[PATCH v5 05/10] x86/resctrl: Parse ACPI CMRC table

[Chen Yu]

The CMRC (Cache Monitoring Registers for CPU Agents Description)
sub-table of ERDT describes the MMIO registers used to read
cache monitoring counters (e.g. LLC occupancy) for an RMD.

Parse each CMRC sub-table, ioremap its register window, and save
the CMRC pointer in the corresponding ERDT domain entry so that
later monitoring code can read the counters via MMIO.

Suggested-by: Tony Luck <tony.luck@xxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxx>
Tested-by: Hongyu Ning <hongyu.ning@xxxxxxxxxxxxxxx>
Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx>
---
v4->v5:
  No change.    
---
 arch/x86/kernel/cpu/resctrl/erdt.c     | 44 ++++++++++++++++++++++++++
 arch/x86/kernel/cpu/resctrl/internal.h |  1 +
 2 files changed, 45 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/erdt.c b/arch/x86/kernel/cpu/resctrl/erdt.c
index 6c1df7e43eab..a5754d64fcc1 100644
--- a/arch/x86/kernel/cpu/resctrl/erdt.c
+++ b/arch/x86/kernel/cpu/resctrl/erdt.c
@@ -26,6 +26,7 @@ static LIST_HEAD(domain_info_list);
 static bool __erdt_enabled;
 
 #define ERDT_VALID_VERSION		1
+#define CMRC_SUPPORTED_INDEX_FN		1
 #define RMDD_FLAG_CPU_L3_DOMAIN		BIT(0)
 
 /* Bitmask of valid sub-tables found in the first RMDD, used to ensure all RMDDs match. */
@@ -79,6 +80,7 @@ static void cleanup_one_domain(struct erdt_domain_info *d)
 {
 	erdt_iounmap_domain(d);
 	free_cpumask_var(d->cpu_mask);
+	kfree(d->cmrc);
 	kfree(d);
 }
 
@@ -112,6 +114,41 @@ static __init int cacd_init(struct acpi_subtbl_hdr_16 *subtbl,
 	return 0;
 }
 
+static __init int cmrc_init(struct acpi_subtbl_hdr_16 *subtbl,
+			    struct erdt_domain_info *domain_info)
+{
+	struct acpi_erdt_cmrc *cmrc = (struct acpi_erdt_cmrc *)subtbl;
+
+	if (subtbl->length < sizeof(*cmrc)) {
+		pr_warn(FW_BUG "Truncated CMRC subtable\n");
+		return -EIO;
+	}
+
+	if (cmrc->index_fn != CMRC_SUPPORTED_INDEX_FN) {
+		pr_info("Unsupported CMRC index function %d\n", cmrc->index_fn);
+		return -EIO;
+	}
+
+	if (!cmrc->clump_size) {
+		pr_warn(FW_BUG "CMRC clump_size is zero\n");
+		return -EIO;
+	}
+
+	domain_info->base[ERDT_MMIO_CMRC_BASE] =
+		erdt_ioremap(cmrc->cmt_reg_base, cmrc->cmt_reg_size, "CMRC base");
+	if (!domain_info->base[ERDT_MMIO_CMRC_BASE])
+		return -EIO;
+
+	domain_info->cmrc = kmemdup(cmrc, subtbl->length, GFP_KERNEL);
+	if (!domain_info->cmrc) {
+		iounmap(domain_info->base[ERDT_MMIO_CMRC_BASE]);
+		domain_info->base[ERDT_MMIO_CMRC_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);
@@ -178,6 +215,13 @@ static __init bool parse_rmdd_entry(struct acpi_subtbl_hdr_16 *rmdd_hdr)
 				goto cleanup;
 
 			subtbl_mask |= BIT(ACPI_ERDT_TYPE_CACD);
+			break;
+		case ACPI_ERDT_TYPE_CMRC:
+			/* TBD: Only 1 CMRR per domain is allowed? */
+			if (!(subtbl_mask & BIT(ACPI_ERDT_TYPE_CMRC)) &&
+			    !cmrc_init(subtbl, domain_info))
+				subtbl_mask |= BIT(ACPI_ERDT_TYPE_CMRC);
+
 			break;
 		default:
 			break;
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 7d9100b7648f..3dab05c38003 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -36,6 +36,7 @@ enum erdt_mmio_type {
 
 struct erdt_domain_info {
 	void __iomem		*base[ERDT_MMIO_NUM_TYPES];
+	struct acpi_erdt_cmrc	*cmrc;
 	cpumask_var_t		cpu_mask;
 	int			max_rmid;
 	struct list_head	list;
-- 
2.45.2