From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x244.google.com (mail-pf0-x244.google.com [IPv6:2607:f8b0:400e:c00::244]) (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 3tyLlj6VLYzDqFR for ; Tue, 10 Jan 2017 16:52:49 +1100 (AEDT) Received: by mail-pf0-x244.google.com with SMTP id y143so6078990pfb.1 for ; Mon, 09 Jan 2017 21:52:49 -0800 (PST) Date: Tue, 10 Jan 2017 15:52:39 +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 v6 05/12] powerpc: reverse the soft_enable logic Message-ID: <20170110155239.03f4c1cb@roar.ozlabs.ibm.com> In-Reply-To: <1483968978-16035-6-git-send-email-maddy@linux.vnet.ibm.com> References: <1483968978-16035-1-git-send-email-maddy@linux.vnet.ibm.com> <1483968978-16035-6-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 Mon, 9 Jan 2017 19:06:11 +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 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 Reviewed-by: Nicholas Piggin