From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x242.google.com (mail-pf0-x242.google.com [IPv6:2607:f8b0:400e:c00::242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3sb9sC5h4JzDsGT for ; Fri, 16 Sep 2016 20:05:51 +1000 (AEST) Received: by mail-pf0-x242.google.com with SMTP id 21so2016555pfy.1 for ; Fri, 16 Sep 2016 03:05:51 -0700 (PDT) Date: Fri, 16 Sep 2016 20:05:37 +1000 From: Nicholas Piggin To: Madhavan Srinivasan Cc: benh@kernel.crashing.org, mpe@ellerman.id.au, anton@samba.org, paulus@samba.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 06/13] powerpc: reverse the soft_enable logic Message-ID: <20160916200537.50562560@roar.ozlabs.ibm.com> In-Reply-To: <1473944523-624-7-git-send-email-maddy@linux.vnet.ibm.com> References: <1473944523-624-1-git-send-email-maddy@linux.vnet.ibm.com> <1473944523-624-7-git-send-email-maddy@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 15 Sep 2016 18:31:56 +0530 Madhavan Srinivasan 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 > --- > 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