Based on SDM Vol2 the monitor uses the RAX register to setup the address
monitored by HW. The mwait uses the rax/rcx as the hints that the process
will enter. It is incorrect that the same value is used for monitor/mwait.
The ecx in mwait specifies the optional externsions.
At the same time it needs to check whether the the value of monitored addr
is already expected before entering mwait. Otherwise it will have possible
lockup.
V1->V2: Add the asm wrappper of monitor/mwait to avoid the mixed usage of
inline assembly in wait_sync_change
v2-v3: Remove the unnecessary line break in asm_monitor/asm_mwait.
Follow Fei's comment to remove the mwait ecx hint setting that
treats the interrupt as break event. It only needs to check whether the
value of psync_change is already expected.
Tracked-On: #3442
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>
baf7d90fdf