On Mon, 9 Jan 2017 19:06:11 +0530 Madhavan Srinivasan <ma...@linux.vnet.ibm.com> wrote:
> "paca->soft_enabled" is used as a flag to mask some of interrupts. > Currently supported flags values and their details: > > soft_enabled MSR[EE] > > 0 0 Disabled (PMI and HMI not masked) > 1 1 Enabled > > "paca->soft_enabled" is initialized to 1 to make the interripts as > enabled. arch_local_irq_disable() will toggle the value when interrupts > needs to disbled. At this point, the interrupts are not actually disabled, > instead, interrupt vector has code to check for the flag and mask it when it > occurs. > By "mask it", it update interrupt paca->irq_happened and return. > arch_local_irq_restore() is called to re-enable interrupts, which checks and > replays interrupts if any occured. > > Now, as mentioned, current logic doesnot mask "performance monitoring > interrupts" > and PMIs are implemented as NMI. But this patchset depends on local_irq_* > for a successful local_* update. Meaning, mask all possible interrupts during > local_* update and replay them after the update. > > So the idea here is to reserve the "paca->soft_enabled" logic. New values and > details: > > soft_enabled MSR[EE] > > 1 0 Disabled (PMI and HMI not masked) > 0 1 Enabled > > Reason for the this change is to create foundation for a third mask value > "0x2" > for "soft_enabled" to add support to mask PMIs. When ->soft_enabled is > set to a value "3", PMI interrupts are mask and when set to a value > of "1", PMI are not mask. With this patch also extends soft_enabled > interrupt disable mask. > > Signed-off-by: Madhavan Srinivasan <ma...@linux.vnet.ibm.com> Reviewed-by: Nicholas Piggin <npig...@gmail.com>
