| Message ID | 1469458342-26233-6-git-send-email-maddy@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On Mon, 25 Jul 2016 20:22:18 +0530 Madhavan Srinivasan <maddy@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 initialed 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 updated > 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 flag > value "2" for "soft_enabled" to add support to mask PMIs. When > arch_irq_disable_* is called with a value "2", PMI interrupts are > mask. But when called with a value of "1", PMI are not mask. > > With new flag value for "soft_enabled", states looks like: > > soft_enabled MSR[EE] > > 2 0 Disbaled PMIs also > 1 0 Disabled (PMI and HMI not masked) > 0 1 Enabled > > And interrupt handler code for checking has been modified to check for > for "greater than or equal" to 1 condition instead. This bit of the patch seems to have been moved into other part of the series. Ideally (unless there is a good reason), it is nice to have each individual patch result in a working kernel before and after. Nice way to avoid adding more branches though. Thanks, Nick
On Tuesday 26 July 2016 11:01 AM, Nicholas Piggin wrote: > On Mon, 25 Jul 2016 20:22:18 +0530 > Madhavan Srinivasan <maddy@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 initialed 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 updated >> 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 flag >> value "2" for "soft_enabled" to add support to mask PMIs. When >> arch_irq_disable_* is called with a value "2", PMI interrupts are >> mask. But when called with a value of "1", PMI are not mask. >> >> With new flag value for "soft_enabled", states looks like: >> >> soft_enabled MSR[EE] >> >> 2 0 Disbaled PMIs also >> 1 0 Disabled (PMI and HMI not masked) >> 0 1 Enabled >> >> And interrupt handler code for checking has been modified to check for >> for "greater than or equal" to 1 condition instead. > This bit of the patch seems to have been moved into other part > of the series. Ideally (unless there is a good reason), it is nice > to have each individual patch result in a working kernel before > and after. Agreed. But I need to reason out the change and hence add all info here. But will edit the info in the next version. Maddy > > Nice way to avoid adding more branches though. > > Thanks, > Nick >
diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h index 09491417fbf7..2b87930e0e82 100644 --- a/arch/powerpc/include/asm/hw_irq.h +++ b/arch/powerpc/include/asm/hw_irq.h @@ -30,8 +30,8 @@ /* * flags for paca->soft_enabled */ -#define LAZY_INTERRUPT_ENABLED 1 -#define LAZY_INTERRUPT_DISABLED 0 +#define LAZY_INTERRUPT_ENABLED 0 +#define LAZY_INTERRUPT_DISABLED 1 #endif /* CONFIG_PPC64 */
"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 initialed 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 updated 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 flag value "2" for "soft_enabled" to add support to mask PMIs. When arch_irq_disable_* is called with a value "2", PMI interrupts are mask. But when called with a value of "1", PMI are not mask. With new flag value for "soft_enabled", states looks like: soft_enabled MSR[EE] 2 0 Disbaled PMIs also 1 0 Disabled (PMI and HMI not masked) 0 1 Enabled And interrupt handler code for checking has been modified to check for for "greater than or equal" to 1 condition instead. Comment here explains the logic changes that are implemented in the following patches. But this patch primarly does only reserve the logic. Following patches will make the corresponding changes. Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> --- arch/powerpc/include/asm/hw_irq.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)