perf/x86/intel/uncore: Parse uncore discovery tables

A self-describing mechanism for the uncore PerfMon hardware has been
introduced with the latest Intel platforms. By reading through an MMIO
page worth of information, perf can 'discover' all the standard uncore
PerfMon registers in a machine.

The discovery mechanism relies on BIOS's support. With a proper BIOS,
a PCI device with the unique capability ID 0x23 can be found on each
die. Perf can retrieve the information of all available uncore PerfMons
from the device via MMIO. The information is composed of one global
discovery table and several unit discovery tables.
- The global discovery table includes global uncore information of the
  die, e.g., the address of the global control register, the offset of
  the global status register, the number of uncore units, the offset of
  unit discovery tables, etc.
- The unit discovery table includes generic uncore unit information,
  e.g., the access type, the counter width, the address of counters,
  the address of the counter control, the unit ID, the unit type, etc.
  The unit is also called "box" in the code.
Perf can provide basic uncore support based on this information
with the following patches.

To locate the PCI device with the discovery tables, check the generic
PCI ID first. If it doesn't match, go through the entire PCI device tree
and locate the device with the unique capability ID.

The uncore information is similar among dies. To save parsing time and
space, only completely parse and store the discovery tables on the first
die and the first box of each die. The parsed information is stored in
an
RB tree structure, intel_uncore_discovery_type. The size of the stored
discovery tables varies among platforms. It's around 4KB for a Sapphire
Rapids server.

If a BIOS doesn't support the 'discovery' mechanism, the uncore driver
will exit with -ENODEV. There is nothing changed.

Add a module parameter to disable the discovery feature. If a BIOS gets
the discovery tables wrong, users can have an option to disable the
feature. For the current patchset, the uncore driver will exit with
-ENODEV. In the future, it may fall back to the hardcode uncore driver
on a known platform.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1616003977-90612-2-git-send-email-kan.liang@linux.intel.com

1 files changed, 105 insertions, 0 deletions

diff --git a/arch/x86/events/intel/uncore_discovery.h b/arch/x86/events/intel/uncore_discovery.h
new file mode 100644
index 000000000000..95afa393145a
--- /dev/null
+++ b/arch/x86/events/intel/uncore_discovery.h
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+/* Generic device ID of a discovery table device */
+#define UNCORE_DISCOVERY_TABLE_DEVICE		0x09a7
+/* Capability ID for a discovery table device */
+#define UNCORE_EXT_CAP_ID_DISCOVERY		0x23
+/* First DVSEC offset */
+#define UNCORE_DISCOVERY_DVSEC_OFFSET		0x8
+/* Mask of the supported discovery entry type */
+#define UNCORE_DISCOVERY_DVSEC_ID_MASK		0xffff
+/* PMON discovery entry type ID */
+#define UNCORE_DISCOVERY_DVSEC_ID_PMON		0x1
+/* Second DVSEC offset */
+#define UNCORE_DISCOVERY_DVSEC2_OFFSET		0xc
+/* Mask of the discovery table BAR offset */
+#define UNCORE_DISCOVERY_DVSEC2_BIR_MASK	0x7
+/* Discovery table BAR base offset */
+#define UNCORE_DISCOVERY_BIR_BASE		0x10
+/* Discovery table BAR step */
+#define UNCORE_DISCOVERY_BIR_STEP		0x4
+/* Mask of the discovery table offset */
+#define UNCORE_DISCOVERY_MASK			0xf
+/* Global discovery table size */
+#define UNCORE_DISCOVERY_GLOBAL_MAP_SIZE	0x20
+
+#define uncore_discovery_invalid_unit(unit)			\
+	(!unit.table1 || !unit.ctl || !unit.table3 ||	\
+	 unit.table1 == -1ULL || unit.ctl == -1ULL ||	\
+	 unit.table3 == -1ULL)
+
+enum uncore_access_type {
+	UNCORE_ACCESS_MSR	= 0,
+	UNCORE_ACCESS_MMIO,
+	UNCORE_ACCESS_PCI,
+
+	UNCORE_ACCESS_MAX,
+};
+
+struct uncore_global_discovery {
+	union {
+		u64	table1;
+		struct {
+			u64	type : 8,
+				stride : 8,
+				max_units : 10,
+				__reserved_1 : 36,
+				access_type : 2;
+		};
+	};
+
+	u64	ctl;		/* Global Control Address */
+
+	union {
+		u64	table3;
+		struct {
+			u64	status_offset : 8,
+				num_status : 16,
+				__reserved_2 : 40;
+		};
+	};
+};
+
+struct uncore_unit_discovery {
+	union {
+		u64	table1;
+		struct {
+			u64	num_regs : 8,
+				ctl_offset : 8,
+				bit_width : 8,
+				ctr_offset : 8,
+				status_offset : 8,
+				__reserved_1 : 22,
+				access_type : 2;
+			};
+		};
+
+	u64	ctl;		/* Unit Control Address */
+
+	union {
+		u64	table3;
+		struct {
+			u64	box_type : 16,
+				box_id : 16,
+				__reserved_2 : 32;
+		};
+	};
+};
+
+struct intel_uncore_discovery_type {
+	struct rb_node	node;
+	enum uncore_access_type	access_type;
+	u64		box_ctrl;	/* Unit ctrl addr of the first box */
+	u64		*box_ctrl_die;	/* Unit ctrl addr of the first box of each die */
+	u16		type;		/* Type ID of the uncore block */
+	u8		num_counters;
+	u8		counter_width;
+	u8		ctl_offset;	/* Counter Control 0 offset */
+	u8		ctr_offset;	/* Counter 0 offset */
+	u16		num_boxes;	/* number of boxes for the uncore block */
+	unsigned int	*ids;		/* Box IDs */
+	unsigned int	*box_offset;	/* Box offset */
+};
+
+bool intel_uncore_has_discovery_tables(void);
+void intel_uncore_clear_discovery_tables(void);