From b39898cd4077f4b6ec706e717c938751c34e1dc4 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 6 Nov 2013 12:30:07 +0100 Subject: genirq: Prevent spurious detection for unconditionally polled interrupts On a 68k platform a couple of interrupts are demultiplexed and "polled" from a top level interrupt. Unfortunately there is no way to determine which of the sub interrupts raised the top level interrupt, so all of the demultiplexed interrupt handlers need to be invoked. Given a high enough frequency this can trigger the spurious interrupt detection mechanism, if one of the demultiplex interrupts returns IRQ_NONE continuously. But this is a false positive as the polling causes this behaviour and not buggy hardware/software. Introduce IRQ_POLLED which can be set at interrupt chip setup time via irq_set_status_flags(). The flag excludes the interrupt from the spurious detector and from all core polling activities. Reported-and-tested-by: Michael Schmitz Cc: Geert Uytterhoeven Cc: linux-m68k@vger.kernel.org Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1311061149250.23353@ionos.tec.linutronix.de --- include/linux/irq.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/irq.h b/include/linux/irq.h index 56bb0dc8b7d4..7dc10036eff5 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -70,6 +70,9 @@ typedef void (*irq_preflow_handler_t)(struct irq_data *data); * IRQ_MOVE_PCNTXT - Interrupt can be migrated from process context * IRQ_NESTED_TRHEAD - Interrupt nests into another thread * IRQ_PER_CPU_DEVID - Dev_id is a per-cpu variable + * IRQ_IS_POLLED - Always polled by another interrupt. Exclude + * it from the spurious interrupt detection + * mechanism and from core side polling. */ enum { IRQ_TYPE_NONE = 0x00000000, @@ -94,12 +97,14 @@ enum { IRQ_NESTED_THREAD = (1 << 15), IRQ_NOTHREAD = (1 << 16), IRQ_PER_CPU_DEVID = (1 << 17), + IRQ_IS_POLLED = (1 << 18), }; #define IRQF_MODIFY_MASK \ (IRQ_TYPE_SENSE_MASK | IRQ_NOPROBE | IRQ_NOREQUEST | \ IRQ_NOAUTOEN | IRQ_MOVE_PCNTXT | IRQ_LEVEL | IRQ_NO_BALANCING | \ - IRQ_PER_CPU | IRQ_NESTED_THREAD | IRQ_NOTHREAD | IRQ_PER_CPU_DEVID) + IRQ_PER_CPU | IRQ_NESTED_THREAD | IRQ_NOTHREAD | IRQ_PER_CPU_DEVID | \ + IRQ_IS_POLLED) #define IRQ_NO_BALANCING_MASK (IRQ_PER_CPU | IRQ_NO_BALANCING) -- cgit v1.2.3 From 54197e43a4a9a0f3fc406d72d9815754e84fab1e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 17 Sep 2013 18:53:05 +0000 Subject: hardirq: Make hardirq bits generic There is no reason for per arch hardirq bits. Make them all generic Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20130917183628.534494408@linutronix.de --- include/linux/preempt_mask.h | 30 ++++++++---------------------- 1 file changed, 8 insertions(+), 22 deletions(-) (limited to 'include/linux') diff --git a/include/linux/preempt_mask.h b/include/linux/preempt_mask.h index 931bc616219f..810d7e386f20 100644 --- a/include/linux/preempt_mask.h +++ b/include/linux/preempt_mask.h @@ -11,36 +11,22 @@ * - bits 0-7 are the preemption count (max preemption depth: 256) * - bits 8-15 are the softirq count (max # of softirqs: 256) * - * The hardirq count can in theory reach the same as NR_IRQS. - * In reality, the number of nested IRQS is limited to the stack - * size as well. For archs with over 1000 IRQS it is not practical - * to expect that they will all nest. We give a max of 10 bits for - * hardirq nesting. An arch may choose to give less than 10 bits. - * m68k expects it to be 8. - * - * - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024) - * - bit 26 is the NMI_MASK - * - bit 27 is the PREEMPT_ACTIVE flag + * The hardirq count could in theory be the same as the number of + * interrupts in the system, but we run all interrupt handlers with + * interrupts disabled, so we cannot have nesting interrupts. Though + * there are a few palaeontologic drivers which reenable interrupts in + * the handler, so we need more than one bit here. * * PREEMPT_MASK: 0x000000ff * SOFTIRQ_MASK: 0x0000ff00 - * HARDIRQ_MASK: 0x03ff0000 - * NMI_MASK: 0x04000000 + * HARDIRQ_MASK: 0x000f0000 + * NMI_MASK: 0x00100000 */ #define PREEMPT_BITS 8 #define SOFTIRQ_BITS 8 +#define HARDIRQ_BITS 4 #define NMI_BITS 1 -#define MAX_HARDIRQ_BITS 10 - -#ifndef HARDIRQ_BITS -# define HARDIRQ_BITS MAX_HARDIRQ_BITS -#endif - -#if HARDIRQ_BITS > MAX_HARDIRQ_BITS -#error HARDIRQ_BITS too high! -#endif - #define PREEMPT_SHIFT 0 #define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS) #define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS) -- cgit v1.2.3 From 00d1a39e69d5afa7523dad515a05b21abd17c389 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 17 Sep 2013 18:53:09 +0000 Subject: preempt: Make PREEMPT_ACTIVE generic No point in having this bit defined by architecture. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20130917183629.090698799@linutronix.de --- include/linux/preempt_mask.h | 15 +++++---------- include/linux/sched.h | 2 +- 2 files changed, 6 insertions(+), 11 deletions(-) (limited to 'include/linux') diff --git a/include/linux/preempt_mask.h b/include/linux/preempt_mask.h index 810d7e386f20..d169820203dd 100644 --- a/include/linux/preempt_mask.h +++ b/include/linux/preempt_mask.h @@ -17,10 +17,11 @@ * there are a few palaeontologic drivers which reenable interrupts in * the handler, so we need more than one bit here. * - * PREEMPT_MASK: 0x000000ff - * SOFTIRQ_MASK: 0x0000ff00 - * HARDIRQ_MASK: 0x000f0000 - * NMI_MASK: 0x00100000 + * PREEMPT_MASK: 0x000000ff + * SOFTIRQ_MASK: 0x0000ff00 + * HARDIRQ_MASK: 0x000f0000 + * NMI_MASK: 0x00100000 + * PREEMPT_ACTIVE: 0x00200000 */ #define PREEMPT_BITS 8 #define SOFTIRQ_BITS 8 @@ -46,15 +47,9 @@ #define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET) -#ifndef PREEMPT_ACTIVE #define PREEMPT_ACTIVE_BITS 1 #define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS) #define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT) -#endif - -#if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS)) -#error PREEMPT_ACTIVE is too low! -#endif #define hardirq_count() (preempt_count() & HARDIRQ_MASK) #define softirq_count() (preempt_count() & SOFTIRQ_MASK) diff --git a/include/linux/sched.h b/include/linux/sched.h index 045b0d227846..55080df48b70 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -22,7 +22,7 @@ struct sched_param { #include #include #include -#include +#include #include #include -- cgit v1.2.3