x86/asm: Add MONITORX/MWAITX instruction support

AMD Carrizo processors (Family 15h, Models 60h-6fh) added a new
feature called MWAITX (MWAIT with extensions) as an extension to
MONITOR/MWAIT.

This new instruction controls a configurable timer which causes
the core to exit wait state on timer expiration, in addition to
"normal" MWAIT condition of reading from a monitored VA.

Compared to MONITOR/MWAIT, there are minor differences in opcode
and input parameters:

MWAITX ECX[1]: enable timer if set
MWAITX EBX[31:0]: max wait time expressed in SW P0 clocks ==
TSC. The software P0 frequency is the same as the TSC frequency.

                MWAIT                           MWAITX
opcode          0f 01 c9           |            0f 01 fb
ECX[0]                  value of RFLAGS.IF seen by instruction
ECX[1]          unused/#GP if set  |            enable timer if set
ECX[31:2]                     unused/#GP if set
EAX                           unused (reserve for hint)
EBX[31:0]       unused             |            max wait time (SW P0 == TSC)

                MONITOR                         MONITORX
opcode          0f 01 c8           |            0f 01 fa
EAX                     (logical) address to monitor
ECX                     #GP if not zero

Max timeout = EBX/(TSC frequency)

Signed-off-by: Huang Rui <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Cc: Aaron Lu <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Andreas Herrmann <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Dirk Brandewie <[email protected]>
Cc: Fengguang Wu <[email protected]>
Cc: Frédéric Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Ross Zwisler <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Tony Li <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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