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23d0b8b053
This patch adds support for systems that cannot receive every interrupt on a single cpu simultaneously, in the check to see if we have enough HARDIRQ_BITS. MAX_HARDIRQS_PER_CPU becomes the count of the maximum number of hardare generated interrupts per cpu. On architectures that support per cpu interrupt delivery this can be a significant space savings and scalability bonus. This patch adds support for systems that cannot receive every interrupt on Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
134 lines
3.6 KiB
C
134 lines
3.6 KiB
C
#ifndef LINUX_HARDIRQ_H
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#define LINUX_HARDIRQ_H
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#include <linux/preempt.h>
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#include <linux/smp_lock.h>
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#include <linux/lockdep.h>
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#include <asm/hardirq.h>
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#include <asm/system.h>
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/*
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* We put the hardirq and softirq counter into the preemption
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* counter. The bitmask has the following meaning:
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*
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* - bits 0-7 are the preemption count (max preemption depth: 256)
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* - bits 8-15 are the softirq count (max # of softirqs: 256)
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*
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* The hardirq count can be overridden per architecture, the default is:
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*
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* - bits 16-27 are the hardirq count (max # of hardirqs: 4096)
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* - ( bit 28 is the PREEMPT_ACTIVE flag. )
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*
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* PREEMPT_MASK: 0x000000ff
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* SOFTIRQ_MASK: 0x0000ff00
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* HARDIRQ_MASK: 0x0fff0000
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*/
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#define PREEMPT_BITS 8
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#define SOFTIRQ_BITS 8
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#ifndef HARDIRQ_BITS
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#define HARDIRQ_BITS 12
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#ifndef MAX_HARDIRQS_PER_CPU
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#define MAX_HARDIRQS_PER_CPU NR_IRQS
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#endif
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/*
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* The hardirq mask has to be large enough to have space for potentially
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* all IRQ sources in the system nesting on a single CPU.
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*/
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#if (1 << HARDIRQ_BITS) < MAX_HARDIRQS_PER_CPU
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# error HARDIRQ_BITS is too low!
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#endif
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#endif
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#define PREEMPT_SHIFT 0
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#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
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#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
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#define __IRQ_MASK(x) ((1UL << (x))-1)
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#define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
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#define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
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#define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
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#define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
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#define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
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#define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
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#if PREEMPT_ACTIVE < (1 << (HARDIRQ_SHIFT + HARDIRQ_BITS))
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#error PREEMPT_ACTIVE is too low!
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#endif
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#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
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#define softirq_count() (preempt_count() & SOFTIRQ_MASK)
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#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK))
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/*
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* Are we doing bottom half or hardware interrupt processing?
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* Are we in a softirq context? Interrupt context?
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*/
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#define in_irq() (hardirq_count())
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#define in_softirq() (softirq_count())
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#define in_interrupt() (irq_count())
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#if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL)
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# define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != kernel_locked())
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#else
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# define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0)
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#endif
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#ifdef CONFIG_PREEMPT
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# define preemptible() (preempt_count() == 0 && !irqs_disabled())
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# define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
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#else
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# define preemptible() 0
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# define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
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#endif
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#ifdef CONFIG_SMP
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extern void synchronize_irq(unsigned int irq);
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#else
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# define synchronize_irq(irq) barrier()
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#endif
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struct task_struct;
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#ifndef CONFIG_VIRT_CPU_ACCOUNTING
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static inline void account_system_vtime(struct task_struct *tsk)
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{
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}
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#endif
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/*
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* It is safe to do non-atomic ops on ->hardirq_context,
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* because NMI handlers may not preempt and the ops are
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* always balanced, so the interrupted value of ->hardirq_context
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* will always be restored.
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*/
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#define irq_enter() \
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do { \
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account_system_vtime(current); \
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add_preempt_count(HARDIRQ_OFFSET); \
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trace_hardirq_enter(); \
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} while (0)
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/*
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* Exit irq context without processing softirqs:
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*/
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#define __irq_exit() \
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do { \
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trace_hardirq_exit(); \
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account_system_vtime(current); \
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sub_preempt_count(HARDIRQ_OFFSET); \
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} while (0)
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/*
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* Exit irq context and process softirqs if needed:
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*/
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extern void irq_exit(void);
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#define nmi_enter() do { lockdep_off(); irq_enter(); } while (0)
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#define nmi_exit() do { __irq_exit(); lockdep_on(); } while (0)
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#endif /* LINUX_HARDIRQ_H */
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