perf: Add mem_hops field in perf_mem_data_src structure

Going forward, future generation systems can have more hierarchy
within the node/package level but currently we don't have any data source
encoding field in perf, which can be used to represent this level of data.

Add a new field called 'mem_hops' in the perf_mem_data_src structure
which can be used to represent intra-node/package or inter-node/off-package
details. This field is of size 3 bits where PERF_MEM_HOPS_{NA, 0..6} value
can be used to present different hop levels data.

Also add corresponding macros to define mem_hop field values
and shift value.

Currently we define macro for HOPS_0 which corresponds
to data coming from another core but same node.

For ex: Encodings for mem_hops fields with L2 cache:

L2 - local L2
L2 | REMOTE | HOPS_0 - remote core, same node L2

Signed-off-by: Kajol Jain <[e-mail]>
Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

include/uapi/linux/perf_event.h

···
 			mem_remote:1,   /* remote */
 			mem_snoopx:2,	/* snoop mode, ext */
 			mem_blk:3,	/* access blocked */
-			mem_rsvd:21;
+			mem_hops:3,	/* hop level */
+			mem_rsvd:18;
 	};
 };
 #elif defined(__BIG_ENDIAN_BITFIELD)
 union perf_mem_data_src {
 	__u64 val;
 	struct {
-		__u64	mem_rsvd:21,
+		__u64	mem_rsvd:18,
+			mem_hops:3,	/* hop level */
 			mem_blk:3,	/* access blocked */
 			mem_snoopx:2,	/* snoop mode, ext */
 			mem_remote:1,   /* remote */
···
 #define PERF_MEM_BLK_DATA	0x02 /* data could not be forwarded */
 #define PERF_MEM_BLK_ADDR	0x04 /* address conflict */
 #define PERF_MEM_BLK_SHIFT	40
+
+/* hop level */
+#define PERF_MEM_HOPS_0		0x01 /* remote core, same node */
+/* 2-7 available */
+#define PERF_MEM_HOPS_SHIFT	43
 
 #define PERF_MEM_S(a, s) \
 	(((__u64)PERF_MEM_##a##_##s) << PERF_MEM_##a##_SHIFT)