x86, SGI UV: TLB shootdown using broadcast assist unit

TLB shootdown for SGI UV.

Depends on patch (in tip/x86/irq):
   x86-update-macros-used-by-uv-platform.patch   Jack Steiner May 29

This patch provides the ability to flush TLB's in cpu's that are not on
the local node.  The hardware mechanism for distributing the flush
messages is the UV's "broadcast assist unit".

The hook to intercept TLB shootdown requests is a 2-line change to
native_flush_tlb_others() (arch/x86/kernel/tlb_64.c).

This code has been tested on a hardware simulator. The real hardware
is not yet available.

The shootdown statistics are provided through /proc/sgi_uv/ptc_statistics.
The use of /sys was considered, but would have required the use of
many /sys files.  The debugfs was also considered, but these statistics
should be available on an ongoing basis, not just for debugging.

Issues to be fixed later:
- The IRQ for the messaging interrupt is currently hardcoded as 200
  (see UV_BAU_MESSAGE).  It should be dynamically assigned in the future.
- The use of appropriate udelay()'s is untested, as they are a problem
  in the simulator.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 331 insertions, 0 deletions

diff --git a/include/asm-x86/uv/uv_bau.h b/include/asm-x86/uv/uv_bau.h
new file mode 100644
index 000000000000..f125f86c89ac
--- /dev/null
+++ b/include/asm-x86/uv/uv_bau.h
@@ -0,0 +1,331 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * SGI UV Broadcast Assist Unit definitions
+ *
+ * Copyright (C) 2008 Silicon Graphics, Inc. All rights reserved.
+ */
+
+#ifndef __ASM_X86_UV_BAU__
+#define __ASM_X86_UV_BAU__
+
+#include <linux/bitmap.h>
+#define BITSPERBYTE 8
+
+/* Broadcast Assist Unit messaging structures */
+
+/*
+ * Selective Broadcast activations are induced by software action
+ * specifying a particular 8-descriptor "set" via a 6-bit index written
+ * to an MMR.
+ * Thus there are 64 unique 512-byte sets of SB descriptors - one set for
+ * each 6-bit index value. These descriptor sets are mapped in sequence
+ * starting with set 0 located at the address specified in the
+ * BAU_SB_DESCRIPTOR_BASE register, set 1 is located at BASE + 512,
+ * set 2 is at BASE + 2*512, set 3 at BASE + 3*512, and so on.
+ *
+ * We will use 31 sets, one for sending BAU messages from each of the 32
+ * cpu's on the node.
+ *
+ * TLB shootdown will use the first of the 8 descriptors of each set.
+ * Each of the descriptors is 64 bytes in size (8*64 = 512 bytes in a set).
+ */
+
+#define UV_ITEMS_PER_DESCRIPTOR 8
+#define UV_CPUS_PER_ACT_STATUS 32
+#define UV_ACT_STATUS_MASK 0x3
+#define UV_ACT_STATUS_SIZE 2
+#define UV_ACTIVATION_DESCRIPTOR_SIZE 32
+#define UV_DISTRIBUTION_SIZE 256
+#define UV_SW_ACK_NPENDING 8
+#define UV_BAU_MESSAGE 200	/* Messaging irq; see irq_64.h */
+				/* and include/asm-x86/hw_irq_64.h */
+				/* To be dynamically allocated in the future */
+#define UV_NET_ENDPOINT_INTD 0x38
+#define UV_DESC_BASE_PNODE_SHIFT 49 /* position of pnode (nasid>>1) in MMR */
+#define UV_PAYLOADQ_PNODE_SHIFT 49
+
+#define UV_PTC_BASENAME "sgi_uv/ptc_statistics"
+#define uv_physnodeaddr(x) ((__pa((unsigned long)(x)) & uv_mmask))
+
+/* bits in UVH_LB_BAU_SB_ACTIVATION_STATUS_0/1 */
+#define DESC_STATUS_IDLE                0
+#define DESC_STATUS_ACTIVE              1
+#define DESC_STATUS_DESTINATION_TIMEOUT 2
+#define DESC_STATUS_SOURCE_TIMEOUT      3
+
+/* source side threshholds at which message retries print a warning */
+#define SOURCE_TIMEOUT_LIMIT            20
+#define DESTINATION_TIMEOUT_LIMIT       20
+
+/* number of entries in the destination side payload queue */
+#define DESTINATION_PAYLOAD_QUEUE_SIZE  17
+/* number of destination side software ack resources */
+#define DESTINATION_NUM_RESOURCES       8
+#define MAX_CPUS_PER_NODE		32
+
+/* Distribution: 32 bytes (256 bits) (bytes 0-0x1f of descriptor) */
+/* If the 'multilevel' flag in the header portion of the descriptor
+ * has been set to 0, then endpoint multi-unicast mode is selected.
+ * The distribution specification (32 bytes) is interpreted as a 256-bit
+ * distribution vector. Adjacent bits correspond to consecutive even numbered
+ * nodeIDs. The result of adding the index of a given bit to the 15-bit
+ * 'base_dest_nodeid' field of the header corresponds to the
+ * destination nodeID associated with that specified bit.  */
+struct bau_target_nodemask {
+	unsigned long bits[BITS_TO_LONGS(256)];
+};
+
+/* mask of cpu's on a node */
+/* (during initialization we need to check that unsigned long has
+    enough bits for max. cpu's per node) */
+struct bau_local_cpumask {
+	unsigned long bits;
+};
+
+/*
+ * Payload: 16 bytes (128 bits) (bytes 0x20-0x2f of descriptor)
+ * only 12 bytes (96 bits) of the payload area are usable.
+ * An additional 3 bytes (bits 27:4) of the header address are carried
+ * to the next bytes of the destination payload queue.
+ * And an additional 2 bytes of the header Suppl_A field are also
+ * carried to the destination payload queue.
+ * But the first byte of the Suppl_A becomes bits 127:120 (the 16th byte)
+ * of the destination payload queue, which is written by the hardware
+ * with the s/w ack resource bit vector.
+ * [ effective message contents (16 bytes (128 bits) maximum), not counting
+ *   the s/w ack bit vector  ]
+ */
+
+/* The payload is software-defined for INTD transactions */
+struct bau_msg_payload {
+	unsigned long address;		/* signifies a page or all TLB's
+						of the cpu */
+	/* 64 bits */
+	unsigned short sending_cpu;	/* filled in by sender */
+	/* 16 bits */
+	unsigned short acknowledge_count;/* filled in by destination */
+	/* 16 bits */
+	unsigned int reserved1:32;	/* not usable */
+};
+
+
+/* Message header:  16 bytes (128 bits) (bytes 0x30-0x3f of descriptor) */
+/* see table 4.2.3.0.1 in broacast_assist spec. */
+struct bau_msg_header {
+	int dest_subnodeid:6;	/* must be zero */
+	/* bits 5:0 */
+	int base_dest_nodeid:15; /* nasid>>1 (pnode) of first bit in node_map */
+	/* bits 20:6 */
+	int command:8;		/* message type */
+	/* bits 28:21 */
+				/* 0x38: SN3net EndPoint Message */
+	int rsvd_1:3;		/* must be zero */
+	/* bits 31:29 */
+				/* int will align on 32 bits */
+	int rsvd_2:9;		/* must be zero */
+	/* bits 40:32 */
+				/* Suppl_A is 56-41 */
+	int payload_2a:8;	/* becomes byte 16 of msg */
+	/* bits 48:41 */	/* not currently using */
+	int payload_2b:8;	/* becomes byte 17 of msg */
+	/* bits 56:49 */	/* not currently using */
+				/* Address field (96:57) is never used as an
+				   address (these are address bits 42:3) */
+	int rsvd_3:1;		/* must be zero */
+	/* bit 57 */
+				/* address bits 27:4 are payload */
+				/* these 24 bits become bytes 12-14 of msg */
+	int replied_to:1;	/* sent as 0 by the source to byte 12 */
+	/* bit 58 */
+
+	int payload_1a:5;	/* not currently used */
+	/* bits 63:59 */
+	int payload_1b:8;	/* not currently used */
+	/* bits 71:64 */
+	int payload_1c:8;	/* not currently used */
+	/* bits 79:72 */
+	int payload_1d:2;	/* not currently used */
+	/* bits 81:80 */
+
+	int rsvd_4:7;		/* must be zero */
+	/* bits 88:82 */
+	int sw_ack_flag:1;	/* software acknowledge flag */
+	/* bit 89 */
+				/* INTD trasactions at destination are to
+				   wait for software acknowledge */
+	int rsvd_5:6;		/* must be zero */
+	/* bits 95:90 */
+	int rsvd_6:5;		/* must be zero */
+	/* bits 100:96 */
+	int int_both:1;		/* if 1, interrupt both sockets on the blade */
+	/* bit 101*/
+	int fairness:3;		/* usually zero */
+	/* bits 104:102 */
+	int multilevel:1;	/* multi-level multicast format */
+	/* bit 105 */
+				/* 0 for TLB: endpoint multi-unicast messages */
+	int chaining:1;		/* next descriptor is part of this activation*/
+	/* bit 106 */
+	int rsvd_7:21;		/* must be zero */
+	/* bits 127:107 */
+};
+
+/* The format of the message to send, plus all accompanying control */
+/* Should be 64 bytes */
+struct bau_activation_descriptor {
+	struct bau_target_nodemask distribution;
+	/* message template, consisting of header and payload: */
+	struct bau_msg_header header;
+	struct bau_msg_payload payload;
+};
+/*
+ *   -payload--    ---------header------
+ *   bytes 0-11    bits 41-56  bits 58-81
+ *       A           B  (2)      C (3)
+ *
+ *            A/B/C are moved to:
+ *       A            C          B
+ *   bytes 0-11  bytes 12-14  bytes 16-17  (byte 15 filled in by hw as vector)
+ *   ------------payload queue-----------
+ */
+
+/*
+ * The payload queue on the destination side is an array of these.
+ * With BAU_MISC_CONTROL set for software acknowledge mode, the messages
+ * are 32 bytes (2 micropackets) (256 bits) in length, but contain only 17
+ * bytes of usable data, including the sw ack vector in byte 15 (bits 127:120)
+ * (12 bytes come from bau_msg_payload, 3 from payload_1, 2 from
+ *  sw_ack_vector and payload_2)
+ * "Enabling Software Acknowledgment mode (see Section 4.3.3 Software
+ *  Acknowledge Processing) also selects 32 byte (17 bytes usable) payload
+ *  operation."
+ */
+struct bau_payload_queue_entry {
+	unsigned long address;		/* signifies a page or all TLB's
+						of the cpu */
+	/* 64 bits, bytes 0-7 */
+
+	unsigned short sending_cpu;	/* cpu that sent the message */
+	/* 16 bits, bytes 8-9 */
+
+	unsigned short acknowledge_count; /* filled in by destination */
+	/* 16 bits, bytes 10-11 */
+
+	unsigned short replied_to:1;	/* sent as 0 by the source */
+	/* 1 bit */
+	unsigned short unused1:7;       /* not currently using */
+	/* 7 bits: byte 12) */
+
+	unsigned char unused2[2];	/* not currently using */
+	/* bytes 13-14 */
+
+	unsigned char sw_ack_vector;	/* filled in by the hardware */
+	/* byte 15 (bits 127:120) */
+
+	unsigned char unused4[3];	/* not currently using bytes 17-19 */
+	/* bytes 17-19 */
+
+	int number_of_cpus;		/* filled in at destination */
+	/* 32 bits, bytes 20-23 (aligned) */
+
+	unsigned char unused5[8];       /* not using */
+	/* bytes 24-31 */
+};
+
+/* one for every slot in the destination payload queue */
+struct bau_msg_status {
+	struct bau_local_cpumask seen_by;	/* map of cpu's */
+};
+
+/* one for every slot in the destination software ack resources */
+struct bau_sw_ack_status {
+	struct bau_payload_queue_entry *msg;	/* associated message */
+	int watcher;				/* cpu monitoring, or -1 */
+};
+
+/* one on every node and per-cpu; to locate the software tables */
+struct bau_control {
+	struct bau_activation_descriptor *descriptor_base;
+	struct bau_payload_queue_entry *bau_msg_head;
+	struct bau_payload_queue_entry *va_queue_first;
+	struct bau_payload_queue_entry *va_queue_last;
+	struct bau_msg_status *msg_statuses;
+	int *watching; /* pointer to array */
+};
+
+/*
+ * This structure is allocated per_cpu for UV TLB shootdown statistics.
+ */
+struct ptc_stats {
+	unsigned long ptc_i;	/* number of IPI-style flushes */
+	unsigned long requestor;	/* number of nodes this cpu sent to */
+	unsigned long requestee;	/* times cpu was remotely requested */
+	unsigned long alltlb;	/* times all tlb's on this cpu were flushed */
+	unsigned long onetlb;	/* times just one tlb on this cpu was flushed */
+	unsigned long s_retry;	/* retries on source side timeouts */
+	unsigned long d_retry;	/* retries on destination side timeouts */
+	unsigned long sflush_ns;/* nanoseconds spent in uv_flush_tlb_others */
+	unsigned long dflush_ns;/* nanoseconds spent destination side */
+	unsigned long retriesok; /* successes on retries */
+	unsigned long nomsg;	/* interrupts with no message */
+	unsigned long multmsg;	/* interrupts with multiple messages */
+	unsigned long ntargeted;/* nodes targeted */
+};
+
+static inline int bau_node_isset(int node, struct bau_target_nodemask *dstp)
+{
+	return constant_test_bit(node, &dstp->bits[0]);
+}
+static inline void bau_node_set(int node, struct bau_target_nodemask *dstp)
+{
+	__set_bit(node, &dstp->bits[0]);
+}
+static inline void bau_nodes_clear(struct bau_target_nodemask *dstp, int nbits)
+{
+	bitmap_zero(&dstp->bits[0], nbits);
+}
+
+static inline void bau_cpubits_clear(struct bau_local_cpumask *dstp, int nbits)
+{
+	bitmap_zero(&dstp->bits, nbits);
+}
+
+/*
+ * atomic increment of a short integer
+ * (rather than using the __sync_add_and_fetch() intrinsic)
+ *
+ * returns the new value of the variable
+ */
+static inline short int atomic_inc_short(short int *v)
+{
+	asm volatile("movw $1, %%cx\n"
+			"lock ; xaddw %%cx, %0\n"
+			: "+m" (*v)		/* outputs */
+			: : "%cx", "memory");	/* inputs : clobbereds */
+	return *v;
+}
+
+/*
+ * atomic OR of two long integers
+ * (rather than using the __sync_or_and_fetch() intrinsic)
+ */
+static inline void atomic_or_long(unsigned long *v1, unsigned long v2)
+{
+	asm volatile("movq %0, %%rax; lea %1, %%rdx\n"
+			"lock ; orq %%rax, %%rdx\n"
+			: "+m" (*v1)		/* outputs */
+			: "m" (v1), "m" (v2)	/* inputs */
+			: "memory");		/* clobbereds */
+}
+
+#define cpubit_isset(cpu, bau_local_cpumask) \
+	test_bit((cpu), (bau_local_cpumask).bits)
+
+int uv_flush_tlb_others(cpumask_t *, struct mm_struct *, unsigned long);
+void uv_bau_message_intr1(void);
+void uv_bau_timeout_intr1(void);
+
+#endif /* __ASM_X86_UV_BAU__ */