From 02cea3958664723a5d2236f0f0058de97c7e4693 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 5 Feb 2015 14:06:23 +0100 Subject: genirq: Provide disable_hardirq() For things like netpoll there is a need to disable an interrupt from atomic context. Currently netpoll uses disable_irq() which will sleep-wait on threaded handlers and thus forced_irqthreads breaks things. Provide disable_hardirq(), which uses synchronize_hardirq() to only wait for active hardirq handlers; also change synchronize_hardirq() to return the status of threaded handlers. This will allow one to try-disable an interrupt from atomic context, or in case of request_threaded_irq() to only wait for the hardirq part. Suggested-by: Sabrina Dubroca Signed-off-by: Peter Zijlstra (Intel) Cc: Arnd Bergmann Cc: David Miller Cc: Eyal Perry Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Quentin Lambert Cc: Randy Dunlap Cc: Russell King Link: http://lkml.kernel.org/r/20150205130623.GH5029@twins.programming.kicks-ass.net [ Fixed typos and such. ] Signed-off-by: Ingo Molnar --- include/linux/interrupt.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/interrupt.h') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index d9b05b5bf8c7..3bb01b9a379c 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -184,6 +184,7 @@ extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id); #endif extern void disable_irq_nosync(unsigned int irq); +extern bool disable_hardirq(unsigned int irq); extern void disable_irq(unsigned int irq); extern void disable_percpu_irq(unsigned int irq); extern void enable_irq(unsigned int irq); -- cgit v1.2.2 From 737eb0301f296d55c22350c6968ff1ef51bacb5f Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Fri, 20 Feb 2015 14:53:46 +0000 Subject: genirq / PM: better describe IRQF_NO_SUSPEND semantics The IRQF_NO_SUSPEND flag is intended to be used for interrupts required to be enabled during the suspend-resume cycle. This mostly consists of IPIs and timer interrupts, potentially including chained irqchip interrupts if these are necessary to handle timers or IPIs. If an interrupt does not fall into one of the aforementioned categories, requesting it with IRQF_NO_SUSPEND is likely incorrect. Using IRQF_NO_SUSPEND does not guarantee that the interrupt can wake the system from a suspended state. For an interrupt to be able to trigger a wakeup, it may be necessary to program various components of the system. In these cases it is necessary to use {enable,disabled}_irq_wake. Unfortunately, several drivers assume that IRQF_NO_SUSPEND ensures that an IRQ can wake up the system, and the documentation can be read ambiguously w.r.t. this property. This patch updates the documentation regarding IRQF_NO_SUSPEND to make this caveat explicit, hopefully making future misuse rarer. Cleanup of existing misuse will occur as part of later patch series. Signed-off-by: Mark Rutland Acked-by: Peter Zijlstra (Intel) Signed-off-by: Rafael J. Wysocki --- include/linux/interrupt.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include/linux/interrupt.h') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index d9b05b5bf8c7..606771c7cac2 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -52,7 +52,9 @@ * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished. * Used by threaded interrupts which need to keep the * irq line disabled until the threaded handler has been run. - * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend + * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend. Does not guarantee + * that this interrupt will wake the system from a suspended + * state. See Documentation/power/suspend-and-interrupts.txt * IRQF_FORCE_RESUME - Force enable it on resume even if IRQF_NO_SUSPEND is set * IRQF_NO_THREAD - Interrupt cannot be threaded * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device -- cgit v1.2.2 From 17f480342026e54000731acaa69bf32787ce46cb Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 27 Feb 2015 00:07:55 +0100 Subject: genirq / PM: Add flag for shared NO_SUSPEND interrupt lines It currently is required that all users of NO_SUSPEND interrupt lines pass the IRQF_NO_SUSPEND flag when requesting the IRQ or the WARN_ON_ONCE() in irq_pm_install_action() will trigger. That is done to warn about situations in which unprepared interrupt handlers may be run unnecessarily for suspended devices and may attempt to access those devices by mistake. However, it may cause drivers that have no technical reasons for using IRQF_NO_SUSPEND to set that flag just because they happen to share the interrupt line with something like a timer. Moreover, the generic handling of wakeup interrupts introduced by commit 9ce7a25849e8 (genirq: Simplify wakeup mechanism) only works for IRQs without any NO_SUSPEND users, so the drivers of wakeup devices needing to use shared NO_SUSPEND interrupt lines for signaling system wakeup generally have to detect wakeup in their interrupt handlers. Thus if they happen to share an interrupt line with a NO_SUSPEND user, they also need to request that their interrupt handlers be run after suspend_device_irqs(). In both cases the reason for using IRQF_NO_SUSPEND is not because the driver in question has a genuine need to run its interrupt handler after suspend_device_irqs(), but because it happens to share the line with some other NO_SUSPEND user. Otherwise, the driver would do without IRQF_NO_SUSPEND just fine. To make it possible to specify that condition explicitly, introduce a new IRQ action handler flag for shared IRQs, IRQF_COND_SUSPEND, that, when set, will indicate to the IRQ core that the interrupt user is generally fine with suspending the IRQ, but it also can tolerate handler invocations after suspend_device_irqs() and, in particular, it is capable of detecting system wakeup and triggering it as appropriate from its interrupt handler. That will allow us to work around a problem with a shared timer interrupt line on at91 platforms. Link: http://marc.info/?l=linux-kernel&m=142252777602084&w=2 Link: http://marc.info/?t=142252775300011&r=1&w=2 Link: https://lkml.org/lkml/2014/12/15/552 Reported-by: Boris Brezillon Signed-off-by: Rafael J. Wysocki Acked-by: Peter Zijlstra (Intel) Acked-by: Mark Rutland --- include/linux/interrupt.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/interrupt.h') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 606771c7cac2..2e88580194f0 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -59,6 +59,10 @@ * IRQF_NO_THREAD - Interrupt cannot be threaded * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device * resume time. + * IRQF_COND_SUSPEND - If the IRQ is shared with a NO_SUSPEND user, execute this + * interrupt handler after suspending interrupts. For system + * wakeup devices users need to implement wakeup detection in + * their interrupt handlers. */ #define IRQF_DISABLED 0x00000020 #define IRQF_SHARED 0x00000080 @@ -72,6 +76,7 @@ #define IRQF_FORCE_RESUME 0x00008000 #define IRQF_NO_THREAD 0x00010000 #define IRQF_EARLY_RESUME 0x00020000 +#define IRQF_COND_SUSPEND 0x00040000 #define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD) -- cgit v1.2.2 From d8bf368d0631d4bc2612d8bf2e4e8e74e620d0cc Mon Sep 17 00:00:00 2001 From: Valentin Rothberg Date: Thu, 5 Mar 2015 15:23:08 +0100 Subject: genirq: Remove the deprecated 'IRQF_DISABLED' request_irq() flag entirely The IRQF_DISABLED flag is a NOOP and has been scheduled for removal since Linux v2.6.36 by commit 6932bf37bed4 ("genirq: Remove IRQF_DISABLED from core code"). According to commit e58aa3d2d0cc ("genirq: Run irq handlers with interrupts disabled"), running IRQ handlers with interrupts enabled can cause stack overflows when the interrupt line of the issuing device is still active. This patch ends the grace period for IRQF_DISABLED (i.e., SA_INTERRUPT in older versions of Linux) and removes the definition and all remaining usages of this flag. There's still a few non-functional references left in the kernel source: - The bigger hunk in Documentation/scsi/ncr53c8xx.txt is removed entirely as IRQF_DISABLED is gone now; the usage in older kernel versions (including the old SA_INTERRUPT flag) should be discouraged. The trouble of using IRQF_SHARED is a general problem and not specific to any driver. - I left the reference in Documentation/PCI/MSI-HOWTO.txt untouched since it has already been removed in linux-next. - All remaining references are changelogs that I suggest to keep. Signed-off-by: Valentin Rothberg Cc: Afzal Mohammed Cc: Arnd Bergmann Cc: Brian Norris Cc: Christoph Hellwig Cc: Dan Carpenter Cc: David Woodhouse Cc: Ewan Milne Cc: Eyal Perry Cc: Felipe Balbi Cc: Greg Kroah-Hartman Cc: H. Peter Anvin Cc: Hannes Reinecke Cc: Hongliang Tao Cc: Huacai Chen Cc: Jiri Kosina Cc: Jonathan Corbet Cc: Keerthy Cc: Laurent Pinchart Cc: Linus Torvalds Cc: Nishanth Menon Cc: Paul Bolle Cc: Peter Ujfalusi Cc: Peter Zijlstra Cc: Quentin Lambert Cc: Rajendra Nayak Cc: Ralf Baechle Cc: Santosh Shilimkar Cc: Sricharan R Cc: Thomas Gleixner Cc: Tony Lindgren Cc: Zhou Wang Cc: iss_storagedev@hp.com Cc: linux-mips@linux-mips.org Cc: linux-mtd@lists.infradead.org Link: http://lkml.kernel.org/r/1425565425-12604-1-git-send-email-valentinrothberg@gmail.com Signed-off-by: Ingo Molnar --- include/linux/interrupt.h | 3 --- 1 file changed, 3 deletions(-) (limited to 'include/linux/interrupt.h') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 3bb01b9a379c..2cee1761c77d 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -39,8 +39,6 @@ * These flags used only by the kernel as part of the * irq handling routines. * - * IRQF_DISABLED - keep irqs disabled when calling the action handler. - * DEPRECATED. This flag is a NOOP and scheduled to be removed * IRQF_SHARED - allow sharing the irq among several devices * IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to occur * IRQF_TIMER - Flag to mark this interrupt as timer interrupt @@ -58,7 +56,6 @@ * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device * resume time. */ -#define IRQF_DISABLED 0x00000020 #define IRQF_SHARED 0x00000080 #define IRQF_PROBE_SHARED 0x00000100 #define __IRQF_TIMER 0x00000200 -- cgit v1.2.2 From 1b7047edfcfb257f69e306c9afbab150cb987717 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 18 Mar 2015 11:01:22 +0000 Subject: genirq: Allow the irqchip state of an IRQ to be save/restored There is a number of cases where a kernel subsystem may want to introspect the state of an interrupt at the irqchip level: - When a peripheral is shared between virtual machines, its interrupt state becomes part of the guest's state, and must be switched accordingly. KVM on arm/arm64 requires this for its guest-visible timer - Some GPIO controllers seem to require peeking into the interrupt controller they are connected to to report their internal state This seem to be a pattern that is common enough for the core code to try and support this without too many horrible hacks. Introduce a pair of accessors (irq_get_irqchip_state/irq_set_irqchip_state) to retrieve the bits that can be of interest to another subsystem: pending, active, and masked. - irq_get_irqchip_state returns the state of the interrupt according to a parameter set to IRQCHIP_STATE_PENDING, IRQCHIP_STATE_ACTIVE, IRQCHIP_STATE_MASKED or IRQCHIP_STATE_LINE_LEVEL. - irq_set_irqchip_state similarly sets the state of the interrupt. Signed-off-by: Marc Zyngier Reviewed-by: Bjorn Andersson Tested-by: Bjorn Andersson Cc: linux-arm-kernel@lists.infradead.org Cc: Abhijeet Dharmapurikar Cc: Stephen Boyd Cc: Phong Vo Cc: Linus Walleij Cc: Tin Huynh Cc: Y Vo Cc: Toan Le Cc: Bjorn Andersson Cc: Jason Cooper Cc: Arnd Bergmann Link: http://lkml.kernel.org/r/1426676484-21812-2-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner --- include/linux/interrupt.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'include/linux/interrupt.h') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 150dde04cf4f..950ae4501826 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -361,6 +361,20 @@ static inline int disable_irq_wake(unsigned int irq) return irq_set_irq_wake(irq, 0); } +/* + * irq_get_irqchip_state/irq_set_irqchip_state specific flags + */ +enum irqchip_irq_state { + IRQCHIP_STATE_PENDING, /* Is interrupt pending? */ + IRQCHIP_STATE_ACTIVE, /* Is interrupt in progress? */ + IRQCHIP_STATE_MASKED, /* Is interrupt masked? */ + IRQCHIP_STATE_LINE_LEVEL, /* Is IRQ line high? */ +}; + +extern int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which, + bool *state); +extern int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which, + bool state); #ifdef CONFIG_IRQ_FORCED_THREADING extern bool force_irqthreads; -- cgit v1.2.2