[PATCH v4 2/6] 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>
---
v3->v4:
  Add Thomas and Hongyu's tags.
v2->v3:
  Make the macros tabular format. (Thomas Gleixner)
---
 arch/x86/kernel/cpu/resctrl/erdt.c | 44 ++++++++++++++++++++++++++++--
 1 file changed, 42 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/erdt.c b/arch/x86/kernel/cpu/resctrl/erdt.c
index b43dcc06f009..a1d5de82d5c9 100644
--- a/arch/x86/kernel/cpu/resctrl/erdt.c
+++ b/arch/x86/kernel/cpu/resctrl/erdt.c
@@ -33,8 +33,9 @@ static bool erdt_enabled_flag;
 
 static DEFINE_XARRAY(erdt_domain_xa);
 
-#define ERDT_VALID_VERSION		1
-#define RMDD_FLAG_CPU_DOMAIN		BIT(0)
+#define ERDT_VALID_VERSION			1
+#define CMRC_VALID_INDEX_FUNC_VERSION		1
+#define RMDD_FLAG_CPU_DOMAIN			BIT(0)
 
 static u32 valid_subtbl_mask;
 
@@ -136,6 +137,7 @@ static void erdt_iounmap_domain(struct erdt_domain_info *domain)
 static void cleanup_one_domain(struct erdt_domain_info *d)
 {
 	erdt_iounmap_domain(d);
+	kfree(d->cmrc);
 	kfree(d);
 }
 
@@ -146,6 +148,40 @@ static __init bool cacd_init(struct acpi_subtbl_hdr_16 *subtbl, int *l3_cache_id
 	return *l3_cache_id != -1;
 }
 
+static __init bool cmrc_init(struct erdt_domain_info *d, struct acpi_subtbl_hdr_16 *subtbl)
+{
+	struct acpi_erdt_cmrc *cmrc = (struct acpi_erdt_cmrc *)subtbl;
+
+	if (subtbl->length < sizeof(*cmrc)) {
+		pr_warn(FW_BUG "Truncated CMRC subtable\n");
+		return false;
+	}
+
+	if (cmrc->index_fn != CMRC_VALID_INDEX_FUNC_VERSION) {
+		pr_info("Unknown CMRC index function %d\n", cmrc->index_fn);
+		return false;
+	}
+
+	if (!cmrc->clump_size) {
+		pr_warn(FW_BUG "CMRC clump_size is zero\n");
+		return false;
+	}
+
+	d->base[ERDT_MMIO_CMRC_BASE] = erdt_ioremap_checked(cmrc->cmt_reg_base,
+							    cmrc->cmt_reg_size, "CMRC base");
+	if (!d->base[ERDT_MMIO_CMRC_BASE])
+		return false;
+
+	d->cmrc = kmemdup(cmrc, subtbl->length, GFP_KERNEL);
+	if (!d->cmrc) {
+		iounmap(d->base[ERDT_MMIO_CMRC_BASE]);
+		d->base[ERDT_MMIO_CMRC_BASE] = NULL;
+		return false;
+	}
+
+	return true;
+}
+
 static inline struct acpi_subtbl_hdr_16 *rmdd_subtbl(struct acpi_erdt_rmdd *rmdd)
 {
 	return (void *)rmdd + sizeof(*rmdd);
@@ -203,6 +239,10 @@ static __init bool parse_rmdd_entry(struct acpi_subtbl_hdr_16 *rmdd_hdr)
 			if (cacd_init(subtbl, &l3_cache_id))
 				subtbl_mask |= BIT(ACPI_ERDT_TYPE_CACD);
 			break;
+		case ACPI_ERDT_TYPE_CMRC:
+			if (cmrc_init(domain_info, subtbl))
+				subtbl_mask |= BIT(ACPI_ERDT_TYPE_CMRC);
+			break;
 		default:
 			break;
 		}
-- 
2.25.1