ -38,6 +40,7 @@ enum erdt_mmio_type {
  * struct erdt_domain_info - Per-domain ERDT information
  * @base:	Array of ioremapped MMIO region base addresses, indexed by ERDT_MMIO_* type
  * @cmrc:	Copy of the ACPI CMRC sub-table for this domain
+ * @mmrc:	Copy of the ACPI MMRC sub-table for this domain
  * @cpu_mask:	CPUs belonging to this resource management domain
  * @max_rmid:	Maximum RMID supported by this domain
  * @dom_id:	L3 cache ID shared by all CPUs in this domain (-1 if unset)
@@ -46,6 +49,7 @@ enum erdt_mmio_type {
 struct erdt_domain_info {
 	void __iomem		*base[ERDT_MMIO_NUM_TYPES];
 	struct acpi_erdt_cmrc	*cmrc;
+	struct acpi_erdt_mmrc	*mmrc;
 	struct cpumask		cpu_mask;
 	u32			max_rmid;
 	int			dom_id;
-- 
2.43.0