On Thu, 15 Sep 2016 18:31:56 +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 flag value "2" > for "soft_enabled" to add support to mask PMIs. When ->soft_enabled is > set to a value "2", PMI interrupts are mask and when set to a value > of "1", PMI are not mask. > > Signed-off-by: Madhavan Srinivasan <ma...@linux.vnet.ibm.com> > --- > arch/powerpc/include/asm/hw_irq.h | 4 ++-- > arch/powerpc/kernel/entry_64.S | 5 ++--- > 2 files changed, 4 insertions(+), 5 deletions(-) > > diff --git a/arch/powerpc/include/asm/hw_irq.h > b/arch/powerpc/include/asm/hw_irq.h > index dc3c248f9244..fd9b421f9020 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 IRQ_DISABLE_MASK_NONE 1 > -#define IRQ_DISABLE_MASK_LINUX 0 > +#define IRQ_DISABLE_MASK_NONE 0 > +#define IRQ_DISABLE_MASK_LINUX 1 > > #endif /* CONFIG_PPC64 */ > > diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S > index aef7b64cbbeb..879aeb11ad29 100644 > --- a/arch/powerpc/kernel/entry_64.S > +++ b/arch/powerpc/kernel/entry_64.S > @@ -131,8 +131,7 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR) > */ > #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_BUG) > lbz r10,PACASOFTIRQEN(r13) > - xori r10,r10,IRQ_DISABLE_MASK_NONE > -1: tdnei r10,0 > +1: tdnei r10,IRQ_DISABLE_MASK_NONE > EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING > #endif > > @@ -1012,7 +1011,7 @@ _GLOBAL(enter_rtas) > * check it with the asm equivalent of WARN_ON > */ > lbz r0,PACASOFTIRQEN(r13) > -1: tdnei r0,IRQ_DISABLE_MASK_LINUX > +1: tdeqi r0,IRQ_DISABLE_MASK_NONE > EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING > #endif > We specifically want to ensure that _LINUX interrupts are disabled here. Not that we allow masking of others without _LINUX now, but current behavior is checking that LINUX ones are masked. Otherwise it seems okay. It might be nice after this series to do a pass and rename soft_enabled to soft_masked. Reviewed-by: Nicholas Piggin <npig...@gmail.com>