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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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7b08729cb2
A CPU that gets stuck with interrupts hard disable can be difficult to debug, as on some platforms we have no way to interrupt the CPU to find out what it's doing. A stop-gap is to have the CPU save it's stack pointer (r1) in its paca when it hard disables interrupts. That way if we can't interrupt it, we can at least trace the stack based on where it last disabled interrupts. In some cases that will be total junk, but the stack trace code should handle that. In the simple case of a CPU that disable interrupts and then gets stuck in a loop, the stack trace should be informative. We could clear the saved stack pointer when we enable interrupts, but that loses information which could be useful if we have nothing else to go on. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
365 lines
8.7 KiB
C
365 lines
8.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
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*/
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#ifndef _ASM_POWERPC_HW_IRQ_H
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#define _ASM_POWERPC_HW_IRQ_H
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#ifdef __KERNEL__
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#include <linux/errno.h>
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#include <linux/compiler.h>
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#include <asm/ptrace.h>
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#include <asm/processor.h>
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#ifdef CONFIG_PPC64
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/*
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* PACA flags in paca->irq_happened.
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*
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* This bits are set when interrupts occur while soft-disabled
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* and allow a proper replay. Additionally, PACA_IRQ_HARD_DIS
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* is set whenever we manually hard disable.
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*/
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#define PACA_IRQ_HARD_DIS 0x01
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#define PACA_IRQ_DBELL 0x02
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#define PACA_IRQ_EE 0x04
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#define PACA_IRQ_DEC 0x08 /* Or FIT */
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#define PACA_IRQ_EE_EDGE 0x10 /* BookE only */
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#define PACA_IRQ_HMI 0x20
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#define PACA_IRQ_PMI 0x40
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/*
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* Some soft-masked interrupts must be hard masked until they are replayed
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* (e.g., because the soft-masked handler does not clear the exception).
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*/
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#ifdef CONFIG_PPC_BOOK3S
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#define PACA_IRQ_MUST_HARD_MASK (PACA_IRQ_EE|PACA_IRQ_PMI)
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#else
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#define PACA_IRQ_MUST_HARD_MASK (PACA_IRQ_EE)
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#endif
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/*
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* flags for paca->irq_soft_mask
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*/
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#define IRQS_ENABLED 0
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#define IRQS_DISABLED 1 /* local_irq_disable() interrupts */
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#define IRQS_PMI_DISABLED 2
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#define IRQS_ALL_DISABLED (IRQS_DISABLED | IRQS_PMI_DISABLED)
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#endif /* CONFIG_PPC64 */
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#ifndef __ASSEMBLY__
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extern void replay_system_reset(void);
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extern void __replay_interrupt(unsigned int vector);
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extern void timer_interrupt(struct pt_regs *);
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extern void timer_broadcast_interrupt(void);
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extern void performance_monitor_exception(struct pt_regs *regs);
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extern void WatchdogException(struct pt_regs *regs);
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extern void unknown_exception(struct pt_regs *regs);
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#ifdef CONFIG_PPC64
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#include <asm/paca.h>
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static inline notrace unsigned long irq_soft_mask_return(void)
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{
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unsigned long flags;
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asm volatile(
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"lbz %0,%1(13)"
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: "=r" (flags)
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: "i" (offsetof(struct paca_struct, irq_soft_mask)));
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return flags;
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}
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/*
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* The "memory" clobber acts as both a compiler barrier
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* for the critical section and as a clobber because
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* we changed paca->irq_soft_mask
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*/
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static inline notrace void irq_soft_mask_set(unsigned long mask)
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{
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#ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
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/*
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* The irq mask must always include the STD bit if any are set.
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*
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* and interrupts don't get replayed until the standard
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* interrupt (local_irq_disable()) is unmasked.
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*
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* Other masks must only provide additional masking beyond
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* the standard, and they are also not replayed until the
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* standard interrupt becomes unmasked.
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*
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* This could be changed, but it will require partial
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* unmasks to be replayed, among other things. For now, take
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* the simple approach.
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*/
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WARN_ON(mask && !(mask & IRQS_DISABLED));
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#endif
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asm volatile(
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"stb %0,%1(13)"
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:
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: "r" (mask),
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"i" (offsetof(struct paca_struct, irq_soft_mask))
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: "memory");
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}
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static inline notrace unsigned long irq_soft_mask_set_return(unsigned long mask)
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{
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unsigned long flags;
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#ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
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WARN_ON(mask && !(mask & IRQS_DISABLED));
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#endif
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asm volatile(
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"lbz %0,%1(13); stb %2,%1(13)"
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: "=&r" (flags)
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: "i" (offsetof(struct paca_struct, irq_soft_mask)),
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"r" (mask)
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: "memory");
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return flags;
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}
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static inline notrace unsigned long irq_soft_mask_or_return(unsigned long mask)
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{
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unsigned long flags, tmp;
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asm volatile(
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"lbz %0,%2(13); or %1,%0,%3; stb %1,%2(13)"
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: "=&r" (flags), "=r" (tmp)
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: "i" (offsetof(struct paca_struct, irq_soft_mask)),
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"r" (mask)
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: "memory");
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#ifdef CONFIG_PPC_IRQ_SOFT_MASK_DEBUG
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WARN_ON((mask | flags) && !((mask | flags) & IRQS_DISABLED));
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#endif
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return flags;
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}
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static inline unsigned long arch_local_save_flags(void)
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{
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return irq_soft_mask_return();
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}
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static inline void arch_local_irq_disable(void)
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{
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irq_soft_mask_set(IRQS_DISABLED);
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}
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extern void arch_local_irq_restore(unsigned long);
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static inline void arch_local_irq_enable(void)
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{
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arch_local_irq_restore(IRQS_ENABLED);
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}
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static inline unsigned long arch_local_irq_save(void)
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{
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return irq_soft_mask_set_return(IRQS_DISABLED);
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}
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static inline bool arch_irqs_disabled_flags(unsigned long flags)
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{
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return flags & IRQS_DISABLED;
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}
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static inline bool arch_irqs_disabled(void)
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{
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return arch_irqs_disabled_flags(arch_local_save_flags());
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}
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#ifdef CONFIG_PPC_BOOK3S
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/*
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* To support disabling and enabling of irq with PMI, set of
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* new powerpc_local_irq_pmu_save() and powerpc_local_irq_restore()
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* functions are added. These macros are implemented using generic
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* linux local_irq_* code from include/linux/irqflags.h.
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*/
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#define raw_local_irq_pmu_save(flags) \
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do { \
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typecheck(unsigned long, flags); \
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flags = irq_soft_mask_or_return(IRQS_DISABLED | \
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IRQS_PMI_DISABLED); \
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} while(0)
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#define raw_local_irq_pmu_restore(flags) \
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do { \
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typecheck(unsigned long, flags); \
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arch_local_irq_restore(flags); \
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} while(0)
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#ifdef CONFIG_TRACE_IRQFLAGS
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#define powerpc_local_irq_pmu_save(flags) \
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do { \
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raw_local_irq_pmu_save(flags); \
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trace_hardirqs_off(); \
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} while(0)
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#define powerpc_local_irq_pmu_restore(flags) \
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do { \
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if (raw_irqs_disabled_flags(flags)) { \
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raw_local_irq_pmu_restore(flags); \
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trace_hardirqs_off(); \
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} else { \
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trace_hardirqs_on(); \
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raw_local_irq_pmu_restore(flags); \
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} \
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} while(0)
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#else
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#define powerpc_local_irq_pmu_save(flags) \
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do { \
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raw_local_irq_pmu_save(flags); \
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} while(0)
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#define powerpc_local_irq_pmu_restore(flags) \
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do { \
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raw_local_irq_pmu_restore(flags); \
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} while (0)
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#endif /* CONFIG_TRACE_IRQFLAGS */
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#endif /* CONFIG_PPC_BOOK3S */
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#ifdef CONFIG_PPC_BOOK3E
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#define __hard_irq_enable() asm volatile("wrteei 1" : : : "memory")
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#define __hard_irq_disable() asm volatile("wrteei 0" : : : "memory")
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#else
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#define __hard_irq_enable() __mtmsrd(MSR_EE|MSR_RI, 1)
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#define __hard_irq_disable() __mtmsrd(MSR_RI, 1)
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#endif
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#define hard_irq_disable() do { \
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unsigned long flags; \
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__hard_irq_disable(); \
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flags = irq_soft_mask_set_return(IRQS_ALL_DISABLED); \
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local_paca->irq_happened |= PACA_IRQ_HARD_DIS; \
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if (!arch_irqs_disabled_flags(flags)) { \
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asm ("stdx %%r1, 0, %1 ;" \
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: "=m" (local_paca->saved_r1) \
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: "b" (&local_paca->saved_r1)); \
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trace_hardirqs_off(); \
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} \
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} while(0)
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static inline bool lazy_irq_pending(void)
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{
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return !!(get_paca()->irq_happened & ~PACA_IRQ_HARD_DIS);
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}
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/*
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* This is called by asynchronous interrupts to conditionally
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* re-enable hard interrupts when soft-disabled after having
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* cleared the source of the interrupt
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*/
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static inline void may_hard_irq_enable(void)
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{
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get_paca()->irq_happened &= ~PACA_IRQ_HARD_DIS;
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if (!(get_paca()->irq_happened & PACA_IRQ_MUST_HARD_MASK))
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__hard_irq_enable();
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}
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static inline bool arch_irq_disabled_regs(struct pt_regs *regs)
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{
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return (regs->softe & IRQS_DISABLED);
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}
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extern bool prep_irq_for_idle(void);
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extern bool prep_irq_for_idle_irqsoff(void);
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extern void irq_set_pending_from_srr1(unsigned long srr1);
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#define fini_irq_for_idle_irqsoff() trace_hardirqs_off();
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extern void force_external_irq_replay(void);
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#else /* CONFIG_PPC64 */
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#define SET_MSR_EE(x) mtmsr(x)
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static inline unsigned long arch_local_save_flags(void)
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{
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return mfmsr();
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}
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static inline void arch_local_irq_restore(unsigned long flags)
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{
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#if defined(CONFIG_BOOKE)
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asm volatile("wrtee %0" : : "r" (flags) : "memory");
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#else
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mtmsr(flags);
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#endif
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}
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static inline unsigned long arch_local_irq_save(void)
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{
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unsigned long flags = arch_local_save_flags();
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#ifdef CONFIG_BOOKE
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asm volatile("wrteei 0" : : : "memory");
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#elif defined(CONFIG_PPC_8xx)
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wrtspr(SPRN_EID);
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#else
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SET_MSR_EE(flags & ~MSR_EE);
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#endif
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return flags;
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}
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static inline void arch_local_irq_disable(void)
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{
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#ifdef CONFIG_BOOKE
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asm volatile("wrteei 0" : : : "memory");
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#elif defined(CONFIG_PPC_8xx)
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wrtspr(SPRN_EID);
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#else
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arch_local_irq_save();
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#endif
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}
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static inline void arch_local_irq_enable(void)
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{
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#ifdef CONFIG_BOOKE
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asm volatile("wrteei 1" : : : "memory");
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#elif defined(CONFIG_PPC_8xx)
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wrtspr(SPRN_EIE);
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#else
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unsigned long msr = mfmsr();
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SET_MSR_EE(msr | MSR_EE);
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#endif
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}
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static inline bool arch_irqs_disabled_flags(unsigned long flags)
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{
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return (flags & MSR_EE) == 0;
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}
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static inline bool arch_irqs_disabled(void)
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{
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return arch_irqs_disabled_flags(arch_local_save_flags());
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}
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#define hard_irq_disable() arch_local_irq_disable()
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static inline bool arch_irq_disabled_regs(struct pt_regs *regs)
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{
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return !(regs->msr & MSR_EE);
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}
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static inline void may_hard_irq_enable(void) { }
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#endif /* CONFIG_PPC64 */
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#define ARCH_IRQ_INIT_FLAGS IRQ_NOREQUEST
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/*
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* interrupt-retrigger: should we handle this via lost interrupts and IPIs
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* or should we not care like we do now ? --BenH.
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*/
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struct irq_chip;
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#endif /* __ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_HW_IRQ_H */
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